10,000 year ice temperature chart (Greenland)

[Shsg Falls]

One of my friends, a decent enough guy, is a global warming denialist and has presented the following chart on more than one occasion.  

 

 

http://joannenova.com.au/2010/02/the-big-picture-65-million-years-of-temperature-swings/

 

I don't want to debate him with radiative forcing and other technical stuff, nor do I want to be rude.  How would you tell him that just because the Earth was warm before doesn't mean A.G.W. isn't occurring right now?

[sokolow]

First question to ask your friend: from when as in what specific year is the last (most recent) data point shown on that graphic and what is the specific year used as the "present" ?

[sokolow]

More generally, well, thats kinda "the thing" is men and women doing paleoclimate have identified a lot of factors contributing to global temperature change, in the past. Climate scientists (sometimes the very same scientists!) consider & try to account for those forcings when running the numbers in the present.

And the conclusion of the IPCC and vast majority of climate science is: human GHG emissions are *very likely* the cause of the warming in the latter half of the 20th century and absent human GHG we would *very likely* have seen cooling in that same period and that the observed trends and system changes in eg land ice are *very unlikely* to be the result of natural variability.

Edit you know I think the latest IPCC went from *very likely* to *almost certainly*

[donsutherland1]

One of my friends, a decent enough guy, is a global warming denialist and has presented the following chart on more than one occasion.  

 

Capture.JPG

 

http://joannenova.com.au/2010/02/the-big-picture-65-million-years-of-temperature-swings/

 

I don't want to debate him with radiative forcing and other technical stuff, nor do I want to be rude.  How would you tell him that just because the Earth was warm before doesn't mean A.G.W. isn't occurring right now?

 

Several points:

 

1. The GISP2 data ends 95 years before present. As per information confirmed by Skierinvermont, that refers to 95 years before 1950. Hence, the last temperature reading is from approximately 1855.

 

ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/isotopes/gisp2_temp_accum_alley2000.txt

 

2. Since 1855 the Arctic region has warmed dramatically:

 

As a result, the Arctic is probably at least as warm as the Roman Warming period and perhaps the warmest it has been since the Minoan Warming Period.

[skierinvermont]

There are 3 major points to make:

 

1. This is a regional/local proxy. It shows more variation in temperature than a global average would.

 

2. Just because temperatures fluctuated in the past does not mean that CO2 is not a GHG and causing our present warming. 

 

3. The final data point on that graph is 95 years before present where present is defined as 1950 (the standard for paleoclimate studies). Thus the last data point is 1855. Since 1855 Greenland has warmed 1.5C. What this looks like plotted on the graph is shown below.

 

4. Even after plotting the present temperature on the graph, the scale is too coarse to see that the present warming occurred much faster than previous warmings. The present warming in Greenland has occurred over a period of just 100 years. The previous warming periods took several hundred and were of similar or lesser magnitude. 

 

[skierinvermont]

Several points:

 

1. Even as the graph ends at 2000, the data is 95 years before present. Hence, the last temperature reading is from approximately 1905.

 

ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/isotopes/gisp2_temp_accum_alley2000.txt

 

2. Since 1905, the Arctic region has warmed dramatically (almost 2°C):

 

http://data.giss.nasa.gov/gistemp/tabledata_v3/ZonAnn.Ts+dSST.txt (64N-90N)

 

As a result, the Arctic is probably at least as warm as the Roman Warming period and perhaps the warmest it has been since the Minoan Warming Period.

 

Don, see my post above. SKS confirmed with the author Richard Alley that the 'present' date is 1950 following convention in the field. Thus the last date on the chart is 1855.

[donsutherland1]

Don, see my post above. SKS confirmed with the author Richard Alley that the 'present' date is 1950 following convention in the field. Thus the last date on the chart is 1855.

Thanks very much, Skierinvermont. I'll revise my message to fix it.

[sokolow]

All this and more is stashed at SKS and desmogblog

http://www.google.com/search?q=skeptical%20science%20gisp2%20ice%20core

The useful thing from an arguing with one's father in law standpoint about SKS's page on that graph is the relevant datasets and papers are linked so everyone involved can -- in the interest of skepticism!! -- just go have a gander.

Joanne Nova, whose website (was that what your friend linked you out to?) is in the OP has her own page at desmog.

http://www.desmogblog.com/joanne-nova

Heartland Institute speaker, coordinator of a science education program for kids sponsored by Shell Oil.

