What is happening to the climate and why there was no snow in Moscow

What is happening to the climate and why there was no snow in Moscow
What is happening to the climate and why there was no snow in Moscow
Anonim

On a long weekend in March, Russians from the central part of the country will experience almost May weather - about 10 degrees Celsius, and somewhere higher. What is happening to the climate, why there was no snow or frost in Moscow last winter, what is the threat of warming and is it worth believing the alarmist activist Greta Thunberg - the head of the climatology laboratory of the Institute of Geography of the Russian Academy of Sciences, Deputy Director of the Institute answered these questions to Lente.ru Physics of the Atmosphere. A.M. Obukhov RAS Vladimir Semenov.

"Lenta.ru": What is happening in Moscow this year? When we talk about global warming, on average, we are talking about a temperature increase of one to two degrees, and this winter the temperature generally rarely dropped much below zero

Semenov: When we talk about global warming, the average is one degree. But if you take the territory of Russia, then here it has warmed not by one, but by two degrees - or even a little more. This is the so-called arctic gain. That is, the closer to the poles, the stronger the global warming is. In the tropics, it is less.

It gets warmer in winter than in summer, and therefore, if in summer it gets warmer, conventionally, a degree and a half, then in winter it is about 2, 5-3 degrees. In the past 30 years, the fastest warming in winter is in December - by four degrees.

Yes, but now we are talking about completely different temperature fluctuations …

I say this to the fact that the real changes in winter temperature over the past 30-40 years amounted to somewhere around 2, 5-3 degrees. This, of course, is not much, but in order to realize how strong the changes are, you need to understand the temperature difference between months. In seasons that are transitional to winter, the temperature changes by 5-6 degrees: from August to September - 4 degrees, from September to October, from October to November and from November to December - about 5-7 degrees. That is, the temperature changes by three degrees in half a month.

This is how, on average, the beginning of winter has shifted. If earlier snow fell in late October or early November, now it falls on average in the second half of November. Against the background of this trend, interannual temperature fluctuations occur. In winter, they are more intense, because in our region, in the North Atlantic, Arctic sector, there is an internal variability of the atmospheric circulation.

Even without external influences, there will always be such leaps from year to year up and down. They are associated with the so-called North Atlantic Oscillation - this is the pressure difference between, roughly speaking, Iceland and the Azores, which determines the zonal flow of the North Atlantic, which creates a mild climate in Europe. Well, it comes to us - the stronger, the further east it all goes

And this North Atlantic wobble was abnormally strong this year?

Yes. There was a colossal transfer of warm air from west to east, from the Atlantic to Europe. The synoptic maps clearly showed cyclones that originated west of Greenland, and they were intensified by the Icelandic depression and moved on with this flow one by one to the north of Eurasia, bringing us constantly warm air masses and strong westerly winds.

Was that before?

It was. Such jumps in the North Atlantic Oscillation caused positive temperature anomalies in our country, but not as much as now. There are two questions here. To one we can answer: to this random jump, we add those 3-4 degrees of winter warming. And earlier, 30 years ago, in such a situation it would have been not minus 1 or minus 2, but minus 4-5, and the snow that fell would probably lie and not melt. Now, against the background of such a leap, we add another three degrees and we get a slightly different situation.

The second question is whether this abnormal jump in the North Atlantic Oscillation is related to global warming, because this possibility, of course, cannot be denied, because the changes come from the Gulf Stream zone, where cyclones are born, and the ocean temperature rises. But, to be honest, this is a speculative question. No one can give an exact answer to it.

Moscow, winter 2020

What do you personally think?

Most likely, this could be an accidental anomaly of atmospheric circulation, which has always happened - warm winters have happened before. But here I say: add a component associated with warming to such jumps, and perhaps we will get this warm winter. Therefore, I explain it this way: this is an anomaly of atmospheric circulation against the background of global warming.

The only thing I will add: the Barents Sea, for example, has completely switched over to an ice-free regime. In a cyclone, air circulation goes counterclockwise, that is, the wind blows in them from north to south. And if earlier the Barents Sea was at least partially covered with ice, and the air masses there were cold, now, on the contrary, there is a free water surface, which has, albeit a small, but positive temperature.

