Global Warming Makes Weather In Boreal Summer More Persistent

[bluewave]

https://wcd.copernicus.org/preprints/wcd-2020-40/

https://wcd.copernicus.org/preprints/wcd-2020-40/wcd-2020-40.pdf
 

Global warming makes weather in boreal summer more persistent

Dim Coumou1,2† and Paolo De Luca1†
1Department of Water and Climate Risk, Institute for Environmental Studies (IVM), Vrije Universiteit Amsterdam,
Amsterdam, 1081 HV, the Netherlands
5 2Royal Netherlands Meteorological Institute (KNMI), De Bilt, 3730 AE, the Netherlands
†These authors contributed equally to the work Correspondence to: Dim Coumou ([email protected])

Abstract. Extreme summer weather often has devastating impacts on society when it lasts for many days. Stalling cyclones can lead to flooding and persistent hot-dry conditions can lead to health impacts and harvest losses. Global warming weakens the hemispheric-wide circulation in boreal summer, which has been shown in both observations and models using multiple circulation metrics. Until now, it is still largely unclear what this weakening implies for regional weather conditions, including their persistence. Using an advanced persistence metric, we show that summer weather has become more-persistent over 1979-2019. State-of-the-art climate models reproduce this upward trend in persistence indicating that it  can be attributed to greenhouse gas forcing. Our persistence metric accounts for the full state of the atmosphere at any given moment and is strongly rooted in dynamical systems theory. Thereby it is able to detect dynamical changes previously unseen in more widely used clustering analyses that sharply reduce the amount of information used. We show that under future high-emission scenarios, summer weather will become increasingly more-persistent due to a weakening of the circulation. Most of this increase in persistence, and the associated societal risks, is avoided under an emission scenario compatible with the Paris agreement.

  
 

[rclab]

9 minutes ago, bluewave said:

https://wcd.copernicus.org/preprints/wcd-2020-40/

https://wcd.copernicus.org/preprints/wcd-2020-40/wcd-2020-40.pdf
 

Global warming makes weather in boreal summer more persistent

Dim Coumou1,2† and Paolo De Luca1†
1Department of Water and Climate Risk, Institute for Environmental Studies (IVM), Vrije Universiteit Amsterdam,
Amsterdam, 1081 HV, the Netherlands
5 2Royal Netherlands Meteorological Institute (KNMI), De Bilt, 3730 AE, the Netherlands
†These authors contributed equally to the work Correspondence to: Dim Coumou ([email protected])

Abstract. Extreme summer weather often has devastating impacts on society when it lasts for many days. Stalling cyclones 10 can lead to flooding and persistent hot-dry conditions can lead to health impacts and harvest losses. Global warming weakens the hemispheric-wide circulation in boreal summer, which has been shown in both observations and models using multiple circulation metrics. Until now, it is still largely unclear what this weakening implies for regional weather conditions, including their persistence. Using an advanced persistence metric, we show that summer weather has become more-persistent over 1979-2019. State-of-the-art climate models reproduce this upward trend in persistence indicating that it  can be attributed to greenhouse gas forcing. Our persistence metric accounts for the full state of the atmosphere at any given moment and is strongly rooted in dynamical systems theory. Thereby it is able to detect dynamical changes previously unseen in more widely used clustering analyses that sharply reduce the amount of information used. We show that under future high-emission scenarios, summer weather will become increasingly more-persistent due to a weakening of the circulation. Most of this increase in persistence, and the associated societal risks, is avoided under an emission scenario compatible with the Paris agreement.

  
 

After Reading this, the idiom “ Bad news travels fast” should be reversed. What troubles me is the “have we gone too far” scenario. Even with a more aggressive reduction in emissions, will the dramatic rise in temperature slow soon enough? I keep thinking of, as some articles/papers, Don and yourself have highlighted, that mention the potential for methane release from extensive areas of melting permafrost. How will that worsen the equation. Has it gone too far. A lay persons worry but to me quite real. As always..... 

[blizzard1024]

1 hour ago, bluewave said:

State-of-the-art climate models reproduce this upward trend in persistence indicating that it  can be attributed to greenhouse gas forcing.

