Sunday, July 13, 2014

Clean Air Act

Here is my submission for the Global Warming Skeptic Challenge, which refutes any warming due to CO2 or other greenhouse gasses:

"Man-made" global warming did occur, 1970 - 2000, but it had nothing to do with greenhouse gasses. All of the warming that occurred was simply a side effexct of the Clean Air Acts and similar efforts abroad.

A large volcanic eruption will inject huge amounts of aerosols (primarilly SO2) into the atmosphere, causing temporary global cooling. Temperatures will recover to pre-eruption levels as the pollution settles out, due to increased insolation.

For example, the Mount Pinatubo eruption (according to Self, et al) injected 17 Megatons of SO2 into the atmosphere, causing approx. 0.4 deg C. of global cooling. When the pollution settled out of the atmosphere, temperatures rose 0.4 deg C due to increased insolation.

Thus, the removal of 17 Megatons of SO2 from the atmosphere, for whatever reason, should result in a temperature rise of approx. 0.4 deg C.

According to the EPA ( "Air Quality Trends, Table III), b etween the years 1980 - 2000, the atmospheric loading of SO2 was reduced by 10 Megatons. In Europe, 1980 - 1998, atmospheric loading of SO2 was reduced by 33 Megatons, for a total of 43 Megatons. (see "GEO-3: Global Environmental Outlook", United Nations Environmental Programme and note the graph) This is almost double the 17 Megatons needed for a tekmperature rise of 0.4 deg. C, thus guaranteeing that at least 0.4 deg C of the approx. 0.48 deg C of warming that occurred 1970 - 2000 was due to the reduction of aerosols in the atmosphere

When one consideres tha SO2 reduction was also occuring in the USA and Europe, 1970 - 1980, and in Europe 1998 - 2000, it is clear that ALL of the warming that occurred 1970 - 2000 was entirely due to aerosol removal from the atmosphere. There is simply no "room" for any warming due to greenhouse gasses.

Warming due to aerosol reduction can be considered to be a Law of Nature, since it occurs after every large volcanic eruption. This warming CANNOT be
ignored in any modeling of the climate.

There are a number of ramifications with respect to the above analysis, most notably that it can be used to explain the 17 year "pause" in global warming.

I look forward to your comments. I am confident tht I can answer any of your objections.

Burl Henry


Mr. Henry's claim is that sulfur emissions (SO2) into the atmosphere caused a cooling and then when we reduced the emissions it led to a subsequent heating. This, in general is a valid thought. It is true that sulfur emissions into the atmosphere result in cooling. It is also true that emission in the U.S. and Europe have gone down. We can put this hypothesis to the test. We can look at sulfur emissions over time, figure out what the expected temperature trend should look like and then compare it to the actual temperature trend.

Yes, SO2 emissions from the U.S. and Europe have dropped. But, what has been going on with emissions from China and India, not to mention the rest of the world? Here is paper about SO2 emissions in China between 2000  and 2006 that illustrates the problem. Emissions went up 53% during that time span, in just China!. Here is a plot of total worldwide sulfur emissions from a report on the subject written for the Pacific Northwest National Laboratory (PNNL) (2004):

Source: PNNL
Mr. Henry quotes sulfur emissions for the specific period of 1980 - 2000. In the plot above, we can see the total emissions steadily increased from 1970 - 1980 (from about 68,000 megatons to 75,000 megatons - an increase of about 10%). Emissions were up and down during the period of 1980 - 1990 (from a peak of about 75,000 megatons to about 70,000 megatons - about a 7% overall decrease). Then, we saw a fairly steady decrease in sulfur emissions from 1990 - 2000 (from about 70,000 megatons to about 62,000 megatons - a decrease of about 11%).

Based on Mr. Henry's hypotheses and this plot of sulfur emissions, we should see the temperature trend decrease from 1970 - 1980; stay pretty steady (or maybe a small rise) from 1980 - 1990; then have a moderate rise from 1990 - 2000.

Here is the plot of surface temperature over these periods taken from the NASA Goddard Institute for Space Studies (GISS):

Source: GISS

What we can see is that the surface temperature is up and down from year to year, but the average from 1970-1980 was pretty flat. The average from 1980 - 1990 was up a great deal. The average of 1990 - 2000 was up a lot, but not as much as the 1980 - 1990 time span. Mr. Henry's hypothesis does not hold up for the 1970 - 1980 time span, or the 1980 - 1990 time span, but does pretty well for the 1990 - 2000 time span.

Now, one of the criticisms I keep making of deniers is that they cite the surface temperature as the global temperature while ignoring the oceans, calling it a 'pause' while ignoring the biggest part of global warming. So, let's take a look at the total heat index.  Here is a plot of the total global heat index (also from GISS):
Source: GISS

Based on this data, we see the total global heat index stay about even from 1970 - 1980 (with a sudden, noticeable rise at the end of the decade); a large rise from 1980 - 1990; and a equally large rise from 1990 - 2000. 

So, we certainly did not see the decrease in the 1970s that Mr. Henry's hypothesis calls for; we did not see the steady - moderate increase in temperature we expected from 1980 - 1990; and we did not see the moderate increase from 1990 - 2000 that was expected. These results are not consistent with Mr. Henry's hypothesis.

However, the story doesn't end there. Thanks mainly to that large increase from China, worldwide sulfur emissions rose from 2000 to 2005, according to an updated report, also from PNNL. So, we would expect to see temperatures drop again, but that isn't what happened. According to deniers, the temperature during from 2000 - 2010 stayed steady, but the record shows it actually rose somewhat during that period. There certainly was not a large increase. When we consider the total heat index we see a continued increase in total worldwide heat. These results are not consistent with the hypothesis.

So, I think we can agree that the Clean Air Act (and equivalent actions in other countries) did not lead to global warming. Does that mean Mr. Henry is completely wrong? No, it doesn't. I refer to the first PNNL report I cited above (Introduction, page 2):

The radiative forcing change wrought by sulfate aerosols may be second only to that caused by carbon dioxide, albeit in the opposite direction...

So, changes in the worldwide emissions of sulfur have an effect on the global climate and that change is in the opposite direction of the effect of CO2, but it does not even negate the CO2 effects, just ameliorates it somewhat.

This was a nice argument and showed how the climate is a complicated system, but did not prove man made global warming is not real.

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