NL gets 2 tropical days for every degree of warming; Mediterranean warming alarmingly

The Netherlands gets two extra tropical days for every degree of global warming, the meteorological institute KNMI reported on Thursday, one day after the Spanish weather institute Aemet raised the alarm about the increasing temperatures of the Mediterranean Sea.

Spain is in the midst of its third heatwave this year. The average temperature of the Mediterranean Sea at the Spanish coast reached 24.6 degrees this month - 2.2 degrees higher than typical for this time of year, Aemet reported. The seawater in Spain hasn’t been this hot since measurements started in 1940.

The Netherlands has had three tropical days - when thermometers top 30 degrees Celsius at the national weather station in De Bilt - so far this summer. A hundred years ago, the average was one tropical day per summer. Now it’s already 4.5, the KNMI said.

“A relatively small warming causes a relatively rapid increase in the number of hot days,” the KNMI said. Summers in the Netherlands have become 2 degrees warmer. “The number of tropical days has increased by more than a factor of four.”

The increase in hot days can be seen throughout Europe and is currently very visible in Spain with its third heatwave. Weather agency Aemet stressed that the record for the warmest seawater wasn’t broken by a little. It was broken by a lot, spokesperson Ruben del Campo told the press agency AFP. The previous record was 24 degrees Celsius in 2015. The new record is 24.6, and the summer is far from over.

Looking at averages doesn’t make you realize the whole story, ecologist Anieke van Leeuwen of the Royal Netherlands Institute for Sea Research (NIOZ) told NOS. “If you only look at the average, it seems like small values. But an average goes up because there are more days with much higher temperatures. And places that are much warmer. With the climate crisis we are in now, extremes are becoming more and more common.”

In the southeast of Spain, sea temperatures have risen to 28 degrees in some places. The measuring point near the Balearic Islands even recorded 29 degrees. The high water temperatures have a significant impact on marine life. But outside the water, it also means that ambient temperatures cool down very little at night.

“If we want to limit a further increase in heat, greenhouse gas emissions must be reduced and CO2 must be removed from the air,” the KNMI stressed.