Where on Earth does paleo-groundwater exist? Where on Earth do we expect to find very old groundwater (infiltrated thousands of years ago)?

In large intracontinental basins where the main rock formations are exposed in adjoining highlands and rare deeply buried within the basin itself.  The Madison Limestone is an example.

The Madison and its equivalent strata extend from the Black Hills of western South Dakota to western Montana and eastern Idaho, and from the Canada–United States border to western Colorado and the Grand Canyon of Arizona.

From Wikipedia.

Ground-water ages vary from virtually modern to
about 23,000 yr. The 14C ages indicate flow velocities of
between 7 to 87 ft/yr. Hydraulic conductivities based on
average carbon-14 flow velocities are similar to those
based on digital simulation of the flow system (Downey,
1984).

From: Geochemical Evolution of Water in the
Madison Aquifer in Parts of Montana,
South Dakota, and Wyoming
By JOHN F. BUSBY, L. NIEL PLUMMER, ROGER W. LEE, andEWJCE B. HANSHAW


Last ice age: did glaciers move South or move downhill? (Note: this is from U.S. point of view)
I keep hearing how the glaciers "moved South" during the last ice age. But I thought glaciers moved downhill.
I can see that the glaciers formed farther and farther south as the temperature fell. But then they presumably moved downhill, following the landscape beneath them.
However: assuming the glaciers were much thicker to the North, then the (hydrostatic?) pressure beneath them would be higher than the Southern glaciers; maybe that pushed everything South.

Did glaciers move South or move downhill?

You are posing this as an either-or question. The answer is "Yes."
The highest points above sea level in Manitoba, Minnesota, Ontario, Michigan, Wisconsin, Iowa, and Illinois are respectively 832 meters, 701 meters, 693 meters, 603 meters, 595 meters, 509 meters, and 376 meters. Central Canada and the United State's upper midwest are very flat.
Even the eastern parts of the US and Canada are relatively flat compared to the huge ~4000 meter thick ice dome centered roughly on Hudson Bay. Every direction was downhill from the peak of this ice dome. The ice flowed to the west to meet ice streams from the Rocky Mountains (and then turn north or south), to the north toward the Arctic Ocean, to the east toward the Atlantic Ocean, and to the south to meet warmer temperatures. The ice at the southern edges was much thinner, but it still was a downhill flow.


How to curb losses during annual heavy rainfalls Every year I see these sort of news articles where states are flooded particularly due to their geographical location and vicinity to flood prone areas, however year after year there is no improvement in the same. Every year lots of lives are lost, properties destroyed, and people displaces and this made me wonder is there no good plan that such an area can follow?
Is there nothing the Government can do for the remainder of the year so that they can prevent and minimize damage? Are there places like this which have successfully minimized damage over the years?
I believe the loss of life and property is too high and happens every year or so hence investing in solutions must be a good choice still we don't see it happening at a large enough scale to make a difference is it due to unwillingness of the bureaucracy?

Flood control measures largely depend on:

The amount of money available to create flood control measures
The availability of raw materials that could be used to create such
measures
The locality of the potentially flood affected region
The source of potential flooding  and its relation to the region that
could be flooded.

One extreme example is Bangladesh.
Most of Bangladesh is located within the delta region of the Ganges and Brahmaputra Rivers; that is where the two rivers meet the ocean.
The region is flat and devoid of easily accessible sources of natural rock. Elsewhere, competent rock, such a basalt, can be located, extracted and crushed to form aggregate  that can be used as a construction material. Because Bangladesh lacks such rock sources it needs to bake clay to create a form of aggregate.
Being positioned at the tail end of two major rivers, the government of Bangladesh does not have control of significant reaches of the rivers to create flood control structures further upstream.
Politically and religiously, flood control measures on either of these rivers could cause a lot Hindus to become very upset.
Financially, Bangladesh is a poor country with a population of 162 million people. If it were able to construct flood control devices on the two rivers, it would also need to construct flood prevention devices along its coast as the combination of flood waters from the rivers and high tides from the ocean can exacerbate flooding and its effects on the country.
Finally, rising sea levels from climate change are only going to make matters worse for Bangladesh, because it is a very low lying country.

Edit 2 August 2020
Concerning successful flood control measures, two quickly come to mind, the Thames Barrier in London, England and the Aswan Dam in Egypt, particularly the Aswan High Dam.

The Thames Barrier is a movable barrier system that is designed to prevent the floodplain of most of Greater London from being flooded by exceptionally high tides and storm surges moving up from the North Sea. It has been operational since 1982. When needed, it is closed (raised) during high tide; at low tide, it can be opened to restore the river's flow towards the sea.

Based on the success of the Low Dam, then at its maximum utilization, construction of the High Dam became a key objective of the government following the Egyptian Revolution of 1952; with its ability to better control flooding, provide increased water storage for irrigation and generate hydroelectricity the dam was seen as pivotal to Egypt's planned industrialization. Like the earlier implementation, the High Dam has had a significant effect on the economy and culture of Egypt.


How much energy is released a year of all the lightning on earth? Imagine we could catch and store all electricity of lightning 'thrown' to earth.
Would that be hugh amount of electricity to invest in?

Some basic math on this:

About 100 bolts of lightning hit the Earth every second and they average about a billion joules of energy be bolt.   That's 3.1 billion lightning strikes per year, coming to about 3.1 billion billion joules per year, or about 860 billion kilowatt-hours (kwh) of electrical energy per year.

That estimate is pretty rough as some estimates have as much as 5 billion joules per bolt of lightning, pushing it up over 4 trillion kwh/year.

Total human electrical usage, per source is about 18.1% of 104 trillion kwh/year, 2012 numbers, 18.9 trillion kwh/year of electricity generated.    So even if all the lightning energy was utilized (which would be unlikley for a few reasons), it would be somewhere in the 4%-20% range of our total electrical demand, which isn't bad, but I think that's the answer to your question.  There's not enough energy in all the lightning on Earth to supply our electrical demand.

Wikipedia has an article on the logistical difficulties.   It's perhaps doable, to some extent, but at best, lightning could provide only a small percentage of our electrical needs, unlike solar panels which could provide, at least in total energy, well in excess of our electrical needs.   Solar runs into problems like it's not always on, which is a limiting factor to it's usefulness, but in terms of total energy provided it's much easier and much more abundant than harnessing lightning.


North Bay of Bengal warm pool anomaly I am looking for an explanation for this warm pool of water in the North and North East Bay of Bengal - North Bay Warm Water Anomaly. Currently the path of the sun is towards the southern hemisphere and we are in the fourth week of October. In contrast there are no warm SSTs along the North Arabian Sea.

Is it possible that warm water from the equator has moved up North along the eastern wall of the Bay of Bengal ? Is that indicated by the gyres on display on the Earth Null site ? I observe that there is a warm pool along the eastern seaboard near the equator(negative Indian Ocean Dipole) - IOD Index. Is it possible to show (if my guess is correct) that there is a south to north pressure gradient that is moving warm water north(ageostrophic circulation)  ?

As you can see the weekly SST global anomaly as well shows a warm pool anomaly in the North Bay of Bengal.

I think the Southeastern Tropical Indian Ocean (SETIO) provides a better hint of what might be happening. It clearly shows a positive pattern since last November.
source

I think it might be related to the recovery from the intense 2015 El Niño. If I remember from Lau & Nath, 2003, when you have a warm ENSO, you get a reduction of the Monsoon intensity with lower wind speeds, which results in a reduction of sensible and latent heat loss. Also, the  cloud cover is reduced because of dryer conditions, which results in a larger percentage of the shortwave radiation reaching the ocean surface.

The WTIO seems pretty normal currently, so it suggest the conditions are mostly eastern Indian Ocean related. The altimetry sea surface height anomaly seems to suggest the currents are counterclockwise in the Bay, so the anomaly seems to be a regional effect.


Explain the Idea of Pangaea and how the continents have reached their current positions I know Pangaea was a supercontinent that existed 270 million years ago and it started to break apart around 200 million years ago. I'm not clear on whether Pangaea was 1,2, or multiple tectonic plates. Can someone help me?

It was almost certainly multiple.    I can't say for 100% but I think it was very very likely - cause of the way they split apart for one.

For example, today: Europe, Asia and in a practical sense, Africa are all connected but contain several different plates.    The Indian Plate and the Eurasian plate are 2 different plates but the land is connected, so you'd never know it was two plates - well, except for the frequent earthquakes.

Source:  http://en.wikipedia.org/wiki/Indian_Plate

Plate Tectonics is thought to be about 3.2 billion years old:   http://sciencenordic.com/modern-plate-tectonics-arose-32-billion-years-ago


Does the meridional overturning circulation slow down the temperature increase from global warming? Does it result in an increased exchange of surface heat and deepwater heat, which, in turn, help increase the amount of CO2 and heat that the deep oceans absorb?

Related-On-Wikipedia: Meridional overturning circulation (Thermohaline circulation)

The short answer is 'yes'. Earth's response to climate change is closely coupled to the deep ocean's uptake of heat and $\ce{CO2}$; the ocean is by far the biggest sink for excess heat (~90% of the excess heat absorbed by the planet goes into the ocean, the rest largely goes towards melting ice sheets/glaciers).
The ocean is also a major sink for carbon.

How effective the ocean is at absorbing heat/$\ce{CO2}$ is closely tied to rates of deep water formation, that is the densification of near surface ocean water by surface fluxes like cooling and evaporation, which then sinks and doesn't come back to the surface for centuries or even millennia. The major deep water formation regions are the Southern Ocean and the North Atlantic. The sinking of North Atlantic Deep Water (NADW) is the northern part of the 'Atlantic Conveyor' (the term sometimes colloquially used to describe the AMOC).

A slowdown in the AMOC, therefore, wouldn't just impact regional climates in N. America and Western Europe, but would also reduce the deep ocean's uptake of heat and $\ce{CO2}$, and by consequence cause a greater increase in surface temperatures.