Oorah kids let's learn about science! *peels out in a cloud of stinking rubber*

[StudentOfClimatology]

There are 3 major points to make:

1. This is a regional/local proxy. It shows more variation in temperature than a global average would.

Actually, the GISP2 is more of a Northern Hemispheric subtropical SST/Hadley Cell proxy. The rumor that it is a local temperature proxy probably started on a skeptic blog somewhere. In terms of climate, the ^18/O-^16/O ratio is used in ice cores. The ^18/O rich H^2O is mostly rained out at lower latitudes, leaving more in the way of ^16/O at the poles. Given that fact, the ocean source is rich in ^18/O.

There are 3 naturally occurring O^2 isotopes (with different atomic masses)..^16/O, ^17/O, and ^18/O. The ^16/O isotope is the most frequently occurring, featuring the slightest atomic mass, followed by ^18/O which is two neutrons heavier than ^16/O. Hence it takes more energy to vaporize H-2_^18/O than H-2_^16/O. So, the first H^2O created via evaporation is highly enriched H-2_^16/O. As warmer airmasses are propelled poleward by the Hadley and Ferrel circulations, H^2O condenses and precipitates. The atomically heavier H-2_^18/O within the droplets is the first to leave the column, leaving a greater ratio of H-2_^16/O, so the colder the airmass gets, the further the 18/O-16/O is lowered.

The temperatures required for these processes are well known. So you have to look toward the SSTs in the subtropics/mid-latitudes..all of which will affect the isotope ratios stored in the ice cores.

2. Just because temperatures fluctuated in the past does not mean that CO2 is not a GHG and causing our present warming.

Skeptics are constantly falling into their own trap here. The more variable the Holocene climate, the higher climate sensitivity subsequently must be to CO2 forcing. If the Holocene climate were stable, then I could see a lower climate sensitivity being plausible. However, the majority of the proxy data suggests a very unstable Holocene climate, hence a very sensitive climate system.

Climate skeptics who realized this then tried to claim the GISP data was a local proxy..which happens to not be true. The lines between truth and rumor were blurred by uneducated commenters and bloggers alike, so we ended up with the clusterf*ck we have now.

[blizzard1024]

Actually, the GISP2 is more of a Northern Hemispheric subtropical SST/Hadley Cell proxy. The rumor that it is a local temperature proxy probably started on a skeptic blog somewhere. In terms of climate, the ^18/O-^16/O ratio is used in ice cores. The ^18/O rich H^2O is mostly rained out at lower latitudes, leaving more in the way of ^16/O at the poles. Given that fact, the ocean source is rich in ^18/O.

There are 3 naturally occurring O^2 isotopes (with different atomic masses)..^16/O, ^17/O, and ^18/O. The ^16/O isotope is the most frequently occurring, featuring the slightest atomic mass, followed by ^18/O which is two neutrons heavier than ^16/O. Hence it takes more energy to vaporize H-2_^18/O than H-2_^16/O. So, the first H^2O created via evaporation is highly enriched H-2_^16/O. As warmer airmasses are propelled poleward by the Hadley and Ferrel circulations, H^2O condenses and precipitates. The atomically heavier H-2_^18/O within the droplets is the first to leave the column, leaving a greater ratio of H-2_^16/O, so the colder the airmass gets, the further the 18/O-16/O is lowered.

The temperatures required for these processes are well known. So you have to look toward the SSTs in the subtropics/mid-latitudes..all of which will affect the isotope ratios stored in the ice cores.

Skeptics are constantly falling into their own trap here. The more variable the Holocene climate, the higher climate sensitivity subsequently must be to CO2 forcing. If the Holocene climate were stable, then I could see a lower climate sensitivity being plausible. However, the majority of the proxy data suggests a very unstable Holocene climate, hence a very sensitive climate system.

Climate skeptics who realized this then tried to claim the GISP data was a local proxy..which happens to not be true. The lines between truth and rumor were blurred by uneducated commenters and bloggers alike, so we ended up with the clusterf*ck we have now.

Actually the Holocene has seen a very stable climate relative to the glacial period and the transition from the last glacial maximum to the interglacial. The shutting down of the North Atlantic Drift current when large influxes of fresh meltwater poured into the North Atlantic from the melting ice sheets rapidly changed climate. As soon as all the ice melted these fluctuations or "flickers" in climate stopped.  The climate is really not that sensitive when we are in interglacial periods. We see slow variations in global temperatures related to changing oceanic currents. That is the main driver of the climate changes assuming a constant sun which you can't. There is no way that the Earth's climate is as sensitive as the GCMs state. If so, during the turbulent times of the glacial-interglacial transitions, the Earth's climate would have spiraled out of control and life would not exist as we know it.   This is common sense. 

