Science of gasses in Earth atmosphere.

[Erina]

I read the following comment on a Telegraph article about Hydrogen power, and the conversation swayed on to Global Warming, and wanted to know if what was written was factually true:

The most abundant greenhouse gases in Earth's atmosphere in decreasing order are water vapor, carbon dioxide, methane, nitrous oxide, ozone, Chlorofluorocarbons, Hydrofluorocarbons and Perfluorocarbons.

Some points that may be of interest:

• Without any greenhouse gases, the average temperature of Earth's surface would be about −18 °C, rather than the current average of 15 °C.

• The atmospheric concentration of carbon dioxide has increased by almost 50%, from 280 ppm in 1750 to 419 ppm in 2021. The last time the atmospheric concentration of carbon dioxide was this high was over 3 million years ago.

• Carbon Dioxide is only 0.04%, and the other greenhouse gases only make up 0.1% of the Earth’s atmosphere. 

• Water vapour is the main greenhouse gas element, but it would be hard to live without clouds and rain. It contributes between 36% to 72% to the greenhouse gas effect. Carbon dioxide contributes between 9% to 26%. Methane contributes between 4% to 9% and Ozone 3% to 7%.

• Water vapour only has a ‘residency’ of about 9 days. The other gases stay in the atmosphere for much longer. Thus, the other gases have a much greater impact. This is the reason why carbon dioxide, methane and nitrous oxide are targeted as they have greater concentrations than the fluorocarbons and stay much longer in the atmosphere than water vapour. 

• Some gases have a cooling effect, such as sulphur dioxide. Unfortunately, sulphur dioxide (along with nitrogen dioxide) caused acid rain and has been removed from emissions to reduce the impact of acid rain since the 1970s. perhaps the reduction in sulphur dioxide is part of the global warming problem. But putting sulphur dioxide back into the atmosphere is not a good idea.

 

It's not the political position that I am interested in, just the science. Also, if anybody can reference to a primary source on these points that would save me the trouble

[studiot]

9 hours ago, Erina said:

It's not the political position that I am interested in, just the science. Also, if anybody can reference to a primary source on these points that would save me the trouble

OK so the Telegraph has done its job as a respectable paper pretty well.
These figures concur with other sources I have.

In particular my Cambridge Handbook of Earth Science Data (mine is the first ed 2009), which gives all sorts of tables of useful data on   - well Earth Science

In the chapter on the atmousphere it lists much more comprehensive composition data, including non gaseous components such as dust and volcanic input.

It also references other reputable sources such as NOAA, The UK Met Ofice, standard texbooks on Geochemistry, Chemistry and Physics.

Amongst many other data tables, it offers a table of of the energy fluxes between the Earth and its atmousphere that may be a useful addition to your Telegraph data.

 

Just a small point about you Telegraph data.

The difficulty with the  halocarbons is not the greenhouse effect, but their chemical action high in the atmousphere to deplete the ozone layer which proctects us from harmful high energy solar radiation.

 

[exchemist]

10 minutes ago, studiot said:

OK so the Telegraph has done its job as a respectable paper pretty well.
These figures concur with other sources I have.

In particular my Cambridge Handbook of Earth Science Data (mine is the first ed 2009), which gives all sorts of tables of useful data on   - well Earth Science

In the chapter on the atmousphere it lists much more comprehensive composition data, including non gaseous components such as dust and volcanic input.

It also references other reputable sources such as NOAA, The UK Met Ofice, standard texbooks on Geochemistry, Chemistry and Physics.

Amongst many other data tables, it offers a table of of the energy fluxes between the Earth and its atmousphere that may be a useful addition to your Telegraph data.

 

Just a small point about you Telegraph data.

The difficulty with the  halocarbons is not the greenhouse effect, but their chemical action high in the atmousphere to deplete the ozone layer which proctects us from harmful high energy solar radiation.

