Like Sean I just got redirected here from a comment made on the recent Ice Surprises post.
I enjoyed the clear explanation of how CO2 impacts on the climate, but a couple of things are missing for me:
1. It is implied that the downwellings are somehow proportional to the concentration of CO2 in the atmosphere, but is this the case? Is the relationship linear?
2. This impact and the others illustrated combine into a very complex mix of climate effects - but even so it's a huge simplification of reality. What prompted my original comment was the statement "the planet has indeed continued to warm due primarily to the combustion of fossil fuels" - and I still see no justification for the word 'primarily'.
I’ve just spotted this post now in 2025. Whilst I can see how added carbon dioxide will make for a warmer world, how does this change our weather? How does carbon dioxide create a heat wave? Or a tropical cyclone? It seems to me that the forces that go into those and other dynamic climate impact drivers are largely independent of a slightly warmer atmosphere, which in reality is dominated by warmer minimums.
Angular momentum, the solar constant, topography, latitude. These all feature with much more influence in what our regional weather is.
A few quick thoughts upon reread. The second diagram is confusing, maybe. The right hand side shows 396 of surface radiation, of which 333 is downwelled? Am I reading that correctly? Just commonsensically that seems like a huge percentage if so. Too huge.
And, with all due respect, and I'm really glad to have your Dad involved, and happy for you that you are so close, I think this explanation falls under Lindzen's critique of being too simple. I abandoned my MatSci degrees to go on to trade options on the 30 yr bond future at the Chicago Board of Trade. We had the early Black-Scholes models to use, and were the first ones to apply them. But, I quickly learned that a normal distribution does not capture the real world volatility of bonds (and stocks too). The reason is that markets are highly complex systems. And highly complex systems cannot be modeled. (I believe that is still true; Engineering stuck with my son and he and I were discussing the limitations of modeling highly complex systems). Weather/climate is, obviously, a highly complex system. That's why the initial models all failed. And current ones will too. And, don't feel bad; a lot of human systems approach highly complex status. My son was working on the next generation of aircraft carriers, and they were essentially highly complex systems. Decades ago I read an engineer who predicted the space shuttles would be destroyed because they were highly complex and thus we could not engineer out every possibility.
Upon reread, I still find Lindzen's argument that CO2 effect is logarithmic to be compelling. And thus any additional CO2 we put into the atmosphere from this point on will have a negligible effect.
If there's any simple glaring errors in my post or any extra explanations anyone has, I'm all ears.
Even if I disagree with you and your Dad on this, I do highly value your integrity and willingness to speak truth to (very well funded!!) power. Thank you.
"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.
Or more simply, consider a thin layer of atmosphere that is both absorbing and emitting thermal infrared atmosphere. Only the components of the radiative fluxes emitted into or absorbed from the vertical direction affect the heating and cooling of our planet. The thermal infrared emitted by the GHGs in the atmosphere depends on the amount of GHGs in the layer, but is emitted equally up and down, so rising GHGs don't change the net vertical flux from emission, which is zero. Absorption is different, however. According to Beer's Law, transmission is a fraction (I/I_0), not an amount of the radiation entering the layer that is proportional to the amount of GHG's in the layer and the distance traveled through the layer. Since the atmosphere generally gets colder with increasing altitude, the upward flux from below is generally larger than the downward flux from above. Therefore, more GHGs reduce absorption of the upward flux of thermal IR by the layer than they reduce the downward flux. Therefore increasing GHGs slow the net vertical flux to space. You know this is true because the outward flux falls from an average of 390 W/m2 near the surface to 240 W/m2 at the TOA.
So where did Miskolczi go wrong? He POSTULATES that the upward flux Aa and downward flux Ed entering any layer are exactly equal. As Spenser points out, in our atmosphere, these quantities are often nearly equal, but not exactly equal. If an emitted photon travels an average of 1 km upward or downward before being absorbed in our thin layer, the upward flux was emitted from GHGs that were 13 degC warmer than the downward flux was emitted (assuming a lapse rate of 6.5 degC/km). If the average vertical distance traveled is only 100 m, the temperature difference is only 1.3 degC. If only 10 m, then 0.13 degC. So it can be hard to measure the difference in the upward (Aa) and downward fluxes (Ed) at some wavelengths and altitudes because our lower atmosphere is fairly opaque to thermal infrared. However, If you go high enough in the atmosphere, at every wavelength the air gets thin enough that photons can travel to where the temperature is different enough to create a difference between the upward and downward flux.
