Shockingly Rapid Climatic Shifts are Real

Compiled by Lewis Loflin


Summary: in recent geological history massive climate shifts have occurred for reasons not understood. Studying fossil plankton and oxygen isotopes shows rapid warming followed by long term cooling. Professor Stanley wonders how the burning of fossil fuels may effect this natural abrupt climate change. If these happen at 10,000 to 15,000 year intervals we're close to that point now from rapid warming 10,000 to 12,000 years ago.

The following extract from Earth System History by Steven M. Stanley P468. Full credit goes to Professor Stanley, but I've done some editing for the non-science reader.

Earth System Shift 19-1
Shockingly Rapid Climatic Shifts Occur during the Ice Age

Detailed studies of the last glacial maximum, between 80,000 and 20,000 years ago, have revealed astoundingly sudden climatic changes separated by longer cooling trends. Part of the evidence comes from a particular species of planktonic foraminifera (marine protozoan's that form chambered skeletons from calcium carbonate) that survives today and is known to flourish in very cold water. Additional evidence comes from oxygen isotope ratios in annual layers of ice that can be observed in cores of the Greenland ice cap...Oxygen isotopes in the ice reflect temperature changes from year to year in the Greenland region.

The foraminifera and isotope records are in accord, showing that climatic oscillations were grouped into long-term cooling cycles that lasted an average of 10,000 to 15,000 years. The average temperature declined within a cycle, but each cycle ended with an abrupt warming event, during which the temperature jumped by several degrees Celsius within only about 10 years.

Interestingly, not long before each pulse of wanning, a Heinrich event occurred. A Heinrich event is a massive discharge of icebergs that release sedimentary debris to the sea as they melt. Heinrich lavers are conspicuous in North Atlantic deep-sea cores. Heinrich events occurred when climates were very cold and glaciers surged to the sea. Why sudden wanning followed Heinrich events is unclear, as is the reason for the lengthening of the cooling cycles.

Whatever may have caused the abrupt warming episodes, such sudden changes serve warning that the global climate can change dramatically as a result of natural causes within the space of a single decade.