Earths cooling trend did not continue beyond 1980, but neither has there been an unambiguous warming trend. Since 1980, precise temperature measurements have been made in Earths atmosphere and on its surface, but the results do not agree. The surface air measurements indicate significant warming (0.25 to 0.4ºC), but the atmospheric measurements show very little, if any, warming... Briefly, then, the record is this: From 1860 to 1940, Earths surface warmed about 0.4ºC. Then Earths surface cooled about 0.1ºC in the first four decades after 1940 and warmed about 0.3ºC in the next two. For those two most recent decades, temperature measurements of the atmosphere have also been available, and, while these measurements are subject to significant uncertainty, they indicate that the atmospheres temperature has remained essentially unchanged.
My schedule is getting better, but I still need a little more time to get everything together. Nonetheless, it bugs me that skeptics continue to repeat the mantra that "atmospheric [meaning lower troposphere] temperatures are not changing" when in fact the NASA group most widely quoted now finds about a +0.07 C /decade warming trend in the lower atmosphere -- and two other groups analyzing the same data find a trend that's about double that. And since they're analyzing a data record that's about 23 years long now, this record is now also showing a warming trend during the short period when the surface record shows a pretty dramatic 0.3 C increase. Note that if the alternate groups to NASA are believed, and they're some pretty sharp folks, their trend essentially matches the surface trend.
The post-1970s warming is the one most oft-cited as due primarily to human causes. The 1900s-1940s warming is usually at least partly attributed to solar forcing.
NASA group most widely quoted now finds about a +0.07 C /decade warming trend in the lower atmosphere
A statistical regression of a mere thirty years of raw data does not consitute a climate trend, especially concidering that data set spans several el-nino/el-nina events as well as volcanic events inducing error in regression measurements that would supposedly be attributable to a longterm "Global Warming".
Note the following data that until Feb 2002 exhibited a .04C/decade, only one additional el-nino event doubled the "trend" measure to that 0.07C/decade regression you are quoting.
Globally Averaged Atmospheric Temperatures This chart shows the monthly temperature changes for the lower troposphere - Earth's atmosphere from the surface to 8 km, or 5 miles up. The temperature in this region is more strongly influenced by oceanic activity, particularly the "El Niño" and "La Niña" phenomena, which originate as changes in oceanic and atmospheric circulations in the tropical Pacific Ocean. The overall trend in the tropospheric data is near zero, being +0.04 C/decade through Feb 2002. Click on the chart to get the numerical data.
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Such instability in regression measurement is a result of the more than 0.2C stand deviation noise in a short term measurement, not the effect of a secular change in Climate do to any effect of mankind.
Mankind's impact is only 0.28% of Total Greenhouse effect
" There is no dispute at all about the fact that even if punctiliously observed, (the Kyoto Protocol) would have an imperceptible effect on future temperatures -- one-twentieth of a degree by 2050. "
Dr. S. Fred Singer, atmospheric physicist
Professor Emeritus of Environmental Sciences at the University of Virginia,
and former director of the US Weather Satellite Service;
in a Sept. 10, 2001 Letter to Editor, Wall Street Journal
Anthropogenic (man-made) Contribution to the "Greenhouse
Effect," expressed as % of Total (water vapor INCLUDED)
Based on concentrations (ppb) adjusted for heat retention characteristics % of All Greenhouse Gases % Natural
% Man-made
Water vapor 95.000% 94.999%
0.001% Carbon Dioxide (CO2) 3.618% 3.502%
0.117% Methane (CH4) 0.360% 0.294%
0.066% Nitrous Oxide (N2O) 0.950% 0.903%
0.047% Misc. gases ( CFC's, etc.) 0.072% 0.025%
0.047% Total 100.00% 99.72
0.28%
Even if one were so foolish as to accept such a raw statistic as representative, the change in temperature acoss a century of time would still amount to only 0.7oC(far less than the IPPC's model projections) with no causual connection with CO2(natural or manmade).
- "(1) correlation does not prove causation, (2) cause must precede effect, and (3) when attempting to evaluate claims of causal relationships between different parameters, it is important to have as much data as possible in order to weed out spurious correlations.
***
Consider, for example, the study of Fischer et al. (1999), who examined trends of atmospheric CO2 and air temperature derived from Antarctic ice core data that extended back in time a quarter of a million years. Over this extended period, the three most dramatic warming events experienced on earth were those associated with the terminations of the last three ice ages; and for each of these climatic transitions, earth's air temperature rose well in advance of any increase in atmospheric CO2. In fact, the air's CO2 content did not begin to rise until 400 to 1,000 years after the planet began to warm. Such findings have been corroborated by Mudelsee (2001), who examined the leads/lags of atmospheric CO2 concentration and air temperature over an even longer time period, finding that variations in atmospheric CO2 concentration lagged behind variations in air temperature by 1,300 to 5,000 years over the past 420,000 years."[ see also: Indermuhle et al. (2000), Monnin et al. (2001), Yokoyama et al. (2000), Clark and Mix (2000) ]
- "Other studies periodically demonstrate a complete uncoupling of CO2 and temperature "
[see: Petit et al. (1999), Staufer et al. (1998), Cheddadi et al., (1998), Raymo et al., 1998, Pagani et al. (1999), Pearson and Palmer (1999), Pearson and Palmer, (2000) ]
- "Considered in their entirety, these several results present a truly chaotic picture with respect to any possible effect that variations in atmospheric CO2 concentration may have on global temperature. Clearly, atmospheric CO2 is not the all-important driver of global climate change the climate alarmists make it out to be."
Global warming and global dioxide emission and concentration:
a Granger causality analysis
- "We find, in opposition to previous studies, that there is no evidence of Granger causality from global carbon dioxide emission to global surface temperature. Further, we could not find robust empirical evidence for the causal nexus from global carbon dioxide concentration to global surface temperature."
"Carbon dioxide, the main culprit in the alleged greenhouse-gas warming, is not a "driver" of climate change at all. Indeed, in earlier research Jan Veizer, of the University of Ottawa and one of the co-authors of the GSA Today article, established that rather than forcing climate change, CO2 levels actually lag behind climatic temperatures, suggesting that global warming may cause carbon dioxide rather than the other way around."
***
"Veizer and Shaviv's greatest contribution is their time scale. They have examined the relationship of cosmic rays, solar activity and CO2, and climate change going back through thousands of major and minor coolings and warmings. They found a strong -- very strong -- correlation between cosmic rays, solar activity and climate change, but almost none between carbon dioxide and global temperature increases."