map projections that minimises differences I have an odd map projection requirement, but I would like a world map projection where even very small countries, like Luxembourg or Belgium are still visible when also showing China and Canada on the same map. The idea is to use this map to show reach and engagement with the hue and therefore a map projection that minimises the area differences would be great as it maximises visibility for small countries for a given map size. Obviously angles, area and distances would be distorted, but as long as the country is recognisable (so not like some maps used in electoral mapping) that is fine. I guess rectangular maps would be great and the highest latitudes can be cut. Any ideas?

I am sorry, but this type of linear map can't exist. You said that you want to minimize differences, so you want to make small countries bigger. But unfortunately, big countries become bigger too (because of linear transformation), so that's not the solution.
I can only think of scaling individual portions of some standard projection. For example, you could scale Europe a little bit because of many small countries. You could also just scale the islands in the Oceania, but not the distances between them. Oops, it seems like we got too far into cheating, but as long as scaling countries to minimize differences is the only thing you want to do, there is no problem. Of course, your decision is the last.
As @KeithMcClary pointed out in his comment, this type of map is called cartogram. Thank you for this useful piece of information!


Would an oceanic asteroid impact really cause a tsunami? As far as I know tsunamis are caused by landslides at the bottom of the sea. But an asteroid impacting the sea is a different phenomena. Could it still cause a "tsunami" as in an unstoppable mass of water propagating towards the shores? Is there a need of distinction between these two phenomena, or do they add up to the same thing?

An asteroid impact in the ocean is an oversized example of throwing a pebble in a pond - both will produce waves in a concentric pattern from the point of impact.

The height of the waves and the energy they would have would depend on the amount of energy the asteroid transferred to the water at the impact sight.

The energy transferred will depend on the kinetic energy of the asteroid at the moment of impact, this being a function of the mass and velocity of the asteroid; based on the classical equation for kinetic energy: $E_k = 0.5mv^2$.

Hence, an asteroid with a very large mass and high velocity could transfer enough energy that could create tsunamis. The best example of this is the impact that created the Chicxulub crater in the Yucatan peninsular, that lead to the creation of the K-T boundary and the extinction of the dinosaurs.

That impact created a mega tsunami that affected the coastal southern state of the USA, from Texas to Florida.


Did climate cool down when underground hydrocarbons stocks formed? As far as I understand, the dominant theory of modern climate change says that recent warming is mainly caused by the massive burning of hydrocarbons that used to be stored in solid form mostly underground as petroleum, coal, etc.

This suggests that the reverse process should contribute to a cooling of the climate (or to a slowed down warming if other processes are at play at the same time).

In particular, a cooling should have occurred throughout the period when the stocks of underground hydrocarbons were formed by the "pilling" of organic remains.

My questions:

Is this roughly what climate theory would predict or am I omitting some things?
Was such an effect observed during the formation of the underground stocks of hydrocarbons?
Can this reasoning be extended to say that a world where no solid hydrocarbons are burnt and the concentration of atmospheric hydrocarbons keeps falling (as it is captured by organism and transformed into solid hydrocarbons) would experience a continuous (if slow) cooling? Or are there some non-linearities by which the stock of solid hydrocarbons would "max out" or the effect of removing carbon from the atmosphere fade away?

Possibly

One thing you have to understand is that natural carbon sequestration via the formation of fossil fuel is VERY slow, it can take millions of years to build up the coal we burn in a day. In addition, one of the more dominant effects on the climate is solar radiance and continental position which changes over such long stretches of time, making matching such slow changes to carbon with climate change more difficult. Continent position also affects carbon sequestration and CO2 concentration directly making it even more confusing. Things like seaways and deserts can have huge effects on CO2.

The real problem is matching coal formation to changes in CO2 concentration.
Most coal comes from the carboniferous and the Permian time periods (along with the evolution of land plants that make it), the carboniferous saw severe cooling and severe drops in CO2. How much of this is CO2 lost to coal versus how much is just the formation of forests and other terrestrial ecosystems combined with changes in contingent positions is still up for debate.

The Permian however saw severe warming near its end and a rapid rise in CO2 at the same time, but most of it was relatively stable and unchanging both in CO2 and temp. It also included one of the largest volcanic events in earth's history, and again changing tectonic position. So although the link between CO2 and temperature is really well established we can't even say for sure such slow coal formation actually reduces atmospheric CO2 concentrations.

source

Compare CO2 above to temp (red line) below. Note that just three variables together predict temprature amazing well.

source


Where can I find archived night microphysics images from EUMETSAT? I I want night microphysics RGB composite from EUMETSAT. I'm looking for archived images. I tried finding them on EUMETSAT's data center page. Data from different channels of SEVIRI is available but composites are not. Any help will be greatly appreciated.

I think only the Day microphysics RGB composite is a standard EUMETSAT product. However, the night microphysics RGB is available from other data portals like the ePort by Eumetrain.org. There you can access and visualize current or archive night microphysics RGB composites. The Java version works better for me, this is an screenshot of how it looks:


Inorganic Limestone and Inorganic Gypsum I read that limestone is made from the compaction of marine animals' bones. But, I am unable to find out why limestone could not have been produced from calcium occurring naturally (5th most abundant element in earth's crust) in the Earth Crust and in the mantle?

Is gypsum also produced from marine animal's bones?

Limestone is a sedimentary rock made up mainly of the mineral calcite (calcium carbonate). It may be made up of biogenic calcite such as shells or inorganic calcite deposited as fine grained "micrite" although some micrite may also have a biological origin.

Animals don't have bones made from gypsum so all gypsum deposits have non-biological origin.


how can a asterisk/star like crack occur on a rock? how can a asterisk/star like crack occur on a hard pyroclastic rock? Could it caused by a meteroite or by some other mechanism?   You may see the shape of the rock on attached photo.

Radial fracture is fairly common. It can form from cooling, drying mud, chemical shrinkage, impact, or several other means.  Since you are looking at volcanics you are probably looking at cooling shrinkage, The interior cools slower which means it shrinks more and that's how your get radial fractures. Fractures form perpendicular to whatever the cooling front shape is, a round shaped lava flow produces radial fractures.

Source


What is the most real-time method of determining SPI? For drought monitoring related to vegetation, I need to calculate Standardized Percipitation INdex for a given area. Where can I find the most real-time percipitation data to do this? The best I've found is CHIRPS data, which has a latency of one month. Is there any freely available data that is more up-to-date?

There are more up-to-date datasets that are available after registration and acceptance of the respective data usage licences.

E.g. two satellite-derived products

GSMaP https://sharaku.eorc.jaxa.jp/GSMaP/
TRMM 3B42RT https://mirador.gsfc.nasa.gov/

For a more comprehensive overview, including evaluation against rain gauge data, see Beck et al. 2017.

Beck, H.E., Vergopolan, N., Pan, M., Levizzani, V., van Dijk, A.I., Weedon, G.P., Brocca, L., Pappenberger, F., Huffman, G.J. and Wood, E.F., 2017. Global-scale evaluation of 22 precipitation datasets using gauge observations and hydrological modelling. Hydrology and Earth System Sciences, 21(12), pp.6201-6217.


Will increased level of ocean acidity lead to more frequent acid rain? Will increased level of ocean acidity lead to more frequent acid rain?

I searched on google and it says acid rain will have minor impact on ocean acidity, but I am not sure if increased ocean acidity will increase frequency.

More likely, it works the other way: increased acid-forming compounds in the atmosphere are the cause of more ocean acidification.
Pio et al. [1] report measurements of sulfur and nitrogen compounds in air masses that they traced to either continental or oceanic origins.  They report that the lowest levels of these compounds were from ocean-origin air masses, indicating that the ocean is absorbing acid-rain causing pollutants such as sulfur dioxide.  Even so, levels of these compounds over the oceans has increased in recent years, likely from increased pollution on land.
In this answer it is noted that increasing acidity can alter the salt composition of the ocean, producing more acidic species (such as $\text{H}_2\text{PO}_4^-$ ions).  However, these tend to remain dissolved in the water rather than evaporate into the atmosphere.
Reference
1.
Casimiro A. Pio, Mário A.Cerqueira, Luis M.Castro, Maria L.Salgueiro, "Sulphur and nitrogen compounds in variable marine/continental air masses at the southwest European coast", Atmospheric Environment
Volume 30, Issue 18, September 1996, Pages 3115-3127.


How does nature dilute Ocean and Seas so that we can swim in them? I have a question about the seas and ocean we swim in. How does the Ocean get rid off all the natural pollutants (for example dead animal debris) and man-made pollutants (human waste, garbage, etc)? I know that there's salt in the water, which helps to kill bacteria, but does salt really do that much? And also, I heard that the Ocean is so big, that pollutants are naturally diluted through the waters, making it safe. Is this true?

Oh, and I don't mean those giant plastic garbage deposits out in the middle of the ocean, I'm talking about our beaches and seas.

I'm asking this because I never see any brownish murky water whenever I go swimming. Any feedback would be highly appreciated. Thanks!

You hit on the main reason why sea water is fairly clean, which is the fact that the sea is so vast. Salt water kills some micro-organisms, but by no means all. The sea is teeming with countless trillions of them, some dangerous but most not. The sea is full of hungry animals which feed on animal detritus. Some of these animals are small, like anemones and corals, and some are large, mostly species of fish and hagfish. Some dead vertebrates like whales sink down into the abyssal ocean depths, where they provide a feast for various deep sea creatures. This has been going on for many millions of years, and many a dinosaur has been eaten and dissolved away by creatures beneath the waves.

The many plants (sea grass and mangroves etc) and algae (seaweeds) also require nourishment, some of which comes from non-biological sources, and some from the excreta and decaying bodies of birds and other animals. Plastic is washed ashore and broken down into smaller and smaller fragments. Some beaches around the word are sufficiently polluted that they are classed as dangerous, and unfit to swim in, but may nevertheless seem to be clean. A few such beaches are in UK, so there must be some in America as well.