 

I don't think your last para is entirely right. HFCs, which have been widely used to substitute for the ozone-depleting CFCs and HCFCs phased out under the Montreal Protocol, are actually very potent greenhouse gases. So now there is a drive to replace these too as refrigerant fluids, with things like ammonia, CO2 and hydrocarbons.  

[Ken Fabian]

Should keep in mind that long term change to atmospheric water vapor content is a feedback induced by change in GHG's - because warmer air holds more water vapor. For each measure of enhanced greenhouse effect from increasing any other GHG's water vapor adds two more measures, so causal attribution of the warming induced is to the other GHG's, not water vapor.

This gives estimations of the climate change forcings in play (from IPCC AR6 SPM)-

 

[Erina]

It was actually a scrape from the comment's section. I rarely read the Editorial.

I thought that it would be a little bit much to digest, so to start with Carbon Dioxide, everybody's favourite:

The most abundant greenhouse gases in Earth's atmosphere in decreasing order are water vapor, carbon dioxide, methane, nitrous oxide, ozone, Chlorofluorocarbons, Hydrofluorocarbons and Perfluorocarbons.

You mention that the above is conducive with Cambridge Handbook of Earth Science Data (c2009).

This data then places Carbon Dioxide at the bottom of the elements in the atmosphere ?

The poster focused on this:

The atmospheric concentration of carbon dioxide has increased by almost 50%, from 280 ppm in 1750 to 419 ppm in 2021. The last time the atmospheric concentration of carbon dioxide was this high was over 3 million years ago.

I found the following from the MetOffice, which put CO2 at around 400ppm: https://www.metoffice.gov.uk/research/approach/monitoring/atmospheric-trends/gases-and-trends/carbon-dioxide

But where do I get hold of the primary source to confirm this ?

The following could perhaps be confirmed by your Cambridge Handbook:

Carbon Dioxide is only 0.04%, and the other greenhouse gases only make up 0.1% of the Earth’s atmosphere.

Where it gets interesting is when touching on water vapour:

Water vapour is the main greenhouse gas element, but it would be hard to live without clouds and rain. It contributes between 36% to 72% to the greenhouse gas effect. Carbon dioxide contributes between 9% to 26%.

If switching to a Hydrogen based energy production, with water vapour being the ejected gas, then wouldn't it be worse than sticking with what we're using now ?

[studiot]

1 hour ago, Erina said:

It was actually a scrape from the comment's section. I rarely read the Editorial.

I thought that it would be a little bit much to digest, so to start with Carbon Dioxide, everybody's favourite:

The most abundant greenhouse gases in Earth's atmosphere in decreasing order are water vapor, carbon dioxide, methane, nitrous oxide, ozone, Chlorofluorocarbons, Hydrofluorocarbons and Perfluorocarbons.

You mention that the above is conducive with Cambridge Handbook of Earth Science Data (c2009).

This data then places Carbon Dioxide at the bottom of the elements in the atmosphere ?

The poster focused on this:

The atmospheric concentration of carbon dioxide has increased by almost 50%, from 280 ppm in 1750 to 419 ppm in 2021. The last time the atmospheric concentration of carbon dioxide was this high was over 3 million years ago.

I found the following from the MetOffice, which put CO2 at around 400ppm: https://www.metoffice.gov.uk/research/approach/monitoring/atmospheric-trends/gases-and-trends/carbon-dioxide

But where do I get hold of the primary source to confirm this ?

The following could perhaps be confirmed by your Cambridge Handbook:

Carbon Dioxide is only 0.04%, and the other greenhouse gases only make up 0.1% of the Earth’s atmosphere.

Where it gets interesting is when touching on water vapour:

Water vapour is the main greenhouse gas element, but it would be hard to live without clouds and rain. It contributes between 36% to 72% to the greenhouse gas effect. Carbon dioxide contributes between 9% to 26%.

If switching to a Hydrogen based energy production, with water vapour being the ejected gas, then wouldn't it be worse than sticking with what we're using now ?

I have a lot of data, too much to scan and post as such.

