The fact that the entire world is gradually increased the average annual temperature, almost no one doubts. About global warming does not write just lazy. Most experts believe that much of an increase in temperature due to the increase in the concentration of atmospheric carbon dioxide, water vapor and other "greenhouse" gases.
The reasons that lead to an increase in CO2 levels in the atmosphere, a lot, but the main - it is human activity. Not long ago, the concentration of carbon dioxide record was made 400 ppm. Climatologists say that CO2 will not have less concentration of this gas will only increase. Recently, scientists have published a new study, the results of which indicate that global warming is influenced by some natural constraints. All the matter in the clouds.
All the matter in the clouds. The faster warming, the more water evaporates, and the more water vapor into the atmosphere. This water vapor affects the dynamics of the formation of clouds. Typically, scientists say that carbon dioxide and water vapor - the two main factors of global warming. It is water vapor, say experts, is responsible for about 36-70% of the greenhouse effect, without taking into account the cloud.
A team of scientists from Lawrence Livermore National Laboratory. E. Lawrence led by Chen Zhou found that in recent years in the lower atmosphere have been actively forming dense clouds, and it now has more than ever before. And these clouds reflect sunlight. The more of this type of cloud is formed, the more sunlight is reflected. Perhaps this is the formation of cloud cover caused the slowing down of global warming in the period from 1998 to 2013.
Interestingly, in the early 21 th century, most scientists, including the International Panel on Climate Change (IPCC) suggested ensuring clouds considerable positive feedback that amplifies the warming effect of the increase of CO2 in the atmosphere. Dr. Roy Spencer of the University of Alabama in Huntsville showed that in fact this relationship is not positive and the negative. According to him, most climate models confused cause and effect, so scientists use the wrong direction feedback. It should take into account the fact that the clouds are located at high altitude, the sun's rays pass, but do not let the heat reflected by the Earth's surface. Clouds are formed directly over the planet's surface to reflect more sunlight and transmit the reflected surface of the Earth warm.
In 2010, it was shown that there is a small possibility of a negative feedback (cooling) under the influence of clouds that are at a low altitude. These clouds are actively formed near the equator, in the tropics and subtropics.
Experts from the Lawrence Livermore National Laboratory decided to see how the climate models, if you enter such factors as the negative feedback of clouds. Scientists decided to simulate climate change over the past 150 years, and compare the calculated data with real. As it turns out, these data are correlated to a high enough degree. Therefore, the researchers concluded that the created model can be used to predict the dynamics of the Earth's climate temperature in the future.
Interestingly, the model showed a period of time, when the clouds provide positive feedback to global warming, that is amplified warming. But as soon as it became more clouds formed at low altitude, the positive feedback is beginning to weaken gradually and over time has shown the opposite sign. The last few decades, this relationship - negative, that is to say, that the cloud layer reduces the rate of global warming.
Now warm water eastern tropical regions of the Atlantic and Pacific oceans heat up faster than the western regions. This situation can be traced to the 1980s. The heated air rises higher in the heated regions, and when moving to cooler areas is reduced. The higher the temperature difference, the more clouds are formed in the lower atmosphere. Accordingly, the more they reflect light and heat, some slowing of global warming. If the process of cloud formation will slow the pace of global warming increase. The impact of clouds on the climate has changed several times over the past decades, it all depends on the formation and dynamics of warm and cold air masses in different parts of the world.
Experts say that slowing warming - only a temporary phenomenon. "In the future, heat the entire surface of the earth is likely to lead to a decrease in the clouds affect the thermal regime of the Earth ... The study showed us that while that we were lucky because the clouds in the lower atmosphere became more and more, they reflect sunlight and heat back in space, slowing down the heating of the planet. But do not hope to maintain operation of this process in the future, "- said Kate Marvel climatologist from NASA.
DOI: 10.1038/NGEO2828