Does a climate change big data provider exist? Does a big data provider (Like a Bloomberg, which is the world's leading financial data provider) exist which includes ALL the possible informations and parameters about climate change or in general about environment?

I happened to catch a 60 minutes interview piece on Bloomberg... while the interview was honestly more adulation than journalism, they showed a little bit about the Bloomberg Terminal at times which really caught my eye.  (The transcript has a few details, but the video would hopefully be more thorough... looks like you can watch the full interview here if you happen to have the pay CBS All Access service).  It really seemed like it was a remarkable tool at gathering diverse data together into sort of like a master dashboard or real-time encyclopedia, and making it very flexible and easily consumable.  It seems to be something that could be of amazing use, and I suggest folks look into to get an idea of what can be done with technology applied well, it may spark some creativity and reshape views.  Knowing what that software is about, the questions seems a very valid one, as I'd always be eagerly on the look out for such a comprehensive and thorough collection of unified data on the topic of climate change.

But that said, I'm quite sure the answer is a firm no; such a comprehensive source of climate data likely doesn't exist.

Bloomberg has really done what they've done because the information they're collecting is worth huge value in the markets, and they can then sell that utility for great prices.

But there's likely not such money in most other topics, including much of scientific data.  If there were such tools developed in science, one would think they may well focus more on aggregating and simplifying subjects that are clearly more lucrative, such as genetic data, or detailed medical records, or, if venturing nearer our fields here, oil/mineral data, or perhaps maybe meteorological data, rather than climate data and one particular prong of it (how it is changing/why).

Yes, there's a lot of attention in climate change these days, and so research may well be funded a bit more than it used to be.  But the focus in the study is still really on developing conclusions to convince the public and policy makers, rather than on generating some tangible asset/information that owners could practically apply to thereby excel in some lucrative market field.  While there are indeed some industries with significant connection to the topic, such as energy generation and pollution credits, their focus is generally on gathering the very specific information they need (e.g., wind/solar data/modeling for renewable energy siting, forecasting politics for predicting policy shifts in generation balance and pollution controls, etc).  I've not known anyone to forsee any giant particular financial use of drawing all the climate change data together.  [Then again I wouldn't have imagined that a group like Bloomberg's would have recognized the potential and then had such technological vision and success in culling such wide-ranging access to make something like there tool... until I saw the story)  But it just doesn't seem there are the obvious grand benefits to doing similar for climate change.

The closest I can think of would be IBM's initiative towards meteorological big data.  Others sites like NOAA's Climate Data Online have a few items, and this open data collection appears it may also offer a good starting point.  But overall, it may well more often still come down to tracking down separate specific datasets yourself when getting into more of the specifics.  Of course you're in a good place here to try asking if you decide there's something specific you're after!
But in terms of company by company data, I expect being related to corporate affairs, there's more hope in finding that using Bloomberg itself than in finding another such source built around this specific subject.  There likely are websites that monitor news stories and such.  And there may be at least some separate piecemeal datasets findable on specific impacts to people/countries/industries/etc.

I've indeed found it frustrating for years that even as piles of articles and webpages have been made focusing on climate change, there really still aren't fantastic options that allow typical folks and experts in other subjects to quickly and easily explore the past and current data very flexibly and graphically, more in line with it appears Bloomberg's software is.  Yes, it's still possible for even novices to dig in with enough work, as even this question here at ESSE did a great job of.  But we have miles to go of improvement in such true accessibility.

I do hope if you unfortunately have to go through the painstaking effort to source and gather such data, that you'll take the time to give back as you're able, to help others who come after you!  We really only do advance anywhere by the progress of those who came before us.

Best of luck, and hope the input was at least of some help to you or others somewhere along the way at least.


Understood cause of sea level rise between 1850 and 1950 This question is based on the following graph from a 2018 report by J. Curry.

(I haven't found any peer-review of the report itself so I can't vouch for the validity of its claims, but that's not the heart of the question)

If I understand correctly, an idea developed by the report is that the observed rate of sea level rise during the 1850-1950 period can hardly be explained due to CO2 emissions, as those are barely significant prior to 1950.

The AR5 IPCC report on sea level change doesn't address this directly.

What is the current consensus (if any) on the causes of the observed rate of sea level rise between 1850 and 1950 ?

(To be clear, I don't intend to question the predicted sea level rise at all. This question is unrelated to the IPCC projections.)

SLR is thought to be caused by temperature rise, which is caused by CO2 rise and other factors. Temperature has been rising since before 1850. It could be another Question: "Why temperature does not correspond with CO2 levels since 1850".

  The reconstructions used, in order from oldest to most recent publication are:
  (dark blue 1000-1991): The Holocene.
  (blue 1000-1980): Geophysical Research Letters.
  (light blue 1000-1965): Ambio. Modified as published in Science.
  (lightest blue 1402-1960): J. Geophys. Res..
  (light green 831-1992): Science.
  (yellow 200-1980): Geophysical Research Letters. doi:10.1029/2003GL017814.
  (orange 200-1995): Reviews of Geophysics. doi:10.1029/2003RG000143
  (red-orange 1500-1980): Geophys. Res Lett.. doi:10.1029/2004GL019781
  (red 1-1979): Nature. doi:10.1038/nature03265
  (dark red 1600-1990): Science. doi:10.1126/science.1107046
  (black 1856-2004): Instrumental data was jointly compiled by the Climatic Research Unit and the UK Meteorological Office Hadley Centre.
  Robert A. Rohde,  Creative Commons Attribution-Share Alike 3.0 Unported


Spatial Continuity in python I have data like this of rocks from 3 blast holes:

These are the rock properties of each blast hole of a mining site. The rock properties come from the Block model of that mining site.

I want to calculate the spatial continuity of these blast holes with up to V(X+12) for having 12 r square values. I am trying to program this in python.

Can anyone help me with the logic of how do we go about calculating that for such data?

Thanks

Your last question was easy to answer, this one is more difficult. You could look at correlation and dependence, but you'd be better off looking at variography. That's the easier part of this question dealt with.  Most resource geologists do not deal with correlation & dependence, they do variography studies.

If you are dealing with a small data set to familiarize yourself with the concept of spatial continuity then writing code in any suitable computer language is okay. If however, you are analyzing a large or complex data set use a package which has been created to analyze such data.

To analyze a large or complex data set, the data will first have to be declustered so that data points are fairly uniformly distributed throughout the data set. The other thing that will then need to be done is to establish a three dimension search ellipsoid so that only data within the 3D ellipsoid is considered with each calculation of the variance - the 3D ellipsoid will be similar in shape to a rugby football or an Australian Rules football. The 3D ellipsoid will also have to be able to orientated in a specified search direction. It will then have to be positioned on each declustered data point and geostatistical variances determined for each point - note, the mathematical expression for geostatistical variance is slightly different to the one used by mathematicians - you can blame George Matheron for that.


Now Mars is pulsing 3 times per night in the UV, can anyone explain these waves in simple terms? Do these waves happen on Earth? I link below to questions on another kind of Mars pulse) Phys.org's NASA's Maven observes Martian night sky pulsing in ultraviolet light links to the new paper Imaging of Martian Circulation Patterns and Atmospheric Tides Through MAVEN/IUVS Nightglow Observations in Journal of Geophysical Research: Space Physics.
This seems to be related to long period of waves in Mars' atmosphere.
Question:

Is it possible to explain in simple terms what makes these waves happen?
Is a similar or at least related wave phenomenon detectable in Earth's atmosphere?

A different (and currently unanswered) question about a different periodic behavior in Mars' atmosphere:

How could the solar wind cause strange magnetic pulses on Mars at midnight?

The Martian nightglow comes from molecules in the atmosphere that react with solar radiation, carry it over to the night side, and give off the energy they gained as ultraviolet light as they free-form stable compounds.  From https://www.nasa.gov/press-release/goddard/2020/mars-nightglow:

The diagram explains the cause of Mars’ glowing nightside atmosphere. On Mars’ dayside, molecules are torn apart by energetic solar photons. Global circulation patterns carry the atomic fragments to the nightside, where downward winds increase the reaction rate for the atoms to reform molecules. The downwards winds occur near the poles at some seasons and in the equatorial regions at others. The new molecules hold extra energy which they emit as ultraviolet light.
Credits: NASA/MAVEN/Goddard Space Flight Center/CU/LASP

The Martian nightglow has been used to trace atmospheric circulation on Mars.
As for a similar phenomenon on Earth, and for that matter on planets generally, the above NASA reference goes on to say:

Many planets including Earth have nightglow, but MAVEN is the first mission to collect so many images of another planet’s nightglow.


Is there a time difference between two points at the same longitude but at different latitudes? Assume we have two cities A and B both at the same longitude (say $45^{0}$ E) but at different latitudes say $8^{0}$N and $90^{0}$ N. Can we get a time difference between these two cities. I raised this question because the shape of the Earth is oblate spheroid,i.e., bulges out at the equator and constricts at the poles. In 24 hours the Earth rotates once. But the circle at the equator traversed by the sun is not equal to the high latitudes because of the shape of the Earth. This difference in circle traversed by the sun makes a difference in time between the two latitudes. Am I wrong to put it that way?

To elaborate a little bit, one day is 24 hours and is the period of time during which the Earth completes one rotation with respect to the Sun. We call it a solar day. One complete rotation around the equator gives big circle (longer circumference) and around the higher latitudes makes small circle (smaller circumference). So the time it takes to complete one complete circle around the equator is not equal to the time it takes in higher latitudes. Or are they equal?

Earth's rotation has a fixed angular speed, therefore time is the same across the entire surface.