But if you can indicate where you want to go with this I can certainly condense it for you.

[exchemist]

1 hour ago, Erina said:

It was actually a scrape from the comment's section. I rarely read the Editorial.

I thought that it would be a little bit much to digest, so to start with Carbon Dioxide, everybody's favourite:

The most abundant greenhouse gases in Earth's atmosphere in decreasing order are water vapor, carbon dioxide, methane, nitrous oxide, ozone, Chlorofluorocarbons, Hydrofluorocarbons and Perfluorocarbons.

You mention that the above is conducive with Cambridge Handbook of Earth Science Data (c2009).

This data then places Carbon Dioxide at the bottom of the elements in the atmosphere ?

The poster focused on this:

The atmospheric concentration of carbon dioxide has increased by almost 50%, from 280 ppm in 1750 to 419 ppm in 2021. The last time the atmospheric concentration of carbon dioxide was this high was over 3 million years ago.

I found the following from the MetOffice, which put CO2 at around 400ppm: https://www.metoffice.gov.uk/research/approach/monitoring/atmospheric-trends/gases-and-trends/carbon-dioxide

But where do I get hold of the primary source to confirm this ?

The following could perhaps be confirmed by your Cambridge Handbook:

Carbon Dioxide is only 0.04%, and the other greenhouse gases only make up 0.1% of the Earth’s atmosphere.

Where it gets interesting is when touching on water vapour:

Water vapour is the main greenhouse gas element, but it would be hard to live without clouds and rain. It contributes between 36% to 72% to the greenhouse gas effect. Carbon dioxide contributes between 9% to 26%.

If switching to a Hydrogen based energy production, with water vapour being the ejected gas, then wouldn't it be worse than sticking with what we're using now ?

No, because water vapour doesn't accumulate. It precipitates as rain. This is what is meant in @Ken Fabian's post above, which says water vapour does not itself cause a warming trend, although it amplifies any warming trend there may be due to persistent greenhouse gases. 

Edited August 2, 2022 by exchemist

[Ken Fabian]

3 hours ago, Erina said:

If switching to a Hydrogen based energy production, with water vapour being the ejected gas, then wouldn't it be worse than sticking with what we're using now ?

Burning fossil fuels emits water vapor too, in similar amounts for similar energy use.

I am not aware of any climate significance for the water vapor from fossil fuels, so not for Hydrogen burning either. I expect that lack of significance is because any immediate atmospheric water vapor content change is very small in proportion to how much is there naturally. And it doesn't accumulate over longer time frames. Any long term change to water vapor content is inextricably tied to and limited by air temperature change, not the "sources", which exist naturally in great abundance.

I also don't expect Hydrogen use to be as ubiquitous as the hype suggests; for all the talk the principle uses for hydrogen are still in oil production, not in replacing fossil fuels. That is all supplied by Hydrogen made from fossil fuels, with emissions, not clean energy and electrolysis. Any hydrogen transport economy will require about 3 times the electricity as battery electric, without the ability to piggyback onto existing electricity grids. A bit cynical of me but I think the big energy users like Hydrogen in direct proportion to how long to become a readily available option; commitment to hydrogen over other options is a commitment to delay. Iron smelting and chemical production may be the most important uses but are unlikely to require more hydrogen than oil refining uses now.

Edited August 2, 2022 by Ken Fabian

[Erina]

My understanding is that shipping container vessels burn the remnants of fuel nobody else wants to touch, which wafts onshore from miles out at port. Such vehicles, are therefore ripe for Hydrogen conversion, but need a lot of it i.e. nuclear generated, for cost purposes.

Granted, they won't put out much water vapour, compared to the surrounding sea, but are numerous as the world heavily relies on these behemoths for the way the world works today. And as an island the UK, which imports around 90% of her goods via the sea, Britain is no exception, and not a special case for an island nation.

