Article Tags: Doug L. Hoffman
Earth’s climate history includes numerous incidents of rapid warming and cooling. While Pleistocene ice-age glacial terminations are arguably the most dramatic recent examples of sudden climate change, during the last glacial period the climate of the Northern Hemisphere experienced several other significant episodes when the climate rapidly warmed. Scientists call these episodes Dansgaard-Oeschger (DO) events after the Danish and Swiss researchers who documented them using ice-core studies. These rapid oscillations are marked by rapid warming, followed by slower cooling. The most prominent coolings are associated with massive iceberg discharge into the North Atlantic Ocean known as Heinrich events (HE). The melting icebergs add large volumes of cold fresh water to the ocean, disrupting circulation patterns and causing further climate changes. Scientists look to past events like these to help us understand how Earth’s climate system functions—what causes our planet to cool or suddenly warm. Recently, new data on past climate changes have led one commentator to predict the end of winter skiing in the American Southwest.
In an attempt to better understand the impact of such events on the American Southwest, Asmerom et al. examined oxygen isotopic data from a well-dated stalagmite recovered from central New Mexico. It seems that speleothems are providing scientists a wealth of new paleoclimate data these days. The data presented in this report, “Variable winter moisture in the southwestern United States linked to rapid glacial climate shifts,” utilizes a new analysis technique, different from the one used to identify ancient sea-level changes I reported on earlier (see “Ancient Sea-levels Rewrite Ice Age Transitions”). Here researchers were trying to fill in a gap in our knowledge regarding precipitation changes in days gone by. As they explain in the article:
Source: theresilientearth.com