What could possibly be a rational basis for rejecting climate science? Here is my logic (thus not opinion) if the anthropogenic global heating AGH deniers actually do not have any rational climate science basis for rejecting anthropogenic global heating then everyone should understand that their position is baseless.

It would seem that consistent failure by global heating deniers to provide a rational basis for their rejection of climate science would form sufficient evidence that no such rational basis exists.

I am diligently striving to use logical analysis to cut to the heart of the truth about global heating in such a way that all true skeptics (not those hired to lie) will immediately see the light of the truth.

I make this post so that all global heating deniers will be provided an opportunity to present their side.

If such a rational basis exists, then it can be provided. If it cannot be provided then no such rational basis exists. If no such rational basis for rejecting climate science exists then the matter of: anthropogenic global heating (AGH) is concluded in closure.

3C ± 1.5C for every doubling of CO2 plus the following 100 PPM spike in global CO2 since 1950 really seem to explain the temperature increase.

If we apply climate sensitivity analysis to the current level of atmospheric CO2 we find that this increase of CO2 predicts a temperature equilibrium of +1.65C: 3 * log2(410 / 280) = 1.65C.

https://en.wikipedia.org/wiki/Climate_sensitivity#Intergovernmental_Panel_on_Climate_Change

If the issue is assessed on other grounds than science ones there can be rational reasons to reject climate science. e.g. if it is being assessed with respect to how addressing versus not addressing AGW impacts costs, competitiveness and profitability of specific business enterprises then rejecting climate science and encouraging other business operators as well as governments, courts and regulators to reject it, to avoid compliance costs of addressing it appears rational. The advice given by lawyers to people and companies facing lawsuits to admit no responsibility and seek to undermine the plaintiff's arguments, including questioning the veracity of expert witnesses is not irrational. Unethical perhaps, but it is not irrational.


Is it dangerous to live in Seattle due to the earthquakes? I'm considering a move/vacation to Seattle, and I'm concerned it may be dangerous due to the risk of an earthquake?

Yes. Earthquakes are Dangerous

No. Because big earthquakes happen so infrequently (~300 years in Seattle's case) that one shouldn't really worry about it. Engineers design buildings to withstand large earthquakes. Of course there is the possibility of failure, but generally the US is very good about their infrastructure. Seattle is not like Oklahoma, where they are completely unprepared for earthquakes. I lived in Los Angeles in 18 years, and while my time there was during the Northridge 1994 earthquake, most of the damage was to the buildings (which were insured) and not to the people. Still there is some risk, but I think the risk of driving in Seattle is probably riskier than living in Seattle for 50 years of earthquakes.


Does the NWS actually name winter storms, or is this exclusive to the Weather Channel? If you occasionally check the Weather Channel (either the smartphone app or online), you'll see they reference strong weather systems by name. (It only seems to be eastern storms.) I've always wondered if this was just something The Weather Channel does--for whatever reason--of if the NWS really does name them.

It is just the Weather Channel. You can tell which businesses frequently watch (or even do business with) the Weather Channel by whether or not they refer to them by these names. The naming of winter storms irks many of the meteorologists I know (including myself).


Difference between model parameter and observable parameter In Inverse problem theory, what is meant by "results of the measurements of observable parameter"?

Inverse problems deal with creating theories based on observed data, as opposed to making predictions about the real world based on existing theoretical models, so the "results of the measurement of observable parameter" is a confusing way of saying "the real measurements being used as data". Parameter simply refers to the value being measured.

An example would be if you have a forestry block and you want to understand why some trees are preforming better than others; you'd measure a whole group of variables that formed a set of parameters, one of which might be "tree health" based on say height, girth, leaf activity, and transpiration rate and another that's "soil fertility" based on key nutrient levels, particle size distribution, bulk density, and water holding capacity. The relationship between those two parameters then lets you formulate a theory that you can apply at other sites that you know the "soil fertility" of to predict the growth of trees there.

In the real world you have to test your theory with what in my GIS classes they called a "Ground Truth", that's where you go out and measure the parameters of a different real world site being used for the same crop and see if your theory accounts for the results at that site (we did them to confirm the relationship between satellite readings and on-the-ground data). When you've done this at a number of sites and the measurements all conform to your theory you can start applying your model as a predictive formula for sites not yet in use.


What are these rocks This Crystal has a couple gas bubbles and impurities in the very center of it it breaks only one way it is 4720 carats very beautiful very hard

looks like a broken block of glass from a glass factory, called glass slag or chunk glass, you can get a whole range of hardness and color depending on what type of glass they were making. People often use it to make art.


Do ringwoodite minerals point to an "ocean's worth" of water, or a true subterranean ocean? Appears that the answer is that it is highly likely that the water that the ringwoodite minerals point to is an "ocean's worth" of water, not a true subterranean ocean.

Do ringwoodite minerals point to an "ocean's worth" of water, or a true subterranean ocean?

A "true subterranean ocean" would suggest a vast amount of liquid water in the mantle. This is most probably not present, for which there are a number of clues.
First of all, when looking at the temperature (~2000K) and pressure (~20GPa) in the transition zone and look at a phase diagram for water it is clear water can't exist as a liquid even though the temperature isn't visible in the diagram. The exact phase isn't clear, it could be a solid or a supercritical liquid.

A second clue is in seismology. Earthquakes produce two types of waves, P-type and S-type, of which only the first can propagate through liquids, see for example this page. As a large body of liquid would produce a large shadow in seismic reflections, and these aren't well known (apart from the outer-core-shadow), it is unlikely there is much liquid water in the mantle.
Also, note that the water in ringwoodite isn't present as water molecules, but as hydrogen and oxygen ions, according to wikipedia.
Therefore, if there is indeed an ocean's worth of water present in the mantle transition zone, it will be there as a solid, which in my opinion can't be called a subterranean ocean.
Phase diagram for water from: http://www1.lsbu.ac.uk/water/phase.html


Why is the South Pole colder than the North Pole? This question popped into my head because I am designing a fictional world map, and I was wondering what factors influence the amount of ice at poles.

I want to know why there is much more ice covering South Pole than North Pole.

An answer I found here states:

What makes the South Pole so much colder than the North Pole is that it sits on top of a very thick ice sheet, which itself sits on a continent.

Does that mean that if there was a continent at North Pole, there would also be much more ice there? Is impact of Gulf stream also a factor in this or no?

I think I am on the right track but someone more knowledgeable than me could really clear this up.

Thank you in advance!

The most obvious reason why the South pole is colder than the North pole is altitude. The Arctic is mostly covered by ocean and low lying land whereas the Antarctic continent is really quite high, with an average height of about 2,400m. The environmental lapse rate in the troposphere is about 6.5°C/km and so this corresponds to about a 15°C temperature difference between the Arctic and Antarctic based on altitude alone. Obviously the actual temperature difference is greater than this so there must be something else at work. Most of Antarctica is only this high because it has a couple of kilometres of ice sitting on top of it and so this doesn't explain why there is a huge, permanent (at least for the last ~35 million years) ice sheet sitting there in the first place.

There are two main reasons why a large ice sheet can persist at the South pole. First is that the southern polar region is currently covered by a large continental land mass (Antarctica). Land has a much lower heat capacity than water and so in the Arctic, the ocean acts as a large reservoir of heat, mainly transported there from lower latitudes and this limits the sea ice thickness. Conversely, in Antarctica snow can accumulate on the land and, if it does not melt in the summer, it will be buried next winter, leading to ice accumulation.

The second reason is the existence of the cold Antarctic Circumpolar Current which flows from west to east and is the largest ocean current in the world, with a mean transport of 100-150Sv. This cold current, transporting huge volumes of water, serves to thermally insulate Antarctica from the warmer subtropical waters to the north, cooling the continent. The openings of the Drake Passage and the Tasman Gateway, the exact timings of which are debated but are generally thought to have both happened by about 30 million years ago, allowed the formation of the ACC and are roughly coincident with the onset of permanent glaciation in Antarctica.

An additional factor in the present day, as mentioned @winwaed, is that southern hemisphere winter solstice currently coincides with aphelion (roughly), which produces colder winters in the southern hemisphere, allowing extreme temperatures of -94.7°C to be reached. The flip side of this is that summer solstice coincides with perihelion, which produces higher summer temperatures.


Plate Tectonics vs Gravity for Creating Highs and Lows I have a question that I thought of when discussing a Worldbuilding scenario here. In that question, a super earth with gravity 1.35 times that of earth's is discussed, and is assumed to have shallow oceans. It is the assumed cause of these shallow oceans that got me thinking.

The question supposes that the shallow oceans are a result of a crust more uniform than that of earth, i.e without significant variations in depth, and that said uniformity is caused by gravity evening things out somehow. However, the imaginary world is also said to have more volcanic activity than earth, which I interpret to mean at least some tectonic activity.

My first thought was that there is no reason for gravity, at the scale we are discussing, to influence the uniformity of a planet's crust after its formation, and that plate tectonics would play a much larger role. I suppose the crust would be a bit denser depending on its original composition, and perhaps the magnitude of gravity influences the tectonics themselves more significantly than I realize. (Obviously with no gravity, there are no plate tectonics, and in fact no planet, so that's not what I'm after).

Earth Science Questions: What effects, if any, does gravity have on the mountains and depths of earth's crust? Assuming earth-like dynamics at play, would plate tectonics have more of an influence on the formation of a planet's crust's highs and lows than gravity? If not, why?

Bonus (World-Building) Question: Is there a way to construct a planet's crust and core such that volcanic activity is possible, yet gravity has the primary influence over crust uniformity?

I think this question is less intuitively obvious than it appears. and I like @Universal_learner 's answer.  I thought I'd give a different approach to the question.

Earth is the only object in the solar system with significant amounts of granite and granite is very important to your question because of it's durability and it's buoyancy.

Granite forms under pressure below the Earth's surface in conditions where the magma gradually cools and it requires the presence of water to form.    Once formed, Granite is more durable than the denser crustal rock and fairly early in the Earth's history, about 3 billion years ago by this article, this granite formed into continental crusts.