Am I right in thinking that any water ejected from the ships funnels would literally be a drop in the ocean. That the vapour would not rival that of its natural surroundings, is not permanently cumulative as the weather naturally cycles such gases, and so as a source of pollution it really is nil ?

[Phi for All]

7 minutes ago, Erina said:

My understanding is that shipping container vessels burn the remnants of fuel nobody else wants to touch, which wafts onshore from miles out at port. Such vehicles, are therefore ripe for Hydrogen conversion, but need a lot of it i.e. nuclear generated, for cost purposes.

Interesting article from the Economist: https://www.economist.com/finance-and-economics/2017/03/11/green-finance-for-dirty-ships

Quote

By burning heavy fuel oil, just 15 of the biggest ships emit more of the noxious oxides of nitrogen and sulphur than all the world’s cars put together.

 

[exchemist]

19 minutes ago, Erina said:

My understanding is that shipping container vessels burn the remnants of fuel nobody else wants to touch, which wafts onshore from miles out at port. Such vehicles, are therefore ripe for Hydrogen conversion, but need a lot of it i.e. nuclear generated, for cost purposes.

Granted, they won't put out much water vapour, compared to the surrounding sea, but are numerous as the world heavily relies on these behemoths for the way the world works today. And as an island the UK, which imports around 90% of her goods via the sea, Britain is no exception, and not a special case for an island nation.

Am I right in thinking that any water ejected from the ships funnels would literally be a drop in the ocean. That the vapour would not rival that of its natural surroundings, is not permanently cumulative as the weather naturally cycles such gases, and so as a source of pollution it really is nil ?

Yes, as Ken Fabian and I have been saying, if you put more water vapour into the atmosphere, you don't change anything.

To put this another way, the water in the atmosphere is, overall, in equilibrium with the vast excess of liquid water that is in the oceans. Evaporation and condensation and precipitation are occurring all the time. So the net effect of adding water vapour by burning a fuel containing hydrogen is that a tiny bit more rain falls at some point, thus correcting the imbalance that the extra water vapour introduces. 

HOWEVER, the equilibrium position is temperature dependent. So if a permanent, or long term, greenhouse gas increases the mean temperature a bit, then the equilibrium position shifts, in favour of more water vapour in the atmosphere, which warms it up more than the effect of just the greenhouse gas alone. In this way water vapour amplifies the effects of the permanent or long term greenhouse gases.

At least, that's the way I understand the process (I'm not an atmospheric chemist). 

 

Edited August 3, 2022 by exchemist

[studiot]

I am not minded to say much about atmospheric water since nobody is very interested but the offered analyses do not hold water (pun noted).

The wavelengths that different gasses operate on for radiative absorbtion and emission effects differ from gas to gas.

But atmospheric water has a net cooling effect on the Earth.

Not only that but the effects depend upon the position (altitude) of that water.

Here is a short extract from a 2018 New Scientist article about the subject ans what different experts around the globe from Canada to the US to New Zealand to the UK are trying to do about it.

 

+1 to phi for his note on the polluting effects of nitrogen oxides.

 

 

[exchemist]

1 hour ago, studiot said:

I am not minded to say much about atmospheric water since nobody is very interested but the offered analyses do not hold water (pun noted).

The wavelengths that different gasses operate on for radiative absorbtion and emission effects differ from gas to gas.

But atmospheric water has a net cooling effect on the Earth.

Not only that but the effects depend upon the position (altitude) of that water.

Here is a short extract from a 2018 New Scientist article about the subject ans what different experts around the globe from Canada to the US to New Zealand to the UK are trying to do about it.

 

+1 to phi for his note on the polluting effects of nitrogen oxides.

 

 

This extract does not say that atmospheric water has a net cooling effect on the earth. What it says is clouds have a net cooling effect.  

As I understand it atmospheric water has a net warming effect, being a blend of IR absorption by vapour and the cooling effect of clouds. In fact, the extract you posted says without clouds the water vapour might lead to a runaway +ve feedback loop. The net effect of water in the atmosphere is described here:

https://climate.nasa.gov/ask-nasa-climate/3143/steamy-relationships-how-atmospheric-water-vapor-supercharges-earths-greenhouse-effect/

 

[studiot]

I can see I'm wasting my time here.

