Europe is warming relatively quickly, but ‘warming alone does not say everything’

Europe is warming relatively quickly, but ‘warming alone does not say everything’

“Europe is the continent that is warming the fastest, with temperatures rising about twice as fast as the global average.” The World Meteorological Organization (WMO), affiliated with the United Nations, and Copernicus, the European Union’s climate agency, reported this earlier this week. It suggests that something exceptional is happening in Europe. But is that correct?

Climate scientist Álvaro Silva, consultant for the WMO, answers questions from NRC.

What does the WMO consider part of Europe?

“Then I’ll start with the fact that the WMO divides the world into six regions in climate analyzes: Africa, Asia, South America, North America, Australia and Europe. For example, the North America region includes Canada, the United States, Mexico, Central America, and the Caribbean.

“The WMO distinguishes two variants in Europe. One variant includes Europe and the European part of Russia. The other variant also includes Greenland and part of the Middle East.”

And in which Europe has the temperature risen by 2.3 degrees Celsius since the pre-industrial period, the number that was in the news?

“That applies to both. It is the average warming over the last five years. If you only look at 2023, you arrive at a warming of about 2.5°C for the smaller Europe variant and 2.6 for the larger one. This is mainly due to Greenland, which is warming quickly.”

How quickly are the other continents warming?

“We do not have a comparison with the pre-industrial period for all continents, because measurement data are not available for all regions that far back. We have dates from 1900 onwards.

“The figures show that Europe is not exceptional. There are more regions that are warming more or less twice as fast as the global average. Europe comes out on top, with a warming of 0.5°C per decade since 1991. Then comes Asia, with 0.4°C per decade. The WMO also includes the part of Russia east of the Urals. North America is in third place, with a warming of almost 0.4°C per decade.”

The air above the oceans warms much more slowly than the air above land

How is it possible that these regions are warming twice as fast as the global average?

“The global average includes warming above land and above sea. And the air above the oceans warms much more slowly than the air above land. Especially because water has a high heat storage capacity. Evaporating water takes a lot of energy. That energy can then no longer be used to heat the air. On land, the soil does not always contain the same amount of moisture, and there is more energy to heat the air.”

And why are the regions in the Northern Hemisphere warming rapidly?

“Because they have large areas of land near the Arctic, and that is warming the fastest worldwide. Much faster than the other pole, Antarctica. This is partly because the Arctic region is ice on water. Antarctica is ice on land. Ice reflects a lot of sunlight and thus limits warming. The ice in the Arctic floats on water. When the ice has melted, you get a dark water surface, which absorbs much more sunlight. In addition, extra heat is transported from the tropics to the poles.

“It is very different in the southern hemisphere. A region like South America, for example, is warming at about the same rate as the global average. Not only because it is far from the Arctic, but also because there is more ocean in the Southern Hemisphere than in the Northern Hemisphere. And ocean currents also play a role.”

And why does Europe score the highest in terms of warming compared to Asia and North America?

“What we know is that the sunlight reaching the land surface of Europe has increased. This is because there are fewer clouds, especially in summer. This has to do, among other things, with reduced air pollution. But I don’t have any idea of ​​what that is like in Asia and North America.”

But Europe is not as exceptional as that sentence in the WMO press release suggests?

“No. And I would also like to add that warming in itself does not say everything. In some regions the warming is a lot less, but the impact is much greater.”




SCIENCE