Because Granite is lighter than other crustal rock, it floats like a cork in the Earth's crust, about 2/3rds below the surface or ocean, and one third, extending above sea level.   (Continental crust extends beyond the land/ocean boundary).

Higher gravity would likely flatten out the granite to a degree in terms of mountains and valleys but continental crust is in balance with the heavier basalt crust, so I don't see how gravity would effect the continents much.  The rate of erosion from land to sea might increase, but the buoyancy of the granite wouldn't be affected by gravity.

The effect on the depth of the oceans is unclear.   Outside of the continental crust that extends below the oceans, and the ridges and trenches, ocean depth is reasonably consistent.

Source of picture

If on Earth, for example, if you were to drain the oceans, with the weight removed the ocean floor would rise and the continents would sink somewhat, much like they do when a mile of glacial ice forms over and then recedes from the continents and the land shifts up and down, but the altitude variation on Earth, average continental height to ocean floor wouldn't change all that much.  A few hundred feet perhaps out of 2-3 miles in variation.

The point is, the ratio of granite continental crust, to surface water would be the primary factor in ocean depth.  Those ratios would be more important than gravity.    Other factors to consider would be weathering and how active the planet's tectonic movement is.

The highest peaks on the Earth are formed by the comparatively rapid movement of two tectonic plates crashing into each other and their height is limited by two factors, gravity and weathering, and I'm not even sure gravity is the bigger of the two factors.    Olympus Mons on Mars is as tall as it is, in part, because Mars has no weathering and in part because Mars has no tectonic movement, so the volcano under Olympus mons keeps adding to the same spot.   That doesn't happen on Earth because our crusts move.    Olympus mons is also very flat because it was formed by lava, not by two crusts pressing against each other, which can form more jagged peaks.

Take two granite continental plates slowly pushing into each other at a fixed speed.   How high the mountain range grows would be a factor of their momentum pushing into each other.  Gravity would play a role in how high the mountains could grow before they spread out/landslide across the surface, but the volume of rock being pushed upwards would be a property of the velocity and mass of the two moving plates.   Gravity would add just as much momentum to the collision as it would discourage building the mountains higher.

So ultimately I think the question boils down to these key factors.

Ratio of continental crust granite to ocean floor.
How much water is on the planet.   It's not hard to imagine a dry planet with almost no oceans to speak of or a water world with no land at all.
how active the tectonic movement is
how much weathering is done by the atmosphere on the planet
and . . . gravity is a factor too.    But to ask the question considering gravity alone, I think there are too many variables to answer.   From a worldbuilding standpoint, you'd have to consider other things as well.

Finally, a planet with 1.35 times Earth's gravity, if we assume similar density, equal density to gravity the ratio is 1 to 1, so such a planet would have 1.35^3 or about 2.5 times the mass of the Earth and 1.8 times the surface area.  It would also cool more slowly, having more heat of formation and would, everything else being equal, probably be more volcanic.   How the extra gravity, extra heat and additional matter would affect continent formation and plate tectonics is above my pay grade.   You might need some super-computer modeling to get a more accurate answer.


Creating regular grid for my data? I have daily spatiotemporal  data with covariates at 10 different locations. My question is is it possible to convert my data into a grid format?

Yes, but it will not be a very good dataset. You will only be limited to the size of the dataset.

You can use Python's griddata function. But of course, you will need to make your grid before using the function. Or you can use the interp2d function.


Is there a seasonal difference in the average cloud floor? It always looks like clouds are so much higher in the sky (altitude) in the summer than in the winter. Is that true? If not, is there some sort of optical illusion? If so, why is that?

I live in Iowa, so I don't know if this is a phenomenon that exists in all climates, just temperate climates, or just the US Midwest. And, for that matter if this actually happens or if I'm just misinterpreting what I'm seeing.

Cloud base varies as response to several factors, normally, cloud bases are lower in the wintertime than during the summer, particularly for stratus clouds.

Cloud development is mostly dependent on temperature and the amount of water vapor in the air. The temperature has to be low enough to cause the air to become saturated. If the air is relatively dry, a colder temperature is required for water vapor to condense into water droplets. During winter, the temperature of the air in the lower part of the atmosphere is lower than during the summer, so stratus clouds can usually form at somewhat lower heights during the winter than during the summer.

This is a generalization that does not hold true under all conditions and at all times.

Also some more regional patterns can be present since the differentiation between Summer and Winter can be difficult to establish, for example in the tropics.

Taken from: https://stab-iitb.org/newton-mirror/askasci/wea00/wea00274.htm


Why are most effects of the predicted climate change negative? Most of the commonly mentioned effects of the ongoing and predicted climate change are negative: more extreme weather effects, more destructive weather, more diseases, rapid extinctions, etc.

Why is this so?

It is clear that any rapid change brings many negative effects. We humans, as well as the biosphere, are adapted to the current conditions. Any sudden deviation from these conditions will take painful re-adaptation.

But my impression is that several of the commonly mentioned negative effects go beyond than what can be explained by just change. Is this really so?  If yes, would a cooling climate (beyond restoring pre-industrial conditions) bring more positive effects?

I would say that the reason is because human civilisation, and particularly agricultural practices, evolved and are adapted to the pre-industrial climate.  This means that any substantial change in the climate will require changes in our civilisation and agriculture, which inevitably has a cost.  So the reason that most of the changes are negative is not to do with the science, but to do with us.


Are there natural-forcings climate projections over the 21st century? CMIP5 offers natural-forcings-only simulations over 1850-2005, which allows comparison with the historical simulations, which allows us to show how anthropogenic forcings have affected the climate over that time.

CMIP5 also offers projections over the 21st century, with a range of RCPs allowing for different emissions scenarios.

However, CMIP5 doesn't include a 21st century natural forcing for comparison, even though this would be useful. Do such simulations exist anywhere else?

I realise that these would not be perfectly possible, since data for natural forcings like volcanoes are not available. However, these might be reasonably simulated using a stochastic model. Other natural forcings, such as orbital forcings, can be calculated fairly easily over the next century. Solar irradiance probably falls somewhere in between the two.

If such simulations do not exist, would it be unreasonable to use the 1850-2005 natural forcings simulations as the basis for a statistical model of the 21st century? Or are some of the natural forcings likely to change substantially (e.g. are 20th century volcanoes unrepresentative of the background, or is the orbital forcing likely to change substantially over the coming century?).

You’re right that there were no future natural forcings experiments defined in the CMIP5 protocol.  The reason being simply that the modeling groups thought that other experiments were more deserving of their limited computing time.  Compare this with the much stronger call for the historicalNat and historicalGHG experiments, which were required for detection and attribution studies.  Individual modeling centers may have run future natural forcings experiments, but that will be hit and miss, and there wasn’t an experiment name to lodge the outputs to in the CMIP5 database.  Incidentally, the situation with the RCP (all forcings) experiments themselves was actually a bit imperfect, because the implementations of future natural forcings were left to the discretion of each modeling group:

  … It is recommended that either volcanic aerosols should be omitted entirely from the control and future runs, or, alternatively, the same background aerosol should be prescribed in both runs.
  It is recommended that some representation of the solar cycle be included in the 20th and 21st century simulations, though that is left up to the discretion of the modeling groups.

  Source: Taylor et al (2011).  A summary of the CMIP5 experiment design. (pdf)

There was a further recommendation for how future solar irradiance forcing should be represented:

  In CMIP5, climate projections were based on a stationary-Sun scenario, obtained by simply repeating solar cycle 23, which ran from April 1996 to June 2008 (Lean and Rind, 2009).

  Source: Matthes et al (2017).  Solar forcing for CMIP6 (v3.2), Geosci. Model Dev., 10, 2247-2302, https://doi.org/10.5194/gmd-10-2247-2017

But, in practice, groups did slightly different things from each other, so you usually have to check the output file metadata and any associated journal papers for individual model runs to get an idea of the details.

This is clearly not a crazy question though, because in CMIP6 some future natural forcings experiments have been defined, albeit in the lower priority tiers. Specifically, the Detection and Attribution MIP (DAMIP) includes ssp245-GHG and ssp245-nat experiments, and the volcano MIP (VolMIP) has the volc-cluster-21C experiment.  If you dig down into those you’ll find that future solar variability is derived more or less the way you describe, i.e., projecting forward based on a set of statistical time series models trained on past variability.  Note, however, that Matthes et al are careful to point out that this is a projection not a prediction:

  As of today, predicting solar activity up to 2300 is very challenging, if not impossible… The unusually long solar cycle number 23 that ended in 2009, and the weak one (no. 24) that followed came as a surprise, and manifested our evident lack of understanding of the solar cycle.

Conversely, future volcanic forcing in ssp245-nat will be prescribed as a near-constant background forcing:

  Volcanic forcing will be ramped up from the value at the end of the historical simulation period (2015) over 10 years to the same constant value prescribed for the piControl simulations in the DECK, and then will be kept fixed.

  Source: O'Neill et al (2016). The Scenario Model Intercomparison Project (ScenarioMIP) for CMIP6. Geosci. Model Dev., 9, 3461-3482, http://doi.org/10.5194/gmd-9-3461-2016

So why not a statistical model for volcanic emissions?  This forcing is episodic rather than cyclic and is prescribed to the CMIP models as several variables on latitude-height-time grids.  As you hint at in your question, this is too many degrees of freedom to pin down satisfactorily from just the 1850-2005 record.  Even if it could be done, you then have the problem of how to use the statistical model, given that each climate model will only run a few realisations of a particular projection.  Do you generate one scenario to be shared by all models, or do you let each group generate its own scenarios using the statistical model?  Either way, you can’t explore enough of the parameter space to avoid ending up with a CMIP6 ensemble containing decadal variability that is strongly influenced by forcing scenarios that are extremely unlikely to happen.