Sorry folks.I am baaackkkk!   I was going to just leave this forum since it seems to be becoming a climate activist forum. I want to keep it a climate change forum so at least one skeptical viewpoint is needed. Climate models don't prove anything. Period. How can you say a model that is tuned to be sensitive to CO2 and assumes that the climate was in perfect balance in 1850 is proof that the warming we have seen recently is related to greenhouse gases. The climate system and natural forcings are so complex and unknown. To say that a small change in the greenhouse effect is causing the warming is presumptuous. I am not lying or trolling as implied by some person on this forum who I won't name because I don't want to attack anyone. I am sticking up for myself and my scientific opinion. That's all.  The wildfires out west are related to a hot summer but it is mostly related to the poor fire management practices and humans causing the fires. Hurricanes are not strengthening because of global warming, the global ACE has been pretty steady. So all this political fallout from an active hurricane and fire season, likely related to La Nina, is very frustrating to see. The politicians fund the climate scientists. So it is in their best financial interest to tow the party line. The peer review process is corrupted by the fact that these same scientists now control what gets published and what doesn't. What dataset is considered good and what isn't. It is the corruption that Dwight D. Eisenhower warned about in his farewell address in 1961. We are living it today in climate science and because of this I believe we have put back climate science advancement at least a generation. It would be FAR better IMO to have climate scientists focus on seasonal forecasting and interannual variability. This would benefit society much more than global doomsday scenarios that will not ever come true. CO2 is a minor GHG. Period. End of story. It is not the control knob on our climate. The ice core data proves that. It is very unscientific to say that something else kicks off global cooling, CO2 remains the same for a thousand years or so while the Earth cools. Then it all of the sudden it becomes a feedback and amplifies the initial cooling? Then at glacial termination something else kicks it off and after a lag, THEN it again becomes a feedback? That is not physics. It's denial that something else controls the climate, not CO2. 

Certainly CO2 values do not cause heat waves or fires or hurricanes. Some warming of course will lead to a slower jet stream but it likely is natural processes combined with some CO2 forcing because CO2 is a small component of the climate system.   

[rclab]

6 minutes ago, blizzard1024 said:

Sorry folks.I am baaackkkk!   I was going to just leave this forum since it seems to be becoming a climate activist forum. I want to keep it a climate change forum so at least one skeptical viewpoint is needed. Climate models don't prove anything. Period. How can you say a model that is tuned to be sensitive to CO2 and assumes that the climate was in perfect balance in 1850 is proof that the warming we have seen recently is related to greenhouse gases. The climate system and natural forcings are so complex and unknown. To say that a small change in the greenhouse effect is causing the warming is presumptuous. I am not lying or trolling as implied by some person on this forum who I won't name because I don't want to attack anyone. I am sticking up for myself and my scientific opinion. That's all.  The wildfires out west are related to a hot summer but it is mostly related to the poor fire management practices and humans causing the fires. Hurricanes are not strengthening because of global warming, the global ACE has been pretty steady. So all this political fallout from an active hurricane and fire season, likely related to La Nina, is very frustrating to see. The politicians fund the climate scientists. So it is in their best financial interest to tow the party line. The peer review process is corrupted by the fact that these same scientists now control what gets published and what doesn't. What dataset is considered good and what isn't. It is the corruption that Dwight D. Eisenhower warned about in his farewell address in 1961. We are living it today in climate science and because of this I believe we have put back climate science advancement at least a generation. It would be FAR better IMO to have climate scientists focus on seasonal forecasting and interannual variability. This would benefit society much more than global doomsday scenarios that will not ever come true. CO2 is a minor GHG. Period. End of story. It is not the control knob on our climate. The ice core data proves that. It is very unscientific to say that something else kicks off global cooling, CO2 remains the same for a thousand years or so while the Earth cools. Then it all of the sudden it becomes a feedback and amplifies the initial cooling? Then at glacial termination something else kicks it off and after a lag, THEN it again becomes a feedback? That is not physics. It's denial that something else controls the climate, not CO2. 

Certainly CO2 values do not cause heat waves or fires or hurricanes. Some warming of course will lead to a slower jet stream but it likely is natural processes combined with some CO2 forcing because CO2 is a small component of the climate system.   

Thank you for not leaving. Perhaps we can agree that the climate is changing. Who, what, when, how or why yet to be agreed upon but subject to healthy respectful discussion by those in the know. In that case I’ll be extremely quiet while I read.  As always ....

