In the Earth's history there have been occasions when the average surface temperature of the planet in a matter of decades jumps ten degrees, and some scientists believe that we are waiting for something like this due to the pumping of the atmosphere with carbon dioxide.
The new study, however, supports those who believe that the cause of sudden warming, and so lies in changes in ocean circulation. "It is possible that the mechanisms for greenhouse gases cause such drastic changes that do exist, but the geological record we did not speak about it," — emphasizes the study co-author David Battisti of the University of Washington (USA).
A team of scientists simulated the so-called Heinrich events that occurred during the last glacial period, 110-10 thousand years ago. It is a massive formation of icebergs in the North Atlantic. They carried with them the material, which became part of the glaciers as they move over land. Icebergs melted, the material sank to the bottom, and its presence in the sediments allows scientists to reconstruct the history of those early years.
In the experiment, the many climate models has been added to the oxygen-isotope, allowing to determine the cause of climate changes already registered, previous analysis of the ratio of oxygen isotopes in carbonate deposits in China and India has shown that the intensity of the monsoon in this region has changed. Modeling based on these isotope ratios.
It turned out that the sudden increase in sea ice in the North Atlantic cooled the Northern Hemisphere, including the surface of the Indian Ocean, which led to a reduction in rainfall in India and the Indian monsoon weakened, but not particularly strong influence in East Asia.
Mr. Battisti notes that, while climate change caused by carbon dioxide, can hardly be harsh, some things do happen very quickly. For example, is the cornerstone of losing ecosystem look like it will change in the blink of an eye. Smooth retreat of sea ice could lead to rapid warming in the range of several thousand kilometers from the coast. If warming slowly dries semi-arid areas, fires are becoming more frequent.