Even though the tangential speed (speed of the point in the surface) is different in each place of the surface, what counts here is the angular speed (the speed of rotation). Different tangential speed compensate the distance to the rotation axis by:

(angular speed) = (tangential speed)/(distance to axis)


Which particles are classified as PM2.5? How exactly is this defined? Question
When discussing "PM2.5", is there any standardized understanding of which particles are or are not included?
Is it everything that's 2.5 microns and smaller? Or Everything between 2.5 and 0.1 microns?
Likewise does PM10 include all of PM2.5?
And by what method is "size" specified? Is this an aerodynamic size from some kind of inertial impactor configuration (virtual or real), or an optical size from scattering, or something else?
Background
PM2.5 and other classes of particulates are a "hot topic" now. From Wikipedia's Particulates; size, shape and solubility matter:

[...]The 10-micrometer size does not represent a strict boundary between respirable and non-respirable particles, but has been agreed upon for monitoring of airborne particulate matter by most regulatory agencies. Because of their small size, particles on the order of 10 micrometers or less (coarse particulate matter, PM10) can penetrate the deepest part of the lungs such as the bronchioles or alveoli; when asthmatics are exposed to these conditions it can trigger bronchoconstriction.
Similarly, so called fine particulate matter (PM2.5), tend to penetrate into the gas exchange regions of the lung (alveolus), and very small particles (ultrafine particulate matter, PM0.1) may pass through the lungs to affect other organs. Penetration of particles is not wholly dependent on their size; shape and chemical composition also play a part. To avoid this complication, simple nomenclature is used to indicate the different degrees of relative penetration of a PM particle into the cardiovascular system. Inhalable particles penetrate no further than the bronchi as they are filtered out by the cilia. Thoracic particles can penetrate right into terminal bronchioles whereas PM0.1, which can penetrate to alveoli, the gas exchange area, and hence the circulatory system are termed respirable particles. In analogy, the inhalable dust fraction is the fraction of dust entering nose and mouth which may be deposited anywhere in the respiratory tract. The thoracic fraction is the fraction that enters the thorax and is deposited within the lung's airways. The respirable fraction is what is deposited in the gas exchange regions (alveoli).
The smallest particles, less than 100 nanometers (nanoparticles), may be even more damaging to the cardiovascular system. Nanoparticles can pass through cell membranes and migrate into other organs, including the brain. Particles emitted from modern diesel engines (commonly referred to as Diesel Particulate Matter, or DPM) are typically in the size range of 100 nanometers (0.1 micrometer). [...]

From AirNow.gov's Particle Pollution (PM):

Coarse dust particles (PM10) are 2.5 to 10 micrometers in diameter. Sources include crushing or grinding operations and dust stirred up by vehicles on roads.

Fine particles (PM2.5) are 2.5 micrometers in diameter or smaller, and can only be seen with an electron microscope. Fine particles are produced from all types of combustion, including motor vehicles, power plants, residential wood burning, forest fires, agricultural burning, and some industrial processes

However, EPA.gov's Particulate Matter (PM) Basics; What is PM, and how does it get into the air? says:

PM10: inhalable particles, with diameters that are generally 10 micrometers and smaller; and

PM2.5: fine inhalable particles, with diameters that are generally 2.5 micrometers and smaller.

Source

I think answering your questions in reverse will make more sense. The "size" of PM is typically the aerodynamic/inertial impaction size, as you guessed. My standard reference for this is this paper. Their figure 8 is a rough schematic of where particles of different size deposit in the lungs. Things with very large or very small inertial impaction size get filtered out by the nose and upper respiratory system. (The "very small" inertial impaction I would consider as the fuzzy boundary between particles and gases, and gases adsorb onto mucous.) It's the particles with an aerodynamic size smaller than 2.5 microns that follow the airflow all the way from the nose and mouth into the lungs. So from a health perspective, aerodynamic size is what matters most.

Similarly, most measurements of particulate matter filter them by size first, and those filters are based on how much they deflect when the airflow has to curve around a bend. So when measurements focus on PM2.5, that's also anything with aerodynamic radius less than 2.5 microns. They might later do optical scattering or other analysis, but AFAIK the aerodynamic filtering always comes first.

I would say that PM2.5 is everything 2.5 microns and smaller, and PM10 includes all of PM2.5. When scientists want to differentiate the two, we usually use the terms for the different "modes": coarse mode for ~1-10 micron, accumulation mode for ~.05-1 micron, and nucleation or Aitken mode for anything smaller. (Fine particulates are nucleation+accumulation.) The reason for PM2.5 including everything is that PM2.5 standards are focused on the mass concentrations, usually in micrograms/cubic meter. The total mass in the nucleation mode is typically negligible compared to the other two. (The number concentrations particles in the nucleation and accumulation modes might be similar, but the masses are way different.)

Edit: I don't think I made this clear, but the reported air quality value for PM10 would include PM2.5, but if something is reported as "coarse particulates" it would be (PM10-PM2.5). You may also see a quantity TSP - total suspended particulates - which may include things even larger than PM10 that are being kicked up by particularly strong winds, or smoke and ash from nearby wildfires.


Are there anti-greenhouse gases? The Greenhouse Effect can be described semi-formally as follows:

With no atmosphere, virtually all of the heat received by the Sun would be radiated back into space at night.  This can be seen on the moon, for example.
Atmospheric gases have a "greenhousivity" property that traps heat and holds it in.  Some gases have more greenhousivity than others.
Let the value of the weighted average of the greenhousivity values for the mixture of gases commonly known as "air" be arbitrarily defined as 100.
There exist certain gases whose greenhousivity value is so much higher than 100 that adding even a few parts per million to our atmosphere--far below any threshold that would make the air unsafe to breathe--can raise the heat retention of our atmosphere by a non-trivial amount.  These are known as "greenhouse gases".  The two best-known examples are carbon dioxide and methane.

With this understanding, an interesting question arises.  Because the value of 100 for the greenhousivity of standard air is an average for a mixture of gases, this necessarily implies the existence of gases with a value less than 100.  "Anti-greenhouse gases," if you will.  So what's stopping us from pumping a few parts per million of anti-greenhouse gases--some of which are normal parts of air, that we're already well-equipped to breathe--into the atmosphere to counteract the influence of greenhouse gases?

Fundamentally your reasoning is flawed because the major composition of the atmosphere is nitrogen and oxygen.  "Pumping a few parts-per-million" of some other gas into the atmosphere won't do anything to the relative contribution of GHGs to global warming.  GHG's contributions will still be felt the same, regardless of the presence of any other gas.  The "anti-greenhouse gas" that you refer does not exist.  All gases scatter and absorb different wavelengths of light in unique ways, and this all varies by temperature. However, no gas destroys light energy.  A realistic answer is to increase clouds and aerosols, which will reflect more energy back to space before it can be absorbed by the Earth's surface.

Humans now account for the majority of greenhouse gases in our atmosphere.  Regardless if we shut off all our GHG emissions, our climate will still be warm for at least the next century.  Realistic solutions to reduce climate warming include:

grow massive tree farms; increase algae production and forest cover.
stop emission sources
cover disturbed and urban surfaces (and rooftops) in reflective color/material
cloud-seeding (which can also increase snow-cover)
Injecting aerosols/particles into the stratosphere to mimic a major volcanic event


How much will sea level rise if all the polar ice melts? There are many movies about global warming, which say that melting of all polar ice would cause the whole world to suffer a huge flood. According my research (teachers, TV, Internet) people hold one of these two viewpoints:

There will be a huge flood, because the polar ice has a huge volume.
There won't be any flood, because the volume of polar ice is small compared to the whole world.

Which one is correct, if all the polar ice melts? What would be the approximate sea-level change (in meters), if this were to happen?

Using the latest numbers from the 2013 IPCC report (Ch. 4, the Cryosphere), Antarctica contains 58.3 m of sea level equivalent (sle) and Greenland 7.36 m sle. Remaining glaciers provide an additional 0.41 m sle. In total and adding very minor contributions from permafrost etc. the total comes out to approximately 66.1 m sle.

EDIT: Just to be complete: If one by "pole ices" also includes sea or other floating ice apart from glaciers terminating in the sea, the contribution from those components to sea level is zero.


Why is the skyline hazy on the Greek islands? I've recently been to Crete, Santorini and am currently on Ios. I've noticed that there is a hazy-ness when I look out on the sea: there's no definitive line where sky meets sea, they just blur together. I feel like I'm in the Truman Show or Stephen King's Dome.

The sky is so hazy that when the sun sets the last I see is the sun just disappearing into the haze instead of "dropping" below the horizon like I am used to seeing on Lake Superior.

Is this phenomenon due to a high amount water molecules (it's April) in the air, that are too think for the sun to penetrate through as it sets? Or is it something else?

Basically, hazyness mostly comes down to particles in the atmosphere (aerosols). Could be water, could be soot and other exhaust from fires or combustion engines, could be simply dust. Sometimes differences in temperature obscure the horizon, too.

In your case my first guess is dust, most likely from northern Africa, which is blown north, out over the sea.


Why are alkali basalts found at rifting centres and on top of 'plumes', whereas MORBs are generally tholeiitic? So I was essentially wondering why it was that the basalts on top of 'plumes' at 'hotspots' (sometimes called OIBs, ocean island basalts) and at continental rifting centres are enriched in alkaline metals (Na and K) compared to the tholeiitic MORBs.

Also, I was wondering if someone could explain to me chemically why it is that alkali basalts are more 'mature' than tholeiites? I.e. Is it that the ions are more incompatible than the calcium ions found in the tholeiites? Why is this?

Geology/Petrology has proposed some models for the origin of basalts which are based upon chemical evidence from rocks. Modern origin-models have been constrained by isotopic chemistry for some time. I do not claim to be current in this subject, but I believe the conclusions in this classic paper are still accepted as the most likely origin models.