What are clouds, if not water in the atmousphere ?

Perhaps you get clouds inside the coal in a coal mine ?

[exchemist]

1 minute ago, studiot said:

I can see I'm wasting my time here.

What are clouds, if not water in the atmousphere ?

Perhaps you get clouds inside the coal in a coal mine ?

You are for some reason not getting my point. Clouds are water in the atmosphere, but not all the water in the atmosphere is in the form of clouds. There is also water vapour. 

[studiot]

Just now, exchemist said:

You are for some reason not getting my point. Clouds are water in the atmosphere, but not all the water in the atmosphere is in the form of clouds. There is also water vapour. 

I didn't say it was all clouds and I didn't say that water vapour did not act as a greenhouse gas.

In fact if your read carefully I said the opposite.

Which is why I said

2 hours ago, studiot said:

But atmospheric water has a net cooling effect on the Earth.

 

 

[Ken Fabian]

7 hours ago, Erina said:

My understanding is that shipping container vessels burn the remnants of fuel nobody else wants to touch, which wafts onshore from miles out at port. Such vehicles, are therefore ripe for Hydrogen conversion, but need a lot of it i.e. nuclear generated, for cost purposes.

Granted, they won't put out much water vapour, compared to the surrounding sea, but are numerous as the world heavily relies on these behemoths for the way the world works today. And as an island the UK, which imports around 90% of her goods via the sea, Britain is no exception, and not a special case for an island nation.

Am I right in thinking that any water ejected from the ships funnels would literally be a drop in the ocean. That the vapour would not rival that of its natural surroundings, is not permanently cumulative as the weather naturally cycles such gases, and so as a source of pollution it really is nil ?

If water vapor were a big problem then nuclear energy won't help reduce it -

 

I don't see shipping as ripe for conversion except as a hope or perhaps an intention; whilst hydrogen can be burned in an internal combustion engine that won't work with existing diesel engines. Whilst some ships are diesel electric, with propellers driven by electric motors hydrogen ships will need to be fuel cell electric. No major shipping companies will commit to them until supply chains and infrastructure is in place and even then there is a lot of development needed. Making shipping zero emissions is a huge task. Short distance ferries running on battery electric already exist, are reliable and a lot less technically challenging to build and operate. Better batteries will emerge, but how much better is still unknown.

I don't know what the best solution to shipping emissions is but I suspect not much will happen until and unless the shipping industry knows in it's bones that they have no choice. Currently they appear to be treating it as optional and making the choice to stick with not doing it.

 

1 hour ago, studiot said:

Perhaps you get clouds inside the coal in a coal mine ?

Coal contains some water. A lot more in brown coal. But whilst cars burning Hydrocarbons (the name says there is hydrogen in the fuel) make H2O by chemical reactions coal power plants make lots of it by evaporative cooling (similar to the nuclear plant cooling towers above) at the power plants.

Whether atmospheric water is overall warming (greenhouse) or cooling (cloud albedo)? Without it as a GHG - the biggest one - I would expect global temperatures to be much lower, probably below freezing, but that is off the top of my head.

Edited August 3, 2022 by Ken Fabian

[Erina]

Hi studiot, I think that I'll take you up on your offer.

My position is that I need bullet-proof stats, and therefore I need to be able to reference them to primary sources.

1/ I can now be confident that Cambridge Handbook of Earth Science Data (c2009) places CO2 near the bottom of a list of commonly found gasses in the atmosphere, correct ?

2/ Carbon Dioxide is only 0.04%, and the other greenhouse gases only make up 0.1% of the Earth’s atmosphere - there was some argument on the thread that the decimal place should shift over, and so I need to confirm this. Also, what it means i.e. how significant this makes CO2 ?

