If global warming is caused by sunspots why is the stratosphere cooling?

Question

If it was caused by increased solar output the upper atmosphere should be warming--it's not.

http://spacescience.spaceref.com/newhome/essd/atmos_temps/strato_temp.gif

It hasn't warmed since 1993, long before 1998 (warmest year).

Temperature graph:

http://upload.wikimedia.org/wikipedia/en/f/f4/Instrumental_Temperature_Record.png

When surface warming is attributed to the greenhouse effect, the upper atmosphere naturally cools. This fact is evidenced by Venus, which has an 800+ degree surface and an upper atmosphere about 5 times cooler than ours.

It makes sense, too. After all, what the greenhouse effect does is compact heat towards the surface, keeping it from escaping. Thus, the upper atmosphere would cool.

If the warming was due to increased solar output, both the surface and upper atmosphere should warm.

and a little extra:

http://upload.wikimedia.org/wikipedia/en/a/a2/Climate_Change_Attribution.png

how solar variations correlate with the temperature anomaly (it doesn't)

Answer 1

Because the current warming is not caused by solar effects.  Few if any scientists argue otherwise, and no scientific study has attributed more than one-third of the recent warming to solar effects (most attribute just 0-10%).  Bottom line - it's not the freaking sun!

As you point out, the cooling of the upper atmosphere (not just the stratosphere, but also the layers further up) is even further evidence that the sun is not to blame.  Not that we needed any more evidence.

As I discuss in the link below, I believe the cooling of the upper atmosphere is the final nail in the AGW denial coffin.  There isn't a good explanation for it except that it's being caused by the increased anthropogenic greenhouse effect.

Answer 2

It's not.

The max to min variation of the previous three 11-year solar cycles can only account for a maximum temperature variation of about 0.1 C.  And since the cycle goes up and down, that's a peak to peak difference, not anything that would cause a 30-year trend-line as we've seen.

http://www.pnas.org/cgi/content/abstract...

"Although solar and volcanic effects appear to dominate most of the slow climate variations within the past thousand years, the impacts of greenhouse gases have dominated since the second half of the last century."

http://www.agu.org/cgi-bin/SFgate/SFgate...

"Thirty years of satellite observations show that solar irradiance changes are of the order of a few tenths of a percent during 11-year solar cycles. Estimates made using a simple climate model indicate that such small changes in the Sun's luminosity are unlikely to significantly influence global temperature change."

Thus, solar changes have certainly been a major factor in some previous climate changes, but the one we're experiencing now cannot be blamed on changes in solar output.

Edit:

Tomcat - You provide a perfect example of why it's important to go the peer reviewed scientific literature or the source of data and NOT to believe what you read in personal blogs.  The actual analysis of RSS Stratosphere data (by RSS vs. some unknown blogger) clearly identifies a -0.313 K/decade cooling in the stratosphere.  Arbitrarily cherry-picking points and calculating "trends" over short-term periods belongs in the realm of bloggers, not real climate scientists.

http://www.ssmi.com/msu/msu_data_descrip...

Answer 3

Why is the stratosphere cooling? Well, its not, and if you had a more up to date graph of stratospheric temperature trends you would know that--yours ends in 1999, but even from there you can see that lower stratospheric temperatures plateaued in roughly 1994, and they have continued to stay flat. However, the lower stratospheric temperature trends are complicated by ozone recovery, so we can look at upper stratosphere and we can see that temperatures have not dropped for at least 12 years. Above that we have no up to date temperature trend analysis.

Two papers by Laštovička et al (2004 and 2006) look at upper atmosphere trends ending in 1997. They both mention 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. CO2 is likely playing a role as well, but we don't know the extent. And in fact, a cooling upper atmosphere works well with a plateau in solar activity--having to do with the shorter time it takes for the upper atmosphere to reach equilibrium versus the oceans.

Ken says:

"The actual analysis of RSS Stratosphere data (by RSS vs. some unknown blogger) clearly identifies a -0.313 K/decade cooling in the stratosphere"

Yes, the overall trend is negative, but that does not mean that the stratosphere continues to cool. And in fact, the only real cooling we see in the lower stratosphere comes directly after the two major volcanic eruptions of the last 30 years (Pinatubo and El Chichon). Though, like I said, the lower stratosphere is complicated by ozone recovery.

Answer 4

It is understood that we do have, always have had a significant Greenhouse Effect.

Increased solar output would then be expected to have a greater effect close to the earth even if there were no increase in that Greenhouse Effect.

But was our evaluation of the upper layers adequately timely? This matters primarily because the warming of upper layers would be of very short duration.  Those upper layers do not have a Greenhouse Effect to retain any heat they build up, so they basically do not build up any amount of heat, it just flies off into space.