[blizzard1024]

1 minute ago, rclab said:

Thank you for not leaving. Perhaps we can agree that the climate is changing. Who, what, when, how or why yet to be agreed upon but subject to healthy respectful discussion by those in the know. In that case I’ll be extremely quiet while I read.  As always ....

Thanks. It would be nice for this to transpire to a tasteful discourse. I will not attack anyone. Just because I don't agree doesn't mean a person should be discredited or called a name etc. Healthy debate is important to learn. I want to learn more and challenge people to really think. YES the climate is warming now. But how much really? How bad is it? What are ALL the causes. I may disagree with some or most of you but I will respect you as a person. But if attacked I will go to the moderators and if nothing happens I will defend my thoughts and not resort to name calling etc.  Take care. 

[bluewave]

39 minutes ago, blizzard1024 said:

To say that a small change in the greenhouse effect is causing the warming is presumptuous. 

Changes to nature that seem small can have very big consequences. 
 

 

[blizzard1024]

How did nature survive the last several glacial to interglacial cycles?  They were far worse they anything we have seen the last 100 years or so. 

[donsutherland1]

5 hours ago, bluewave said:

https://wcd.copernicus.org/preprints/wcd-2020-40/

https://wcd.copernicus.org/preprints/wcd-2020-40/wcd-2020-40.pdf
 

Global warming makes weather in boreal summer more persistent

Dim Coumou1,2† and Paolo De Luca1†
1Department of Water and Climate Risk, Institute for Environmental Studies (IVM), Vrije Universiteit Amsterdam,
Amsterdam, 1081 HV, the Netherlands
5 2Royal Netherlands Meteorological Institute (KNMI), De Bilt, 3730 AE, the Netherlands
†These authors contributed equally to the work Correspondence to: Dim Coumou ([email protected])

Abstract. Extreme summer weather often has devastating impacts on society when it lasts for many days. Stalling cyclones can lead to flooding and persistent hot-dry conditions can lead to health impacts and harvest losses. Global warming weakens the hemispheric-wide circulation in boreal summer, which has been shown in both observations and models using multiple circulation metrics. Until now, it is still largely unclear what this weakening implies for regional weather conditions, including their persistence. Using an advanced persistence metric, we show that summer weather has become more-persistent over 1979-2019. State-of-the-art climate models reproduce this upward trend in persistence indicating that it  can be attributed to greenhouse gas forcing. Our persistence metric accounts for the full state of the atmosphere at any given moment and is strongly rooted in dynamical systems theory. Thereby it is able to detect dynamical changes previously unseen in more widely used clustering analyses that sharply reduce the amount of information used. We show that under future high-emission scenarios, summer weather will become increasingly more-persistent due to a weakening of the circulation. Most of this increase in persistence, and the associated societal risks, is avoided under an emission scenario compatible with the Paris agreement.

  
 

This is another significant paper. It confirms exactly what one would expect from the prior research showing a slowing and more wavy jet stream. It provides a unifying explanation for such events as last summer’s historic heat in Europe and Alaska, this year’s heat in Siberia, the record summer in parts of the Southwest, not to mention slowing forward motion of some recent hurricanes. 

[Bhs1975]

This is another significant paper. It confirms exactly what one would expect from the prior research showing a slowing and more wavy jet stream. It provides a unifying explanation for such events as last summer’s historic heat in Europe and Alaska, this year’s heat in Siberia, the record summer in parts of the Southwest, not to mention slowing forward motion of some recent hurricanes. 

It’s also melting more ice by bringing warm moist air all the way to the north pole.

[donsutherland1]

7 hours ago, Bhs1975 said:

It’s also melting more ice by bringing warm moist air all the way to the north pole.

It is. This year’s record low ice in the central Arctic region, as part of a long-term trend of declining ice, is an example.

[LibertyBell]

15 hours ago, bluewave said:

Changes to nature that seem small can have very big consequences. 
 

 

Isn't the Starfish one of those key biomarkers that is undergoing a massive die off?

[LibertyBell]

15 hours ago, blizzard1024 said:

How did nature survive the last several glacial to interglacial cycles?  They were far worse they anything we have seen the last 100 years or so. 

well we have had several mass extinction events; we are in the middle of one right now.