[skierinvermont]

Actually the Holocene has seen a very stable climate relative to the glacial period and the transition from the last glacial maximum to the interglacial. The shutting down of the North Atlantic Drift current when large influxes of fresh meltwater poured into the North Atlantic from the melting ice sheets rapidly changed climate. As soon as all the ice melted these fluctuations or "flickers" in climate stopped.  The climate is really not that sensitive when we are in interglacial periods. We see slow variations in global temperatures related to changing oceanic currents. That is the main driver of the climate changes assuming a constant sun which you can't. There is no way that the Earth's climate is as sensitive as the GCMs state. If so, during the turbulent times of the glacial-interglacial transitions, the Earth's climate would have spiraled out of control and life would not exist as we know it.   This is common sense. 

 

Everything is relative. The Holocene is more stable than other periods, but there are still relatively large swings in temperature in response to relatively small changes in forcing. 

[skierinvermont]

And thank you, SoC, for the correction on GISP2 as a northern hemisphere subtropical SST proxy. I had forgotten that. 

[StudentOfClimatology]

Actually the Holocene has seen a very stable climate relative to the glacial period and the transition from the last glacial maximum to the interglacial.

Skierinvermont is correct. Relative to the typical stadial climate, yes the Holocene is "stable". But wouldn't classify the Holocene interstadial as stable in of itself. There have been many notable global climate swings throughout the Holocene. The peer reviewed literature has reached a healthy consensus on the topic of abrupt climate change throughout the Holocene. And our continued CO2 emissions are putting the climate system at immense risk..it could literally change on a dime if we don't start using some common sense and regulate the oil giants behind it.

http://m.sciencemag.org/content/299/5615/2005.short

Although abrupt climate changes can occur for many reasons, it is conceivable that human forcing of climate change is increasing the probability of large, abrupt events.

1 Department of Geosciences and EMS Environment Institute, Pennsylvania State University, University Park, PA 16802, USA.

2 Southampton Oceanography Centre, University of Southampton, Southampton SO14 3ZH, UK.

3 Department of Economics, Yale University, New Haven, CT 06520, USA.

4 Institute for the Study of Planet Earth, University of Arizona, Tucson, AZ 85721, USA.

5 Lamont Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA, and NASA Goddard Institute for Space Studies, New York, NY 10025, USA.

6 Center for Science and Technology Policy Research, Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, CO 80309, USA.

7 Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA.

8 Department of Atmospheric Sciences and

9 Department of Oceanography, University of Washington, Seattle, WA 98195, USA.

10 Climate and Environmental Physics, Physics Institute, University of Bern, 3012 Bern, Switzerland.

11 The Scripps Institution of Oceanography, University of California–San Diego, La Jolla, CA 92093, USA.

http://m.sciencemag.org/content/278/5341/1257.short

G. Bond, M. Cheseby, R. Lotti, P. Almasi, P. deMenocal, P. Priore, and H. Cullen are at the Lamont-Doherty Earth Observatory of Columbia University, Route 9W, Palisades, NY 10964, USA. W. Showers is in the Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, 1125 Jordan Hall, Raleigh, NC 27695, USA. I. Hajdas and G. Bonani are in the AMS 14C Lab, ITP Eidgenössische Technische Hochschule (ETH) Honeggerberg, CH-8093 Zurich, Switzerland.

The shutting down of the North Atlantic Drift current when large influxes of fresh meltwater poured into the North Atlantic from the melting ice sheets rapidly changed climate. As soon as all the ice melted these fluctuations or "flickers" in climate stopped. The climate is really not that sensitive when we are in interglacial periods.

I disagree with this logic. I understand that the Atlantic Conveyor-belt theory has a loyal following in part of the climate science community, but it is beginning to come under scrutiny as being anti-physical in many respects.

This is finally beginning to take hold in the peer reviewed literature.

Publications

Seager, R., D. S. Battisti, J. Yin, N. Gordon, N. H. Naik, A. C. Clement and M. A. Cane, 2002: Is the Gulf Stream responsible for Europe's mild winters? Quarterly Journal of the Royal Meteorological Society, 128(586): 2563-2586. PDF

Seager, R. and D. S. Battisti, 2007: Challenges to our understanding of the general circulation: abrupt climate change. In: T. Schneider and A.S. Sobel (Editors), The Global Circulation of the Atmosphere: Phenomena, Theory, Challenges. Princeton University Press, pp. 331-371. PDF.