3/ Meanwhile I read that: the atmospheric concentration of carbon dioxide has increased by almost 50%, from 280 ppm in 1750 to 419 ppm in 2021. The last time the atmospheric concentration of carbon dioxide was this high was over 3 million years ago - again, is it true ?

4/ We went through the water vapour issue just previously, so I am happy with that (although, it could go either way, so I still cannot be sure), but outstanding were the percentages quoted: Water vapour contributes between 36% to 72% to the greenhouse gas effect. Carbon dioxide contributes between 9% to 26% - independent confirmation of this would be useful, but it seems to lean toward the equilibrium position issue that you spoke of.

 

Many thanks.

[exchemist]

11 hours ago, studiot said:

I didn't say it was all clouds and I didn't say that water vapour did not act as a greenhouse gas.

In fact if your read carefully I said the opposite.

Which is why I said

 

 

I don't think that is right. The NASA link I provided seems clear that water in the atmosphere has a warming effect overall. The way I read the extract you supplied is that clouds mitigate the greenhouse warming due water vapour - and maybe prevent it running away.  

How do you come to the conclusion that water in the atmosphere - in all forms, vapour and clouds - has a net cooling effect?  

[studiot]

10 hours ago, Erina said:

Hi studiot, I think that I'll take you up on your offer.

My position is that I need bullet-proof stats, and therefore I need to be able to reference them to primary sources.

1/ I can now be confident that Cambridge Handbook of Earth Science Data (c2009) places CO2 near the bottom of a list of commonly found gasses in the atmosphere, correct ?

2/ Carbon Dioxide is only 0.04%, and the other greenhouse gases only make up 0.1% of the Earth’s atmosphere - there was some argument on the thread that the decimal place should shift over, and so I need to confirm this. Also, what it means i.e. how significant this makes CO2 ?

3/ Meanwhile I read that: the atmospheric concentration of carbon dioxide has increased by almost 50%, from 280 ppm in 1750 to 419 ppm in 2021. The last time the atmospheric concentration of carbon dioxide was this high was over 3 million years ago - again, is it true ?

4/ We went through the water vapour issue just previously, so I am happy with that (although, it could go either way, so I still cannot be sure), but outstanding were the percentages quoted: Water vapour contributes between 36% to 72% to the greenhouse gas effect. Carbon dioxide contributes between 9% to 26% - independent confirmation of this would be useful, but it seems to lean toward the equilibrium position issue that you spoke of.

 

Many thanks.

 

You have a PM.

 

Carbon dioxide concentration is fourth on the Cambridge list of 24 atmospheric gases and particulates and stood at 384 ppm in 2007 with an annual increase over the previous decade of 1.65 ppm.

Ther primar source (referenced) was NOAA.

So something over 400 is hardly suprising today.

Edited August 4, 2022 by studiot

[exchemist]

11 hours ago, Erina said:

Hi studiot, I think that I'll take you up on your offer.

My position is that I need bullet-proof stats, and therefore I need to be able to reference them to primary sources.

1/ I can now be confident that Cambridge Handbook of Earth Science Data (c2009) places CO2 near the bottom of a list of commonly found gasses in the atmosphere, correct ?

2/ Carbon Dioxide is only 0.04%, and the other greenhouse gases only make up 0.1% of the Earth’s atmosphere - there was some argument on the thread that the decimal place should shift over, and so I need to confirm this. Also, what it means i.e. how significant this makes CO2 ?

3/ Meanwhile I read that: the atmospheric concentration of carbon dioxide has increased by almost 50%, from 280 ppm in 1750 to 419 ppm in 2021. The last time the atmospheric concentration of carbon dioxide was this high was over 3 million years ago - again, is it true ?

4/ We went through the water vapour issue just previously, so I am happy with that (although, it could go either way, so I still cannot be sure), but outstanding were the percentages quoted: Water vapour contributes between 36% to 72% to the greenhouse gas effect. Carbon dioxide contributes between 9% to 26% - independent confirmation of this would be useful, but it seems to lean toward the equilibrium position issue that you spoke of.