As I understand it, the current assumption is that volcanic forcing is stationary and, in the absence of knowing the future sequence of eruptions, its effect on slowly varying climate components like ocean heat content is best represented by a constant mean forcing.


How many times in total has Earth formed a super continent? I know there was a Pangaea at one point in history that broke into the continents of today, but I could have sworn there was another instance in Earth's history that there was a super continent, maybe even more, so how many in total?

According to a review by Nance & Murphy (2013), there are five known supercontinents, from the most recent to the most ancient:

Pangea (of course)
Pannotia (though it depends on how you define supercontinent), ca. 600 Ma
Rodinia, breakup at ca. 750 Ma (see e. g. Torsvik, 2003)
Columbia (also called Nuna), ca. 1.6 Ga
Kenorland, ca. 2.7 Ga

Some additional ones such as Vaalbara in the Archean are still mostly speculative.


Interpolating spatial data in contiguous sea areas only I have a dataset consisting of irregularly spaced points in the ocean. For each point I have coordinates and a data value.
I need to interpolate to a regular grid. So far, so easy.

There are areas of land within the area covered by the dataset, and in the original dataset there are simply no points there. I have polygons of the land boundaries.

I need to exclude the land from the output. This is fairly straightforwardly accomplished by checking which of the points on the target grid are within the polygons and removing them.
However, I also need to make sure that whatever interpolation technique is used does not consider points that are (for example) the other side of a peninsula - potentially a short distance away in a straight line, but a long way (or possibly not connected at all) by sea.

I'm sure that this must be a solved problem - I imagine any GIS package will have a way to deal with it - but I am at a loss as to what search terms to use in looking for the solution.

I have been debating whether to ask this question here, or on stats.SE, or on GIS.SE, or on Stackoverflow... but let's see how it goes.

A very neat approach for optimal interpolation, which consider not only breaklines along the coast but also anisotropies caused by currents and horizontal diffusion, was given by Lynch & McGillicuddy (2001). Their approach is quite elegant and takes advantage of the finite element methodology to avoid the transfer of information across boundaries.


What's the difference between the upper & lower mantle? Recently I checked a picture about the geologic layers of the Earth, and I saw that the mantle is divided into upper and lower mantle. What's the reason of this differentiation?

The boundary between the upper and lower mantle is today believed to be due to the phase change because of increasing pressure of:

$$\text{Ringwoodite} \xrightarrow{\text{660 km, about 24.5 GPa}} \text{Mg-Perovskite} + \text{Mg-Wüstite}$$

The boundary was originally found in the form of a seismic discontinuity (the "660 km discontinuity"). This information was combined with the knowledge that the most primitive meteorites have roughly the chemistry of the bulk Earth. Accounting for the chemical differentiation (into crust, mantle and core) the chemistry of the mantle was known. Additional clues for the chemistry come from mantle-xenoliths. The crystal structure (important for the density of a chemical compound or mineral) can be deduced from high pressure experiments and natural laboratories such as meteorite impact craters. For example, the mineral majorite was found, which is also postulated for the lower mantle.

Some literature on this: http://mahi.ucsd.edu/shearer/PDF/30NT92a.pdf


Olympus Mons sized volcano on Earth? The shield volcano Olympus Mons on Mars has the distinction of being the most massive single volcano in the solar system - this volcano, according to NASA, is 25km high with a diameter of over 600km - with a base that would cover the American state of Arizona (as in the image below).

Image source: NASA

What evidence, if any, has been found to prove that there ever has been a volcano the size of Olympus Mons on Earth?

Recent studies have recognised what could be the most massive volcano in the world, a geological feature already known, but was not recognised until recently as being a single volcano.

It is the Tamu Massif in the north-west Pacific (location map shown below), what was thought to be one of the vents of the Shatsky Rise - but recent seismic studies, reported in the article An immense shield volcano within the Shatsky Rise oceanic plateau, northwest Pacific Ocean (Sager et al. 2013) have revealed that it is one single shield volcano. The Geology.com article states that it covers an area of approximately 310,800 square kilometers (120,000 square miles), about "the size of New Mexico" - and, according to Sager et al., making it comparable with the size of Olympus Mons.

Location of the Tamu Massif

Map source: Daily Mail

According to the article Underwater volcano is Earth's biggest (Witze, 2013), that although the 140 million year old Tamu Massif is not as tall as Olympus Mons (nor even Mauna Kea) - in fact, it is still an impressive 4km above the sea floor, its 'footprint rivals that of Olmpus Mons', a comparison is shown below (the source is the linked article):

The authors hint that seismic studies could well find more shield volcanoes on a par or even more massive than Olympus Mons. Of course, as they state, the identification of Tamu Massif as a Olympus Mons sized megavolcano suggests that there have been more such megavolcanoes in Earth's early history, most of course would be eroded, lost to tectonic processes etc.


Why is this "independently reproducible proof of non-curvature" wrong? I'm currently having a (possibly useless) argument with somebody over the internet who is adamantly claiming that the Earth is flat. I know that this person could just be pulling my leg or trying to get a rise out of me but I'm still taking the challenge.

They are using this image in response to almost any argument.

What is this document even 'proving' and why is it wrong (or misleading)?

The biggest flaw I see in a cursory look at this work is failure to compensate for atmospheric refraction.  Density varies in the atmosphere enough that the refractive index varies.  At low angles above the horizon the temperature structure of the atmosphere becomes very important in determining optical refraction and at low angles very close to the ground it becomes extremely important.

When cool air is at the surface and warms with height (e.g. a temperature inversion), which is likely above a cool body of water like a canal (or in winter, or at night and early morning), the resulting density gradient causes light to bend toward the ground.  This means whatever you are observing is actually lower than you perceive it.

http://images.tutorvista.com/content/light-refraction/looming.jpeg

In the situation where it is warm near the surface and cools aloft you get the opposite and light bends up toward the sky.  This gives rise to the water mirages you can see on hot days on roads or sand (where there is a very strong temperature gradient with height).


What is the geochemical origin of carbon dioxide with the 'white smokers' of the Champagne Vent? Associated with the NW Eifuku volcano, a small submarine volcano in Japan's Volcano Island chain in the Pacific Ocean is a carbon dioxide rich hydrothermal vents called white smokers by NOAA (see image below):

Image source: NOAA Ocean Explorer

In research reported in the Science Daily article Scientists Discover Liquid Carbon Dioxide 'Champagne' Bubbles At Hydrothermal Vent (NOAA, 2005), it has been determined by measurements of the hydrothermal fluids that there appeared to be from 2 vent fluids:

a hot (>100 C >212 F) fluid that has been found to contain about 60 L of gaseous carbon dioxide per kilogram.
alongside the hot vent, the researchers found that there were cold droplets of about 90% liquid carbon dioxide.

These droplet give the vent its name, as it is 'effervescent' like champagne.

What is the geochemical origin of the carbon dioxide associated with the 'white smokers' of the Champagne Vent?

Observations and geochemical measurements presented in a study published soon after the article in the question, Submarine venting of liquid carbon dioxide on a Mariana Arc volcano (Lupton et al. 2006) sheds considerable light on the processes involved in the unique Champagne vent.

The key unique features of the Champagne Vent are the presence of CO2 droplets and the CO2 concentration - 2.7 moles/kg - the highest for any underwater hydrothermal vent. This concentration is also supersaturated, being considerably higher than what should be possible at the temperature and pressure present at the vent.

The proposed model, based on Lupton et al's observations and measurements, suggests that there is a subsurface layer of CO2 liquid and hydrates that is penetrated by the vent, resulting in the CO2 becoming entrained in the hydrothermal fluids, providing for the observed 'cold' CO2 droplets and also increasing the concentration to supersaturation levels.

Lupton et al. also explain that from geochemical analyses, the source of the carbon is mostly (90%) from subducted carbonate melt, with a small amount coming organic matter and mantle derived carbon.  Further, chemical measurements reported in the later research Chemistry of hydrothermal plumes above submarine volcanoes of the Mariana Arc (Resing et al. 2009) indicate that there is an absence of chemical reactions between the host rocks and the CO2 and further suggest that the magma chamber is deep within the NW Eifuku volcano (Champagne Vent source) and the gases rise into colder, older substrate.


Why do tropical cyclones not tear themselves apart? A tropical cyclone is the generic term for a hurricane, typhoon, or tropical storm.  Tropical cyclones derive their energy from evaporation of water at the ocean surface which ultimately recondenses when it cools to the saturation point.  The rotation of a tropical cyclone is caused by the Coriolis effect.

What is unclear to me is: Why do these massive bodies of warm, moist air clump together over thousands of kilometers?  What physical process causes them to be drawn in towards the center of the storm?

*image taken from the Wikipedia article on tropical cyclones

The equation of motion for a fluid parcel in the atmosphere (in Cartesian space) is

$$\dfrac{D\mathbf u}{Dt} = -\dfrac{1}{\rho}\nabla p-2 \mathbf \Omega \times \mathbf u + \mathbf g + \mathbf F,$$

where $\mathbf u$ is the wind, $\rho$ is density, $p$ is pressure, $\mathbf\Omega$ is the angular velocity of the Earth, $\mathbf g$ is gravity and $\mathbf F$ is friction.  The derivative is a material derivative (Lagrangian perspective) where

$$\dfrac{D\varphi}{Dt} = \dfrac{\partial\varphi}{\partial t} + \mathbf u\cdot\nabla\varphi.$$

There is a non-dimensional number called the Rossby number ($Ro$) that determines when a flow behaves geostrophically.  This number is given by

$$Ro = {U\over fL},$$

where $U$ is a velocity scale, $L$ is a length scale and $f$ is the Coriolis parameter ($f=2\Omega\sin\phi$, $\Omega = 7.2921 \times 10^{-5}\ \text{s}^{-1}$, and $\phi$ is latitude).  When $Ro << 1$, the flow exhibits geostrophic balance.  This occurs when $L$ becomes large, which it does as the storm grows.  When I say the flow is geostrophic, what I really mean is that the net acceleration of a parcel is small.  In a tropical cyclone the isobars are roughly circular and this curvature gives rise to the gradient wind balance.