Seager, R., 2006: The source of Europe's mild climate. American Scientist, 94(4): 334-341. PDF.

Seager, R., 2008: Setting the record straight on Europe's mild winters. The Plantsman, Royal Horticultural Society,7, Part 1 March, p.22-27. PDF.

Seager, R., 2003: Gulf Stream la fin d'un mythe. La Recherche(361): 40-46.PDF

We show that there are three processes that need to be evaluated:

- The ocean absorbs heat in summer and releases it in winter. Regions that are downwind of oceans in winter will have mild climates. This process does not require ocean currents or ocean heat transport.

- The atmosphere moves heat poleward and warm climates where the heat converges. In additions, the waviness in the atmospheric flow creates warm climates where the air flows poleward and cold climates where it flows equatorialward.

- The ocean moves heat poleward and will warm climates where it releases heat and the atmosphere picks it up and moves it onto land.

Using observations and climate models we found that, at the latitudes of Europe, the atmospheric heat transport exceeds that of the ocean by several fold. In winter it may even by an order of magnitude greater. Thus it is the atmosphere, not the ocean, that does the lion's share of the work ameliorating winter climates in the extratropics. We also found that the seasonal absorption and release of heat by the ocean has a much larger impact on regional climates than does the movement of heat by ocean currents.

Seasonal storage and release accounts for half the winter temperature difference across the North Atlantic Ocean. But the 500 pound gorilla in how regional climates are determined around the Atlantic turned out to be the Rocky Mountains. Because of the need to conserve angular momentum, as air flows from the west across the mountains it is forced to first turn south and then to turn north further downstream. As such the mountains force cold air south into eastern North America and warm air north into western Europe. This waviness in the flow is responsible for the other half of the temperature difference across the North Atlantic Ocean.

http://www.ldeo.columbia.edu/res/div/ocp/pub/seager/Seager_Battisti_2007.pdf

We see slow variations in global temperatures related to changing oceanic currents. That is the main driver of the climate changes assuming a constant sun which you can't. There is no way that the Earth's climate is as sensitive as the GCMs state. If so, during the turbulent times of the glacial-interglacial transitions, the Earth's climate would have spiraled out of control and life would not exist as we know it. This is common sense.

The way this tends to be viewed is that the high amplitude global climate shifts witnessed throughout the Holocene imply a sensitive climate system, thus a large (yet non linear) response to CO2 forcing. If the Sun affects climate, it likely has nothing to due with its radiational output, which is rather constant.

There is some support for a seasonal scale solar influence on the dynamics that govern Rossby wave train (annular modes, Hadley cells, electroscaveging, particulate conversion and nucleation via electrodynamic magnokinetics, etc). However, this research is still in its infant stages, and cannot explain the warming witnessed to date...and it requires a solar forcing on the global electric circuit, which is very hard to quantify, or even measure. Plus, even if the science gets that far (without encountering obstacles), then we still don't know how it'd affect the planetary energy budget, if at all.

In short, you cannot invoke the Sun to explain climate change without staying from the scientific method.

[blizzard1024]

Skierinvermont is correct. Relative to the typical stadial climate, yes the Holocene is "stable". But wouldn't classify the Holocene interstadial as stable in of itself. There have been many notable global climate swings throughout the Holocene. The peer reviewed literature has reached a healthy consensus on the topic of abrupt climate change throughout the Holocene. And our continued CO2 emissions are putting the climate system at immense risk..it could literally change on a dime if we don't start using some common sense and regulate the oil giants behind it.

http://m.sciencemag.org/content/299/5615/2005.short

Although abrupt climate changes can occur for many reasons, it is conceivable that human forcing of climate change is increasing the probability of large, abrupt events.

1 Department of Geosciences and EMS Environment Institute, Pennsylvania State University, University Park, PA 16802, USA.

2 Southampton Oceanography Centre, University of Southampton, Southampton SO14 3ZH, UK.

3 Department of Economics, Yale University, New Haven, CT 06520, USA.

4 Institute for the Study of Planet Earth, University of Arizona, Tucson, AZ 85721, USA.

5 Lamont Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA, and NASA Goddard Institute for Space Studies, New York, NY 10025, USA.

6 Center for Science and Technology Policy Research, Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado, Boulder, CO 80309, USA.