 

Many thanks.

Just to clarify your point (1), where CO2 appears in a ranking by concentration in the atmosphere is irrelevant. 

What is relevant is the degree to which a gas absorbs IR radiation. The principal gases in the atmosphere (N2, O2, Ar,)  do not absorb at all in the IR. They are transparent to it. Neither N2 nor O2 has a dipole in the molecule for the IR radiation to couple to, which is what one needs to get a molecule to absorb and vibrate. Ar is a monatomic gas, so there is nothing to vibrate and so it can't absorb at all in the IR region.  

The first gas on a list, in descending order of concentration, that has a dipole and can absorb in the IR is H2O, followed by CO2. So forget about CO2 being "near the bottom" of the list, at "only" 0.04% of the atmosphere. That tells you nothing of relevance in this context.   

Edited August 4, 2022 by exchemist

[Erina]

I take it then that 0.04% is the correct level of CO2 in the atmosphere then ?

At 0.04% CO2 of the atmosphere, how relevant to climate change is its IR absorption rate, how does that relationship have such an impact ?

[TheVat]

Even volcanoes, usually associated with global cooling events, can sometimes pump water vapor into the stratosphere and achieve a warming effect for several years.  This seems to be the case wrt the Tongan blast a few months ago. (just what Earth needs right now, right?)

https://www.npr.org/2022/08/03/1115378385/tonga-volcano-stratosphere-water-warming

 

Quote

Earlier large volcanic eruptions have affected climate, but they usually cool temperatures, because they send light-scattering aerosols into the stratosphere. Those aerosols act as a sort of massive layer of sunscreen. But since water vapor traps heat, the Tongan eruption could temporarily raise temperatures a bit, the researchers said.

It normally takes around 2-3 years for sulfate aerosols from volcanoes to fall out of the stratosphere. But the water from the Jan. 15 eruption could take 5-10 years to fully dissipate.

Given that timeframe and the extraordinary amount of water involved, Hunga Tonga-Hunga Ha'apai "may be the first volcanic eruption observed to impact climate not through surface cooling caused by volcanic sulfate aerosols, but rather through surface warming," the researchers said in their paper.

 

[Ken Fabian]

13 hours ago, Erina said:

I take it then that 0.04% is the correct level of CO2 in the atmosphere then ?

At 0.04% CO2 of the atmosphere, how relevant to climate change is its IR absorption rate, how does that relationship have such an impact ?

Approaching 0.042% -

 

Keep in mind that there is ~10 - 15km of atmosphere before outward travelling IR escapes to space - plenty of opportunity for such concentrations of CO2 to absorb IR (to re-radiate in all directions, ie as much down as up... almost the textbook definition of Greenhouse Effect) and enough to prevent most IR from the ground getting to space in one go, even before concentrations were raised.

"Only" 0.04% is a very misleading description; very small relative to what? The earliest calculation of the greenhouse effect from lowered and raised CO2, by Svante Arrhenius was in the 1890's, following on from prior work of others that reconciled known incoming solar energy with global average temperatures much higher than could be explained in an absence of greenhouse effect; it is highly significant, even at lower concentrations than 0.04%.

And even if CO2 greenhouse contribution to the total GHE is not the largest - 2nd after water vapor - it is what we are changing by fossil fuel burning. With (as previously mentioned) water vapor concentrations changing in response to the warming from other GHG's and amplifying the effect.

Edited August 5, 2022 by Ken Fabian

[Doctor Derp]

On 8/1/2022 at 1:47 PM, Erina said:

 

Some points that may be of interest:

 

 

-1 gram of methane can trap as much thermal energy in the atmosphere as 30 grams of carbon

-Melting permafrost releases frozen methane into the atmosphere aka "methane burps"

-Over the last 2,000 years humanity has chopped down more than 50% of forests in the world, reducing the capacity of trees to store or sequester carbon