Models of Earth Structure Inferred from Neodymium and Strontium Isotopic Abundances

G. J. Wasserburg and D. J. DePaolo
Proceedings of the National Academy of Sciences of the United States of America
Vol. 76, No. 8 (Aug., 1979), pp. 3594-3598
Published by: National Academy of Sciences
Article Stable URL: http://www.jstor.org

Free copies of this paper are available in several place from the Web. Here is the brief abstract.

  ABSTRACT: A simplified model of earth structure based on the Nd and Sr isotopic characteristics of oceanic and continental tholeiitic
  flood basalts is presented, taking into account the motion of crustal
  plates and a chemical balance for trace elements. The resulting
  structure that is inferred consists of a lower mantle that is still
  essentially undifferentiated, overlain by an upper mantle that is the
  residue of the original source from which the continents were
  derived.


Are lightning storms more common at night? I have, to my knowledge, seen far more lightning strikes and heard more thunderclaps at night than I have during the day.

Are lightning storms more common at night, or are they just more noticeable at night?  If it is significant, my experience is from the Great Lakes region of the US (Western New York state).

Googling, at least for me, has not been fruitful in answering this question.

The answer is dependent on the geographical location. Over sea, there is hardly any diurnal cycle of lightning (this means that there is no time of the day when lightning is more/less often observed).
In continental regions (e.g. Siberia), however, there is a strong diurnal cycle of lightning: it is most common in the late afternoon, and least common in the early morning.
The third type of regions are regions mainly affected by mesoscale systems (as is the Great Lake region in the US): here, there is also a strong diurnal cycle, but the peak (most lightning) is shifted towards the late evening or early morning. Thus, to answer your question: in these regions, there is indeed more lightning at night.

Reference:
Blakeslee, Richard J., et al. "Seasonal variations in the lightning diurnal cycle and implications for the global electric circuit." Atmospheric research 135 (2014): 228-243.


Where is the hot air for Australia's record spring heatwave coming from? Spring/September temperature records on Australia's East coast are set to tumble in the coming days, due to a heatwave, as described here.

So the hot air is being pulled from the interior of the continent to the coast. That makes sense. But some of the towns in the interior of the country are setting temperature records as well. So what is the explanation for why the air in the interior is the hottest on record? What is the ultimate cause of the hot air?

There are 2 causes of record high daytime temperatures: insolation and subsidence. As air is forced to subside, heat of compression adds to insolation. This happens at the poleward margins of the tropical Hadley cells, at or near the latitude where the deserts of Australia are located. Cloud cover (or dustiness in deserts) contributes to record high nighttime temperatures by trapping infrared radiation from the Earth.


What are the approximate dimension of this iceberg? Any chance the ratio is 1:4:9? From 17-Oct-2018 NASA ICE tweet:

I'm curious of the actual dimensions, and if possible a complete photo. And curious in a scifi sort of way if they have a ratio of 1:4:9

  From yesterday's #IceBridge flight: A tabular iceberg can be seen on the right, floating among sea ice just off of the Larsen C ice shelf. The iceberg's sharp angles and flat surface indicate that it probably recently calved from the ice shelf.

from a following tweet (for clarification):

Not likely.

Quoting Kelly Brunt, an ice scientist with NASA and at the University of Maryland, from What the Heck Is the Deal with This Weird, Square Iceberg? at LiveScience.com:

  What makes this one a bit unusual is that it looks almost like a square,

which does not rhyme with anything in your suggested 1:4:9 ratio.

The article mentions the obvious

  And, as with all icebergs, the part visible above the surface is just the top 10 percent of its mass.

but that only tells you that 90% is under water, nothing about its absolute height above sea level.


How is the distribution of Argo floats managed over the Earth's oceans? The BBC News article Climate change: Oceans 'soaking up more heat than estimated' mentions Argo floats as one technology to measure the temperature of the oceans, and links to argo.ucsd.edu where there is the map below that looks surprisingly uniform.
I had thought that an initial distribution of floating objects would, over the course of years, end up clumpy and gyre-bound. Is there something that is actively managing this uniformity, or at least passively maintaining it?
From the UCSD link:

What is Argo?
Argo is a global array of 3,800 free-drifting profiling floats that measures thetemperature and salinity of the upper 2000 m of the ocean.  This allows, for the first time, continuous monitoring of the temperature, salinity, and velocity of the upper ocean, with all data being relayed and made publicly available within hours after collection.
Positions of the floats that have delivered data within the last 30 days :

I think, there are two factors which prevent the forming of clusters of floats:

The floats' lifespan. Batteries supposedly last for four years, then the floats become debris which sink to the bottom of the ocean (yeah, not that great from an environmentalist point of view). So the lifespan of the battery prevents the floats from clustering.
The introdcution of new floats. Derelic floats are replaced by new ones to keep the network working. Naturally, these new floats are placed somewhere in the ocean, where they don't end up immediately in a gyre but will most likely provide the most possible diversity of data.


About the effectiveness of sand-bags Are there any recognized studies on the effectiveness of sand-bags in protecting property in some disaster or flood? Many times on the major news they talk about how sand-bags are used in a flood , how many people 'pull' together and make a great effort to save various properties. The thing is in many such instances the News people do not follow up on whether the sand-bags held. There has been a few mentions of it being successful but they do not mention much if or when the sand bags actually fail. So have there been any official studies in the effectiveness of sand bags?

There have been a few studies related to the effectiveness of sandbags in flood events, these are usually based on observations performed after flood events.  Overall, studies have shown that sandbags only have modest protection in its use as a domestic (1).

A major factor the research shows is that the maximum effectiveness occurs to about 1 metre depth (1), they can, on occasion, hold out in higher flood levels, but as Reeve and Badr (2) determined, leakage between the bags increases rapidly with increasing flood water levels.  However, due to the unique nature of each flood conditions, there is still a large degree of uncertainty as to what effectiveness actually means in terms of sandbags (1).  However, the major degree of effectiveness is highly dependent on the number of rows of sandbags and the duration of the flood (2).

Asides from floodwater height and duration, and height of sandbags, other factors that affect their effectiveness include:

Waves on the flood waters increase instability of sandbag walls/dikes, especially as floodwater depth increases (5).
Ambient conditions - temperature mainly, if low enough - ice could form between the bags decreasing their effectiveness (5).
Speed of flood waters - having eyewitnessing (and being caught in) a flash flood (3), fast moving water itself (and the debris it invariably contains) can severely degrade the effectiveness of sandbags.
The time taken to build the sandbag wall, as well as build up the height of the wall should the flood levels rise.

In reference to the comment about alternatives, one major alternative is preventative action, even though it is impossible to fully protect against floods, particularly large-scale and flash-flooding. After the 2002 floods of the Elbe River in Germany, it was found that household preventative measures lessen the damage from a large scale flood (4).  Related, flood minimalisation techniques are explored including soil bioengineering (6).

References

(1) Botzen et al. 2008 Willingness of Homeowners to Mitigate Climate Risk through
Insurance

(2) Reeve and Badr, 2003 Performance of sandbags for domestic flood defence, Proceedings of the ICE - Water and Maritime Engineering, Volume 156, Issue 4, 01

(3) Worst Queensland Floods In 35 Years 11/01/11 YouTube news clip

(4) Kreibich et al. 2005 Flood loss reduction of private households due to building precautionary measures -- lessons learned from the Elbe flood in August 2002 Natural Hazards and Earth System Science

(5) Raymond, 2009, Wave action and the effects of the environment on sandbag dike performance Thesis - University of Manitoba

(6) Dhital and Tang, 2015 Soil bioengineering application for flood hazard minimization in the foothills of Siwaliks, Nepal Ecological Engineering


Which percentage of $\text{CO}_2$ emissions are human made emissions? I was watching a science/myth Youtube channel (science mixed with a lot of speculative/fantasy content) with 2M+ followers and the Youtuber said volcano made emissions were higher than human made emissions. Now, I thought this was wrong and apparently some figures I saw in articles showed this was wrong, but then, I found this article

Skeptical - Human CO2 smaller than natural emissions

  Although our output of 29 gigatons of CO2 is tiny compared to the 750
  gigatons moving through the carbon cycle each year, it adds up because
  the land and ocean cannot absorb all of the extra CO2.

So this article seems to be stating than in general natural emissions (not only volcano emissions) are indeed higher than human made emissions but human made emission are really bad anyway because they can't be absorbed and break the natural balance.

So now I really don't know if they are higher or lower. Then my question is , which percentage of CO2 emissions are human made emissions? and how volcano only natural emissions compare with human made emissions?

First of all, the amount of carbon cycling trough the Earth's system is irrelevant to the discussion of the changes in atmospheric $\text{CO}_2$ concentration or ocean acidification. In the same way that the volume of water cycled by the filtering system of a swimming pool is irrelevant to the level of the pool. What matters are the net inputs and outputs of water.

Let's look at this diagram of the Earth's carbon storage and fluxes through the carbon cycle.

Figure by Dave Bice at Carleton College.

The total amount of carbon is indeed huge, and the total fluxes add up to almost 700 Gigatons of carbon per year. Note that only ~400 Gt are transferred as $\text{CO}_2$, the rest is organic matter.

The number in the diagram are not precise, but they are very good approximations. The figure given in the diagram for humans burning fossil fules is 6 Gt of carbon, that corresponds to 22 Gt of $\text{CO}_2$, which added to other human made emissions probably add up to something similar to the 29 Gt of the reference you cited.