What the consensus over-simplifies and fails to tell us is that the "greenhouse effect" is not produced by the absorption of thermal infrared alone. It is produced by the interaction of the absorption and emission of thermal infrared with the TEMPERATURE GRADIENT in our atmosphere. If there were no temperature gradient, there would be no greenhouse effect. (In Antarctica on the average there is no vertical temperature gradient and no greenhouse effect.) As it turns out, most of the absorption and emission of thermal infrared in our atmosphere occurs in the troposphere, where the temperature decreases with altitude, causing rising GHGs to warm our planet.
You can use the online Modtran radiative transfer calculator to see how the upward and downward fluxes differ at a given altitude and wavelength and vary with GHG concentration using the "look up" and "look down" options. When CO2 is 4000 ppm the upward and downward fluxes at those wavelengths strongly absorbed by CO2 have "blackbody intensity". (This is effectively "saturation".) As the CO2 concentration is reduced to 400, then 40, then 4 ppm, the upward and downward fluxes begin to differ. But if you remove all of the other GHGs, at other wavelengths the upward and downward flux are always different.
Frank many thanks for taking the trouble to go through that. It will take me a while to get my head round it! I have read Roy Spencer's article but you made it a bit clearer! I still nevertheless am far from convinced that CO2 - man made or ocean emitted - has more than a very small role to play in the planet's temperature. It seems to me that atmospheric pressure is more significant that the make-up of the atmosphere but that's another discussion for another day!
Henry: Before you can say something has a small effect, you need to quantify that effect. The simplest thing to calculate is the reduction in radiative cooling to space caused by an instantaneous doubling of CO2 (before complicated changes follow). That reduction (called radiative forcing) is about 3.6 W/m2 (about 1.5% of the 240 W/m2 that satellites observe exiting the top of the atmosphere for space. Assuming incoming SWR is unchanged, the law of conservation of energy demands that our planet warm until it emits an additional 3.6 W/m2, restoring a balance between incoming and outgoing radiation.
The crucial question is: "How much does our planet need to warm to emit (and reflect) an additional 3.6 W/m2 of radiation to space? This fundamental property of our planet isn't known. Climate scientists call it climate sensitivity: DegC of warming per doubling of CO2 or degC/3.6 W/m2. The reciprocal - W/m2 emitted per degC of warming - is what restores balance. If the Earth behaved like a gray body with a temperature of 288 degK and an emissivity of 0.61 (and therefore emitted 240 W/m2 of thermal infrared to space according to the Stefan-Boltzmann law). However, we are quite confident that a warmer planet will have more water vapor in the atmosphere and that water vapor will slow radiative cooling to space, just like CO2. Changes in radiative cooling to space in response to warming are called feedbacks and are reported in terms of W/m2/degC, while radiative forcing is independent of temperature and reported in terms of W/m2. If more water vapor produces more clouds that reflect more incoming SWR to space, that would be a negative feedback that would reduce climate sensitivity.
Fortunately, we have observations from space that prove feedbacks are real. Every year, global mean surface temperature rises about 3 degC because the land rich northern hemisphere warms more than the ocean dominated southern hemisphere. During such seasonal warming, the planet emits about 2.2 W/m2 of LWR per degC of warming from clear skies, almost exactly what our climate models predict for combined water vapor and lapse-rate (also caused by water vapor) feedback. However, our models predict modestly too much feedback in thermal infrared from cloudy skies and don't predict what we observe for changes in reflected SWR with warming. Worst of all seasonal warming is a combination of warming in the NH and cooling in the SH while "global warming" occurs in both hemispheres and most in the Arctic. So observing seasonal warming from space can tell us that feedbacks are real and that our models can't properly reproduce feedbacks from cloudy skies, but it can't tell us what climate sensitivity is.
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.
Hi Roger
Like Sean I just got redirected here from a comment made on the recent Ice Surprises post.
