"Adding carbon dioxide to the atmosphere thus allows more upwelling long wave radiation to be captured before it can escape to space, and this energy is re-radiated back towards the Earth’s surface, thus resulting in a warming of the Earth system. The result is global warming due to the radiative effect of carbon dioxide." This does not convince me that man-made CO2 accumulation is driving massive changes in climate. The key issue is not some warming but how much warming, and this article does not address that issue, except to cite an IPCC graph, which, to me, is the opposite of convincing. If, as I'm convinced by the science, increasing CO2 concentration has a diminishing effect per unit added, and if the greater part of the maximum CO2 greenhouse effect has already been obtained at 400 ppm, sure, there is SOME "warming due to the radiative effect of carbon dioxide," but so what? Wasn't the earth warmer or as warm as now during the Holocene Optimum (10k ya), the Roman Warm Period, the Medieval Warm Period? I feel that perhaps the greatest bit of bad luck humanity has had in the last 1000 years is the coincidence of the end of the Liitle Ice Age with the beginning of fossil fuel use. But, as they say, correlation is not causation. I could add a quote or two from Feynman about how science is done, but you probably already know them. P.S. Why no mention of H2O, by far the most important greenhouse gas?
I think you are correct that nearly all the effect of CO2 has occurred by 400ppm. All the radiation in the wavelength that CO2 has been absorbed at this point. Adding more CO2 is negligible because there’s little for it to absorb.
You are correct that merely citing IPCC is an error. There are two Cardinal Sins in Science: Assuming correlation means causation. And Appeal To Authority. Merely Citing IPCC is the latter.
The notion of CO2 in the atmosphere radiating heat back to the surface is wrong. The 2nd law of thermodynamics states that heat cannot transfer from a colder body (the atmosphere) to a warmer one the earth surface and lower atmosphere. If heat did follow a downward route then entropy would be decreasing which is only allowed by a part of a closed system which is more than offset by increases in the rest of the system
Hi! Thank you for this; I am somewhat late to the climate change debate and continue to look for words that can help me understand all sides of the controversy. I am particularly interested because I spent over 20 years in the electric utility industry and have some concept of the magnitude of changes the current net-zero goals are likely to bring. For year, I have told friends that I will know utilities (and their regulators and other stakeholders) are 'serious' about CO2 and climate change when they actually begin to work with customers on increasing their comfort with an intermittent supply of electricity to the premise (what counts as a customer in utility-speak). Instead, if anything, utilities and their cohorts seem to just more loudly proclaim the continuing validity of "as much as you want, whenever you want it."
In any event, a couple of questions you might address in a future piece:
1. The historical record, as seen through ice and other types of cores, seems to show a lag between temperature and CO2 increases. Wouldn't one usually think of the first as causal and the second as effect? Why is that not true here?
2. Can you explain in the same clear way as in this article how human-caused CO2 can be distinguished from all other CO2 and why it is safe to assume that all other CO2 would be the same now as in 1750 if it weren't for fossil fuels?
3. I am confused by the variation in how long people say that CO2 stays in the atmosphere. Can you shed some light on this?
I think Roger was going to forward you a couple of other really basic questions I had about the output of the IPCC radiative forcing models and the time/area scales used to make the necessary calculations. Again, I know my questions are really basic but I honestly didn't know until today what the numbers on the IPCC scenarios everyone talks about even meant! And I worked in an industry close to this whole issue. Imagine the lack of understanding out there by people not close to this at all. That scares me even though the notion of climate change does not. Thank you for your generous time in contributing to this Substack.
It would seem that the biogeophysical would result in negative forcing. CO2 is absorbed thus decreasing the amount in the atmosphere. This is especially true as the earth greens with ever increasing CO2 absorption by flora. Also the oceans are absorbing CO2 with increased phytoplankton, I doubt that that is being considered in climate warming. The complexity and currently little understood impact of the total biogeophysical forcing may be why current climate models have not been able to forecast current observed global temperatures.
Also i would think that El Nino, Pacific and Atlantic multi decadional osselations are much too large and persistent to be caused by spacial gradients in the horizontal pressure fields. Their existence as oceanographic phenomena drives the climate not visa versa.
A warm welcome to Roger Sr, his work was amongst the first I encountered in my efforts to understand the issues of climate change. I am delighted to know he will be writing more here.
I do have aquestion related to the uptake of anthropogenic CO2 in the atmosphere. As I understand it, about 40% of our annual emissions end up in the atmosphere. This fraction has stayed constant while our emissions have almost triple since the 1970's.