The amount of $\text{CO}_2$ released by volcanic activity varies widely in time, but the amount given in the figure is an average value, and amounts to 0.6 Gt of Carbon, equivalent to 2.2 Gt of $\text{CO}_2$. But pretty much the same amount is removed by subduction. Therefore, volcanic activity is not a significant LONG TERM source of $\text{CO}_2$. And by long term I mean millions of years.

So you can argue that natural emissions are larger than human emissions. Sure. The respiration of plants and animals produce 8 times more $\text{CO}_2$ than humans, but plants take it back through photosynthesis.

Atmospheric $\text{CO}_2$ have varied widely through Earth's history, but in the last several thousands years it have been pretty stable, because all the sources were in balance with the sinks, leading to a very small net change in $\text{CO}_2$ concentration in the atmosphere and oceans (there in the form of carbonic acid).

However, this balance was disrupted by the industrial revolution and human emissions, mostly due to the use of fossil fuels.

Going back to the swimming pool analogy: evaporation might be tiny compared with the volume of water turned around by the filtering system, but give it long enough time and your swimming pool will be dry.

We added a source of carbon in the carbon cycle, and if we don't remove it or add an equivalent sink (carbon sequestration), the concentration of $\text{CO}_2$ in the atmosphere and carbonic acid in the oceans will keep rising.

Returning to your question, using the figures in the diagram, human emissions would account for ~3% of total emissions. But that doesn't matter at all. The point is that human emissions are the ones upsetting a system that was in balance, and are triggering an increase in atmospheric $\text{CO}_2$ concentrations and consequent ocean acidification.


Why a stratus cloud does not always reach all the way to the ground? The surface of the ground at night cools down because of outgoing long-wave radiation. In my understanding the cooling of the surface also causes cooling of the adjacent air. If the air contains enough water vapor, dropping of the temperature causes condensation of liquid water droplets and formation of fog.

In my region (Central Europe near 50°N) in winter, stratus clouds can be observed much more often than fog. Typically the base of the stratus cloud is 100 meters or higher above ground surface and the thickness of the stratus is several hundred meters. What puzzles me is the "empty" layer between the ground surface and the cloud base. Why does the stratus cloud often not reach all the way to the ground? What factors determine the stratus cloud base height?

I'd postulate that this is purely temperature-driven.

If the dew point temperature of your 'empty' layer is not reached then the water vapour will not condense to form fog.

Do you observe the clouds there during the day? Thin clouds such as stratus primarily transmit incoming solar radiation whilst trapping some of the outgoing long-wave radiation, thus insulating the air between the ground and the base of the cloud layer and preventing dew point temperature being reached.


Vortices in the Atmosphere Sustained only by PGF In a cyclone, the pressure gradient force (PGF) and the Coriolis force sustain the spinning motion and causes the direction of spin (counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere). Are there vortices in the atmosphere which are sustained only by the pressure gradient force?

Tornadoes, land/waterspouts and supercell thunderstorm mesocyclones are examples of vortices where Coriolis is unimportant.  Tornadoes are in cyclostrophic balance.  Land and waterspouts (as well as non-supercell tornadoes) arise from horizontal convergence of vertical vorticity.  The supercell mesocyclone spin originates as horizontal vorticity that is tilted and stretched into vertical vorticity.  These vorticies can spin in either direction in either hemisphere.


What do quasi-geostrophic and ageostrophic mean? I know that geostrophic flow means straight wind flow that is balanced by the pressure gradient and Coriolis forces. But what do quasi-geostrophic and ageostrophic mean specifically?

Ageostrophic winds are merely the component of the actual wind that is not geostrophic.  In other words, given the actual wind ($\mathbf v$) and the geostrophic wind ($\mathbf v_g$), the ageostrophic wind ($\mathbf v_a$) is the vector difference between them.  The ageostrophic wind represents friction and and other effects.  This, for example, is responsible for surface wind crossing isobars rather than following them.

$$\mathbf v_a =\mathbf v - \mathbf v_g$$

Quasigeostrophic refers to a modified set of equations that are make a number of assumptions, approximations and neglecting terms due to scaling.  The equations are only valid for Rossby numbers much less than 1 (Ro << 1)

Some of these include:

neglect advection by $\mathbf v_a$
neglect advection by vertical velocity
neglect the time tendency of $\mathbf v_a$
neglect advection of $\mathbf v_a$ by $\mathbf v_g$
replace $f$ with the beta plane approximation ($f = f_0 + \beta y$)
neglect friction
horizontally constant static stability ($\sigma$)

Starting with the frictionless horizontal momentum equations you end up with a number of "Q-G" equations: a thermodynamic energy equation, a vorticity equation and the omega equation.  The Q-G omega equation:

$$\left( \nabla^2_p + \dfrac{f^2_0}{\sigma}\dfrac{\partial^2}{\partial p^2} \right)\omega =  - \dfrac{f_0}{\sigma} \dfrac{\partial}{\partial p} \left[ - \mathbf v_g \cdot \mathbf \nabla_p(\zeta_g + f) \right] + \dfrac{R}{\sigma p}\left[ -\nabla^2_p(- \mathbf v_g \cdot \mathbf \nabla_p T) \right]$$

The first term on the RHS vertical change in advection of geostrophic absolute vorticity by the geostrophic wind.  Positive vorticity advection increasing with height results in upward vertical motion.  Negative vorticity advection increasing with height results in downward vertical motion. The second term on the RHS is related to temperature advection by the geostrophic wind.  Cool air advection (CAA) correlates with upward vertical motion.

This is the traditional form of the equation and other forms exist to aid in diagnosing vertical motion with specific variables (e.g. the Sutcliffe-Trenberth recasts the equation using the thermal wind and Hoskins et al. (1978) defines the equation in terms of $\vec Q$, "Q vectors").

There isn't much NWP utility to the Q-G equations with todays computers, but they are good for diagnosing vertical motion in hand map analysis.

(will add the QG chi equation here)

Further reading:

Real-time anlyses and forecasts of the QG diagnostic equations
The QG equations (Thanks @DrewP84)
An abbreviated derivation


What's up with the "jelly sandwich" analogy of the lithosphere, asthenosphere and mesosphere? Here's what I know:

The lithosphere is hard because it is cold and low-pressure.
The asthenosphere is more deformable because of higher temperatures and pressures.
The mesosphere is below the asthenosphere and presumably experiences higher temperatures and pressures than the asthenosphere.

Why does the asthenosphere act like a lubricant for tectonic plates to slide over? Why is the mesosphere more viscous than the asthenosphere?

What's causing the differences in the viscosity between these regions, and is there more than viscosity going on?

The introduction to Morgan et al., 2013 has a good summary of the features you are asking about, as well as proposing a mechanism for why it happens.

From the intro:

  The Earth’s mantle underneath the tectonic plates, commonly referred
  to as asthenosphere, is known to be the lowest viscosity region of the
  upper mantle. Several potential mechanisms have been suggested to be
  responsible for this low viscosity zone. These mechanisms...include:
  (1) the temperature and pressure dependence of the mantle rheology may
  lead to a viscosity minimum between 70 and 200 km depth; (2) a small
  and immobile fraction of partial melts may weaken the mantle; (3) wet
  mantle below its dry solidus (deeper than about 70 km) would be
  expected to be weaker than shallower mantle that dehydrated during
  partial melting at mid-ocean ridges (MOR)—but this mechanism does not
  explain the physical origin for the base of the asthenosphere; (4) a
  reduction in mantle grain size within the asthenosphere.

The paper's proposed cause for this is that:

  the sub-oceanic asthenosphere forms because it is the ‘graveyard’ for
  rising (i.e. hotter-than-average mantle) plumes. In this view, below
  the plate-age-dependent 60–100 km-thick oceanic lithosphere there
  exists a pool of hot plume material that has risen as far as the
  overlying thermal and/or compositional lithosphere  will allow.

Whether that mechanism is correct or not, only time will tell. In conclusion, due to the temperature and pressure characteristics of the asthenosphere, it is less viscous than the chemically identical mesosphere. This may be because of its place on temperature and pressure curves, because it contains pockets of partially molten rock, because rising mantle plumes make the asthenosphere actually hotter than the mesosphere, or otherwise.


Hypothetically, what would happen to the earth if a large hole was drilled through the center? This may be a slightly unusual question. I know it wouldn't be possible, but what would the short and long term effects be, if a large (say, 1 mile diameter) round hole appeared, and went straight through the center of the earth, through the crusts on both sides. Would it be different if they opened on land, rather than ocean?

The best place to ask this question is going to be at xkcd: http://what-if.xkcd.com/ but I will give it a shot.

I'm not a geophysicist, but I'll try to give you a reasonable enough answer.
As you said, making such a hole is not possible.

However, let's try to think what if some magical force made a hole 1 km wide and then suddenly released it. This is what the Earth is made of:

(taken from here: http://www.nature.com/nature/journal/v479/n7374/fig_tab/479480a_F1.html)

The easiest part to explain will be to see what happens in the core. Both the inner and outer core are basically made out of impure iron. The liquid iron will just flow into itself and close the hole rather quickly (think about a similar hole in water). The solid iron is also ductile as there high pressures and temperatures, so it will also flow and close the hole. Think chocolate close to the melting temperature. It's still solid, but it moves. Probably some of the liquid iron will manage to flow into the hole of the solid iron, but it will then solidify because it will have to endure higher pressures.

Now, what happens at the mantle? The lower mantle is also ductile and it will also flow under the pressure. You have to remember the the walls of the hole are under huge pressures - 24 to 136 GPa according to the figure. Some things may "fall inside", but remember that it has to fall over hundreds of kilometers while the hole is only 1 km wide.

