With a straightforward scheme for allocating overlaps, we find that water vapour is the dominant contributor (~50% of the effect), followed by clouds (~25%) and then CO2 with ~20%. All other absorbers play only minor roles.
They say that overlaps are accounted for in their attribution. But the real point is that water vapor and clouds, which again are two distinct things, are only feedbacks because their levels in the atmosphere are dependent on atmospheric conditions. CO2 levels on the other hand are independent of atmospheric conditions. Water vapor and clouds depend on the greenhouse warming of CO2 (and the other minor GHG's) for their levels. CO2 is the main driver.
I don't disagree with you at all on toxic pollutants as a serious issue. It's going to be an ongoing problem of civilization.
But it's very unlikely that the global warming we're seeing is just natural variation. If someone comes up with a different theory that explains global warming better than the current theory I'll accept it but no one has even come close yet.
Well, it was a serious response to the absolutist tone of your original statement. I don't think the human race is going extinct any time soon. We are an intelligent and adaptable species. As long as we can find air, water, food and shelter we'll survive. And as long as there are any substantial number of people around there will be some form of civilization. But considering the changes that are likely to occur with global warming there will be a lot of painful adjustments to be made adapting to it and we may not be able to support even the number of humans on the planet now in 100 years. Like it or not we're still completely dependent on the natural processes of the planet for the air we breathe, the fresh water we drink and the food we eat. If we disrupt those natural processes enough it could be pretty costly. But then I guess I'm just an alarmist.
No one has demonstrated without a doubt that it means the end of civilization.
What if the end of civilization is only 90% probable? Is that good enough odds for you? How about 50%? What's your cutoff of acceptable risk? Is it 100% or nothing?
I like your post but weather is as much about energy moving through the atmosphere as it is about water. Of course water vapor is often the carrier of that energy through convection but energy also moves through radiative transfer and some conduction at the surface.
I don't think the penguins could survive the polar bears. There are no large land predators in Antarctica, just in the ocean around it and as clumsy as penguins are on land they are graceful and powerful swimmers able to evade leopard seals pretty well.
That didn't deserve to be modded down. Must be the RealClimate reference.
Replying to Burnhard about what Phil Jones said, here is the transcript:
BBC: Do you agree that from 1995 to the present there has been no statistically-significant global warming
Phil Jones: Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods.
BBC: How confident are you that warming has taken place and that humans are mainly responsible?
Phil Jones: I'm 100% confident that the climate has warmed. As to the second question, I would go along with IPCC Chapter 9 - there's evidence that most of the warming since the 1950s is due to human activity.
I believe the confidence level Jones calculated was 93% so not that far from being statistically significant. As Jones said statistical significance is less likely with shorter time scales so your 1/2 of the significant time scale is meaningless.
You are comparing the US temperature record with the global temperature record. That is not a valid comparison because the US temperature record is but a small part (2%) of the global area.
Did you even read the rest of the page you linked to? It's a total refutation of the part you quoted.
The 1+ metre rise in sea level prediction was published after the last IPCC report was finalized. It was recognized by the authors at the time that the IPCC prediction was extremely conservative.
That was more of a theological position that was taken until we had sufficient knowledge to over turn it. I suppose you could say AGC is a theological position too but the knowledge keeps piling up in support of it. There isn't much against it.
Actually the Holocene climactic optimum occurred from about 9000-5000 years ago and the Earth has cooled off a bit since then. But temperatures within the last decade or so appear to be a bit above what they were during the HCO.
I'm not going through your whole list but coral reefs dying is a documented fact. You can argue that it's not due to global warming but not that it isn't happening.
The 2010 arctic sea ice minimum was the 3rd lowest on record (after 2007 & 2008) and below the 2009 minimum. They are still the 4 lowest on record. I wouldn't call that really growing.
2010 has been the warmest year on record so far (until the end of September) but it may not set the new record depending on how strong the developing La Nina is. The decade from 2000 to 2009 is the warmest on record. I wouldn't call that cooling.
Its a law of physics that CO2 is an infrared absorber - is someone questioning that?
