North Atlantic region more affected by climate change
A disruption of the thermohaline circulation in the North Atlantic caused by global warming would not result in any abrupt climate changes for East Asia, in contrast to its immediate neighbors.
Although there would also be a gradual cooling in Japan and northern China, this would largely be limited to the winter months. At the same time, the winter monsoons over Japan would intensify, bringing higher precipitation – and more snow – to the islands. An international research team led by Takeshi Nakagawa from the University of Newcastle came to this prognosis after looking at the climatic past of the earth 10,000 to 16,000 years ago.
After the end of the last ice age, temperatures rose worldwide, but 12,000 years ago there was another thousand-year cold spell in the Younger Dryas. It was triggered by a massive inflow of fresh water into the North Atlantic, as a result of which the northern branch of the Gulf Stream came to a standstill and the heat transport from the tropics to higher latitudes also dried up. In the direct sphere of influence of the Gulf Stream, temperature drops of seven to ten degrees Celsius therefore occurred. However, the analysis of fossil pollen from sediments of Lake Suigetsu in Japan gave a differentiated picture of the changes in vegetation and climate in East Asia. The detected plant species suggest that the temperature drops in East Asia were significantly lower, with a maximum of five degrees in winter and three degrees in summer.
The cause was apparently the seasonal Asian monsoon front, whose air masses acted as an effective barrier to block the effects of the North Atlantic cooling. Since these mechanisms are still at work today, another disruption of the thermohaline circulation in the Atlantic would have similar consequences, according to Nakagawa.