 

[LibertyBell]

16 hours ago, blizzard1024 said:

Sorry folks.I am baaackkkk!   I was going to just leave this forum since it seems to be becoming a climate activist forum. I want to keep it a climate change forum so at least one skeptical viewpoint is needed. Climate models don't prove anything. Period. How can you say a model that is tuned to be sensitive to CO2 and assumes that the climate was in perfect balance in 1850 is proof that the warming we have seen recently is related to greenhouse gases. The climate system and natural forcings are so complex and unknown. To say that a small change in the greenhouse effect is causing the warming is presumptuous. I am not lying or trolling as implied by some person on this forum who I won't name because I don't want to attack anyone. I am sticking up for myself and my scientific opinion. That's all.  The wildfires out west are related to a hot summer but it is mostly related to the poor fire management practices and humans causing the fires. Hurricanes are not strengthening because of global warming, the global ACE has been pretty steady. So all this political fallout from an active hurricane and fire season, likely related to La Nina, is very frustrating to see. The politicians fund the climate scientists. So it is in their best financial interest to tow the party line. The peer review process is corrupted by the fact that these same scientists now control what gets published and what doesn't. What dataset is considered good and what isn't. It is the corruption that Dwight D. Eisenhower warned about in his farewell address in 1961. We are living it today in climate science and because of this I believe we have put back climate science advancement at least a generation. It would be FAR better IMO to have climate scientists focus on seasonal forecasting and interannual variability. This would benefit society much more than global doomsday scenarios that will not ever come true. CO2 is a minor GHG. Period. End of story. It is not the control knob on our climate. The ice core data proves that. It is very unscientific to say that something else kicks off global cooling, CO2 remains the same for a thousand years or so while the Earth cools. Then it all of the sudden it becomes a feedback and amplifies the initial cooling? Then at glacial termination something else kicks it off and after a lag, THEN it again becomes a feedback? That is not physics. It's denial that something else controls the climate, not CO2. 

Certainly CO2 values do not cause heat waves or fires or hurricanes. Some warming of course will lead to a slower jet stream but it likely is natural processes combined with some CO2 forcing because CO2 is a small component of the climate system.   

Fire seasons have been getting more and more active over the past 20 years and on a global scale.  Furthermore the Siberian heatwave isn't something one would expect to occur naturally because of its extremely long duration as well as the extremity of its anomalies.  About hurricanes, we were specifically talking about those rapidly strengthening as they approach the coast in Gulf waters, where the waters are abnormally warm, as well as forward speed slowing down- both have been happening more frequently for a few years now.

 

[bluewave]

28 minutes ago, LibertyBell said:

Isn't the Starfish one of those key biomarkers that is undergoing a massive die off?

Yeah, they believe that it’s related to the record marine heatwave.

https://advances.sciencemag.org/content/5/1/

 

[LibertyBell]

Just now, bluewave said:

Yeah, they believe that it’s related to the record marine heatwave.

https://advances.sciencemag.org/content/5/1/

 

Saw an excellent doc on PBS that showed how the Starfish is one of those very important keystone species that indicates the health of the overall environment- and based on that, it isn't looking so good.

 

[bluewave]

23 minutes ago, LibertyBell said:

Saw an excellent doc on PBS that showed how the Starfish is one of those very important keystone species that indicates the health of the overall environment- and based on that, it isn't looking so good.

 

That was the great episode that the starfish clip posted above was from.

https://www.pbs.org/wnet/nature/the-serengeti-rules-41dfru/20105/

[donsutherland1]

40 minutes ago, LibertyBell said:

Fire seasons have been getting more and more active over the past 20 years and on a global scale.  Furthermore the Siberian heatwave isn't something one would expect to occur naturally because of its extremely long duration as well as the extremity of its anomalies.  About hurricanes, we were specifically talking about those rapidly strengthening as they approach the coast in Gulf waters, where the waters are abnormally warm, as well as forward speed slowing down- both have been happening more frequently for a few years now.

