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Re: [Phys-l] global temperatures



Rick and others,

There has been a flattening and perhaps a slight decline in global temperatures, depending on the
dataset you look at. One could draw the conclusion that there is not a direct connection between
increased CO2 and global temperatures or that there are more parameters that need to be considered.
The modelers claim that the influence of the Sun is minimal. However, it is curious that the flattening
and slight decrease are coming at a time when solar activity is at a century minimum.

In the late 90s and first few years of this decade, solar activity was at a long term high...
http://news.bbc.co.uk/2/hi/science/nature/3869753.stm

Check out the report from NASA this week...
http://science.nasa.gov/headlines/y2009/01apr_deepsolarminimum.htm



On 16 Mar 2009 at 14:43, Rick Tarara wrote:

I noticed nobody has answered Bob's question about global temps over the
last ten years. I'm sure he knows, but I actually didn't. So I Googled
'Global Temperature by year'. I would suggest two quick looks....

www.boston.com/bostonglobe/editorial_opinion/oped/articles/2008/01/06/br_r_r_where_did_global_warming_go/

This one gives a typical newspaper (and GW skeptic) account, but

http://www.cru.uea.ac.uk/cru/info/warming/

is not from a skeptic and has an informative graph.

The bottom line is that the temp hasn't really changed in the past 10
years--it has been high, but that is the predominant trend that has been
clear for some time now. If anything the trend looks to be turning some
(but too little data to be sure). Now this flattening is during a time of a
4% CO-2 increase, but what is interesting to me is that the rate of increase
from 1975 to 2000 is about the same as it was between 1915 and 1940, when
the CO-2 concentrations weren't nearly what they were at the end of the 20th
Century.

These are, IMO, the types of data that should trigger some caution, at least
some healthy skepticism concerning the model predictions. Again, this is
just SO complicated. Is the leveling because of increased aerosols and
Global dimming -- or is the global air quality better than earlier which
makes a ten year leveling more mysterious? What about the other natural
drivers--the sun for example. What's it been doing during this ten year
period--has it cooled off enough to compensate for the greenhouse increases
or is it pumping in more energy such that we would have expected continuing
record setting temps (1998 is still the hottest--according to the graph and
the Boston Globe story). I would point to the last paragraph of the Globe
story! ;-)

Rick

***************************
Richard W. Tarara
Professor of Physics
Saint Mary's College
Notre Dame, IN
rtarara@saintmarys.edu
******************************
Free Physics Software
PC & Mac
www.saintmarys.edu/~rtarara/software.html
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