Does the 2007 IPCC Statement for Policymakers Accurately Present the Observations of Recent Global Temperature Trends?
Climate Science: Roger Pielke, Sr. Research Group Weblog, May 10, 2007
HYPERLINK "http://climatesci.colorado.edu/2007/05/10/does-the-ipcc-statement-for-policymakers-accurately-present-the-observations-of-recent-global-temperature-trends/" http://climatesci.colorado.edu/2007/05/10/does-the-ipcc-statement-for-policymakers-accurately-present-the-observations-of-recent-global-temperature-trends/
The HYPERLINK "http://www.ipcc.ch/" 2007 IPCC Statement for Policymakers (SPM) makes the following finding,
“Eleven of the last twelve years (1995 -2006) rank among the 12 warmest years in the instrumental record of global surface temperature (since 1850)” [based on “The average of near surface air temperature over land, and sea surface temperature.”].
and
“Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures…”
This claim, which is repeated throughout the media reports on the IPCC report, however, is disingenuous. Other analyses of global heat system changes do not support the claim of continued warming of the climate system.
Climate Science has discussed ocean heat content changes (e.g. HYPERLINK "http://climatesci.colorado.edu/2007/03/28/did-the-oceans-really-cool-between-mid-2003-and-mid-2005/"see) and has reported on the recent correction which concluded that the upper ocean did not cool during this time period ( HYPERLINK "http://climatesci.colorado.edu/2007/04/15/the-correction-to-the-lyman-et-al-2006-paper-is-available/" see), although the upper ocean has not warmed either which is at variance to what is expected from the IPCC Statement of Policymakers.
In this weblog, we report on data that was conveniently ignored in the 2007 IPCC SPM in their report on whether or not the climate system is continuing to warm. The data are the global average temperatures for different layers in the atmosphere from satellite measurements of the Earth’s microwave emissions by HYPERLINK "http://www.remss.com/msu/msu_data_description.html" \l "msu_decadal_trends" Remote Sensing Systems (RSS).
This data can be used to assess whether the warming trends reported in the 2007 IPCC SPM have continued in recent years. As shown clearly in Figure 7 on the RSS website>, the following conclusions can be made:
1. Since about 2002 there has been NO statistically significant global average warming in the lower and middle troposphere,
and
2. Since about 1995 there has been NO statistically significant cooling in the stratosphere.
The IPCC SPM conclusion that “warming of the climate system is unequivocal” is wrong as it ignores the lack of such warming in recent years by these other metrics of climate system heat changes [there is also an informative comment #11 on this issue under the weblog HYPERLINK "http://climatesci.colorado.edu/2007/04/15/the-correction-to-the-lyman-et-al-2006-paper-is-available/#comment-167200" http://climatesci.colorado.edu/2007/04/15/the-correction-to-the-lyman-et-al-2006-paper-is-available/#comment-167200.
Their focus on the global average near surface temperature trends neglects to report that there are major issues with the robustness of this climate metric of global warming as reported in the papers cited in
Pielke Sr., R.A., C. Davey, D. Niyogi, S. Fall, J. Steinweg-Woods, K. Hubbard, X. Lin, M. Cai, Y.-K. Lim, H. Li, J. Nielsen-Gammon, K. Gallo, R. Hale, R. Mahmood, R.T. McNider, and P. Blanken, 2007: HYPERLINK "http://climatesci.colorado.edu/publications/R-321.pdf" Unresolved issues with the assessment of multi-decadal global land surface temperature trends. J. Geophys. Res. in press,
many of which were available to the writers of the IPCC SPM but conveniently ignored. At the very least, the lack of recent tropospheric warming and stratospheric cooling in the RSS data and the warming claimed for the near surface air temperatures conflicts with the multi-decadal global climate models in terms of how these temperatures are predicted to change.
Perhaps global warming will begin again. However, the neglect to include the recent lack of tropospheric warming and stratospheric cooling (both of which are predicted to continue quasi-linearly for the coming decades by the multi-decadal global climate models, except for major volcanic eruptions) results in a seriously biased report by the IPCC. It has been disappointing that the media so far has chosen to parrot the statements in the IPCC SPMs rather than do investigative reporting on these issues.