 

Here’s the attribution report on the Siberian heat: https://www.worldweatherattribution.org/wp-content/uploads/WWA-Prolonged-heat-Siberia-2020.pdf

 

[blizzard1024]

6 hours ago, donsutherland1 said:

Here’s the attribution report on the Siberian heat: https://www.worldweatherattribution.org/wp-content/uploads/WWA-Prolonged-heat-Siberia-2020.pdf

 

I saw this. I am not saying that the Earth is not warming, it clearly is. So in a warming world, we would see extremes like this. The central question to me is how much is related to the enhanced greenhouse effect specifically from CO2 BUT also increases in upper level water vapor. I really would like to see real-time upper tropospheric water vapor data monthly like what you can get on the NCEP reanalysis. If you look at this monthly data, the greenhouse effect pretty much is stable since CO2 increases are offset by drying in the upper troposphere. This would suggest the warming is natural. HOWEVER, other datasets show upper tropospheric moistening and a positive feedback. Many don't agree with NCEPs data.  That is fine. I would like to see the other dataset. In this way, we can monitor the greenhouse effect monthly. But this data is very hard to come by. I just can't find it. I also would like to see total cloud fraction of the Earth. NASA did this from 1983-2009. These two datasets on a monthly basis would be awesome to monitor the effect of clouds and the water vapor feedback.  Until I can see this data, I am stuck with NASAs cloud data which showed an inverse relationship w/ global temperatures 1983-2009. And NASA NVAP water vapor data at high levels which was consistent with NCEP reanalysis data up until 2001. NASA never released this data to 2009 which is frustrating. AIRs satellite data apparently shows a positive feedback. Where is the upper level water vapor dataset in a time series. You can then tease out the ENSO signal to make sure it is not driven by ENSO. Soden's study in the 1990s showed a positive feedback after Pinatubo cooling. But when I examined the data in detail, his data started during an El Nino and ended in a La Nina which would affect the level of moisture in the upper troposphere. So it is hard IMO to separate the two out factors out. So if anyone can find a time series of AIRS data and also cloud fraction to recent years please share. Thank you. 

[blizzard1024]

Here are two papers related to AIRs moisture retrievals and ENSO that concerns me. 

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2008GL035333

So the premise is Dessler looked at global temperature and water vapor datasets from a warmer period DJF 2006-2007 El Nino and then subtracted a colder DJF 2007-2008 from a La Nina. The figure below does show warmer temperatures coincide with higher values of upper level water vapor, q. But mainly over the equatorial regions. There is drying north and south of the tropics is related to subsidence from enhanced tropical convection.

 

Tropical convection does indeed increase during El Ninos vs La Ninas... see

https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019JD031026#:~:text=Convective organization has a large,scale circulations in the tropics.&text=The occurrence of organized deep,twofold outside of these regions.

So with more tropical convection, it is the heat AND moisture fluxes associated with said enhanced tropical convection leading to this apparent positive feedback. You can't separate out the ENSO signal. To me, this clearly does not prove a long term positive feedback from warming. It is just tropical convection and heat/moisture fluxes upward. 

 

 

[bdgwx]

That first paper says the water vapor feedback is strongly positive at about 2 W/m^2 per C. They end with "The existence of a strong and positive water‐vapor feedback means that projected business‐as‐usual greenhouse‐gas emissions over the next century are virtually guaranteed to produce warming of several degrees Celsius."

Unfortunately the second paper is paywalled and I cannot find an open copy. I will say that I took the opportunity to read other publications by the lead author Dr. Sullivan. So far I've not seen anything that leads me to believe he doubts the water vapor feedback or GHGs contribution to warming.

[donsutherland1]

3 hours ago, blizzard1024 said:

I saw this. I am not saying that the Earth is not warming, it clearly is. So in a warming world, we would see extremes like this. The central question to me is how much is related to the enhanced greenhouse effect specifically from CO2 BUT also increases in upper level water vapor. I really would like to see real-time upper tropospheric water vapor data monthly like what you can get on the NCEP reanalysis. If you look at this monthly data, the greenhouse effect pretty much is stable since CO2 increases are offset by drying in the upper troposphere. This would suggest the warming is natural. HOWEVER, other datasets show upper tropospheric moistening and a positive feedback. Many don't agree with NCEPs data.  That is fine. I would like to see the other dataset. In this way, we can monitor the greenhouse effect monthly. But this data is very hard to come by. I just can't find it. I also would like to see total cloud fraction of the Earth. NASA did this from 1983-2009. These two datasets on a monthly basis would be awesome to monitor the effect of clouds and the water vapor feedback.  Until I can see this data, I am stuck with NASAs cloud data which showed an inverse relationship w/ global temperatures 1983-2009. And NASA NVAP water vapor data at high levels which was consistent with NCEP reanalysis data up until 2001. NASA never released this data to 2009 which is frustrating. AIRs satellite data apparently shows a positive feedback. Where is the upper level water vapor dataset in a time series. You can then tease out the ENSO signal to make sure it is not driven by ENSO. Soden's study in the 1990s showed a positive feedback after Pinatubo cooling. But when I examined the data in detail, his data started during an El Nino and ended in a La Nina which would affect the level of moisture in the upper troposphere. So it is hard IMO to separate the two out factors out. So if anyone can find a time series of AIRS data and also cloud fraction to recent years please share. Thank you. 

