On Nov 16, 7:24 am, "Edward K. Ream" <[EMAIL PROTECTED]> wrote:
> Furthermore, the evaluation of evidence, and indeed the creation of > new *kinds* of evidence if close to the center of scientific > enterprise. I have just finished reading out loud to Rebecca a truly sensational article in Science: "A Test of Climate, Sun, and Culture Relationships from an 1810-Year Chinese Cave Record." You can read (for a few days at most) this article here: it is 940.pdf. The authors obtain very high resolution data from a stalagmite. New kinds of evidence indeed. That's nifty enough, but their conclusions could be a "smoking gun" establishing the anthropogenic origins of global warming. In the long quotation below, AM stands for Asian Monsoon, NH stands for Northern Hemisphere. QQQ Our record shows general AM weakening over the past half century, with much of the change taking place in the past two decades, which is consistent with other AM indices (fig. S9) and anticorrelating with rising NH temperature (5–7). This late-20th-century anticorrelation is distinctly anomalous as compared to earlier times, which are characterized by millennial- and centennial-scale correlation between NH temperature and the AM (Fig. 2), as well as similar correlations between the AM and North Atlantic temperature much deeper in time (2, 16). This anomaly suggests that the dominant forcing of AM variability changed from natural to anthropogenic around 1960 (25–27). Possible mechanisms include differences in the nature of solar versus greenhouse forcing, the effect of anthropogenic black carbon on the AM, and/or the effect of anthropogenic sulfate aerosols. Solar forcing is more seasonally and spatially heterogeneous than greenhouse gas forcing and thus is more likely to induce feedbacks involving temperature gradient–driven circulation such as the AM (25). Models have also shown that lower troposphere cooling coupled with mid- and upper-troposphere heating caused by black carbon could reduce East Asian Monsoon precipitation as observed (28). Finally, models also suggest that the indirect effect of differential anthropogenic sulfate aerosol loading shifts tropical rainfall southward (29), plausibly weakening the monsoon as observed. Thus, variability in late– 20th-century precipitation and temperature in the region is probably caused, in large part, by both anthropogenic greenhouse gases and aerosols. In reaching this conclusion, the key observation was not our late–20th-century trend, which is also observed in instrumental records, but rather the relationships at earlier times, observed in this and other proxy records. The proxy records establish the character of natural climate change, from which we distinguish late–20th-century trends as clearly anomalous. QQQ This is truly great stuff. The entire article is fascinating. Edward --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "leo-editor" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/leo-editor?hl=en -~----------~----~----~----~------~----~------~--~---