Its a fact that CO2 levels are rising in our atmosphere - is someone questioning that?
Its a fact that most of that rise is due to man - is someone questioning that?
No?
Just in case someone still doesn't get it - the 3 facts you listed above are not suitable as premises when you're trying to reach the conclusion that man-made CO2 is the direct and main cause behind global temperature rise. You would have to include something about no other chemical/elemental changes being observed in the atmosphere to even come close to asserting that man-made CO2 is the main cause - and that would still be an incredibly simplified explanation.
The first two are of course simple scientific facts, easily measurable. The third is more complex but the fact that the increase in atmospheric carbon (primarily in the form of CO2) year after year is less than half of the total fossil carbon emitted by human activities is a pretty strong implication that man is the primary cause. The first fact that CO2 is an IR absorber and the second fact that CO2 concentrations have increased would lead you to believe that IR absorption has increased leading to higher temperatures. That's my simplified explanation.
You are confusing water vapor with clouds which while they are related are two different things. Water vapor is always a positive forcing. Clouds can be either positive or negative depending on a number of factors. Also CO2 alone accounts for around 20% of GHG forcing, not the 5% you said.
Climate sensitivity to CO2 is on the order of a few tenths of a degree.... Did we see such feedbacks with the previous CO2 doubling (from, say, 190ppm to 380ppm)?
Considering that the last time atmospheric CO2 levels were around 190 ppmv was at the height of the last glaciation some 20,000 years ago and that global temperatures have risen some 8 C since then I don't think 3-9C is really wrong.
Those "toxic chemicals" and "plastics going into the oceans" don't have anything to do with global warming. Habitat destruction can have an effect. But increased CO2 in the atmosphere due mostly to human use of fossil fuel is the primary cause of global warming. Therefore it is something to pay attention to.
IPCC predictions have if anything proven to be too conservative about what will happen in general. I think you need to look at the time frames they have put on their predictions because most of the worst stuff they have predicted is scheduled for later this century.
To trot out the tired old/. cliche, correlation is not causation. Just because CO2 levels trailed temperature rises coming out of glaciations as shown by ice core data does not do anything to prove that rising atmospheric CO2 levels can not lead to increases in temperatures on their own.
When the model results don't match they don't "tweak" the models. They are not merely trying to match the curve of the real data. Instead they examine the underlying physics the models are based on to see where they got it wrong, fix that and update the models.
As far as the accuracy of projections of future climate go they have been not that bad. The problem with trying to project future climate is that there are a number of things that affect climate that are not easily predictable on a short term basis. Things such as the timing and strength of El Nino/La Nina episodes, the current longest solar minimum in more than a century and the exact level of CO2 in the atmosphere which depends largely on how much fossil fuel we burn. So what the climate scientists and model builders do is devise several realistic scenarios to feed in to the model. The model projections are only accurate to the extent that the scenarios they feed in to it are accurate. Regardless of how accurate the projections are they all say that continuing to increase the level of CO2 in the atmosphere will lead to increasing global temperature.
The Earth may have had much higher atmospheric levels of CO2 in the past but not since long before the genus Homo evolved. Humans have never experienced CO2 levels this high in their existence.
And the problem is even if it is open source how can you be sure the executable code running on the machine is from the open source code unless you personally compiled and loaded it yourself.
Boy, you don't give up. In bank machines there is no reason to hide the transaction that took place and you can actually receive a paper receipt of the transaction as you entered it. Having a secret ballot is incompatible with that kind of transaction receipt.
I've been a sys admin for 25 years and I'll never trust electronic voting because I know the sorts of things you can do with computers. Fortunately here in Oregon all voting is on paper ballots.
And how would you know that the Open Source program that you trust was what was actually put on the hardware unless you personally compiled and loaded it? Give me a paper ballot every time.
Slashdot Mirror
I'd like to see a constitutional amendment that people who do not vote are not counted for purposes of representation.
So are you saying children who are too young to vote should not be counted as well?
In Oregon felons are not allowed to vote while in custody but once they are released they are allowed to vote. That seems reasonable to me.