The gradient wind is the balance of the pressure gradient force, Coriolis force and centripetal acceleration.  In this flow, just as in geostrophic flow, the wind will follow the isobars, flowing cyclonically around the center of low pressure, though slower than a geostrphic flow with the same pressure gradient.  Close to the ocean surface friction plays a role, and for the near surface winds the friction will cause the wind to be slightly deflected toward low pressure, or inward across the isobars.

Close to the center of the storm, in and near the eyewall, the length scale $L$ is reduced and the Coriolis force places a smaller role.  Here the flow attains cyclostrophic balance -- a balance between centrifugal and pressure gradient forces.

The gradient and cyclostrophic balances explain the wind rotating around the storm and surface friction will give a radially inward component at low levels, advecting angular momentum toward the center of the storm.  Convection in the eyewall will lift air to the tropopause where it will flow anti-cyclonically (due to the thermal wind) away from the storm before subsiding.  The core of the storm is warm and the air there is subsiding, creating the cloud free eye. The flows around the storm are balanced flows and the flow inward/upward/outward/downward is a thermodynamic carnot engine.

This gives us a fairly stable setup and this is why once a tropical storm forms it tends to persist rather than tear itself apart.  The key to sustaining this balance is a warm ocean surface and weak vertical windshear.  If you take away the warm ocean the storm will start to spin down and if you have strong shear you will disconnect the lower and upper level circulations and the storm will weaken.


Why does Japan get so much snow? Japan seems to get a surprising amount of snow in winter, compared to other places that are as cold or colder.
The snow seems to be concentrated on the west side of the country, which suggests the lake effect, only with the sea instead of a lake; the prevailing wind from the west brings air that has picked up moisture going over the sea, and the moisture freezes and falls as snow.
But why then do places like Oregon and Ireland not get so much snow, despite being similarly on the receiving end of moist air?
Those places have an entire ocean to the west, as opposed to Japan which has a narrow sea and then a continent. Conjecture: it's the combination that does the trick. Air blowing over the continent becomes very cold, then blows over the narrow sea and picks up moisture, which then freezes out. So to get maximum snow, you need a continent and then a narrow sea or lake, followed by the land which is to receive the snow.
Is that conjecture correct? Or if not, what is the reason for the amount of snow?

From my understanding, you are thinking along the right lines but also need to take mountains into account.
Ireland's mountains are lower than Japans. I think that Japan's mountains are a similar height to Oregon's but the high mountains are closer to the coast in Japan. (I don't know either area well, so this statement could be wrong.)
Another thing to consider is that in winter, convective showers are common over the sea. A longer sea track will have more showers and therefore more mixing of the atmosphere, raising the temperature of the air mass.
Winter convection cuts off over land, but showers can penetrate inland a little with the momentum they already have. The closeness of the mountains to the coast in Japan, as well as their height, will give more orographic enhancement to the amount of precipitation as well as possibly reinvigorating the unstable convection by forcing it to rise. Ireland's lower lying status won't have this effect as much.
Oregon has two ranges of mountains, the lower Coastal Range (<1000m) and the higher but 150km inland Cascades (~3000m). The Coastal Range has a similar height to the Irish mountains but are longer in their extent. The orographic enhancement of the Coastal Range will be much less than in Japan. The Cascades will then be in a rain shadow as the air will be less humid downwind of the Coastal Range. While the Cascades still cause orographic enhancement, this is nowhere near as much as if the Cascades were by the coast, which in Japan they effectively are. You can see this effect on the annual average precipitation map of Oregon:

As an aside, I had wondered if the Sea of Japan might be warmer than around Oregon and Ireland; this would provide more heat, moisture and instability to the air reaching Japan. I had a quick look at February sea surface temperatures, and they seem broadly comparable to the other areas, at least for the past three years, so this enhancement mechanism seems unlikely. February appears to be the month that Japan gets the most snow, although I'm not sure if that's talking about peak snowfall or peak accumulation.
I found a few articles about Japan's snow online:

National Geographic: The world's snowiest place is starting to melt
Ski.com: Why is there so much snow in Japan?


ISA Model and GFS data I have a newbie question...

I always used the International Standard Atmosphere model whenever I needed to calculate the temperature in a given altitude.
It always looked accurate to me...

However, doing some work using GFS data, I found something intriguing..

At a given high altitude (let's say : 150 hpa/44000ft), the temperature I saw in the GFS model was almost always colder than the ISA temperature for that altitude

This was mostly TRUE for latitudes between -30 and 30º, and the OPPOSITE for abs(latitudes) > 30º.

Example:

So, I came with a hypothesis... Want I want to know if it is crazy or not.

The ISA model is an average model. Temperatures in the tropics are lower (for high altitudes) and the temperatures near the poles are higher. The final average is the ISA model.

I would agree with your hypothesis, but I must point out that it will likely break down further and further as you approach the tropopause. Whether the ISA model is actually a average, I cannot say. However, the idea that the ISA model is a horizontal average is plausible.


Difference between Earthquake Seismographs How can we tell the difference between a seismograph of a local earthquake and that of a distant earthquake?

An earthquake generates waves that move through the earth in different ways. Two of the principle waves are the compressional P wave and the shear S wave.  P waves move faster than S waves, so by timing the difference in arrival time of the two waveforms we can estimate the distance to the epicentre.

https://www.bgs.ac.uk/discovering-geology/earth-hazards/earthquakes/how-are-earthquakes-detected/


Which type of plant absorbs the most net carbon dioxide per year per square km? The answer to How many trees would I have to plant to solve Global Warming? demonstrates how unviable it would be to simply plant trees to counter climate change (we'd need to plant ~60 millions km$^2$ of trees - that's 6 times the area of Australia!)
But it's based on the assumption of trees absorbing just 5.9 kg of carbon dioxide per year, but after a quick google there seems to be other estimates many times higher than that.
Question: how high can CO$_2$ absorption go - that is, what species of plant (or combination of species) absorbs the most CO$_2$ per square km, and what is that figure approximately?
Assumptions:

Assume favourable circumstances i.e. the conditions the plant(s) most prefer
If possible, assume net average absorption over the life of the plant to take into account differing absorption rates as the plant grows, as well as the 'net' part handling for plants releasing some carbon as they grow

I have no personal expertise in this matter, but performed a quick search of recent literature. From what I can tell, the interest in fast-growing plants is motivated primarily by the desire to maximize bioenergy production, not as a means of carbon sequestration. The typical goal is therefore multiple harvests per year in favorable conditions, meaning any carbon removed from the atmosphere by these plants is returned back to the atmosphere in a matter of months. Two plants commonly mentioned are eucalyptus trees and elephant grass.
Humbertode Jesus Eufrade Junior, et al., "Sustainable use of eucalypt biomass grown on short rotation coppice for bioenergy", Biomass and Bioenergy, Vol. 90, July 2016, pp. 15-21

According to the results obtained, the density planting and fertilization levels have a greater influence on the dry matter yield, energy yield, and nutrient exports. The higher density planting reaches mean values of 30.9 tonnes of dry matter per hectare

Rafael Fiusa de Morais, et al., "Elephant grass genotypes for bioenergy production by direct biomass combustion", Pesq. agropec. bras., Vol. 44, No.2, Feb. 2009

The objective of this work was to evaluate elephant grass (Pennisetum purpureum Schum.) genotypes for bioenergy production by direct biomass combustion. Five elephant grass genotypes grown in two different soil types, both of low fertility, were evaluated. [...] The dry matter yields ranged from 45 to 67 Mg ha-1

There are 100 hectares in a square kilometer, and one Mg is one metric ton, so the reported annual yields correspond to 3090 tons per square kilometer for eucalyptus, and up to 6700 tons per square kilometer for elephant grass. Obviously the dry mass of plants is not just composed of carbon. The FAO provides this helpful data:

The carbon content of vegetation is surprisingly constant across a wide variety of tissue types and species. Schlesinger (1991) noted that C content of biomass is almost always found to be between 45 and 50% (by oven-dry mass).

Assuming 45% carbon content, this means eucalyptus trees can bind 1390 tons of carbon / km2 / year and elephant grass can bind 3015 tons of carbon / km2 / year. A CO2 molecule has atomic weight 44 while carbon has atomic weight 12, so the CO2 tonnage is the 3.66-fold of these numbers, that is ~5100 tons and ~11000 tons, respectively.


What are monsoons caused by? Traditionally we think of them as being caused by differences in land-sea heating.

But more recently, some researchers, like Simona Bordoni and William Boos, have argued otherwise.

Thats a very heavy question and might need a dozen pages to briefly answer, but however its better to summarize the answer and refer to the most detailed review work of Pin Xian Wang and his team entitled "The global monsoon across time scales: Mechanisms and outstanding issues".

I hope this can answer all the questions anyone have in mind. General definition can be that (Global Monsoon (GM) as a planetary scale circulation system. The primary driver of the GM is solar insolation, and the specific features in the underlying surface, such as land-sea distribution, topography, and oceanic circulations, are mainly responsible for the differences among regional monsoon systems.) derived from the above work.

The most important point to be considered that the paper listed above is based on CMIP5 models, however many authors in the region have documented the deviations and differences in all CMIP5 models globally. I will also suggest the work of Alexis Berg for African monsoon system.


How do I extract seismic amplitude on an interpreted horizon? It seems that seismic amplitude extracted on an interpreted horizon is good for showing channels. E.g.:http://seismicatlas.org/entity?id=98a83c60-ea81-47cc-9304-6041f6ec5277.

It seems that often the RMS amplitude is used instead.

When do one use amplitude and when do one use RMS amplitude?

When using RMS amplitude one must integrate over a window around the horizon.

Which window do one use?

I often see images of RMS amplitude maps where the caption simply says something like "lower tertiary horizon with RMS amplitude extraction".