The upper mantle is where it becomes interesting. This is just thinking out loud though. The upper mantle is where magmas are being formed, and one of the reasons magma is formed is decompression. Usually this happens because of mid ocean spreading or mantle plumes, but removing one side of let's say a cube of rock is also going to decompress it somewhat. This may cause generation of magma. No worries though - I don't see any reason why it should rise to the surface. If anything at all, it's going to fall down through the hole (but not much, see above). Also, decompression may cause release of volatiles or gas, the most common being CO2 and H2O I guess, also H2S or SO2 depends exactly what is down there. Also, the movement of rocks in an area of the Earth that's not ductile anymore but rather brittle (lithosphere) is sure to cause some earthquakes. Are there earthquakes going to be dangerous for anyone? I don't know.

What would this hole look like if you peeked down? My guess that it will be filled with water. If this hole starts at the ocean, then the ocean will just flow inside and fill it. It is possible that some mega waves or tsunamis will accompany it. It will pour down until it either meets the closed rock, or just evaporates. Remember - it's pretty hot down there. It will evaporate and rise, then cool and starts raining down again and you will have a nice convective cell in the upper few kilometers of this hole.

In contrast, if this was not in the ocean but rather on land, groundwater will fill it in. I guess most of the earth has groundwater (maybe except the large deserts, but even there some water exists) that will just flow inside and create a similar convective cell.


What is meant by Monte-carlo simulation? (would like an elaborated answer with some references) I have come up with simulations which involves monte-carlo method that I am not fully aware of. I would be very happy if someone can help me with some references to read and learn.

There are times when any realistic 'answer' has to incorporate some degree of randomness. For example, when interpolating missing data in a rainfall time-series. You can do this 'informally', or through a slightly more rigorous 'Monte-Carlo' approach - there are several possible ways to deal with such problems. J.E. Gentle's book; Random Number Generation and Monte Carlo Methods, is a good read, although being 2003, it's starting to look a bit dated. But it's more than enough to get you started, and then the rest you can do with off-the-shelf software.

Alternatively, as Farrenthorpe points out, the Wikipedia reference may give you all you need to know.


Is it possible for rivers to freeze completely and stop flowing? Is it possible for rivers to freeze completely in the winter and stop flowing?  Are there known examples of this?  If yes, how large can these rivers be and where does the water go?

There are several large Siberian rivers that empty into the Arctic Ocean.

I am interpreting your question as referring to rivers with flowing water freezing as as opposed to glaciers, which are already frozen.

Under current climatic conditions, small rivers can freeze throughout: from bank to bank, surface to river bed. I'm avoiding using the word solid as some people use that word when a river's surface has frozen from bank to bank.

Large rivers do not freeze "through out" because,

  Water, ice, and snow are good insulators and poor conductors of heat.
  The portions of a lake or river that are exposed to the cold winter
  air will freeze into ice and this ice insulates the water below from
  further rapid freezing. Also contributing to the prevention of bodies
  of water freezing solid is an interesting characteristic of water.
  Like most other forms of matter, water become denser as it cools, but
  beginning at about 39°F (4°C) something odd happens - water begins to
  lose density as it gets colder, becoming least dense when it freezes
  into ice. This is why ice floats. As water becomes colder it rises to
  the top, eventually freezing to the layers of ice that are already
  there. Insulation of the water beneath is increased as the ice
  thickens so cooling of the water beneath slows.

From The Great Land of Alaska: Why don't lakes and rivers freeze solid?

Also, while water is flowing its potential energy is constantly being converted to heat energy that resists freezing on the molecular level and subsequent crystallization.

For flowing water to freeze, the temperature would have to be exceptionally cold.


Haean, South Korea: is it of volcanic or meteor impact origin? This is a layman's question. While looking for something I read in the news today, I stumbled upon the Haean region in South Korea (38°17'15.96"N, 128° 7'57.18"E) in Google Earth.

To me it looks either like a caldera or like a meteor impact site. Does anyone know from available facts whether one or the other is true? Wikipedia doesn't say anything about it. Is there any way to tell from the geometric features alone, or does it require taking soil samples from the site?

Interestingly there are some more crater-like features in South Korea (e.g.  37°49'5.12"N, 127° 3'12.53"E, almost perfect circular shape). Can this be considered a result of the proximity of the pacific ring of fire, or is it just too far away?

A Korean here.
Haean Myeon in Gangwon-do has two theories of creation. One is Meteor impact and another is differential erosion. There were no meteor related evidence found at Haean so the erosion theory is more agreed upon at the moment.

Direct translation from introduction website for Hae An:

  According to the analysis of the granite of the punchbowl basin [nickname for Haean], it consists of 71% feldspar, 22% quartz and 5.7% mica. Feldspar is much more weathering than quartz and mica, and since it is rapidly clayed at room temperature, the lowland is eroded earlier than the current highland with high resistance to weathering, resulting in this unusual branching form.


Why does volcanic dust pose such a hazard to air travel? What properties does volcanic ash have that make it a hazard to aircraft jet engines which are not posed by other sources of atmospheric dust, such as Saharan dust? Is it merely a question of atmospheric concentration or relative height?

Particle size is the key issue. Saharan loess (wind-blown dust) must have a small enough particle size that it can be lofted by ordinary wind speeds: typically, it is in the 20-50μm size range.

Particle sizes lofted into the upper atmosphere during explosive volcanic eruptions can be much higher: "The explosive ash was bimodal in size distribution with peaks at about 25- and 200-μm diameter... For the
typical ash, diameter peaked at approximately 500μm" (Gislason et al., 2011), though this effect only has particular significance in close proximity to the vent.

The risk to aircraft is explained:

  Fears about danger to aircraft arose from an incident when a British Airways 747 flew through an ash cloud during the 1982 eruption of Mount Galunggung in Indonesia. The pilot reported sparks from the windows and wings as ash sandblasted all surfaces and all four jet engines failed when melted ash coated their interior.

(There's an absolutely classic paper on this, and a lot of the literature is well worth a read for the sheer understated "well, yep, that was a problem.")

In fact the ash lofted across Europe following the Eyjafjallajökull eruption was mostly below 63μm in diameter, since that's what can persist without rapidly sedimenting out, but the explosive nature of the initial eruption meant that "... even the nanoparticles are far from round. Their sharpness makes them particularly abrasive." In contrast, loess has been extensively weathered. The authors add: "The very sharp, hard particles put aircraft at risk from abrasion on windows and body and from melting in jet engines."

For more details on volcanic ash and turbine engines, see Gunn & Wade and, for that matter the rest of the volume.


Should Imilac (meteorite) be singular or plural? I first saw the term "Imilac meteorite" in this BBC News article. It shows a photograph of a meteorite on display along with the caption:

The Imilac meteorite was found in the Atacama Desert in Chile in 1822.

I then looked it up in Wikipedia's article Imilac and saw:

Imilac is a pallasite meteorite found in the Atacama Desert of Northern Chile in 1822.

Both of these sound like there is one meteorite, and it's is called the Imilac meteorite.
But then the article goes on to say:

Classification:
Imilac is classified as a stony–iron pallasite. Imilac specimens are highly prized by meteorite collectors due to its high concentration of beautiful olivine grains.
Strewn field:
Numerous masses were found in a valley to the SW of Imilac. The total weight of the Imilac fall is estimated to be around 1,000 kilograms (2,200 lb). The primary strewn field is long about 8 kilometres (5.0 mi).

There seems to be multiple, distinct specimens, and yet I don't see "Imilac meteorites" (plural) written here or anywhere. For example, in this British Natural History Museum article The Imilac meteorite: a gem as old as the solar system:

Pallasite meteorites like the Imilac formed in the asteroid belt, located between Mars and Jupiter. They are made up of minerals and metal, remnant materials from the first few million years of the solar system.
They formed inside asteroids at a time when planets were only just coming together.

So are all of these Imilac specimens believed to be fragments of one single object that exploded before reaching the surface? If so, why not call them Imilac meteorites (plural) instead of talking about "Imilac meteorite" as a name for a material that is uncountable?

Without knowing if there's an official statement on that, I can give my common sense opinion.

These are fragments that came from one single meteorite, or one single
"formation". Let's say that we have a basalt flow, let's call it the Michael Basalt. It's fragmented, right? So there are a bunch of pieces of it. If I collect the pieces, those are still several pieces of the "Michael Basalt". If I would refer to basalts instead, that would imply that there were several flows, not only one. But there is one. So I have several samples of the singular Michael Basalt. Therefore, there are several samples of the singular Imilac meteorite.


In the past, why did the levels of individual greenhouse gases rise and fall at the same time? According to ice core samples from Vostok in Antarctica, methane and carbon dioxide levels seem to have risen and fallen at around the same time over a 450 thousand year period.

I was unable to find any article or explanation on why the levels of individual greenhouse gases in the past seem to coincide. Could someone please offer an explanation for this?

CO2 and methane both have natural feedback loops that can cause increasing temprature to release more of both, which in turn causes more warming which causes more release and so on and so forth. This is one of the big worries about human caused greenhouse gasses, that they will trigger these feedback loops causing far more drastic warming. Negative feedback loops also exist so making it colder can trap more or release less of these gases. I will give a few examples of those feedback loops.

Methane hydrates, A lot of the seafloor has methane hydrates trapped in the sediment, if you warm that material it releases methane gas, a lot of it. This material builds up very slowly but can be released very quickly, so there is plenty available to warming water to release. Higher pressure can mitigate this but the temprature has a stronger effect than pressure from rising sea levels. Of course if you cool the sea more of this methane is trapped as hydrates reducing the amount in the atmosphere.

Permafrost also contains methane hydrates and other organics, the cold and ice keeps them inactive and trapped but warming it triggers the release of both methane and trapped carbon (which is released as CO2). so as the polar regions warm the release out these stored gasses, if they get colder they trap more it.

Biology, there is a really interesting feedback loop in microbial life, ocean and wetland life in particular respond to warmer temperatures by releasing more CO2(or absorbing less), how much is difficult to estimate but that they do increase CO2 has been repeatedly confirmed even if weak on a geological time scale this will quickly add up.