I got my figures from a 2010 paper on "The attribution of the present-day total greenhouse effect"
With a straightforward scheme for allocating overlaps, we find that water vapour is the dominant contributor (~50% of the effect), followed by clouds (~25%) and then CO2 with ~20%. All other absorbers play only minor roles.
They say that overlaps are accounted for in their attribution. But the real point is that water vapor and clouds, which again are two distinct things, are only feedbacks because their levels in the atmosphere are dependent on atmospheric conditions. CO2 levels on the other hand are independent of atmospheric conditions. Water vapor and clouds depend on the greenhouse warming of CO2 (and the other minor GHG's) for their levels. CO2 is the main driver.
I don't disagree with you at all on toxic pollutants as a serious issue. It's going to be an ongoing problem of civilization.
But it's very unlikely that the global warming we're seeing is just natural variation. If someone comes up with a different theory that explains global warming better than the current theory I'll accept it but no one has even come close yet.
Well, it was a serious response to the absolutist tone of your original statement. I don't think the human race is going extinct any time soon. We are an intelligent and adaptable species. As long as we can find air, water, food and shelter we'll survive. And as long as there are any substantial number of people around there will be some form of civilization. But considering the changes that are likely to occur with global warming there will be a lot of painful adjustments to be made adapting to it and we may not be able to support even the number of humans on the planet now in 100 years. Like it or not we're still completely dependent on the natural processes of the planet for the air we breathe, the fresh water we drink and the food we eat. If we disrupt those natural processes enough it could be pretty costly. But then I guess I'm just an alarmist.
They're talking about Portland, Maine, not Oregon.
No one has demonstrated without a doubt that it means the end of civilization.
What if the end of civilization is only 90% probable? Is that good enough odds for you? How about 50%? What's your cutoff of acceptable risk? Is it 100% or nothing?
I like your post but weather is as much about energy moving through the atmosphere as it is about water. Of course water vapor is often the carrier of that energy through convection but energy also moves through radiative transfer and some conduction at the surface.
I don't think the penguins could survive the polar bears. There are no large land predators in Antarctica, just in the ocean around it and as clumsy as penguins are on land they are graceful and powerful swimmers able to evade leopard seals pretty well.
fuzzy... LOL.
That didn't deserve to be modded down. Must be the RealClimate reference.
Replying to Burnhard about what Phil Jones said, here is the transcript:
BBC: Do you agree that from 1995 to the present there has been no statistically-significant global warming
Phil Jones: Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods.
BBC: How confident are you that warming has taken place and that humans are mainly responsible?
Phil Jones: I'm 100% confident that the climate has warmed. As to the second question, I would go along with IPCC Chapter 9 - there's evidence that most of the warming since the 1950s is due to human activity.
I believe the confidence level Jones calculated was 93% so not that far from being statistically significant. As Jones said statistical significance is less likely with shorter time scales so your 1/2 of the significant time scale is meaningless.
You are comparing the US temperature record with the global temperature record. That is not a valid comparison because the US temperature record is but a small part (2%) of the global area.
Did you even read the rest of the page you linked to? It's a total refutation of the part you quoted.
The 1+ metre rise in sea level prediction was published after the last IPCC report was finalized. It was recognized by the authors at the time that the IPCC prediction was extremely conservative.
That was more of a theological position that was taken until we had sufficient knowledge to over turn it. I suppose you could say AGC is a theological position too but the knowledge keeps piling up in support of it. There isn't much against it.
Actually the Holocene climactic optimum occurred from about 9000-5000 years ago and the Earth has cooled off a bit since then. But temperatures within the last decade or so appear to be a bit above what they were during the HCO.
I'm not going through your whole list but coral reefs dying is a documented fact. You can argue that it's not due to global warming but not that it isn't happening.
The 2010 arctic sea ice minimum was the 3rd lowest on record (after 2007 & 2008) and below the 2009 minimum. They are still the 4 lowest on record. I wouldn't call that really growing.