I enjoyed the clear explanation of how CO2 impacts on the climate, but a couple of things are missing for me:
1. It is implied that the downwellings are somehow proportional to the concentration of CO2 in the atmosphere, but is this the case? Is the relationship linear?
2. This impact and the others illustrated combine into a very complex mix of climate effects - but even so it's a huge simplification of reality. What prompted my original comment was the statement "the planet has indeed continued to warm due primarily to the combustion of fossil fuels" - and I still see no justification for the word 'primarily'.
Thanks for all your work (and also to your Dad!)
I’ve just spotted this post now in 2025. Whilst I can see how added carbon dioxide will make for a warmer world, how does this change our weather? How does carbon dioxide create a heat wave? Or a tropical cyclone? It seems to me that the forces that go into those and other dynamic climate impact drivers are largely independent of a slightly warmer atmosphere, which in reality is dominated by warmer minimums.
Angular momentum, the solar constant, topography, latitude. These all feature with much more influence in what our regional weather is.
A few quick thoughts upon reread. The second diagram is confusing, maybe. The right hand side shows 396 of surface radiation, of which 333 is downwelled? Am I reading that correctly? Just commonsensically that seems like a huge percentage if so. Too huge.
And, with all due respect, and I'm really glad to have your Dad involved, and happy for you that you are so close, I think this explanation falls under Lindzen's critique of being too simple. I abandoned my MatSci degrees to go on to trade options on the 30 yr bond future at the Chicago Board of Trade. We had the early Black-Scholes models to use, and were the first ones to apply them. But, I quickly learned that a normal distribution does not capture the real world volatility of bonds (and stocks too). The reason is that markets are highly complex systems. And highly complex systems cannot be modeled. (I believe that is still true; Engineering stuck with my son and he and I were discussing the limitations of modeling highly complex systems). Weather/climate is, obviously, a highly complex system. That's why the initial models all failed. And current ones will too. And, don't feel bad; a lot of human systems approach highly complex status. My son was working on the next generation of aircraft carriers, and they were essentially highly complex systems. Decades ago I read an engineer who predicted the space shuttles would be destroyed because they were highly complex and thus we could not engineer out every possibility.
Upon reread, I still find Lindzen's argument that CO2 effect is logarithmic to be compelling. And thus any additional CO2 we put into the atmosphere from this point on will have a negligible effect.
If there's any simple glaring errors in my post or any extra explanations anyone has, I'm all ears.
Even if I disagree with you and your Dad on this, I do highly value your integrity and willingness to speak truth to (very well funded!!) power. Thank you.
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!
Henry: The prominent skeptic Roy Spenser explains the flaws in Miskolczi's work here:
https://www.drroyspencer.com/2010/08/comments-on-miskolczi’s-2010-controversial-greenhouse-theory/
Or more simply, consider a thin layer of atmosphere that is both absorbing and emitting thermal infrared atmosphere. Only the components of the radiative fluxes emitted into or absorbed from the vertical direction affect the heating and cooling of our planet. The thermal infrared emitted by the GHGs in the atmosphere depends on the amount of GHGs in the layer, but is emitted equally up and down, so rising GHGs don't change the net vertical flux from emission, which is zero. Absorption is different, however. According to Beer's Law, transmission is a fraction (I/I_0), not an amount of the radiation entering the layer that is proportional to the amount of GHG's in the layer and the distance traveled through the layer. Since the atmosphere generally gets colder with increasing altitude, the upward flux from below is generally larger than the downward flux from above. Therefore, more GHGs reduce absorption of the upward flux of thermal IR by the layer than they reduce the downward flux. Therefore increasing GHGs slow the net vertical flux to space. You know this is true because the outward flux falls from an average of 390 W/m2 near the surface to 240 W/m2 at the TOA.
So where did Miskolczi go wrong? He POSTULATES that the upward flux Aa and downward flux Ed entering any layer are exactly equal. As Spenser points out, in our atmosphere, these quantities are often nearly equal, but not exactly equal. If an emitted photon travels an average of 1 km upward or downward before being absorbed in our thin layer, the upward flux was emitted from GHGs that were 13 degC warmer than the downward flux was emitted (assuming a lapse rate of 6.5 degC/km). If the average vertical distance traveled is only 100 m, the temperature difference is only 1.3 degC. If only 10 m, then 0.13 degC. So it can be hard to measure the difference in the upward (Aa) and downward fluxes (Ed) at some wavelengths and altitudes because our lower atmosphere is fairly opaque to thermal infrared. However, If you go high enough in the atmosphere, at every wavelength the air gets thin enough that photons can travel to where the temperature is different enough to create a difference between the upward and downward flux.