And this is the third factor that contributes to and will continue to facilitate the flow of warm air, as ice in the Arctic as a whole continues to shrink at a rapid pace. Moscow is surrounded on three sides by warm regions, from which cold cannot come. From the west it is the Atlantic, in the north it is the Barents Sea, free of ice, in the south it is the southern regions, where it is warmer. And it turns out that the only area from where cold air can come to us is the east.

So, we can say that very soon our climate will be similar to that of Western Europe, and there will be practically no snow at all in winter? Or is it a one-off occurrence that is unlikely to happen again soon?

Of course, this winter is not an indicator. The next one with a very high probability will not be like that, it will be snowy. These anomalies around the mean are random and occur in both positive and negative directions. The norm in January was, as far as I remember, minus 10 degrees, and now it has become somewhere minus 7, 5. The heat will continue, it will not be minus 7, but minus 5 in 20 years, nevertheless, these are negative temperatures. So what we are seeing now is, on the one hand, an anomaly, but on the other hand, it gives us an example of what winters will be like in about 30 years.

Indeed, the climate will not be the same as in the southern regions, but rather as in Northern Europe, where the influence of the North Atlantic masses is felt: Holland, northern Germany … This is what we will observe - positive temperatures in winter, rare jumps in the negative direction, snow as an anomaly. Here is such a window to the future, we have now been slightly opened

I wonder what will happen then in Europe and further south? For example, it will become so hot at the equator that it will be completely impossible to live there, but in Europe, plus 15 in winter?

No, it won't. First of all, as I said, it gets warmer at the equator twice as slow as in the Arctic. There the temperature rose not by a degree, but by half a degree. In 30 years it will increase by the same amount. Even by the end of the century, the equator will get warmer by one and a half or two degrees, and this region will not become a “stove”.

With Europe, the situation is as follows: there is a mild climate, and the difference between winter and summer temperatures is small due to the proximity of the ocean. It warms up much more slowly than dry land - it's like a thermostat. In winter, say, it will be 12 degrees, but in summer it will still be 22-23 degrees in the North Atlantic region. And these two values ​​will restrain the rise in temperature, and therefore it is also impossible to say that there will be a bath.

The continental regions and the center of Siberia will suffer the most in this regard. There we will see the highest warming values. For example, in Yakutia it was minus 40, and it became minus 32. It has warmed by eight degrees - a crazy figure, but I don't know if they will notice the difference between minus 40 and minus 32.

Melting permafrost will lead to the release of greenhouse gases - and if so, what is the threat?

Indeed, when permafrost thaws, carbon is released, which was frozen in organic remains, swamps appear, in which all this begins to rot, in contact with air, carbon dioxide or methane appears, an even more dangerous greenhouse gas.

In addition, there are also the so-called methane hydrates - this is methane together with water molecules under high pressure. With warming, they also begin to be released, including large reserves of them on the Arctic shelf. Thus, warming could indeed cause a large flow of methane, which will continue to heat the Earth.

But so far all this is a subject of discussion. For example, those flows of methane that are now observed on the Arctic shelf: someone says that this is evidence of a "methane bomb", and only this methane will heat the planet a few more degrees. Others say that these are flows in the exit zones of geothermal faults, that they have always been, that these are point areas that do not indicate any extensive methane release.

Rudolf Island, Franz Josef Land Archipelago

The same is with swamps - very uncertain estimates of how the flows of greenhouse gases will react to the ongoing processes. Plus, if we have a lot of greenhouse gases, this should have a positive effect on vegetation, which will absorb more carbon dioxide.

In general, potentially - yes, there is such a possibility, but there is a very large uncertainty in the quantitative estimates of these effects.

Politicians, when talking about global warming, always whip up: the planet needs to be saved, time is short. Is it really that bad? And will any of our actions really help to cope with the consequences of global warming? Or is it more speculation for earning political points?

This is the problem: the answer is yes and no. Rapid climate changes in decades can significantly change both the economy and the lives of people. It is a fact. And the fact is that a person influences this. Together, we can try to influence this and reduce greenhouse gas emissions.

Is this used by politicians to break up the wave and achieve political interests? Of course. It is just important to understand here that when they begin to deny global warming and the anthropogenic factor - this is science! Scientists have nothing to do with it. Physics, climate, atmosphere have nothing to do with it.