7 Department of the Geophysical Sciences, University of Chicago, Chicago, IL 60637, USA.

8 Department of Atmospheric Sciences and

9 Department of Oceanography, University of Washington, Seattle, WA 98195, USA.

10 Climate and Environmental Physics, Physics Institute, University of Bern, 3012 Bern, Switzerland.

11 The Scripps Institution of Oceanography, University of California–San Diego, La Jolla, CA 92093, USA.

http://m.sciencemag.org/content/278/5341/1257.short

G. Bond, M. Cheseby, R. Lotti, P. Almasi, P. deMenocal, P. Priore, and H. Cullen are at the Lamont-Doherty Earth Observatory of Columbia University, Route 9W, Palisades, NY 10964, USA. W. Showers is in the Department of Marine, Earth and Atmospheric Sciences, North Carolina State University, 1125 Jordan Hall, Raleigh, NC 27695, USA. I. Hajdas and G. Bonani are in the AMS 14C Lab, ITP Eidgenössische Technische Hochschule (ETH) Honeggerberg, CH-8093 Zurich, Switzerland.

I disagree with this logic. I understand that the Atlantic Conveyor-belt theory has a loyal following in part of the climate science community, but it is beginning to come under scrutiny as being anti-physical in many respects.

This is finally beginning to take hold in the peer reviewed literature.

Publications

Seager, R., D. S. Battisti, J. Yin, N. Gordon, N. H. Naik, A. C. Clement and M. A. Cane, 2002: Is the Gulf Stream responsible for Europe's mild winters? Quarterly Journal of the Royal Meteorological Society, 128(586): 2563-2586. PDF

Seager, R. and D. S. Battisti, 2007: Challenges to our understanding of the general circulation: abrupt climate change. In: T. Schneider and A.S. Sobel (Editors), The Global Circulation of the Atmosphere: Phenomena, Theory, Challenges. Princeton University Press, pp. 331-371. PDF.

Seager, R., 2006: The source of Europe's mild climate. American Scientist, 94(4): 334-341. PDF.

Seager, R., 2008: Setting the record straight on Europe's mild winters. The Plantsman, Royal Horticultural Society,7, Part 1 March, p.22-27. PDF.

Seager, R., 2003: Gulf Stream la fin d'un mythe. La Recherche(361): 40-46.PDF

We show that there are three processes that need to be evaluated:

- The ocean absorbs heat in summer and releases it in winter. Regions that are downwind of oceans in winter will have mild climates. This process does not require ocean currents or ocean heat transport.

- The atmosphere moves heat poleward and warm climates where the heat converges. In additions, the waviness in the atmospheric flow creates warm climates where the air flows poleward and cold climates where it flows equatorialward.

- The ocean moves heat poleward and will warm climates where it releases heat and the atmosphere picks it up and moves it onto land.

Using observations and climate models we found that, at the latitudes of Europe, the atmospheric heat transport exceeds that of the ocean by several fold. In winter it may even by an order of magnitude greater. Thus it is the atmosphere, not the ocean, that does the lion's share of the work ameliorating winter climates in the extratropics. We also found that the seasonal absorption and release of heat by the ocean has a much larger impact on regional climates than does the movement of heat by ocean currents.

Seasonal storage and release accounts for half the winter temperature difference across the North Atlantic Ocean. But the 500 pound gorilla in how regional climates are determined around the Atlantic turned out to be the Rocky Mountains. Because of the need to conserve angular momentum, as air flows from the west across the mountains it is forced to first turn south and then to turn north further downstream. As such the mountains force cold air south into eastern North America and warm air north into western Europe. This waviness in the flow is responsible for the other half of the temperature difference across the North Atlantic Ocean.

http://www.ldeo.columbia.edu/res/div/ocp/pub/seager/Seager_Battisti_2007.pdf

The way this tends to be viewed is that the high amplitude global climate shifts witnessed throughout the Holocene imply a sensitive climate system, thus a large (yet non linear) response to CO2 forcing. If the Sun affects climate, it likely has nothing to due with its radiational output, which is rather constant.

There is some support for a seasonal scale solar influence on the dynamics that govern Rossby wave train (annular modes, Hadley cells, electroscaveging, particulate conversion and nucleation via electrodynamic magnokinetics, etc). However, this research is still in its infant stages, and cannot explain the warming witnessed to date...and it requires a solar forcing on the global electric circuit, which is very hard to quantify, or even measure. Plus, even if the science gets that far (without encountering obstacles), then we still don't know how it'd affect the planetary energy budget, if at all.

In short, you cannot invoke the Sun to explain climate change without staying from the scientific method.

