Climate change making hot days even hotter: KNMI

Hot days are already getting hotter due to climate change, said climate scientist Karin van der Wiel of the meteorological institute KNMI. The heat of Monday and Tuesday is increasingly common, and the temperature is often higher than it would have been before. “Climate change is happening here and now. It’s not just something of the future.”

On average, the annual temperature of the whole world has already warmed by 1 degree Celsius compared to 1850, Van der Wiel explained. But there are regional differences. For example, the land surface warms up faster than the sea surface. “The Netherlands has therefore already warmed by an average of 2 degrees annually. And if you look at the average temperature of the hottest day of the year in the Netherlands, it is already about 4 degrees higher,” said Van der Wiel.

That does not mean that all hot days are 4 degrees warmer than before. “Warm days are caused by a combination of ‘ingredients,’” said the climate scientist. “For example, the heat depends on the sun’s strength, high-pressure areas, and where the air is coming from. With every warm period, one of the ingredients nowadays is also climate change.”

These regional differences mean that it is not entirely clear how warm the Netherlands will be if the average global temperature is 2 degrees higher, the upper limit that world leaders set with each other in the 2015 Paris Climate Agreement. The KNMI is therefore drawing up climate scenarios for our country. These calculations should show how warm the Netherlands is getting on average. Research can also reveal what our country can expect regarding extreme drought or extreme rainfall.

Several scientists at the KNMI are researching the climate. “With code red or orange, we warn about the weather of today and tomorrow, but with climate research, we can also warn about the weather of the future,” said Van der Wiel.