Here’s one paper that shows increasing water vapor:

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JD024917

I’m not sure if NASA makes the underlying data for its cloud fraction maps public.

 

[blizzard1024]

15 minutes ago, donsutherland1 said:

Here’s one paper that shows increasing water vapor:

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JD024917

I’m not sure if NASA makes the underlying data for its cloud fraction maps public.

 

Thank you for this paper.  Here is the fundamental problem with their results. They are using global precipitable water vapor(PWV). Since water vapor rapidly decreases with height, this metric of water vapor is mostly what is happening in the lower troposphere. Since the oceans have been warming GPW has increased in all datasets (even NCEP). It is the upper troposphere that matters when it comes to the greenhouse effect. More greenhouse gases in the lower troposphere actually cool the layers above them. Similar to how the stratosphere cools above the troposphere with enhanced GHGs (assuming ozone is constant which it is not).  So the upper troposphere is where it counts for both CO2 and H2O. These researchers do not seem to understand this.  Here is a quote from the paper...

"The increased greenhouse gases reduce the outgoing longwave radiation and contribute to the global warming phenomenon. Studies have shown that the global mean surface temperature has increased by 0.7–0.8°C since the beginning of the twentieth century [Hansen et al., 2001; Smith and Reynolds, 2005; Parker et al., 2007]. Atmospheric water vapor provides the single largest positive feedback on global warming [Dai, 2006; Mieruch et al., 2008; Zhang et al., 2013]. Both climate models and observations suggest that an upward trend in water vapor is expected to appear as a response to the surface temperature increase [Held and Soden, 2006; Santer et al., 2006; Zhang et al., 2013]. Monitoring the variation of atmospheric water vapor is thus significant not only for the detection of climate change but also for a better understanding of water vapor feedback on global warming."

So they understand the role of water vapor as a feedback but use the wrong measurement. They use the whole troposphere. It needs to be upper troposphere. That is why you have to be careful about peer reviewed papers. These authors probably don't understand radiative transfer that well and the reviewers also. 

 

 

 

[Bhs1975]

Thank you for this paper.  Here is the fundamental problem with their results. They are using global precipitable water vapor(PWV). Since water vapor rapidly decreases with height, this metric of water vapor is mostly what is happening in the lower troposphere. Since the oceans have been warming GPW has increased in all datasets (even NCEP). It is the upper troposphere that matters when it comes to the greenhouse effect. More greenhouse gases in the lower troposphere actually cool the layers above them. Similar to how the stratosphere cools above the troposphere with enhanced GHGs (assuming ozone is constant which it is not).  So the upper troposphere is where it counts for both CO2 and H2O. These researchers do not seem to understand this.  Here is a quote from the paper...

"The increased greenhouse gases reduce the outgoing longwave radiation and contribute to the global warming phenomenon. Studies have shown that the global mean surface temperature has increased by 0.7–0.8°C since the beginning of the twentieth century [Hansen et al., 2001; Smith and Reynolds, 2005; Parker et al., 2007]. Atmospheric water vapor provides the single largest positive feedback on global warming [Dai, 2006; Mieruch et al., 2008; Zhang et al., 2013]. Both climate models and observations suggest that an upward trend in water vapor is expected to appear as a response to the surface temperature increase [Held and Soden, 2006; Santer et al., 2006; Zhang et al., 2013]. Monitoring the variation of atmospheric water vapor is thus significant not only for the detection of climate change but also for a better understanding of water vapor feedback on global warming."