Does this mean RMS calculated over a window from z =horizon - 10 m to horizon + 10 m for instance?

Or could it mean RMS calculated over a window from z = 3 peaks above horizon to 3 peaks below horizon?

The answer to most of your questions is: it depends.
Is amplitude good for mapping channels?
Amplitude maps can be great for finding and interpreting channel systems. It depends on the geology and on the seismic data's characteristics. Sometimes you can just see the channels, which might be qualitatively useful, and sometimes you can infer quantitative information, such as width, thickness, composition, porosity, or fluid content. It depends.
Here's a workflow for any kind of attribute analysis. I'll try to add to it in the next day or two.
When should I use RMS amplitude?
Before confusing yourself with what others do (they are not necessarily a good guide), it's worth reading about different kinds of average.
The main feature of the RMS average, for geophysicists anyway, is that it works on zero-mean data like seismic:

So it's not really that "when using RMS amplitude one must integrate over a window", more that if you want to measure amplitude over a window, you must use RMS.
Because the values are squared, RMS has two other features (or bugs, depending on your point of view): large values are emphasized, and noise may therefore be emphasized.
An alternative is to use the envelope of the trace (sometimes also called 'energy' or 'absolute amplitude'), which is the magnitude of the Hilbert transform (also called 'complex trace'). It is always positive and has the added benefit of being phase-independent. Read more about envelope..
Which window to use?
Let the expected geology and basic geophysics and statistics guide all of your decisions. Use a window that captures the interval of interest (look at the wells!) without too much non-interesting stratigraphy. But use a big enough window that you don't see a lot of artifacts from large amplitude values coming in and out of the window (this also depends on the quality of the horizons and smoothness of the geology).
Windows don't have to be symmetrical about a horizon. It depends where the features you're interested in are. In my experience, stratigraphic windows are often useful — from one horizon to the next. If you're interested in the horizon itself, consider just using its amplitude directly. If it's too noisy, try improving the pick or smoothing the amplitude map, before confusing things by throwing more geology in there.
What does that caption mean?
Who knows what that caption means? Vague captions plague the geophysics literature. Don't be part of the problem! If only for the sake of your future self, record the exact statistic and its parameters on every image — even put it all in the filename.
Remember what you're trying to do
You're trying to relate the seismic to reservoir properties you care about. This means proving that the property is related to the seismic in as quantitative way as possible. A nice way to do this is to crossplot the property with the seismic attribute — that way you also know the error of the estimate. A map showing wiggly channels is interesting, but nowhere near enough.
I tend not to believe attribute analyses that don't include a crossplot.


Why does foliage coloration vary on north/south sides of ridge (Northeast USA)? I recently flew into New Jersey over the Delaware river and took this photo of the ridgeline at the Delaware Water Gap.  The trees are mostly green (early October) but on the south-east side of the ridge there is a bright streak of reddish foliage along the entire length of the ridge.  (I noticed this on other hills in the area as well.)

What could be causing this color change?  My first guess would be that it is related to sun exposure.

Your photo doesn't show the strip of autumn-coloured trees very well; without your description I would have taken it for a strip of bare earth. All sorts of things could account for the autumn shades, there are too many unknowns to give a definite answer.       We don't know whether the red-leaved trees are the same species as the others, for example.

I doubt if sun exposure alone could account for it, though it might be a combination of sun exposure and soil conditions, or soil conditions alone. The red trees seem to follow a line where strata different from the rest reach the surface. This would affect the soil conditions, nutrients and perhaps available moisture. Without an investigation on the ground it is impossible to be sure what the cause is, but I think a difference in soil conditions is the most likely explanation.


Are there other divisions of Earth following beyond hemispheres? I know it's a silly question, but it really bothers me since the word hemisphere derives from Greek ημί- (i.e. hemi-) which cannot be further expanded, while the English equivalent semi- can be further expanded to quarter-.

So, my question has three parts:

Firstly, does the choice of "hemi-" instead of "semi-" only from geology or is it used as such in mathematics in the same manner?
If the Earth were instead flat, would we refer to a hemicircle or semicircle?
If I want to refer to the northwestern part of Earth, what's the correct word, since hemisphere is obviously wrong?

Thank you in advance

Not, IMO an ES question, but depending on what level of division, and if you are talking about the surface only or a partition of the sphere extending to the core, terms such as spherical sector, spherical cap, and quadrant would be fairly common descriptive terms for parts of a sphere.

Cap would be the portion of the sphere cut by a plain passing though the sphere.  The Hemispheres are caps cut by the plane passing through either the equator or the poles.  Normally a cap would describe an area formed by cutting the plane parallel to the equator, as in the lines of latitude.

A sector would be a cone centered and the center of the sphere and extended to the surface.  Think of a cone capped by a cap as described above.

A quadrant would typically be a wedge, think of an orange wedge, or a part of one.

I do not think any of there really are especially common to use in relationship to Earth though they are valid descriptors.  Lines of longitude and latitude are the common differentiation that describe these divisions, and phrases such as above/below the 45th parallel to describe the halves of the Northern Hemisphere.


Why is Arizona the fastest-warming state in the U.S. (since 1970)? The states that have warmed the most — whether you look at the past
  100 years or just the past 40 — include northern-tier states from
  Minnesota to Maine and the Southwest, particularly Arizona and New
  Mexico. Places that have warmed the least include Southeast states,
  like Florida, Alabama, Georgia and South Carolina, along with parts of
  the central Midwest, like Iowa and Nebraska.

Why is Arizona responding so strongly to climate change in a way that other states aren't?

The University of Arizona's South West Climate Network webpage Precipitation Changes  (Lenart, 2008) provides a detailed account of the causes of the warming in Arizona and the south-west region of the United States.  Principally, a major factor to consider is that the region is already arid, with low precipitation and high temperatures to begin with.

According to Lenart, global climate models predict that precipitation in the region is expected to drop in the region by between 5-10% by the end of the century.  Less rainfall, coupled with higher temperatures would cause an increase in dryness, hence droughts and sudden downpours.

The mechanism behind this precipitation drop is described by Lenart as being due to an increase in the area under the Hadley Cell circulation, resulting in a movement of the jet stream further north - resulting in winter storms bypassing the southwest altogether.  Some of the models predict there would be a northward shift of the subtropical anticyclone.

So how do these models match the observations?

Observations and measurements have found that

  lower precipitation rates in the Southwest correlated with positive phases of the atmospheric pattern known as the Northern Annular Mode (NAM), which they attributed to an associated northward shift of the jet stream during these years. Meanwhile, the Rocky Mountains, headwaters of the Colorado and Rio Grande rivers, tended to register higher precipitation rates during these positive phases, consistent with the observation that the jet stream was shifting north.

However, extreme precipitation events, such as the record breaking September, 2014 floods in Phoenix, as the remains of Hurricane Norbert swept through, are increasingly likely.  Crucially, from Lenart:

  Precipitation records contain a high degree of variability, however, as they are influenced by a variety of other factors in addition to climate change. For instance, much of the upward trend in the precipitation record from 1950 probably stemmed from an abundance of El Niño events in the second half of the record, according to Martin Hoerling, the researcher who conducted the analysis.

An interesting and somewhat ironic twist implied in the document The Heat Is On: U.S. Temperature Trends is a speculative point that

  points out that since cleanair
  regulations have dramatically reduced these
  emissions over the past 20-30 years, the cooling
  e"ect has already disappeared and will no longer
  be a factor in the future. If the study’s findings turn
  out to be applicable to the warming hole, then it
  is possible that without aerosols screening solar
  radiation these regions will catch up.

Anthropogenic sources, including land use can, according to the article Mesoscale Disturbance and Ecological Response to Decadal Climatic Variability in the
American Southwest (Swetnam and Betancourt, 1997), can amplify, mute or be utterly confounded by anthropogenic effects.


Other than tectonic activity, what can reshape a world's surface? Take our world and look at its surface geography: we have continents and oceans, mountains ridges and canyons, and so on. To my knowledge, most of it has been shaped by tectonic activity (feel free to correct me).
I'm looking into other things that would reshape a world on a large scale. It can be natural phenomena or artificial activities, it can occur over millions of years or in a matter of hours or days, and so on. Anything you can think of, which realistically would be able to change a worlds geography.
To be clear, I'm not looking for "small" regional changes (Mount St. Helen comes to mind), I'm looking for something that would at least reshape a big chunk of a continent, if not more.
At the same time, I don't want it to be so extreme to completely destroy the world (eg. Earth's early days meteor shower, which pretty much melted its entire surface, or worse).
Hope it makes sense...
EDIT: I've read some interesting replies so far. I'd like to point out that the changes I'm referring to would be noticeable on a world map.
For example, the creation of new landmasses (eg. volcanic islands), their disappearance, or their movement. Seas and oceans, mountain ridges, stuff like that.
Is there something that could explain the sea level lowering permanently, leading to new lands emerging? Other than volcanoes (and tectonic activity), are there other ways for mountains to form? Is there something that would explain a huge (as in the sized of a large nation like the US or China) depression to appear? Stuff like that...

Erosion is a powerful but slow and time consuming process that can make dramatic changes. The best example of this is the Grand Canyon. Carved by a river over at least 17 million years, 5000 to 10,000 feet deep, 277 miles long and 18 miles wide.
Erosion, whether it be due to wind, rain, water flow in rivers, glaciers is a major cause of geology, in the form of mineral grains, boulders and rocks to be mobilized and dispersed over a wide region.
Weathering is another force that reshapes the surface of the Earth. Australia is a perfect example of this. Weathering results in the physical breakdown of the of the surface geology due to weather, thermal stresses, frost, crystal formations and decomposition, oxidation, biological activity, alternating patterns of hydration and dehydration over a very prolonged period of time. The difference between erosion and weathering is erosion causes movement of material, weathering happens  in situ.
Fire tolerant plants such as eucalyptus and fire as a result of natural forms of ignition, such as  lightening  can change the botany of a large region, again see Australia. Eucalyptus has been described as a weedy tree that came to dominate a landscape when less fire tolerant plants became extinct.
Persistent fire or drought over a prolonged period can lead to permanent loss of flora resulting in desertification. Similarly, excessive rain due to climate change can lead to landslides and excessive erosion.