What the consensus over-simplifies and fails to tell us is that the "greenhouse effect" is not produced by the absorption of thermal infrared alone. It is produced by the interaction of the absorption and emission of thermal infrared with the TEMPERATURE GRADIENT in our atmosphere. If there were no temperature gradient, there would be no greenhouse effect. (In Antarctica on the average there is no vertical temperature gradient and no greenhouse effect.) As it turns out, most of the absorption and emission of thermal infrared in our atmosphere occurs in the troposphere, where the temperature decreases with altitude, causing rising GHGs to warm our planet.
You can use the online Modtran radiative transfer calculator to see how the upward and downward fluxes differ at a given altitude and wavelength and vary with GHG concentration using the "look up" and "look down" options. When CO2 is 4000 ppm the upward and downward fluxes at those wavelengths strongly absorbed by CO2 have "blackbody intensity". (This is effectively "saturation".) As the CO2 concentration is reduced to 400, then 40, then 4 ppm, the upward and downward fluxes begin to differ. But if you remove all of the other GHGs, at other wavelengths the upward and downward flux are always different.
https://climatemodels.uchicago.edu/modtran/
Frank many thanks for taking the trouble to go through that. It will take me a while to get my head round it! I have read Roy Spencer's article but you made it a bit clearer! I still nevertheless am far from convinced that CO2 - man made or ocean emitted - has more than a very small role to play in the planet's temperature. It seems to me that atmospheric pressure is more significant that the make-up of the atmosphere but that's another discussion for another day!
Henry: Before you can say something has a small effect, you need to quantify that effect. The simplest thing to calculate is the reduction in radiative cooling to space caused by an instantaneous doubling of CO2 (before complicated changes follow). That reduction (called radiative forcing) is about 3.6 W/m2 (about 1.5% of the 240 W/m2 that satellites observe exiting the top of the atmosphere for space. Assuming incoming SWR is unchanged, the law of conservation of energy demands that our planet warm until it emits an additional 3.6 W/m2, restoring a balance between incoming and outgoing radiation.
The crucial question is: "How much does our planet need to warm to emit (and reflect) an additional 3.6 W/m2 of radiation to space? This fundamental property of our planet isn't known. Climate scientists call it climate sensitivity: DegC of warming per doubling of CO2 or degC/3.6 W/m2. The reciprocal - W/m2 emitted per degC of warming - is what restores balance. If the Earth behaved like a gray body with a temperature of 288 degK and an emissivity of 0.61 (and therefore emitted 240 W/m2 of thermal infrared to space according to the Stefan-Boltzmann law). However, we are quite confident that a warmer planet will have more water vapor in the atmosphere and that water vapor will slow radiative cooling to space, just like CO2. Changes in radiative cooling to space in response to warming are called feedbacks and are reported in terms of W/m2/degC, while radiative forcing is independent of temperature and reported in terms of W/m2. If more water vapor produces more clouds that reflect more incoming SWR to space, that would be a negative feedback that would reduce climate sensitivity.
Fortunately, we have observations from space that prove feedbacks are real. Every year, global mean surface temperature rises about 3 degC because the land rich northern hemisphere warms more than the ocean dominated southern hemisphere. During such seasonal warming, the planet emits about 2.2 W/m2 of LWR per degC of warming from clear skies, almost exactly what our climate models predict for combined water vapor and lapse-rate (also caused by water vapor) feedback. However, our models predict modestly too much feedback in thermal infrared from cloudy skies and don't predict what we observe for changes in reflected SWR with warming. Worst of all seasonal warming is a combination of warming in the NH and cooling in the SH while "global warming" occurs in both hemispheres and most in the Arctic. So observing seasonal warming from space can tell us that feedbacks are real and that our models can't properly reproduce feedbacks from cloudy skies, but it can't tell us what climate sensitivity is.
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.