The fact that CO2 passively followed temperatures in ice core data shows that it didn't drive the climate in the past. There just isn't that much of it in the atmosphere. It is hard to believe that it is now driving the climate. There is no way to prove it unless you invoke computer models which have their assortment of issues. 

[skierinvermont]

The fact that CO2 passively followed temperatures in ice core data shows that it didn't drive the climate in the past. There just isn't that much of it in the atmosphere. It is hard to believe that it is now driving the climate. There is no way to prove it unless you invoke computer models which have their assortment of issues. 

 

False. All you need to know is the radiative forcing of CO2 and climate sensitivity. Both concepts have nothing to do with computer modeling. 

[StudentOfClimatology]

The fact that CO2 passively followed temperatures in ice core data shows that it didn't drive the climate in the past. There just isn't that much of it in the atmosphere. It is hard to believe that it is now driving the climate. There is no way to prove it unless you invoke computer models which have their assortment of issues.

So, are you saying the world's physicists somehow got it all wrong? Do you have any peer reviewed evidence to support your view on this matter? I'm not sure how to respond to this.

The only way to deny CO2 induced warming at this stage would be to

1) Deny atomic theory

2) Claim saturation

Both are theoretically possible, but highly unlikely and have virtually no scientific support.

[blizzard1024]

So, are you saying the world's physicists somehow got it all wrong? Do you have any peer reviewed evidence to support your view on this matter? I'm not sure how to respond to this.

The only way to deny CO2 induced warming at this stage would be to

1) Deny atomic theory

2) Claim saturation

Both are theoretically possible, but highly unlikely and have virtually no scientific support.

 

CO2 has some influence, just not a lot. I am not denying that my friend. It is not the main GHG. H2O is. CO2 is a trace gas. It only absorbs

IR radiation in the 15 micron spectral band. It can only have influence at around -50C which is in the upper troposphere, especially

the tropics. There has been little of any warming there. The argument that warmer air can "hold" more water vapor is indeed true.  

Warmer temperatures do lead to more evaporation by basic science. However, in the real atmosphere the upper troposphere is

far away from any liquid water source and you have this thing called convection which moistens AND dries this region of the atmosphere.

There are fluid dynamical, thermal dynamical to cloud microphysical processes in the global circulation that govern how much water vapor

remains in the atmosphere. The simplistic view that CO2 levels somehow set the level of H20 in the atmosphere is incredibly naive IMO. 

You need this argument to then make a leap of faith that CO2 will lead to dangerous warming. 

 

Climate sensitivity is at the heart of all this debate. No one with a scientific mind will deny that CO2 is a GHG and all things being

equal would cause some warming. It is just how much. That is the question.  I disagree that the Holocene temperature fluctuations

are known well enough that we know what the real climate sensitivity is. No one does. We can use computer models to try to estimate

it and that is what is being done. 

 

Computer models of the atmosphere are tremendously inadequate because of the high non-linear processes. To think we have this

all figured out is very arrogant. I know this because I use computer models all the time to try to forecast the weather. We all know that a doubling

of CO2 alone increases external forcing by 3.7 W/m2. This translates to about 1.2C. The huge amount of heat storage in the

oceans could easily slow the response of this forcing over the next 100 years or more. Heck, what has stopped the present warming

trend? Probably the oceans.  The present warming trend (that ended in 1998 )could easily be a recovery from the LIA plus a small

component of CO2  warming. 

[sokolow]

Interesting! What are the proportional contributions of CO2, CH4, and the other trace gases to net absorbtion?

[FloridaJohn]

 It only absorbs IR radiation in the 15 micron spectral band. It can only have influence at around -50C which is in the upper troposphere, especially

the tropics.

 

Source, please. Thanks.

[The_Global_Warmer]

Student of Climo.

 

If you are bethesda I hope you are being geniune and not playing along.

 

You have seemed to mature and have gotten fully behind legit science.

 

It would be a shame if it was some sort of rouse.

[skierinvermont]

CO2 has some influence, just not a lot. I am not denying that my friend. It is not the main GHG. H2O is. CO2 is a trace gas. It only absorbs

IR radiation in the 15 micron spectral band. It can only have influence at around -50C which is in the upper troposphere, especially

the tropics. There has been little of any warming there. The argument that warmer air can "hold" more water vapor is indeed true.  

Warmer temperatures do lead to more evaporation by basic science. However, in the real atmosphere the upper troposphere is

far away from any liquid water source and you have this thing called convection which moistens AND dries this region of the atmosphere.