So, if we take measurements of temperature way up there, they reflect only very current levels of insolation.

We know it would be too late now to do those checks because insolation has definitely declined off its maxima. But did we take readings too late to tell us anything?

Do understand that this is not about whether we have seen an increase in our Greenhouse Effect. It is just about the attempt to use temperatures way up there to demonstrate it.

We can have had both increasing Greenhouse Effect and increased solar output, just as we can have both an increase in Greenhouse Effect simultaneous with dimming resulting from volcanic dust in the upper atmosphere. And we can have both of those with variation in solar output.

Drought and advancing deserts also can  very significantly influence not only the temperatures we measure, but even influence our Greenhouse Effect. (Drought affected areas consume far less CO2).

Answer 5

I showed you graphs of Sun Spot 22 and 23 in another answer. Sun Spot 22 shows a rise in Sun Spot activity and it also corrolates with the warming that occured from 1984 to 2000. Sun Spot 23 is a decreasing Sun spot activity and it corrolates with our flat to decreasing temperature. During Sun Spot Cycle 22 we had an El Nino year and with both occuring at the same time it caused this climate effect to be more dramatic than expected. We are now at the very bottom of Sun Spot cycle 23 and imagine that we had one of the coldest winters and springs we had in a long time (This is also an El Nina year.)

All this could be coincidental, but it was eye opening to me when I first saw the charts a few months ago.

Answer 6

the fact of green house gases causes this temperature difference, but the amount of additional greenhouse gases being produced by humans has not had an impact.  increased solar activity is providing the heat that gets trapped by greenhouse gases.  There is no additional heating or cooling as a result of human activity.

this planet has had a "greenhouse effect" from millions of years, and past levels of CO2, prior to humans inhabiting this planet, have been much higher than current levels.

Answer 7

Sunspots wouldn't cause global warming; however, sun spots are more common when solar output is greater.  It could be that solar flares and magenetic storms influence climate but that is another subject.  Everyone acknowledges that CO2 has increased.  IMO it increased mostly due to natural variations and natural warming, and partially due to human activity.  This increase in a greenhouse gas will tend to moderate the temperature and therefore it wouldn't be surprising to me that upper stratosphere cooling might take place.  This doesn't mean that humans have been the primary cause or that it is necessarily harmful.  Sunspot activity is currently at a minimum so your question makes very little sense to me.  Graphs and statistics are easily manipulated to exaggerate a point.  If you notice your graphs have convenient starting points and different units and scales to exaggerate (i.e mislead).

Answer 8

The sun heats the earth through radiation, not convection. The radiation heats objects (solid) not the air. That's why its warm near the ground when the sun heats it up and not warm way up in the sky.

Answer 9

The stratosphere is not cooling, if you graph global stratospheric temperatures up to the current date there has been no noticeable stratospheric cooling since 1993 which was associated with ozone depletion from volcanic SO2 emissions from the Mt. Pinatubo eruption.

http://blog.360.yahoo.com/blog/popup_sli...

Thats almost fourteen years of warming, almost half the period that the consensus of AGW advocates are so sure of. Could the last fourteen tears of warming be associated with natural ozone recovery from Pinatubo and El-Chichon,? yes it could, the data from the stratosphere certainly does not support AGW, in my opinion.

Ken:

With all do respect, to take anything from the Stratosphere without acknowledging the major contamination of volcanic SO2 emmissions is an absolute joke. No trend can be established before the Pinatubo erruption, so it is not an arbitrary trend, and the last fourteen years is not an insignificant time period.

.

Answer 10

You assume man fully understands the mechanics of Earth's climate.  We don't.  The correlation between historic sunspot activity and climate change is irrefutable.  We're currently in the Modern Maximum, a level of solar activity not seen in a thousand years.  Guess what....we're seeing high temperatures, too.  Go figure.

Edit:  I read the question.  It assumes an understanding of the link between sunspot activity, solar "output", and the sampled temperature of the stratosphere.  I answered with "we have no such understanding"...but we don't need it to show CO2 isn't the cause of today's climate change.  Please try harder to keep up.

Edit:  "we do, however, understand an increase in the greenhouse effect would decrease stratospheric temperatures" ...Congratulations!  Know of any other causes, or is that the extent of your knowledge?  If we actually had a way to quantify the greenhouse effect, this limited understanding might be sufficient......in fact, if we could quantify the greenhouse effect, there wouldn't BE a debate!  So, given we know "a fair bit", I'm curious as to why proponents can't simply give us a "Greenhouse Index" number and the equation or formula by which it's contrived...