CAUSES OF ABRUPT GLOBAL CLIMATE CHANGES AND GLOBAL WARMING: PREDICTIONS FOR THE COMING CENTURY

Abrupt Younger Dryas (YD) climate oscillations occurred synchronously in both the Northern and Southern Hemispheres with no significant lag between hemispheres, as shown by double YD moraines in the Pacific NW, Rocky Mts., Swiss Alps, Canada, Scandinavia, and New Zealand. The lack of a time lag between hemispheres means that changes in the North Atlantic deep current cannot adequately explain the abrupt global climate changes.

As shown in the GISP2 ice cores, late Pleistocene abrupt temperature fluctuations occurred in only 20–100 years, clearly not caused by atmospheric CO2. During these climatic changes, 10Be and 14C production rates also varied, suggesting the possibility of solar changes. Similar changes also occurred during climate changes in the early Holocene and the Little Ice Age, again suggesting a connection between climatic changes and solar variation.

Historic fluctuations of alpine glaciers, solar activity, and measured isotope changes suggest that the present global warming could well be solar in origin, rather than a result of increased atmospheric CO2. Alpine glaciers in the Pacific Northwest and elsewhere show distinct oscillations, having a period of ~25-30 years. Glaciers advanced from about 1890–1920 (cool cycle), then retreated rapidly from the late 1920s to the early 1950s (warm cycle). Then readvanced again from ~1955 to ~1977 (cool cycle) and the present warm cycle that began in 1977 continues today. Comparable, cyclical, fluctuations occurred in the North Pacific Ocean, the North Atlantic Ocean, and in Europe, and Greenland.

Global temperature curves show a cool reversal from ~1955 to ~1980), inferring that global temperatures then were not driven by atmospheric CO2. Solar irradiance curves almost exactly match the global temperature curve and satellite data suggest that the earth has received increased solar radiation over the past 25 years, coinciding with the present 25–year warm cycle. If the cycles continue as in the past, the current warm cycle should end soon, and global warming should abate, rather than increase, in the next 25-30 years. Using these data as a basis, the coming century should experience a cooler climate from ~2006 to ~2035, a warmer period (probably warmer than the 1977–2005 warm period) from ~2035 to ~2065, followed by another cooler period from ~2065 to about the end of the century. The coming decades will test this prediction.