There are fluid dynamical, thermal dynamical to cloud microphysical processes in the global circulation that govern how much water vapor

remains in the atmosphere. The simplistic view that CO2 levels somehow set the level of H20 in the atmosphere is incredibly naive IMO. 

You need this argument to then make a leap of faith that CO2 will lead to dangerous warming. 

 

Climate sensitivity is at the heart of all this debate. No one with a scientific mind will deny that CO2 is a GHG and all things being

equal would cause some warming. It is just how much. That is the question.  I disagree that the Holocene temperature fluctuations

are known well enough that we know what the real climate sensitivity is. No one does. We can use computer models to try to estimate

it and that is what is being done. 

 

Computer models of the atmosphere are tremendously inadequate because of the high non-linear processes. To think we have this

all figured out is very arrogant. I know this because I use computer models all the time to try to forecast the weather. We all know that a doubling

of CO2 alone increases external forcing by 3.7 W/m2. This translates to about 1.2C. The huge amount of heat storage in the

oceans could easily slow the response of this forcing over the next 100 years or more. Heck, what has stopped the present warming

trend? Probably the oceans.  The present warming trend (that ended in 1998 )could easily be a recovery from the LIA plus a small

component of CO2  warming. 

 

This is one or two true facts strewn together by a bunch of gibberish dressed up to sound clever and contrarian. There's nothing to support it. The few true facts you have presented are completely inadequate to support the conclusions drawn. Doing so would require huge leaps of faith. 

 

For example you point out that the upper troposphere is very far a way from the surface and that such a thing as convection exists and potentially can prevent moistening. From this you conclude that the upper troposphere will not moisten. This is a massive logical leap. Why would convection increase exactly enough to balance out all of the extra evaporation?

 

There are dozens of peer-reviewed papers proving that the atmosphere is and will moisten with AGW. This is universally agreed upon. Moreover, it is intuitively obvious. Are you saying that if surface temperatures rose to 100C the atmosphere would only contain exactly the same amount of water it does today? Relative humidity would be like 2% and the earth would be a barren desert. Of course, that doesn't make any sense intuitively and we also know that in periods when the earth was much warmer, like the Jurassic, the earth was not a barren desert and humidity levels must have been fairly similar to today (meaning far more water in the atmosphere). 

[SVT450R]

Student of Climo.

 

If you are bethesda I hope you are being geniune and not playing along.

 

You have seemed to mature and have gotten fully behind legit science.

 

It would be a shame if it was some sort of rouse.

We seem to go threw this every couple months when someone new is here is it the writing style that makes you think this?  I know it's not just you and have seen it many times brought up with other people.

[The_Global_Warmer]

We seem to go threw this every couple months when someone new is here is it the writing style that makes you think this?  I know it's not just you and have seen it many times brought up with other people.

 

Writing style is like a refined mature version of Bethesda.

 

Location. 

 

And viewpoint.

 

It really screams Bethesda.

[TerryM]

Writing style is like a refined mature version of Bethesda.

 

Location. 

 

And viewpoint.

 

It really screams Bethesda.

Amen

[blizzard1024]

This is one or two true facts strewn together by a bunch of gibberish dressed up to sound clever and contrarian. There's nothing to support it. The few true facts you have presented are completely inadequate to support the conclusions drawn. Doing so would require huge leaps of faith. 

 

For example you point out that the upper troposphere is very far a way from the surface and that such a thing as convection exists and potentially can prevent moistening. From this you conclude that the upper troposphere will not moisten. This is a massive logical leap. Why would convection increase exactly enough to balance out all of the extra evaporation?

 

There are dozens of peer-reviewed papers proving that the atmosphere is and will moisten with AGW. This is universally agreed upon. Moreover, it is intuitively obvious. Are you saying that if surface temperatures rose to 100C the atmosphere would only contain exactly the same amount of water it does today? Relative humidity would be like 2% and the earth would be a barren desert. Of course, that doesn't make any sense intuitively and we also know that in periods when the earth was much warmer, like the Jurassic, the earth was not a barren desert and humidity levels must have been fairly similar to today (meaning far more water in the atmosphere). 

 

You are full of gibberish yourself. You apparently have no clue about how the atmosphere works so don't call my posts gibberish!!  Your quote itself speaks volumes of your lack of understanding on how the real atmosphere works.

 

"Why would convection increase exactly enough to balance out all of the extra evaporation?"  Precipitation will do this....pretty basic stuff here. Precipitation is a sink of H20 the primary GHG. The more precipitation you get...the more H20 in vapor form you lose. Convection does this efficiently.  Models are TERRIBLE with convective precipitation.  