What's the story of the shear face in the new Mac OS Catalina wallpaper? The new Mac OS boasts a beautiful default desktop background with the western tip of Santa Catalina Island.  The rock formation in the foreground looks like it was sliced on the diagonal with a power tool, but I assume this uninhabited side of the island hasn't actually been altered.  What accounts for this smooth rock face?

This is a bedding plane, once horizontal, but geological forces have tilted it to the diagonal. The strata above have been eroded and washed into the sea, perhaps by a storm, leaving the ancient bedding plane exposed. Tilted strata are not unusual in very ancient rock formations.


What does global weirding mean regarding temperature extremes? Global weirding is a term used to describe how, with global warming, we will see more extreme weather events:

Avoid the term “global warming.” I prefer the term “global weirding,” because that is what actually happens as global temperatures rise and the climate changes. The weather gets weird. The hots are expected to get hotter, the wets wetter, the dries drier and the most violent storms more numerous.
The fact that it has snowed like crazy in Washington — while it has rained at the Winter Olympics in Canada, while Australia is having a record 13-year drought — is right in line with what every major study on climate change predicts: The weather will get weird; some areas will get more precipitation than ever; others will become drier than ever.

I have a decent understanding of physics but don't know much about weather and climate. I think I understand a few things about global weirding:

Warmer waters mean typhoons can form more often, so in locations where extreme weather is also caused by typhoons they will see this more often

Warmer air can transport more water and since steam pressure rises greater than linear with temperature, the same temp. swing around a high mean means that more water can precipitate.

I often here a statement to the effect that more energy in a weather system means it has more extreme 'swings' in its behaviour. I find this rather opaque and unconvincing.

Here's what I don't understand: Does 'extreme heat wave' in this context mean

In 2100, we'll see more extreme heat events relative to 2015 mean temperatures or

In 2100 we'll see more extreme heat events relative to 2100 mean temperatures

I think it means the latter, but given that today's heat waves can cost lives and damage crops, I think it would be relevant to point out that we will see more of this so the first definition has some merit. So I want to be clear about the terminology.
But my main question is, will we see more extreme temperature swings and what are the main mechanisms driving this?

First things first.   Global "Weirding" is very difficult to quantify.  That doesn't mean it's not happening, but it's inexact.  The idea came from climate models, which produced a lot of unexpected variations as opposed to more smooth and consistent warming and weather patterns are so complicated that there's still a lot of unknowns in this area.

  Warmer waters mean typhoons can form more often, so in locations where
  extreme weather is also caused by typhoons they will see this more
  often

Typhoons/Hurricanes are formed not just by warm water but by warm air and wind direction.   If the wind is too strong, the hurricane doesn't form, it needs to build and as it builds, begin to spin.    That's a dummies explanation, more details here

Warmer water can make hurricanes grow larger (unclear if it makes the wind blow faster too, it might).  One of the fun little jokes made about global warming is that in the IPCC's 4th assessment report (4AR) they predicted fewer hurricanes and in the 5th (5AR) they predicted more, though both were stated with some uncertainty and in the 4AR they predicted fewer with a chance of larger so those predictions aren't nearly as contradictory as this cartoon writers tries to make it sound.

I personally trust 5AR over 4AR cause it's had 7 more years of research behind it, but whatever ends up being true, predicting hurricanes is complicated.   Short article on the debate of cause of the apparent recent increase here

  Warmer air can transport more water and since steam pressure rises
  greater than linear with temperature, the same temp. swing around a
  high mean means that more water can precipitate.

I'm not sure about stream pressure, though warmer air can hold significantly more water vapor, so that I agree with.

Every 1 ° warmer, the atmosphere can hold in saturation about 6% more water.   So warmer air can hold quite significantly more water and as a result, lead to larger rain storms, though it's not just air temperature, but temperature variation as the warm air rises, etc.   But more precipitation per storm is a very likely consequence of man made climate change.   Source.

Also, while the Earth has warmed less than 1 ° C so far, most of the surface temperature over land has warmed over 1 ° C (1.53 ° C on average - see here) and it's the rainfall over land that affects us.   This means that the atmosphere over the land can hold as much as 10% more water on average than it did at pre-climate change levels.   Now, the temperature increase is lower in the upper atmosphere, so it's not really 10%.  but we've seen a few percent increase in how much water our atmosphere can store over land over just the last few decades and that's expected to continue to increase.

Water evaporation and atmospheric water-vapor replenishment is trickier and depends on a few factors, river flow rate is based on rainfall and snow-melt upstream, wind speed and plant transpiration are also important.   Some people say CO2 is plant food but it's not that simple.  Plants need to take in oxygen to capture CO2 which they use to grow.   Sunlight and soil neutralists are the actually the "food" for plants, CO2 is what they use to grow and with higher levels of CO2 in the air, they need to take in less atmosphere to get what they need and as a result, they lose less water, so less water is returned to the atmosphere from forests and trees, as CO2 increases.

So, in a nutshell, the global warmed atmosphere on average can hold more water, it can also take more time for the atmosphere "fill up again" after a rainfall or after passing over high mountains and dropping a lot of water-vapor.  That's why you get more floods and more droughts.  That much is simple physics.

If snow melt is high, that can lead to greater river flow and more flooding, and snow tends to fall in greater amounts with more water-vapor in the air.   There's a number of factors.

That strange 5 feet of snow event on Buffalo in 2014 happened when cold air blew over warm great lakes and the temperature difference caused the wind to draw a lot of water off the lakes.  Which, as it blew inland a mile or two, it quickly turned to snow and not the houses on the lake, but the houses a mile away from the lake got covered in snow.  The lake effect isn't unique to climate change.  It happened in the 1940s and 1970s, but warm lakes and a cold blast of air are the 2 drivers.  2014 was perfect for that with the polar vortex and the warm temperature colliding.  It was (I think) the largest lake effect Buffalo has on record.

Cool video here,

  I often hear a statement to the effect that more energy in a weather
  system means it has more extreme 'swings' in its behaviour. I find
  this rather opaque and unconvincing.

I think I agree with you here.  More "energy" is at best, vague, and it explains nothing.

Water vapor condensation is one way that air temperature can rapidly change.   Condensation/cloud formation releases heat so more water vapor can play a role in faster temperature change, but I'm not sure how big a factor that is.

Changes in ocean currents, perhaps caused by salinization changes and glacier melt can have significant effects.  Europe's moderate winters relative to high latitude are in large part caused by the gulf-stream and the gulf-stream may be slowing, article here.  There's still some uncertainty on the extent of this effect, but there appears to be a connection.

The Polar Vortex may also be growing as a result of climate change, based on some complicated models.   Despite the earth being warmer, harsh winters in some northern locations are still possible based on weather patterns.   Key point from article here:

  As strange as it sounds, Kim believes the intense cold air outbreaks
  in recent winters across Europe, Asia, and North America are, in his
  words, “a side effect of global warming.”

  In 2100, we'll see more extreme heat events relative to 2015 mean
  temperatures or

  In 2100 we'll see more extreme heat events relative to 2100 mean
  temperatures

This is a tough one.

First point is that there really is no 2015 mean in terms of temperature.  We can generate a global average temperature for 2015, but local temperature fluctuates too much to have a 2015 standard.   Temperature variation vs a standard is generally measured against a baseline over a few decades.   For example, see chart below.  (I couldn't get it to embed), but it compares 2014 local temperature to a baseline of 30 years, 1981-2010.

https://www.ncdc.noaa.gov/sotc/service/global/map-blended-mntp/201401.gif

If your question is rewritten as, will 2015, 2016, 2017, 2018, 2019, etc, compared to a 1981-2010 baseline have fewer extremes and look less "weird" than 2100, 2101, 2102, 2103, 2104, etc compared to a 2066-2095 baseline, then that's an interesting question but very hard to answer.   Individual years will be hit or miss, but on average, …hard to say.

As ice melt increases and as oceans continue to store heat and slowly grow warmer the weird weather variation could increase, but as CO2 levels begin to perhaps at some point, stop rising and reach a leveling off, we might see a decrease in "weirdness" compared to previous years, though the planet would still be warmer, but the rate of change might drop, so the best answer I can give you is that it could go either way.

The IPCC models suggest a gradual increase in the rate of warming for surface temperatures between now and 2100, as well as an expected increase in sea level rise but that corresponds to a steady increase in CO2.  The future CO2 growth rate could be a factor.

Guesses aside, when the experts say that weather will continue to get stranger, they are talking about compared to a consistent baseline, not a moving baseline cause that's a safer prediction, so your first sentence is the prediction that's usually put forth, but your 2nd sentence has a ballparkish 50% chance of being true too.

At some point the degree of weirdness has to level off simply because nothing builds indefinitely and for now global "weirding" appears to be gradually increasing, though as far as I know, precise measurements don't really exist.   It's too hard to quantify.


What happens if a magnitude 13 earthquake occurs? What would happen if a Richter magnitude 13 earthquake occurred? I read (at http://www.tulane.edu/~sanelson/Natural_Disasters/impacts.htm; about halfway down the page) that if a comet were to ever hit Earth, it would create a Richter magnitude 13 earthquake.

It can be problematic to use an earthquake magnitude scale for such purposes. To explain why, you have to look at the different scales how they were produced. The magnitude scales are normally used related to earthquakes on earth, resulting from elastic rebound effects from fault activity. The Richter scale (local magnitude, ML) is, easily said, measured by the amplitude of a seismograph in < 100 km distance the centre. It gets inaccurate at a magnitude greater than 6.5. From a magnitude greater than ca. 8, even the teleseismic calculated surface-wave magnitude scale (MS) gets inaccurate. For greater magnitudes, the magnitude has to be modelled in a completely different way: Here, the moment magnitude scale (MW) is used. It is defined in relation to the seismic moment:

$M_{W} = \frac{2}{3} log (M_{0}) - 10.7 $

The seismic moment M0 is defined as:

$M_{0} = D *A * m$

where $D$ is mean displacement at the total fault, $A$ is the fault and $m$ the rigidity (shear strength) of the faulted rock. It can only be modelled by visible surface offset/displacement.

