How do AGW skeptics explain the cooling stratosphere?

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They can't....Show more

I fail to see where this directly attributable to CO2. Perhaps you could enlighten me with some empirical evidence that links CO2? The Laštovička 2004 paper (and the 2006 paper, which I believe used the upper atmosphere trends ending in 1997) mentions that geomagnetic and solar activity have played some role in the cooling upper atmosphere, but there hasn't been any particularly good assessment of the extent of their roles. And increased water vapor likely makes up a majority of the rest. Maybe CO2 is playing a role, and it is likely, but we just don't know. Beyond that, the SSU data shows a lack of cooling for at least 12 years at altitudes of 50km--well into the upper stratosphere and generally high enough to remove the influences of the H2O/ozone interaction. Above that, we have no temperature record, and I have yet to see a more up to date assessment of the trends. "The higher up one goes, the more important the CO2 related cooling is. It's interesting to note that significant solar forcing would have exactly the opposite effect (it would cause a warming) - yet another reason to doubt that solar forcing is a significant factor in recent decades." Read the climate commitment studies of Wigley, et al, and Meehl, et al, to understand how the argument that recent solar activity has not increased is simplistic and wrong. If the level of solar forcing reached prior to 1940 continues (which is unlikely per Solanki), then there will be a solar contribution to the energy imblance resulting in sea level rise for several more centuries. Presumably most of the temperature response occurs in the first few decades, although arguably, that response was delayed by the causes of the midcentury cooling (aerosols, among other things)....Show more

Yeah, I hear this argument a lot; “the stratosphere is cooling, just look at this graph.”

But, (and I’m prepared to accept that I’m hallucinating, or something, here) I just don’t see it.

Let’s analyse the graph in your second link…

The graph starts in 1958 and shows cooling until about 1971.

From 1971 until 1982 the cooling stops completely or even reverses slightly.

Then in 1982 we get the El Chichon volcanic eruption which causes a sudden rise and fall that completely obscures the natural trend. Clearly there has been a sudden and dramatic drop between the before and after temperatures.

When the effects of the El Chichon eruption end in about 1985 we then see very slight warming for about 6 years until about 1991 when we get the Pinatubo eruption.

Again, the Pinatubo eruption results in a sudden rise and fall that completely obscures the natural trend and, once again, there is a sudden and dramatic drop between the before and after temperatures.

After Pinatubo we see cooling from 1994 until about 1998.

Finally, from 1998 to the present we see no cooling at all, if anything there is a very slight warming trend.

So, we are lead to believe that the steadily increasing levels of CO2 in the atmosphere should cause a steady cooling of the stratosphere as more and more outgoing radiation is prevented from reaching it.

However, you are showing a graph covering 50 years that, outside of the effects of volcanic activity, only shows cooling for 17 years, while showing no trend or warming for 26 years. Thus, it is not immediately obvious from your graph that continuous, steady stratospheric cooling is actually happening.

It seems to me that since 1971, outside of the effects of volcanic activity there has been very little stratospheric cooling and none at all over the last 10 years when CO2 levels have been rising faster than ever.

Keith, could you educate me as to exactly where this supposed CO2-induced cooling is on your graph?...Show more

It's nice to see so much science flown around.

I'm a skeptic because the global warming debate is buried in political and economic agenda.

Skepticism is required.

The decisions made by our politicians impacts their reelection chances and the economy in serious ways.

http://www.epa.gov/ocfo/budget/2008/2008bib.pdf
"EPA estimates that the $35 million for National Clean Diesel Campaign grants will leverage at least an additional $72 million in funding assistance and reduce PM by approximately 5,040 tons, achieving up to an estimated $1.4 billion dollars in health benefits."

This is just a portion of the EPA's budget. Look at the rest of it. There are big dollars here. See the Appendix D Budget tables.

Also see Goal 1 (Clean Air and Global Climate Change)page 1-1
"...protect the stratospheric ozone layer, minimize the risks from radiation releases, reduce greenhouse gas intensity, and enhance science and research."

Note that Reduce Green House Gas Intensity and Enhance Science and Research had an increase in dollars while the other parts of Goal 1 were decreased. The other major goals also include sections for enhancing science and research. The scientific community has a vested interest in the amount of spending in these areas.

I use this source to illustrate the big money associated with the global warming debate. This just shows one gov't agency.

Should we really think that our politicians and those in other nations are trying to save the planet? I think it's just a way for scientist and government to fatten their pockets....Show more

The dominant factor in stratospheric cooling is ozone depletion. Ozone scattering UV energy is the main source of heat in the stratosphere.


"Ozone depletion also explains much of the observed reduction in stratospheric and upper tropospheric temperatures.[6][7] The source of the warmth of the stratosphere is the absorption of UV radiation by ozone, hence reduced ozone leads to cooling. Some stratospheric cooling is also predicted from increases in greenhouse gases such as CO2; however the ozone-induced cooling appears to be dominant.
"

http://en.wikipedia.org/wiki/Ozone_depletion

EDIT:

Keith

If we are going to cherry pick then lets cherry pick, According to your graph neither the surface nor the troposphere showed any warming until 1975 but the stratosphere shows cooling, doesn't exactly explain AGW, does it? And Ozone levels were sparsely monitored before satellite data, so there is no way of knowing what ozone levels were before 1978 with any granularity.

I repeat, Ozone scattering of UV energy in the stratosphere is the primary source of heat in the stratosphere, regardless of latitude.

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