Why is this fraction constant, and what does that mean for the estimation of residence time for CO2?
One thing that I didn't get from this article is how a gas that is only 0.04% or the atmosphere can have such a large effect on warming. What's the explanation for this out sized effect?
Best I’ve seen explaining the role of CO2! A question. Can we see the pandemic in recent data? Presumably the shutdown/slowdown of various economies resulted in less CO2 emissions from the burning of fossil fuels for a time. Has this shown up in the data? Thanks.
Thank you! Reading the paper it appears, despite the reduction in CO2 emissions during the pandemic, there was not the expected response in atmospheric CO2 concentration. More work to be done on the models??
“Some of this absorbed heat is also reflected back into space. The fraction of the reflected heat is called the albedo, with larger albedo values indicating greater reflection.”
I’m confused. I thought albedo is the fraction of the sun’s irradiation that is reflected back into space at unaltered wavelength, without being absorbed and converted to heat.
I'm glad to see Sr. join the Honest Broker. Good straightforward write up on carbon dioxide in the atmosphere, although I've never seen the terms upwelling and downwelling used in the context of atmospheric radiation but then again my training in MetOcean goes back to the '60s.
Ultimately though the questions remain:
1. Is climate change an existential issue?
2. Will climate change have catastrophic effects?
3. Is there any reason we must achieve "Net Zero" by 2030 or 2050?
4. Given what we know, are the effects of climate change likely to fall within the envelope of adaptability.
I know nothing about this science except what I read and hear. Warming is always presented as bad. There must be some benefit to a warmer planet? Longer growing seasons, less cold weather that get actually kill people. The question is what is a reasonable approach to the problem? The other question is what can reverse this cycle other then the destruction of the world economy along with keeping poor areas of the world in continuous poverty.
According to the only Nobel laureate climate economist, the benefits exceed the dis benefits until warming exceeds 3 deg C. So far, climate change has been delivering net benefits, and this sho7ld continue for another century or so.
I have read that the residence time for any "new" CO2 molecule is actually less than a day. BUT that molecule then becomes an addition to the carbon cycle for more than a hundred years.
Because CO2 molecules are fungible, the outcome is that the atmospheric concentration of CO2 is increased by one molecule on a long-term basis. OTOH, scientists who claim that CO2 has a very short residence time at a molecular level, are not necessarily mistaken.
I wondered about that too. If plants life is continuously pulling CO2 from the atmosphere it doesn't seem like any new CO2 is necessarily long lasting. Unless as you say it is the amount of carbon in the carbon cycle they are talking about.
Once a plant absorbs CO2 and emits O2 the carbon remains as part of the plant, the O2 is breathed by life forms that exhale CO2.
You both are describing a short term phenomenon. The burning of fossil fuels involves the conversion of millions of years of trapped plant carbon at a rate far exceeding the time of short term "recapture". Not enough plants on Earth to balance the release from burning fossil fuel.
Why do you use the words "far exceeding"? The Keeling curve from Mauna Loa shows that approximately 60% of anthropogenic CO2 emissions end up elsewhere than the atmosphere. This fraction has remained constant throughout the period of measurements, and is there regardless of the amount of emissions. That in itself says that whatever processes are re-capturing CO2, they are in lockstep with the rate of release and keeping well up.
It's great to read an article which doesn't try to implicate "Goodies or Baddies"!
I am firmly against climate alarmism, although I cannot disagree with anything written here by Roger Sr.
The issue that the wider subject faces is the politicisation of scientific reports or papers that arises when interested parties try to force their chosen narrative for political or ideological reasons.
Keep up the unbiased and non-partisan work. We desperately need steady hands on the tiller right now.
By what mechanism is radiation re-radiated down to Earth? And why only in that direction?