2010 has been the warmest year on record so far (until the end of September) but it may not set the new record depending on how strong the developing La Nina is. The decade from 2000 to 2009 is the warmest on record. I wouldn't call that cooling.
Its a law of physics that CO2 is an infrared absorber - is someone questioning that?
Its a fact that CO2 levels are rising in our atmosphere - is someone questioning that?
Its a fact that most of that rise is due to man - is someone questioning that?
No?
Just in case someone still doesn't get it - the 3 facts you listed above are not suitable as premises when you're trying to reach the conclusion that man-made CO2 is the direct and main cause behind global temperature rise. You would have to include something about no other chemical/elemental changes being observed in the atmosphere to even come close to asserting that man-made CO2 is the main cause - and that would still be an incredibly simplified explanation.
The first two are of course simple scientific facts, easily measurable. The third is more complex but the fact that the increase in atmospheric carbon (primarily in the form of CO2) year after year is less than half of the total fossil carbon emitted by human activities is a pretty strong implication that man is the primary cause. The first fact that CO2 is an IR absorber and the second fact that CO2 concentrations have increased would lead you to believe that IR absorption has increased leading to higher temperatures. That's my simplified explanation.
You are confusing water vapor with clouds which while they are related are two different things. Water vapor is always a positive forcing. Clouds can be either positive or negative depending on a number of factors. Also CO2 alone accounts for around 20% of GHG forcing, not the 5% you said.
Climate sensitivity to CO2 is on the order of a few tenths of a degree. ... Did we see such feedbacks with the previous CO2 doubling (from, say, 190ppm to 380ppm)?
Considering that the last time atmospheric CO2 levels were around 190 ppmv was at the height of the last glaciation some 20,000 years ago and that global temperatures have risen some 8 C since then I don't think 3-9C is really wrong.
Those "toxic chemicals" and "plastics going into the oceans" don't have anything to do with global warming. Habitat destruction can have an effect. But increased CO2 in the atmosphere due mostly to human use of fossil fuel is the primary cause of global warming. Therefore it is something to pay attention to.
IPCC predictions have if anything proven to be too conservative about what will happen in general. I think you need to look at the time frames they have put on their predictions because most of the worst stuff they have predicted is scheduled for later this century.
To trot out the tired old /. cliche, correlation is not causation. Just because CO2 levels trailed temperature rises coming out of glaciations as shown by ice core data does not do anything to prove that rising atmospheric CO2 levels can not lead to increases in temperatures on their own.
LOL, if the temperature is 160 degrees there is no ice core record (unless you're talking about 160K).
When the model results don't match they don't "tweak" the models. They are not merely trying to match the curve of the real data. Instead they examine the underlying physics the models are based on to see where they got it wrong, fix that and update the models.
As far as the accuracy of projections of future climate go they have been not that bad. The problem with trying to project future climate is that there are a number of things that affect climate that are not easily predictable on a short term basis. Things such as the timing and strength of El Nino/La Nina episodes, the current longest solar minimum in more than a century and the exact level of CO2 in the atmosphere which depends largely on how much fossil fuel we burn. So what the climate scientists and model builders do is devise several realistic scenarios to feed in to the model. The model projections are only accurate to the extent that the scenarios they feed in to it are accurate. Regardless of how accurate the projections are they all say that continuing to increase the level of CO2 in the atmosphere will lead to increasing global temperature.
The Earth may have had much higher atmospheric levels of CO2 in the past but not since long before the genus Homo evolved. Humans have never experienced CO2 levels this high in their existence.
And the problem is even if it is open source how can you be sure the executable code running on the machine is from the open source code unless you personally compiled and loaded it yourself.
Boy, you don't give up. In bank machines there is no reason to hide the transaction that took place and you can actually receive a paper receipt of the transaction as you entered it. Having a secret ballot is incompatible with that kind of transaction receipt.
I've been a sys admin for 25 years and I'll never trust electronic voting because I know the sorts of things you can do with computers. Fortunately here in Oregon all voting is on paper ballots.
And how would you know that the Open Source program that you trust was what was actually put on the hardware unless you personally compiled and loaded it? Give me a paper ballot every time.