So, let's come back to the question: The magnitude of an earthquake is related to the length of the fault. The problem of a magnitude 13 is, that it is not possible according to this concept due to the earth's physical limitations. Keep in mind, that with one magnitude higher, a quake has about 32 times more energy. Of course, you can compare the energy for instance to that of an impact event - which is also often done. However, it is not easy to presume the intensity.


Plotting wind barbs in python (no U,V component) I've got 4 different .txt files for longitude, latitude, wind speed and wind direction (so no U and V components of the wind). Is there any way to plot wind barbs from such a dataset?

I can answer this in two steps

Calculate $u$ and $v$. This site has formulas for $u$ and $v$. They are as follows: $$u=-|\vec{v}|\sin(\frac{\pi}{180}\phi)$$ and $$v=-|\vec{v}|\cos(\frac{\pi}{180}\phi)$$
where $\phi$ is the wind direction in the meteorological system, and $|\vec{v}|$ is the wind speed.
Having calculated $u$ and $v$, you can plot the wind barbs by following the example found at this site.


How to measure global temperature? people always talk about global temperature (such as the global temperature goal of 1,5 K) - but how is this value achieved? It seems to me that it clearly depends on where the measuring stations are, how far they are apart and how one weighs them. Has anyone got any paper/report at hand that declares how this is done (at the moment)?
Thank you very much!

Measuring stations are used, but to fill in the gaps that are inherently there. Satellite observations of surface level temperatures are used to smooth out the data (and gather information about the oceans) to create a full look at the global temperature.
Then the observed temperatures are compared to averages from recorded history and hot and cold spots are determined. Then finally the temperature deviations are added and subtracted respectively from each other until all deviations have been accounted for and a determination of above or below average is determined.
ECMWF uses their Copernicus satellites for this type of research which is documented in this presentation. The data is available through their ERA5 database.


Possible and probable source of Curiosity Rover's $\small\sf{CH_4}$ detection on Mars Past week, NASA announced Curiosity Rover measured 21 ppbv of $\small\sf{CH_4}$ on Mars.

  This week, NASA's Curiosity Mars rover found a surprising result: the largest amount of methane ever measured during the mission — about 21 parts per billion units by volume (ppbv).

However, apparently, Mars atmosphere is methane free. ESA satellites are not measuring it:

  "We did not detect any methane over a range of latitudes in both hemispheres, obtaining an upper limit for methane of about 0.05 parts per billion by volume, which is 10 to 100 times lower than previously reported positive detections" (Korablev et al.,2019).

What is the possible and probable source of the methane Rover is measuring?

-Korablev, O. et al. (2019):"No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations." Nature 568, pages 517–520

The possible source of methane is biological, and that is what everyone is hoping for, but the more likely source is geological, produced by chemical reactions between rock and water deep underground and issuing though fissures to the surface. We are dealing with very small amounts here which are difficult to detect and measure with precision. Once out in the open, they are dispersed by breezes and decomposed by sunlight, so that could explain why they come and go. It has been suggested that methane abundance varies with the seasons, but I can't see any mechanism for that, apart from clathrates. Clathrates are a sort of ice composed of water and methane, and are abundant on Earth in the ocean and in Arctic tundra. When heated, clathrates decompose and release methane. Another suggestion is that the Curiosity rover is incontinently leaking methane wherever it goes and contaminating the samples it analyses, but I cant see any explanation for that either. I think methane has been detected on Mars, but we will have to keep an open mind on the source until more data has been gathered. My own opinion is that there has never been life on Mars, but I agree that we can't rule out the possibility that 4 billion years ago conditions were sufficiently Earth-like that Mars evolved its own primeval soup and life got started in the same way as it did on Earth, but has since been eradicated or driven underground.


Is 2,000 years from now a credible figure for return to glaciation? I read this article,

https://www.technologyreview.com/s/416786/global-warming-vs-the-next-ice-age/

"In about 300 years, all available fossil fuels may well have been consumed.Over the following centuries, excess carbon dioxide will naturally dissolve into the oceans or get trapped by the formation of carbonate minerals. Such processes won’t be offset by the industrial emissions we see today, and atmospheric carbon dioxide will slowly decline toward preindustrial levels. In about 2,000 years, when the types of planetary motions that can induce polar cooling start to coincide again, the current warming trend will be a distant memory."

2,000 years is a lot sooner than other estimates, which can be in the hundreds of thousands of years, so is this an unrealistic estimate ?

It's a little dated and brief, but it's a cool article and I believe it's overall sound in it's predictions and arguments presented.

On the overall point, the author isn't predicting an ice age in 2,000 years, so the answer to your title question is that he didn't really say that, though he writes the article somewhat poorly because that's not very clear, especially when he writes the words "double whammy".   But he's predicting a natural correction to the added CO2 within about 2,000 years, after which the glaciation cycle, but not necessarily an ice age, should return.

The next ice age is hard to predict because Earth's Milankovich cycles aren't adding up right for another 150,000 years, so if an ice age can be triggered by a small push, one could happen in 10,000 years, but a big push isn't due for some time.   More details on the timing of the next glaciation here.

Your author's primary point is that man made climate change won't prevent the next ice age because the Earth will reabsorb the CO2 before then.   He may be right, and I think that's a very sound and fair point to make.  He's not actually saying an ice age will begin in about 2,000 years, though he does seem to imply the possibility.

I think, 2,000 years is likely too soon.   The triggering of ice ages requires cold northern hemisphere summers (He says that in his article too).  Basically, the red line on this chart should be low, and we're in a leveling off and small warming period for the next 50,000 years.  The cycles are adding up in such a way that predicting the next ice age is hard.

On his predictions:

Predicting that mankind will run out of fossil fuels in 300 years is reasonable.   It's something that can't be predicted with accuracy and I personally think it's wrong.   I think we'll move away from coal as climate change gets worse and with abundant deep shale that can be fracked (natural gas is good for cooking and planes need fossil fuels), so I think fossil fuels will remain in use and to some extent, untapped considerably past 300 years, but my opinion aside, his prediction is still reasonable and possible.

Predicting that it will take the Earth about 2,000 years to reabsorb the added CO2 is also reasonable.  I don't think anyone knows how long, or if a new equilibrium will be reached as opposed to a return to how it was, and making this kind of prediction is replete with uncertainties, but 2,000 years is fair.   We should keep in mind that a science based hypothesis can be reasonable and still end up being wrong.   In science as "good" hyopthesis is one that can be tested.   A "good" hypothesis can still be wrong and for estimates this far out, there's room for both his estimate being reasonable and his estimate being very far off the mark.    People sometimes yell at scientific predictions for being wrong, but predicting the future is hard, and people should stop yelling about that because it's not helpful.   Scientists know that not all hypothesis based predictions are accurate, what matters is that a prediction is science based, has correlated cause and effect and can be studied and tested.   (I hope you forgive my little rant, but I wanted to say what a good hypothesis actually means).

Some studies on oceanic absorption of CO2 and other estimates of how long it would take for the Earth to recover might improve this answer, or be the subject for another question, but I'm not feeling the urge right now.   That's a tricky thing to estimate and 2,000 years seems fair enough to me.

It's funny that, today, it's in our best interest to try to stop using fossil fuels, but if/when the next ice age is coming, people might be encouraged to use clean fossil fuels to release more CO2 and prevent the coming ice age.   "go for a drive, it's good for the environment" . . . anyone who's still around in 100,000 years, feel free to put that on your bumper-sticker.   The author also indirectly makes the point that we might want to save some of our fossil fuels as a means of ice-age prevention.   It's a sound point.

I think the article should have been longer and more fleshed out, but it's a good basic article.

I also want to add that while the article is short, he has a 267 page e-book which I imagine, goes into more detail.   https://books.google.com/books/about/Energy_Demand_and_Climate_Change.html?id=EdAgjDtBsNsC


How did a tropical storm starting with "D" end up next to a typhoon starting with "T"? While keeping a close eye on typhoon Talim, I noticed that tropical storm Doksuri is also on the map and has caused serious damage and loss of life. I had thought that the naming of tropical storms is alphabetical (within a given area) so it seems that Doksuri with a "D" must be quite old by now, and Talim fairly young.

Do I have the basic idea correct? I've tried to read the Wikipedia article Tropical cyclone naming but it gets a little complicated to read as it start to break things down by East Pacific and West Pacific and I am not sure from where these two originated.

How did a "D" and a "T" end up so close together? Is this unusual?

below: Screen shot from the Taiwan Central Weather Bureau's Typhoon News page.

The naming of typhoons, in the north west pacific region, is different to that used by other parts of the world. According to accuweather,

  For typhoons, there is one list with 140 names submitted from nations in the region such as China, Japan, Vietnam and Cambodia. There is no restrictions to how many can be used in a calendar year.

  “Unlike hurricanes, lists are not year-specific, so they scroll through the whole list irrespective of calendar

  The Philippines are also a part of the list of nations which submit names. However, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), they will use local names whenever a cyclone is within the Philippine Area of Responsibility (PAR).

NOAA has a list of the names for the north west pacific region. At the end of the webpage, in column V of the last table you will see Talim followed by Doksuri, then Khanun. This is why you are seeing Tropical Storm Doksuri just after Tropical Storm Talim.

It appears that Doksuri, which means eagle, Korean, is the replacement name for Nabi. South Korea submitted the name Nabli to the list of typhoon names, but the name Nabi was retired when Typhoon Nabi hit Japan in 2005.

Tropical Storm Doksuri (2017) was initially named Maring by the Philippine authorities.