"Adding carbon dioxide to the atmosphere thus allows more upwelling long wave radiation to be captured before it can escape to space, and this energy is re-radiated back towards the Earth’s surface, thus resulting in a warming of the Earth system. The result is global warming due to the radiative effect of carbon dioxide." This does not convince me that man-made CO2 accumulation is driving massive changes in climate. The key issue is not some warming but how much warming, and this article does not address that issue, except to cite an IPCC graph, which, to me, is the opposite of convincing. If, as I'm convinced by the science, increasing CO2 concentration has a diminishing effect per unit added, and if the greater part of the maximum CO2 greenhouse effect has already been obtained at 400 ppm, sure, there is SOME "warming due to the radiative effect of carbon dioxide," but so what? Wasn't the earth warmer or as warm as now during the Holocene Optimum (10k ya), the Roman Warm Period, the Medieval Warm Period? I feel that perhaps the greatest bit of bad luck humanity has had in the last 1000 years is the coincidence of the end of the Liitle Ice Age with the beginning of fossil fuel use. But, as they say, correlation is not causation. I could add a quote or two from Feynman about how science is done, but you probably already know them. P.S. Why no mention of H2O, by far the most important greenhouse gas?
Ron,
I think you are correct that nearly all the effect of CO2 has occurred by 400ppm. All the radiation in the wavelength that CO2 has been absorbed at this point. Adding more CO2 is negligible because there’s little for it to absorb.
You are correct that merely citing IPCC is an error. There are two Cardinal Sins in Science: Assuming correlation means causation. And Appeal To Authority. Merely Citing IPCC is the latter.
Forgot the link! ( https://doi.org/10.53234/scc202304/05)
This is an interesting paper which pretty much debunks the whole CO2 theory and does explain why it has never been the cause of warming previously!
The notion of CO2 in the atmosphere radiating heat back to the surface is wrong. The 2nd law of thermodynamics states that heat cannot transfer from a colder body (the atmosphere) to a warmer one the earth surface and lower atmosphere. If heat did follow a downward route then entropy would be decreasing which is only allowed by a part of a closed system which is more than offset by increases in the rest of the system
Hi! Thank you for this; I am somewhat late to the climate change debate and continue to look for words that can help me understand all sides of the controversy. I am particularly interested because I spent over 20 years in the electric utility industry and have some concept of the magnitude of changes the current net-zero goals are likely to bring. For year, I have told friends that I will know utilities (and their regulators and other stakeholders) are 'serious' about CO2 and climate change when they actually begin to work with customers on increasing their comfort with an intermittent supply of electricity to the premise (what counts as a customer in utility-speak). Instead, if anything, utilities and their cohorts seem to just more loudly proclaim the continuing validity of "as much as you want, whenever you want it."
In any event, a couple of questions you might address in a future piece:
1. The historical record, as seen through ice and other types of cores, seems to show a lag between temperature and CO2 increases. Wouldn't one usually think of the first as causal and the second as effect? Why is that not true here?
2. Can you explain in the same clear way as in this article how human-caused CO2 can be distinguished from all other CO2 and why it is safe to assume that all other CO2 would be the same now as in 1750 if it weren't for fossil fuels?
3. I am confused by the variation in how long people say that CO2 stays in the atmosphere. Can you shed some light on this?
I think Roger was going to forward you a couple of other really basic questions I had about the output of the IPCC radiative forcing models and the time/area scales used to make the necessary calculations. Again, I know my questions are really basic but I honestly didn't know until today what the numbers on the IPCC scenarios everyone talks about even meant! And I worked in an industry close to this whole issue. Imagine the lack of understanding out there by people not close to this at all. That scares me even though the notion of climate change does not. Thank you for your generous time in contributing to this Substack.
How does the radiative effect of CO2 become radiative forcing?
It would seem that the biogeophysical would result in negative forcing. CO2 is absorbed thus decreasing the amount in the atmosphere. This is especially true as the earth greens with ever increasing CO2 absorption by flora. Also the oceans are absorbing CO2 with increased phytoplankton, I doubt that that is being considered in climate warming. The complexity and currently little understood impact of the total biogeophysical forcing may be why current climate models have not been able to forecast current observed global temperatures.
Also i would think that El Nino, Pacific and Atlantic multi decadional osselations are much too large and persistent to be caused by spacial gradients in the horizontal pressure fields. Their existence as oceanographic phenomena drives the climate not visa versa.
A warm welcome to Roger Sr, his work was amongst the first I encountered in my efforts to understand the issues of climate change. I am delighted to know he will be writing more here.
I do have aquestion related to the uptake of anthropogenic CO2 in the atmosphere. As I understand it, about 40% of our annual emissions end up in the atmosphere. This fraction has stayed constant while our emissions have almost triple since the 1970's.
Why is this fraction constant, and what does that mean for the estimation of residence time for CO2?
It would be great to hear from Steve Koonin in Honest Broker.