This effect is much stronger in wetlands and wetlands have the additional effect of releasing more methane with warming temprature at the same time, Methanogenesis. additionally  they also convert CO2 into methane and how much is based on CO2 concentration and temprature, so increasing CO2 will result in more methane directly.

Ocean circulation, warming the planet changes ocean circulation patterns, and the current pattern with a lot of mixing due to wide differences in temperature. is really good at absorbing methane and CO2 into sediment and microorganisms. warmer oceans result in less mixing which means less gases released by other means getting absorbed.

On a geologic scale the movement of continents can affect all of these, so that adds one more thing that will tend to change both in the same ways.


Break in human nitrogen input in 1990s I'm in an AP Environmental Science course, and while reading part of the chapter in my textbook about the nitrogen cycle, I saw this picture.

What I was wondering is what caused that dip in the nitrogen input in about 1995? I've researched online, but I haven't found anything.

First, don't take that graph too literally, it is just a cartoon version and isn't quantitatively correct.

The USSR heavily subsidized fertilizer until 1988.  When they ended the subsidy, fertilizer prices increased to market prices and use of fertilizer decreased.  Fertilizer use decreased further after the USSR fell a couple years later.

Fertilizer use in France, Germany, UK and Japan peaked in the 1980s and contributed to the decline.


Circular rain cloud observed in rain radar This circular rain pattern was observed in Sydney’s rain radar today. It remained for the entire loop, wiggling around a bit but mostly staying in the same place.

The fact that it’s centred around the radar made me suspect it is some kind of artifact. Is that the case? Or this this real? If it’s real, why would it look like that?

A way to check if those clouds and precipitation are real is to check the same area and time with another radar.

This is the image loop of Sidney (Terrey Hills) radar for the same time (the same you used). It shows the same pattern than your image. In the animated images that arch centered in the radar looks even weirder.

This is the image loop of Newcastle radar for January 17th, which in great part overlaps the Terrey Hills radar image. It shows an arched pattern, too, and with similar radius, but this one is centered in Terrey Hills radar instead of the Newcastle radar.

Therefore, since those patterns are different for each radar, I would say that they are artefacts, and that both radars suffered from the same kind of artefacts.

Interestingly, that kind of artifact seems consistent with the situation explained in dplmmr's comment: if both radar were just scanning an individual elevation angle (the same angle for both radars) and precipitation were just in a range of heights, we could expect that kind of pattern.


Using accelerometer as a seismograph I'm using ADXL345 accelerometer with Raspberry Pi to build a seismograph. I've successfully hooked it up and can plot the accelerometer data in three axis. Is there any way to express these data in the form of the magnitude of an earthquake, of course, at the point of sensing? I know that it might be imprecise, but any representation would be helpful (e.g. Richter scale), and how to accomplish that.

The magnitude of an earthquake is related to the total energy released, therefore to estimate it from a seismogram you need to know the distance to the source. In the case of the Richter scale for example, the relationship between magnitude and seismogram amplitude is defined for a standard distance.

If you have only one seismograph, you can not triangulate the location of the source (hypocenter). Therefore, you can not estimate the magnitude of a seismic event (Richter or moment magnitude).

But you can estimate the local seismic intensity of the event at the particular location of your instrument. With the accelerometer data you can easily measure the peak ground acceleration, that can be used to estimate the intensity in any of the existing scales. For example, the peak ground accelerations associated to each intensity level in the commonly used Mercalli intensity scale are:

Those g values would be easy to calculate with the accelerometer data and proper calibration constants.

Table taken from the Wikipedia page for peak ground acceleration

You might want to have a look at this question. There are some nice answers and references that you might find useful.


Can you please help me to identify this thing I found inside a rock in the Almanzora riverbed Spain Can someone please help me identify this thing I found inside a rock in the Almanzora riverbed Spain

Read below for my initial response which was incorrect. My revision is: It is not an ammonite. It is a gastropod of the genus Cepaea, family Helicidae. I do not know the species, unfortunately.

My initial response, which is incorrect; I've kept it here for future reference:
What you found is a small fossilized sea creature known as an ammonite. Ammonite were a squid-like creature that had tenticles and a spiral shell. They existed from the Permian (300 million years ago) up to the end of the Triassic (65 million years ago) and are some of the most common fossils found.
The specimen you have resembles the species Simoceras.

http://www.thefossilforum.com/index.php?/gallery/image/44911-simoceras-lytogyroceras-subbeticum/


What drove the Puy de Dôme volcano? The Puy de Dôme is an extinct volcano located pretty much smack in the middle of France. It last erupted some seven thousand years ago, which in geological terms is fairly recent - prehistoric humans might even have born witness to that eruption! What I'm wondering, though, is what drove this volcano, seeing as it is not located where tectonic plates meet? Was there a hot spot underneath central France that powered this volcano, and if so, could we witness future volcanic activity in this region?

According the an Oregon State website,

  Volcanism far from the edges of tectonic plates, such as Chaine des
  Puys, is rare. Changes in the mantle may have led to volcanism at
  Chaine des Puys. Several lines of evidence indicate thinning of the
  crust and upwelling of the asthenosphere. The rising mantle "diapir"
  was probably a total of 30-60 miles (50-100 km) in diameter.

Chain des Puys is the 40km long chain of volcanic features to which Puy de Dome belongs. It sounds like the causes are not completely understood. Unfortunately, all the papers I could find on the topic are in French (understandably), so if you can read French you can try Google Scholar to see if there is more info there.


Atmospheric Carbon: Whence the discrepancy? The news tells us that global carbon emissions are now more or less constant, as in the 2014-16 data points of Global carbon emissions flatline continues.

On the other hand, the Keeling graph of mean global CO2 keeps climbing upwards.

So clearly there is some feedback which continues to put CO2 into the atmosphere, for at least 3 years after the emissions plateau. What is the source of this feedback? Is it one dominant process or a multitude of lesser feedbacks?

There's no discrepancy here.  The first graph (total emissions from fossil fuels and industry; Fig. 4a of Le Quéré et al, 2016) is an input to the system, and the second graph is a proxy for the amount stored in one part of the system (the atmosphere).  For the latter, it probably makes more sense to look at the total atmospheric growth rate (Fig. 4c of Le Quéré et al), which has remained positive for decades.

Note that when you add in emissions from land-use it's likely that the total emissions have continued to increase.  But that doesn't detract from the main point here: if you keep putting stuff in the bucket, the amount in the bucket will continue to increase.  You don't need to invoke any feedbacks for that to happen.


What exactly is ammonite? I miss the definition of ammonite. In my opinion, many authors confuse the term "Ammonite" and "Ammonoid". Ammonoids (Ammonoidea) are large group of cephalopods including for example goniatites (Goniatitida), ceratites (Ceratitida) and ammonites (Ammonitida?).

EDIT: If you think that ammonites and ammonoids are the same, you are not right. Notice that researchers try to avoid using the term ammonite when talking about paleozoic ammonoids. Ammonites are usually refered to jurassic and cretaceous ammonoids.
"While goniatites proliferated during the Carboniferous, ammonites thrived in Mesozoic times."
https://www.researchgate.net/publication/262048294_Goniatites

But how can we strictly define "true ammonite"? Is it because of the ammonitic suture? This way, many triassic, jurassic, creataceous and possibly paleogenic (danian) ammonoids could be called true ammonites, because they have complex (ammonitic) sutures.

Can we call all jurassic and cretaceous ammonoids (phylloceratina, psiloceratina, lytoceratina, ammonitina, haploceratina, perisphinctina and ancyloceratina) ammonites? Can you show me where ammonites are on phylogenetic tree?

There is no strict definition of ammonites

Ammonites are not strictly defined. One can reffer to ammonites as to the whole group of ammonoids (Ammonoidea, ammonites sensu latto). This is common, but not supported by most researchers. Researchers use the term "ammonoid" for paleozoic ammonoidea and "ammonite" for Jurassic and Cretaceous Ammonoidea (ammonites sensu stricto). Ammonites sensu stricto reffer to ammonoids with complex (ammonitic) sutures, which are typical for Jurassic and Cretaceous ages. However, complex ammonitic sutures are not exclusive for Jurassic and Cretaceous ammonoids. Ceratitic sutures are not exclusive for Triassic either and occur in Jurassic ammonoids, too.

  So caution must be exercised when using suture lines as a means of classification. To obviate some of the problems posed by this
  simplistic classification, Wedekind, in 1918, introduced the terms
  palaeo-, meso- and neoammo-noids to classify ammonoids better.

(PDF) Goniatites. Available from: https://www.researchgate.net/publication/262048294_Goniatites [accessed May 10 2019].


Is there a standard definition of a "dry-down" event in hydrology? When studying the land surface, dry-down periods - periods after rain where the soil moisture is decreasing due to evapotranspiration and drainage - are of great interested, because soil moisture has such a strong effect on nearly every aspect of the land surface (carbon uptake, heat distribution, albedo, etc. etc.).

Obviously dry-downs at different time-scales (and different soil depths) are of interest for different processes. But I was wondering if there was any kind of standardised method for defining dry-down periods. e.g. is it relevant how much rain happened before the event? Or does a small shower in the middle of a long dry-down nullify the event? Or is it all arbitrary and defined differently for each individual piece of research?

Dry down is mainly dependent on the speed where a local water storage would be depleted, considering those components extracted from the simplified water balance equation

water input (precipitation)
local drainage capacity (runoff, infiltration, percolation)
evapotranspiration
storage change and capacity (pores in the rock and soil)

To generalize your question

  is it relevant how much rain happened before the event?

I would say yes, as all input / output and potential changes in the storage need to be taken into account to calculate the balance, and ultimately the moment of depletion of the reservoir and thus the beginning of the dry-down.

