GEOLOGIC EVIDENCE OF RECURRING CLIMATE CYCLES AND THEIR IMPLICATIONS FOR THE CAUSE OF GLOBAL WARMING AND CLIMATE CHANGES IN THE COMING CENTURY

Synchronous, interhemispheric, Holocene and late Pleistocene climate changes are recorded by glacier fluctuations, oxygen isotope ratios, CO2, and dust in ice cores, historic observations, and tree rings. Recurring cycles of global climate change are apparent in these records over the past several centuries and millennia and clearly show that natural climatic warming and cooling have occurred many times, long before anthropogenic CO2 emissions raised atmospheric CO2 levels. In addition to showing that climate changes can occur without human CO2 emissions, past climate changes follow cyclic decadal patterns that can be traced for 400–1000 years.

The Earth is now near the end of a 30–year warm cycle, which coincidently corresponds to high atmospheric CO2 levels. However, the preceding 30–year global cooling cycle (1945-1977) occurred despite the dramatic rise in CO2 emissions that began about 1945, and about half of the global warming of the past century occurred before 1945. Because ~80% of manmade CO2 emissions occurred after 1945, increased atmospheric CO2 clearly did not control climate in either case.

Similar warming and cooling cycles that have occurred over the past 400 to 1000 years have implications for understanding present–day global warming. The only time that global warming coincided with high atmospheric CO2 was from 1977 to 2007, but the present warm cycle is just what would be expected from the pattern of past cycles. If the cyclic pattern continues, the present warm cycle should soon end and global cooling should begin and continue until about 2040. The succeeding warm period (2040-2070) may be somewhat warmer than the present one, but well below temperatures predicted by the IPCC. The projected cool cycle from 2070 to 2100 would cool climates slightly, so by 2100, the temperature increase above the present would amount to only ~0.5 C (1° F), compared to as much as 6° C (10° F) predicted by the IPCC.

The predicted IPCC temperature increase by 2011 is 1° F greater than that predicted by extrapolation of the climatic cycles and nearly 2° F greater by 2030. These differences are greater than warming of the entire past century, so should be easily detectible. Thus, the next few years may tell us whether we're heading for the global catastrophe predicted by IPCC or minor warming predicted by climate cycles.