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- "In the coming years, summers will lengthen and periods of heat and cold will change dramatically"
"In the coming years, summers will lengthen and periods of heat and cold will change dramatically"
The weather in the European part of Russia will increasingly be determined by blocking cyclones, which form prolonged periods of heat or cold, depending on the climatic situation. At the same time, the rains will come more often and become heavier, and summer will come earlier and end a few weeks later. Global warming is leading to these changes. Climatologist Alexander Chernokulsky, Deputy director of the Obukhov Institute of Atmospheric Physics of the Russian Academy of Sciences, told Izvestia in an interview about how climate processes change the weather we are used to.
"We are seeing a general increase in temperatures"
— Summer heat in April. Cold May and June, followed by sudden heat waves and frequent rains in July. Residents of the capital faced unusual weather this year. Can all this be considered an anomaly or a normal situation?
— In general, this is quite normal weather. Which is noted against the background of a general increase in temperature. The heat in April was abnormal, and the cold in May is common. There have been more severe cold snaps. Also, with the return of cold weather in June. The temperature in June generally corresponded to the old norm of 1961-1990, we just got out of the habit of it.
In June, we were on the eastern periphery of a large blocking cyclone. It was abnormally hot in Europe at that time — up to 45 degrees. And we have the flip side of the coin. In 2010, exactly the same thing happened. It was hot in Moscow, but cold in Siberia, where there was no summer. There were generally blocking anticyclones in the old climate, but there will be many more in the new one.
— Are the blockers the ones that last a long time?
— They seem to block the western transfer (the predominant movement of air masses from west to east. — Izvestia). Therefore, there will be less moderate weather, which is typical for western migration. Meridional transport (movement of air masses from north to south and from south to north) will be observed more often. — Izvestia).
The weather will depend on which part of the blocking anticyclone we are in. If it's in the west, it's very hot, if we're talking about summer. And in the east, it's damp and cool. In the last few years, this has been happening so that it is very hot in western Europe in the summer, where it is below 45 degrees. But in Eastern Europe, including the European territory of Russia, it is still cooler.
— Will thunderstorms occur more often?
— Summer is a common time for thunderstorms. They occur due to convection (the process of heat exchange between air streams. — Izvestia). Another thing is that the new atmosphere contains more moisture. Storm clouds rise higher, and more water is poured into the rains. That is, the amount of rain that pours out of one thunderstorm cloud is getting bigger. Due to global warming, there is more warm air with more moisture in it.
— So these are the consequences of global warming?
— Yes, global warming is manifested locally in different regions. There is warming in our region: more moisture in the warm air means more rain. In the middle zone, in the south of Siberia, we often observe favorable conditions for the development of such dangerous phenomena as heavy rains, large hail, convective squalls (a sharp, short-term increase in wind associated with thunder clouds. — Izvestia).
The issue of lightning intensification remains open. In order for lightning to form, the vertical extended part of the cloud is important, where ice crystals and grains collide together. The ice crystals receive a positive charge after impact, while the grain receives a negative charge. At the same time, the crystals rise, and the grain, as heavier, falls down. As a result, the charge is separated in the cloud, and lightning is formed. Depending on whether this vertical part is large or small, one or another intensity of lightning is formed. Due to climate change, this extent is changing, but apparently in different regions in different ways.
We can see that the total vertical extent of convective clouds is growing. Since the beginning of the 21st century, according to satellite data, the height of such clouds above our latitudes has increased at a rate of about 300 m in 10 years. There is definitely more lightning in the northern regions, in the Arctic, and in the polar regions. But in the middle zone, for example, we do not see such significant growth. As for the intensity of the charge inside the lightning, we do not have data for long periods. And if you look at the stations on stormy days, then the changes in the middle band are even negative.
"Winter is getting shorter"
— And how does all this affect the change of seasons?
— In the coming years, summers will lengthen and periods of heat and cold will change dramatically. The summer period starts a few weeks earlier and ends later. Winter is getting shorter on both sides. For example, the first half of September becomes summer.
— Besides thunderstorms, how else does global warming affect?
— The temperature is rising. Cold waves appear less frequently, and heat waves appear more often. This is the main thing that we record. Reduction of the amount of ice, sea ice and cover ice, mountain glaciers, melting of permafrost. These are lengthy processes. The permafrost is moving away from us. And the ocean level is rising.
— And how does this influence appear in different regions?
— For example, in the north and in the center of Siberia, permafrost is melting and forest fires are increasing. The south of the Far East, the Krasnodar Territory, and the Black Sea coast are experiencing increased heavy rains and floods. The south of the European part of Russia is dry in summer, but there is more precipitation in winter. Large cities, Moscow, the Black Earth region, and the Volga region are, again, increasing heat waves. But in northern cities, reducing cold waves is even a plus.
— People who often visit St. Petersburg note that there is more sun there, is this part of this process?
— Yes, in general, we see a redistribution of the type of clouds. There are fewer layered clouds and more cumulus clouds. The nature of precipitation is also changing. Less heavy, tedious, monotonous rains, but more heavy short showers.
— And if we talk about weather forecasts, it seems that they are becoming more accurate than before. It happens that forecasts come true for 10 days ahead. Is it due to the development of technology?
— Yes, the quality of observations and predictive models is improving. Forecasts for the next day reach 97.5–98% accuracy. And, for example, for three days in advance — about 75%. But we at the Institute of Physics and Atmosphere do not make weather forecasts, but study longer-term trends.
— What periods are we talking about?
— As a rule, from 10 years. What was predicted in the 1980s and 1990s, we see, is now coming true. It is quite possible to check it.
— And what can we expect in the 2030s?
— The continuation of what is happening now... there will not be any dramatic changes. In Russia, warming occurs at a rate of about half a degree in 10 years. This will be especially evident in the northern regions. Winters will be one to one and a half to two degrees warmer on average. In the summer, it will not be so noticeable: 0.2— 0.3 degrees on average.
— Will there be any consequences?
— Yes, the main thing is the melting of ice. There are two sides to this process. Firstly, it is the transition to seasonal feeding of rivers where they depend on mountain glaciers. These are mainly Central Asia. If there is no snow in winter, there will be problems with drinking water. The second point is that if the ice has melted, sooner or later the water will fall into the ocean. And this is an increase in ocean levels. The big question is: where is the limit of glacier stability in West Antarctica? Modern research suggests that the stability threshold is somewhere in the order of 1.8 degrees relative to pre-industrial values. That is, it's getting close. This is a slightly smaller problem for Russia, but it is serious for most countries of the world.
It is expected that by the end of the century, 40 centimeters will be added to the ocean level. And if it is not possible to slow down the warming, then another 70 centimeters will be added. This is, of course, a key problem that can lead to the flooding of some island States.
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