On the other hand, if you take Russia, Moscow: is this winter really bad? I think that's great, and many people think so. Global warming has not only negative but also positive effects. But, of course, on average for most countries, and especially for the densely populated countries of Asia and Southeast Asia, it is a big problem.

First, we must leave science to scientists, not deny the obvious and not condone some alternative hypotheses just because they fit into the political point of view of the opponents of those who advocate the fight against global warming. Secondly, we see that this problem arises in political discourse, then disappears from it …

It seems that this has been talked about quite loudly for 30 years already

Well, not 30 - maybe 20, but with different intensities. Against the backdrop of economic crises and wars, this topic is now somewhat muted. I noticed that in the last year - and, perhaps, Greta Thunberg served here as a drop that overflowed the cup - even in Europe there are voices of people who say: “Listen, let's not be hysterical, there is a problem, but not so acute that take some crazy steps - give up meat completely, carry out some campaigns, not go to school "…

Analogs of Greta Thunberg appear on the other hand, and if scientists used to unequivocally dwell on the fact that global warming is an evil, we must fight it, now they say differently - that it exists, but this has happened before, and warming itself is not a deadly threat. Because a person has lived and will live, even if the temperature changes by plus 10 degrees and by minus 10.

Do you mean global temperature?

Yes, even global. Because during the ice ages there was already a man, and the temperature was 6-8 degrees lower. He also lives in Africa, where it is significantly higher. All this is not a problem, the problem is in adapting to such rapid changes. Our fragile infrastructure is tuned to a certain climate, and it can no longer quickly adapt to this. This is associated with large economic losses, and this is the problem. Man has tuned a lot of things close to the coast, based on average climatic norms. And now they are changing qualitatively. And this is precisely the problem, and not that high or low temperatures will destroy humanity.

You mentioned Greta Thunberg - and, if you remember, when the problem of the ozone hole was acute, a girl also spoke at the UN in 1992, who drew attention to the need to limit freon emissions. It seems that we have reduced them, and now the issue of thinning the ozone layer is not so acute

The effect of freons on ozone is a scientific fact, it is chemistry. It is also a fact that the ozone hole depends on the dynamics of the atmosphere, and the changes that occurred there from freon can happen because of this. As for girls, this is just such a PR trick, quite successful, so such girls will constantly appear and protest.

You say that the ozone hole can grow and shrink as a result of natural phenomena. But now we can say that the decrease in freon emissions in this case led to a positive trend?

We can say that if we continued to increase the emission of freons, then we would have continued the destruction of the ozone layer. That is, this effect was calculated, it is significant, noticeable, dangerous, and the fact that it was stopped is a fact.

Here is another important thing - when they say: why do you want to reduce some emissions, but it will only appear in 40-50 years, prove that there is some effect … This is the power of science to predict the effect without sticking your hand into molten lead, which seems to gurgle like water. Why else do we need it? The assessments that are made are physically justified. We say: yes, this can happen, let's try to reduce the danger.

You said that Asian countries will be hit particularly hard by global warming. What about epidemics? Could this be their catalyst?

For our country, the main problem in this regard is anthrax in cattle burial grounds located in a fairly large number of places where animals were buried in frozen ground. Now it is thawing, and all this with melt water appears on the surface, all this is carried away. There is a danger of an outbreak of such diseases.

And the area of ​​distribution of insects - carriers of infectious diseases - increases as the climate warms, they begin to cover an ever larger territory.

As for viruses, coronavirus - here I will not say anything. It seems to me that this is not directly related to warming.

Let's return to the local situation in Russia. Will this summer be abnormally hot too?

Summer does not depend on winter in any way, and a warm winter does not guarantee either warm or cold summers. Therefore, we cannot predict it now - this is a matter of fortune-telling. Closer to summer, somewhere in April-May, seasonal forecasts will already appear, because it is in two or three months that the meteorological services can make at least a more or less accurate forecast. They are made by our Hydrometeorological Center, and it is relatively true, in terms of whether it will be warmer or colder than normal.Predictability mainly depends on ocean surface temperature anomalies. Knowing it, we can understand the response of the atmosphere, but the lifetime of these oceanic anomalies is just two or three months. It is now the beginning of March, so by the summer everything can change a lot.

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