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Nowadays, only the lazy is not talking about global warming. Between the average air temperature on the planet over the past 16 years practically did not increase. Scientists are constantly trying to figure out whether this process is natural or has anthropogenic character, that is, depends on the activities of mankind. Many climate models that scientists build on the basis of collected data, predicted a further increase in temperature, which manifested itself in the 90s of the XX century after an increase in greenhouse emissions gases. But while they, apparently, do not work. Some skeptics Believing that there can be no global warming at all, point to this and question not only the role the greenhouse effect, but also the fact of global changes. However most researchers believe that we observe only temporary lull It doesn’t even contradict long-term warming. run. In two new studies, scientists tried to identify the reasons for this pause. They concluded that they had a place natural cyclic processes occurring in the oceans. Ka-Kit Tung from the University of Washington in Seattle and his colleagues studied the circulation of water in the Atlantic and in the southern regions around Antarctica. Scientists have been particularly interested in currents, which carry warm waters from the tropics to high latitudes. There these flows cool, sink to a depth and go in the opposite direction to the equator. From the 1970s to the 1990s, this movement was relatively slow, which allowed warm water to linger on surface long enough. In this case, a significant part of the heat transmitted to the air, contributing to global warming. But in 1999 the year accelerated, and now the water does not have time enough cool before diving into deeper layers. Thun explains that the speed of the currents depends on the salinity of the water at high latitudes. When flows slowly, intensive evaporation leads to an increase their salinity. As a result, closer to the poles, the water becomes more dense and sinks faster. At some point, the dive speed begins to disperse the entire course. To test your hypothesis, researchers studied the performance of oceanographic instruments, which have been measuring the parameters of ocean waters since the 1970s. Scientists tried to find the missing heat, which according to their calculations distributed in depth. It turned out that the moment of deceleration climate change corresponds to the onset of temperature rise ocean at a depth of one and a half kilometers. According to the authors of the article, published in Science, the results are convincing explanation why the dynamics of air and ocean temperature reached plateau after the abnormally hot 1998. Professor Reto Knutti (Reto Knutti) from the Swiss Higher Technical School of Zurich (ETH Zurich) and his colleagues also searched for the reasons for the interruption warming. They found the effect of upper temperature fluctuations layer of the Pacific, known as El Niño and La Niña, on atmospheric processes. In the course of El Nino, which is translated from Spanish means “boy”, heated water is shifting to the east direction. In the opposite phase, La Niña, or “girl,” flows moving west. The duration and strength of each period is strong varies. So already mentioned 1998 was marked by El Niño’s powerful phase in the history of observations. While subsequent phases of La Niña were somewhat cooler than usual. In addition, scientists argue that the pause in global warming coincided with an unusual decrease in solar activity. Normal eleven-year sunspot reduction and growth cycle This time, for unknown reasons, it has been going on for 13 years. Also the impact of solar radiation on climate can be reduced after eruptions of the Icelandic volcano Eyyafyatlayokudl in 2010. A large number of small volatile particles that were thrown into the upper atmosphere, act like a screen from the sun, scientists say. The results of this work were published in the publication. Nature Geoscience. The authors of both works see no reason suggest that global warming has stopped. Judging by everything, the pause is caused by a whole complex of natural processes, which overlap each other. Scientists believe that soon time, the increase in temperature on the planet will continue.
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