So they understand the role of water vapor as a feedback but use the wrong measurement. They use the whole troposphere. It needs to be upper troposphere. That is why you have to be careful about peer reviewed papers. These authors probably don't understand radiative transfer that well and the reviewers also. 

 

 

 

Lol I think you don’t understand.

[blizzard1024]

5 hours ago, Bhs1975 said:

Lol I think you don’t understand.

Please explain. It is well known that it is upper tropospheric water vapor that is the most important when it comes to the Greenhouse effect. Why do you think they criticize NCEPs specific humidity?  It does show rises in the lower troposphere but declines in the very dry upper troposphere. There was a peer reviewed paper that looked at this very effect and found a constant greenhouse effect based on NCEPs dataset of water vapor showing declines in the upper troposphere. This paper has been ignored because scientists don't believe NCEPs dataset showing declining upper tropospheric water vapor.  I know I am correct on this, it is the upper troposphere that counts for the greenhouse effect. CO2 does nothing in the lower and even mid-troposphere, it is the high levels where it counts. This is fundamental. 

[chubbs]

HM had a series of tweets on tropical moisture and Atlantic hurricanes. For the area he looked at moisture increased at all levels of the atmosphere. Why wouldn't it? Temperature controls atmospheric moisture and temperature is increasing at all levels of the troposphere.

[blizzard1024]

Now 400 mb would have more of an effect as shown here. BUT you can easily see the ENSO signature which suggests the moistening is more from El Ninos and less from overall warming. You can't separate out the two. El Ninos lead to more tropical convection which moistens and heats the upper troposphere. 400 mb is not quite upper troposphere but it would easily be heated and moistened by said convection.  This is basic radiative transfer. 

[chubbs]

4 minutes ago, blizzard1024 said:

Please explain. It is well known that it is upper tropospheric water vapor that is the most important when it comes to the Greenhouse effect. Why do you think they criticize NCEPs specific humidity?  It does show rises in the lower troposphere but declines in the very dry upper troposphere. There was a peer reviewed paper that looked at this very effect and found a constant greenhouse effect based on NCEPs dataset of water vapor showing declines in the upper troposphere. This paper has been ignored because scientists don't believe NCEPs dataset showing declining upper tropospheric water vapor.  I know I am correct on this, it is the upper troposphere that counts for the greenhouse effect. CO2 does nothing in the lower and even mid-troposphere, it is the high levels where it counts. This is fundamental. 

Per the discussion 20 pages ago. NCEP is an older re-analysis product. Newer products like ERA5 have corrected errors and show increasing upper troposphere moisture. What is the point of providing you with additional information? The data and theory is all very consistent. Temperature is rising, moisture is rising, just as expected. Would take a large non-linearity for moisture to not increase as temperature increases. Note that this would cascade into precipitation and clouds.

[chubbs]

6 minutes ago, blizzard1024 said:

Now 400 mb would have more of an effect as shown here. BUT you can easily see the ENSO signature which suggests the moistening is more from El Ninos and less from overall warming. You can't separate out the two. El Ninos lead to more tropical convection which moistens and heats the upper troposphere. 400 mb is not quite upper troposphere but it would easily be heated and moistened by said convection.  This is basic radiative transfer. 

You can lead a horse to water but you can't make him drink. Comments: 1) rising temperature due to forcing has swamped ENSO effects, 2) Doesn't matter why warming occurred, warming temperatures have lead to increased moisture in the upper layers of the troposphere. The distribution is just as expected with biggest increase in areas with strong convection.

[chubbs]

Saw this chart on twitter (PW is petawatts which is estimated by taking forcing per meter squared times surface area of earth). There is a very close relationship between forcing changes and global temperature. Now that data has been updated, can see that the hiatus and subsequent temperature spike are mainly due to short-term forcing changes. Not much room for natural variation.

[Bhs1975]

Saw this chart on twitter (PW is petawatts which is estimated by taking forcing per meter squared times surface area of earth). There is a very close relationship between forcing changes and global temperature. Now that data has been updated, can see that the hiatus and subsequent temperature spike are mainly due to short-term forcing changes. Not much room for natural variation.

Looking at that chart you can see that 350ppm CO2 is that upper limit before feed backs kick in and set off runaway warming.