You probably saw my review of Koonin's book here: https://rogerpielkejr.substack.com/p/unsettled-climate-science-so-what
I've been told (a bit ago) that he has written a response to my review for TNA, which I would be happy to share here and invite his participation.
This recent paper by Richard Lindzen provides a different view on the roll of CO2 in climate change. https://co2coalition.org/wp-content/uploads/2022/09/2022-09-22-Lindzen-global-warming-narrative.pdf
It would be interesting to get Sr's take on the science and Jr's take on the comments re. current policies.
One thing that I didn't get from this article is how a gas that is only 0.04% or the atmosphere can have such a large effect on warming. What's the explanation for this out sized effect?
Best I’ve seen explaining the role of CO2! A question. Can we see the pandemic in recent data? Presumably the shutdown/slowdown of various economies resulted in less CO2 emissions from the burning of fossil fuels for a time. Has this shown up in the data? Thanks.
Here is a recent paper on exactly this question: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2021GL095396
Thank you! Reading the paper it appears, despite the reduction in CO2 emissions during the pandemic, there was not the expected response in atmospheric CO2 concentration. More work to be done on the models??
“Some of this absorbed heat is also reflected back into space. The fraction of the reflected heat is called the albedo, with larger albedo values indicating greater reflection.”
I’m confused. I thought albedo is the fraction of the sun’s irradiation that is reflected back into space at unaltered wavelength, without being absorbed and converted to heat.
Good catch! That’s a typo👍
And I should say, at the fault of the editor not the author 😉
I'm glad to see Sr. join the Honest Broker. Good straightforward write up on carbon dioxide in the atmosphere, although I've never seen the terms upwelling and downwelling used in the context of atmospheric radiation but then again my training in MetOcean goes back to the '60s.
Ultimately though the questions remain:
1. Is climate change an existential issue?
2. Will climate change have catastrophic effects?
3. Is there any reason we must achieve "Net Zero" by 2030 or 2050?
4. Given what we know, are the effects of climate change likely to fall within the envelope of adaptability.
Excellent, informative article. It is a pleasure to read something science based without emotion, etc. I learned a lot from this. Thank you.
I know nothing about this science except what I read and hear. Warming is always presented as bad. There must be some benefit to a warmer planet? Longer growing seasons, less cold weather that get actually kill people. The question is what is a reasonable approach to the problem? The other question is what can reverse this cycle other then the destruction of the world economy along with keeping poor areas of the world in continuous poverty.
According to the only Nobel laureate climate economist, the benefits exceed the dis benefits until warming exceeds 3 deg C. So far, climate change has been delivering net benefits, and this sho7ld continue for another century or so.
Good point.
About 12,000 years ago most of North America was covered by a glacier a mile thick. Warming is what allowed modern civilization to develop.
I have read that the residence time for any "new" CO2 molecule is actually less than a day. BUT that molecule then becomes an addition to the carbon cycle for more than a hundred years.
Because CO2 molecules are fungible, the outcome is that the atmospheric concentration of CO2 is increased by one molecule on a long-term basis. OTOH, scientists who claim that CO2 has a very short residence time at a molecular level, are not necessarily mistaken.
Is this a correct description?
I wondered about that too. If plants life is continuously pulling CO2 from the atmosphere it doesn't seem like any new CO2 is necessarily long lasting. Unless as you say it is the amount of carbon in the carbon cycle they are talking about.
Once a plant absorbs CO2 and emits O2 the carbon remains as part of the plant, the O2 is breathed by life forms that exhale CO2.
You both are describing a short term phenomenon. The burning of fossil fuels involves the conversion of millions of years of trapped plant carbon at a rate far exceeding the time of short term "recapture". Not enough plants on Earth to balance the release from burning fossil fuel.
Why do you use the words "far exceeding"? The Keeling curve from Mauna Loa shows that approximately 60% of anthropogenic CO2 emissions end up elsewhere than the atmosphere. This fraction has remained constant throughout the period of measurements, and is there regardless of the amount of emissions. That in itself says that whatever processes are re-capturing CO2, they are in lockstep with the rate of release and keeping well up.
Good morning from the UK.
It's great to read an article which doesn't try to implicate "Goodies or Baddies"!
I am firmly against climate alarmism, although I cannot disagree with anything written here by Roger Sr.
The issue that the wider subject faces is the politicisation of scientific reports or papers that arises when interested parties try to force their chosen narrative for political or ideological reasons.
Keep up the unbiased and non-partisan work. We desperately need steady hands on the tiller right now.