The Physical Evidence of Earth's Unstoppable 1,500-Year Climate Cycle
Friday, September 30, 2005
by S. Fred Singer & Dennis T. Avery
Table of Contents
Cave stalagmites vary with temperature and moisture, in their carbon and oxygen isotopes and in their trace element contents. Moreover, the stalagmites go back farther in time than the tree evidence. Cave stalagmites have been found in Ireland, Germany, Oman, China and South Africa whose layers all show the Little Ice Age, the Medieval Warming, the Dark Ages and the Roman Warming. Most also show the unnamed cold period that preceded the Roman Warming.48, 49, 50, 51
On the Arabian Peninsula, a stalagmite study also emphasized the “globalness” of climate. Germany’s Ulrich Neff found oxygen-18 isotopes yielded a very precise record of the 1,500-year climate cycle in the region’s monsoon rainfall. Neff says the monsoons were considerably stronger during the Climate Optimum (5,000 to 7,000 years ago), which also produced an era of heavy rainfall in the Sahel regions of Africa, in Arabia and in India. The Oman stalagmite’s cycles were also in phase with the temperature fluctuations recorded in Greenland ice cores 10,000 years ago, indicating that both were then controlled by glacial boundaries. Since the melt-off of the huge ice sheets, however, the stalagmite proxy says the Indian Ocean monsoon has been governed by variations in solar activity instead.52
In China, researchers analyzed a cave stalagmite near Beijing using the manganese/strontium ratio as a “geochemical thermometer.”53 The team found a strong warming from 700 to 1000, corresponding to the Medieval Warm Period, which may have reached China earlier than Europe. From 1500 to 1800, the air temperature was about 1.2° C lower than now.
"The effects of warming and cooling are global."
In South Africa, a cave stalagmite from the Makapansgat Valley shows that the Medieval Warming started before 1000 and lasted until around 1300. [See Figure III.] Temperatures there may have been 3 to 4° C higher than at present. The Little Ice Age in the region extended from around 1300 to 1800, and was about 1° C cooler than today.54 The lowest temperatures were recorded during the Maunder and Sporer minimums when low sunspot counts indicated low solar activity. The same South African stalagmite revealed cold periods in the cave region between 800 and 200 B.C. — corresponding to the unnamed cooling period before the Roman Warming.55 (The stalagmite doesn’t show unusual warming in the 20th century.)
In New Zealand, the oxygen-18 isotopes in a stalagmite show the coldest recent period was 1600 to 1700, following exceptionally warm temperatures from 1200 to 1400.56 A. T. Wilson and Chris Hendy of New Zealand’s Waikato University state specifically that since their country is “in the Southern Hemisphere and a region meteorologically separated from Europe,” finding the Medieval Warming and the Little Ice Age there demonstrates they are “not just a local European phenomenon.”