THE waxing and waning of ocean currents almost as far south as Antarctica may have triggered regular growth spurts in Arctic ice sheets over the past 140 000 years. Researchers in Britain and Germany studying fossilised protozoans in the southern Atlantic say that their finding may lead to better predictions of the rate of global warming.
Many scientists believe that major climate changes are triggered by events in the northern hemisphere alone. But in a study to be published in
At issue is the genesis of Heinrich events, regular surges and collapses of ice sheets that occur in the northern hemisphere every 8000 to 10 000 years. During an event, the ice sheets over North America, Greenland and Eurasia grow ...