 

Universally agreed upon by peer review that the upper troposphere is moistening?? No dataset proves this.  There are scientists who also don't ascribe to this moistening as you claim.  Only the scientists who are pushing the CAGW agenda are pushing a moistening upper troposphere  So you cut the gibberish. You are the cluelessand  brainwashed one here.

 

 

[blizzard1024]

Source, please. Thanks.

 "It only absorbs IR radiation in the 15 micron spectral band. It can only have influence at around -50C which is in the upper troposphere, especially

the tropics." 

 

This is BASIC radiative transfer. Look it up on google or in a textbook. 

[blizzard1024]

You are full of gibberish yourself. You apparently have no clue about how the atmosphere works so don't call my posts gibberish!!  Your quote itself speaks volumes of your lack of understanding on how the real atmosphere works.

 

"Why would convection increase exactly enough to balance out all of the extra evaporation?"  Precipitation will do this....pretty basic stuff here. Precipitation is a sink of H20 the primary GHG. The more precipitation you get...the more H20 in vapor form you lose. Convection does this efficiently.  Models are TERRIBLE with convective precipitation.  

 

Universally agreed upon by peer review that the upper troposphere is moistening?? No dataset proves this.  There are scientists who also don't ascribe to this moistening as you claim.  Only the scientists who are pushing the CAGW agenda are pushing a moistening upper troposphere  So you cut the gibberish. You are the cluelessand  brainwashed one here.

 

 

 

This is one or two true facts strewn together by a bunch of gibberish dressed up to sound clever and contrarian. There's nothing to support it. The few true facts you have presented are completely inadequate to support the conclusions drawn. Doing so would require huge leaps of faith. 

 

For example you point out that the upper troposphere is very far a way from the surface and that such a thing as convection exists and potentially can prevent moistening. From this you conclude that the upper troposphere will not moisten. This is a massive logical leap. Why would convection increase exactly enough to balance out all of the extra evaporation?

 

There are dozens of peer-reviewed papers proving that the atmosphere is and will moisten with AGW. This is universally agreed upon. Moreover, it is intuitively obvious. Are you saying that if surface temperatures rose to 100C the atmosphere would only contain exactly the same amount of water it does today? Relative humidity would be like 2% and the earth would be a barren desert. Of course, that doesn't make any sense intuitively and we also know that in periods when the earth was much warmer, like the Jurassic, the earth was not a barren desert and humidity levels must have been fairly similar to today (meaning far more water in the atmosphere). 

 

"Moreover, it is intuitively obvious. Are you saying that if surface temperatures rose to 100C the atmosphere would only contain exactly the same amount of water it does today? Relative humidity would be like 2% and the earth would be a barren desert. Of course, that doesn't make any sense intuitively and we also know that in periods when the earth was much warmer, like the Jurassic, the earth was not a barren desert and humidity levels must have been fairly similar to today (meaning far more water in the atmosphere)."

 

If the Earth warmed dramatically like to 50C (so that the water does not boil), there would be many complex processes taking place that we can only imagine. The Earth's relative humidity would rise but not necessarily in all locations and all altitudes. Things are a lot more complicated. Tropical convection would become epic and spread around the oceans, precip rates would be tremendous. It is hard to say how moist the upper troposphere would be. The lower troposphere would be more moist. Also the process by which we get to 50C or 100C would also have a lot of changes to regional circulation patterns etc. You can't use this as a plausible " intuitively obvious " reason why 1C of warming will amplify to 3-5C or more. You are talking an order of magnitude larger temps ranges. Again your simplistic view of the atmosphere shows yet again. 

[sokolow]

This is BASIC radiative transfer. Look it up on google or in a textbook.

Since you're clued in, I'd really be grateful if you could help me out with this basic question. There's a greenhouse effect -- we know THAT for sure. So,

What are the proportional contributions of CO2, CH4, and the other trace gases to net absorbtion?

[blizzard1024]

Since you're clued in, I'd really be grateful if you could help me out with this basic question. There's a greenhouse effect -- we know THAT for sure. So,

as soon as I can remember how to attach images i will answer your question. Google absorption spectra for greenhouse gases and you

will see a lot for the time being. It has been a while. sorry. 

[sokolow]

Go to imgur.com and you should be able to drag-and-drop your image into the upload box. Failing that, goto more reply options in the postbox and "attach files" is available in the lower right (see below). And thanks!