Effects of climate change in South America
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Contents |
Past 1,000 Years
For full article see Past 1,000 years in South America
It is difficult to believe that the strong synchronicity of the century-long Northern Hemispheric and South American warm and cold periods was coincidental. It is much more realistic to believe it was the result of a millennial-scale oscillation of climate that is global in scope and driven by some regularly varying forcing factor. Although one can argue about the identity of that forcing factor and the means by which it exerts its influence, one thing should be clear: It is not the atmosphere’s CO2 concentration, which has exhibited a significant in-phase variation with global temperature change only over the Little Ice Age to Current Warm Period transition. This being the case, it should be clear that the climatic amelioration of the past century or more has had little or nothing to do with the concomitant rise in the air’s CO2 content but everything to do with the influential forcing factor that has governed the millennial-scale oscillation of earth’s climate as far back in time as we have been able to detect it.
Temperature
For full article see Temperature in South America
Polissar et al. (2006) worked with data derived from sediment records of two Venezuelan watersheds along with ancillary data obtained from other studies that had been conducted in the same general region. They developed continuous decadal-scale histories of glacier activity and moisture balance in a part of the tropical Andes (the Cordillera de Merida) over the past millennium and a half, from which they were able to deduce contemporary histories of regional temperature and precipitation. The international (Canada, Spain, United States, Venezuela) team of scientists write that “comparison of the Little Ice Age history of glacier activity with reconstructions of solar and volcanic forcing suggest that solar variability is the primary underlying cause of the glacier fluctuations,” because (1) “the peaks and troughs in the susceptibility records match fluctuations of solar irradiance reconstructed from 10Be and δ14C measurements,” (2) “spectral analysis shows significant peaks at 227 and 125 years in both the irradiance and magnetic susceptibility records, closely matching the de Vreis and Gleissberg oscillations identified from solar irradiance reconstructions,” and (3) “solar and volcanic forcing are uncorrelated between AD 1520 and 1650, and the magnetic susceptibility record follows the solar-irradiance reconstruction during this interval.” In addition, they write that “four glacial advances occurred between AD 1250 and 1810, coincident with solar-activity minima,” and that “temperature declines of -3.2 ± 1.4°C and precipitation increases of ~20% are required to produce the observed glacial responses.”
In discussing their findings, Polissar et al. say their results “suggest considerable sensitivity of tropical climate to small changes in radiative forcing from solar irradiance variability.” This research from South American strongly suggests that the IPCC is failing to take into account the effect of solar cycles on temperatures.
Glaciers
For full article see Glaciers in South America
Polissar et al.’s acknowledgement that “during most of the past 10,000 years, glaciers were absent from all but the highest peaks in the Cordillera de Merida,” which indicates that warmer-than-present temperatures are the norm for this part of the planet, and that any significant warming that might yet occur in this region (as well as most of the rest of the world) would mark only a return to more typical Holocene (or current interglacial) temperatures, which have themselves been significantly lower than those of all four prior interglacials. What is more, atmospheric CO2 concentrations were much lower during all of those much warmer periods.
References
Polissar, P.J., Abbott, M.B., Wolfe, A.P., Bezada, M., Rull, V. and Bradley, R.S. 2006. Solar modulation of Little Ice Age climate in the tropical Andes. Proceedings of the National Academy of Sciences USA 103: 8937-8942.
Related Links
Effects of climate change in Africa
Effects of climate change in Asia
Effects of climate change in Europe
Effects of climate change in North America
Effects of climate change at the Poles