Antecedent conditions are of an utmost importance when estimating a dry down moment.If the storage was relatively empty prior to a rain event, it could take a lot of input to recharge it, this without neglecting the other factors.

To translate as an example, a huge rain event when the reservoir was empty prior to the event could recharge the reservoir and provide some surface runoff. A similar rain event when the reservoir was half-full prior would recharge for a while and then flood the area because of the important water excess.

This is dependent on the climatic zone (ex Köppen classification), say a warm and dry desert region will have a quite different balance than a polar region, because various input sources and different underground geophysical properties. Yet, within each regions, much variability will be encountered locally, depending on

the ground/soil porosity (sands or weathered rocks can store more water. A clay layer will prevent downward infiltration)
the presence/absence of vegetation (vegetation facilitate percolation/infiltration)
the temperature of the soil : permafrost hydrology is quite complex - generally cold permafrost have a poor drainage capability
maybe a floodplain will contribute to ground recharge one year, but maybe not the next, depending on the current year precipitations and antecedent conditions
plus many other factors etc...

It may be possible at the scale of a single watershed to do a prediction model on the probable schedule of a dry down - or a restricted land unit, because a lot of drilling and geophysical all around surveys would be necessary to know the ground properties, the storage properties. Also a couple of monitoring station (discharge) at higher stream order segments would be required. Rain meters stations too. Moisture would be monitored in representative ground units.

But this would apply locally, and be hardly exportable at a larger scale, in my opinion. I would go with this statement of yours:

  Or is it all arbitrary and defined differently for each individual piece of research?

yes generally


What's the prospect of air quality forecasting based on machine learning? Air quality forecasting  models which are useful for atmospheric scientist and government can be built based on numerical theory or statistic theory.

The first approach outline the basic physics & dynamic process, chemical reaction of true atmosphere and the various kind of emission. The second approach use statistical tools to capture the pattern of historical meteorology, air quality dataset and train a predictive model. With evaluating the model for unseen data instances predicting, it can be used for air quality forecasting.

Many researchers choose numerical models to achieve their target as computation results based on the emulation of real world, could reproduce spatial-temporal variation of pollutants to some extent.

Machine learning is becoming the cutting-edge of data science even in all scientific field and showing its great ability in non-linear problems(secondary pollutants(O3, SOA, etc) are formed through non-linear chemistry reactions).

What are the possibilities to use a machine learning approach to improve air quality forecasting?

While the prospects are more of an economic question, I can answer that there is at least one study using machine learning methods (https://etda.libraries.psu.edu/catalog/13561nvb5011).

There are problems such as the attribution of error to physical processes are not feasible, the spatial extent of the model is very limited, the accuracy of the model is dependent on the history and integrity of the data, etc. Perhaps a hybrid, some sort of Model Output Statistics could be formed, but this would be doubly expensive.


Who are winners from the global warming? Are there any? As a person living in Russia, I always had mixed feelings when hearing appeals to fight global warming. On the one hand, I completely understand that it is going to be a disaster for lots of people. On the other hand (a more egoistic one), it seems like it would be good for my country if the temperature would rise by a few degrees. The average temperature will become more comfortable for living in most Russian cities and Siberia may become more habitable. However, I might be overlooking some effects like coastal area flooding, damage to infrastructure or changes in flora or fauna.
This makes me wonder, who might actually win from the global warming? Is it just all cold countries (Russia, Canada, Scandinavian states, Iceland, etc.), or only part of them, or maybe everyone will lose?

Global economic costs of natural disasters:

In the period 1998-2017, disaster-hit countries reported direct
economic losses of 2,908 billion dolars of which climate-related disasters
accounted for 2,245 billion dolars or 77% of the total.
This compares with total reported losses for the period 1978-1997 of 1,313 billion dolars of which climate-related disasters accounted for 895 billion dolars or 68%.
Source: undrr.org

The economic figures are frightening and climate change has been shown to increase these events all over the world. It is difficult to claim for specific countries winning anything at all with global warming after this introduction.
Your assumption "...Siberia may become more habitable." is proven false. Science find more extrem winters in East Asia and Europe after CC, even the average temperature raises and winters become shorter (emphasis mine):

Our simulations with the ECHAM5 general circulation model demonstrate that lower‐troposphere heating over the B‐K seas in the Eastern Arctic caused by the sea ice reduction may result in strong anticyclonic anomaly over the Polar Ocean and anomalous easterly advection over northern continents. This causes a continental‐scale winter cooling reaching −1.5°C, with more than 3 times increased probability of cold winter extremes over large areas including Europe. Our results imply that several recent severe winters do not conflict the global warming picture but rather supplement it.
Source: A link between reduced Barents‐Kara sea ice and cold winter extremes over northern continents", Climate and Dynamics, cited in Expect more extreme winters thanks to Global Warming, say scientists, Independent.

It could be debated the global beneficts of the opening of sea routes if the Arctic melts, but the costs all over the globe would exced the beneficts if we arrive to that scenario (economic looses due to floods in coastal cities among others).
At a regional and local scale some industries may benefict from CC:

Places where summer heat atract new tourists.
New agricultural products adapted to heat.
....

But the costs for the region again far outweigh the benefits.
In the first case the region will encounter problems as desertification, availability of water, biodiversity loss, ....
The second case imply the ruling agriculturists loose their crops; as an example imagine what Bordeaux can win planting oranges instead of his known red wine despite some opportunistic individual may do fortune with it (...).


Why are deserts hotter than other places on Earth We all know that deserts are the hottest places on Earth, but what makes them different from other parts of the world?

We all know that deserts are the hottest places on Earth.

That is not necessarily true. What is true is that the hottest places on Earth are in deserts. Note the reversal. Much of the Arctic and Antarctic are technically deserts due to extremely low precipitation. Excluding these polar deserts, some deserts are quite cool, even if they are close to the equator. For example, Arica, Chile (the driest inhabited locale in the world), has a rather mild climate temperature-wise, despite being at 18°29′ south latitude. This is the case for much of the Atacama desert.

What makes them different from other parts of the world?

I'm assuming you are asking about those deserts that are hot in the summertime rather than deserts in general. A key ingredient for extremely high temperatures is a desert, but not a high latitude desert, high altitude desert, or coastal desert.
Very low precipitation is what distinguishes desert from non-desert biomes. Lack of precipitation is not sufficient for very high temperatures, as exhibited by the very cold polar deserts and the rather cool deserts that are well outside polar areas. Much of the Atacama is at a high altitude, as are the Gobi in China and Mongolia, the Taklamakan in China, and the high desert in the Mexico and the US. While some of these deserts can be hot during summer, they aren't ridiculously hot. Areas along the coast of the previously mentioned Atacama desert and the Namib in Africa are kept somewhat cool by ocean breezes. These coastal deserts can be uniformly mild year-round.
What is needed to create the possibility for extremely high temperatures is a desert that is not at extreme latitudes, that is well removed from coastal cooling, and that is at low altitudes. A desert is needed so as to receive the full brunt of solar radiation. Equatorial regions don't work because they tend to be cloudy and rainy. High latitude areas don't work because they don't receive very much insolation. High altitude areas don't work because temperature tends to decrease with increased altitude.
A low altitude desert in the horse latitudes is exactly what is needed, and this is why Furnace Creek in Death Valley, California (supposedly the hottest place in the world) and Tirat Zvi, Isreal (supposedly the hottest place in Asia) can be very, very hot. The horse latitudes are where the Hadley cell and mid latitude cell converge, creating long-lived high pressure areas where rain is highly unlikely. Most of the world's non-polar deserts are in or near the horse latitudes.
Even better than Furnace Creek are those areas that are so ridiculously hot that nobody sane would live there and hence there are no weather stations. We don't know, for example, how hot it gets in the Lut desert in Iran. It's too hot there for people to fathom, and is almost certainly hotter than is Furnace Creek.


Could we sequester CO$_2$ by dumping forests in deep oceans? We know that trees are the most efficient "tool" we have to get CO$_2$ out of the air, but the problem is that most of their fixated CO$_2$ will naturally reenter the carbon cycle through decomposition.
Would it be possible to remove this carbon by sinking the trees deep underwater (and possibly putting some rocks / sand on them)? How effective would this be, if at all?
(I was unable to find any studies on this, if there are please point my to them.)

Update: I found a study regarding wood burial on land, for those interested. This might or might not be easier than under water, are there are any field trials either way? https://cbmjournal.biomedcentral.com/articles/10.1186/1750-0680-3-1

So, there's really two questions here.

1) if we were to take wood and store it in a way that prevents decomposition, would this help reduce atmospheric CO2? and

2) Would sinking it into the bottom of an ocean trench achieve this?

So, first things first, yes removing wood from the contemporary carbon cycle does reduce atmospheric CO2. We already do this (at least temporarily) by using timber for making things - depending on the type of product this has a half-life of anything from a couple of years (paper or biomass fuel) to about 50 (for sawlogs). You can achieve a similar effect by planting new forests - so carbon is locked up in living biomass.

We could come up with a more permanent solution, and this would have to be economic (and not require more CO2 emissions to accomplish than we saved in the first place). Current research is looking at sequestration of carbon as charcoal (as this is more biologically stable than wood which is a source of food for a lot of species). This can either be spread on the land as biochar, or I suppose buried terrestrially - I'm thinking of abandoned coal mines.

I'm not aware of deep sea storage as a widely considered option, and I suspect that this is mainly due to the techno-economic cost, and lack of research - the debate is still ongoing for many other more established carbon sequestration technologies. I don't believe there has been much investigation into the stability of wood in deep water (though it lasts for thousands of years in anoxic peat bog conditions - so I see no obvious reason why it wouldn't work).