Science – North Atlantic heat record could bring hot summer – Wikiwand

Berlin (dpa) – The North Atlantic is currently much warmer than it has been at this time of year since satellite measurements began 40 years ago. According to the researchers, this could mean a hot summer and heavy rains in Central Europe. In mid-June, the ocean area was about one degree warmer than the average for the comparative period from 1982 to 2011, according to data from the US climate agency NOAA.

The temperature of the analyzed sea surface from the equator to the southern tip of Greenland is currently about 0.5 degrees warmer than the previous record for this time. According to the measurements, the North Atlantic and most oceans around the world have shown record temperatures for the respective day since March.

Deep seas are warmer

The main reason: “The world’s oceans have absorbed 90 percent of the heat from man-made greenhouse gases,” says Mujeeb Latif of the Geomar Helmholtz Center for Ocean Research in Kiel. As a result, it is getting noticeably warmer at depths of up to 2,000 metres, and even deeper in a few regions – with consequences not only for ecosystems. They would also have absorbed a quarter of the carbon dioxide made by humans.

The North Atlantic is currently enjoying particularly high temperatures, with an average of about 23°C. The North Atlantic subtropical region in particular has warmed significantly since April. The persistent low pressure area has led to an influx of warmer air from the southwest and cooler air from the northeast into the subtropical North Atlantic, says Helge Gosling, a climate physicist at the Alfred Wegener Institute in Bremerhaven. In addition, the wind currents in the region weakened, which also led to an increase in surface temperature.

Anomalies of air currents

At the same time, according to Latif, there are also anomalies in air currents in the northern North Atlantic that are contributing to global warming. “This could be a random fluctuation in atmospheric flow, which in general is very variable,” Latif says. “It used to be a westerly wind, but now it’s coming in from the south and east and supplying warm air to the North Atlantic,” Gosling adds. The reasons are not clear. “In general, air currents over the world’s oceans are subject to large random fluctuations, which, however, increase global warming and can then lead to particularly high temperatures,” says Gosling. Thus climate change increases the likelihood of severe weather.

“With up to five degrees above normal, the water temperature off the western and southern coasts of France has warmed particularly strongly,” says Gosling. Warmer water temperatures in the North Atlantic can lead to hotter summers in Central Europe through August. Warm air also absorbs more water, which can be carried by westerly and southerly winds to Europe. This encourages heavy rainfall.

The absence of desert dust

Some researchers attribute the emerging El Niño climate phenomenon to the warming of the North Atlantic. “I don’t think it has to do with it because it’s just getting started,” Latif said. According to Gosling, the absence of Saharan dust over the Atlantic could have a certain contribution to the warming of the North Atlantic, but this has not been clearly demonstrated yet. The fine granules reflect sunlight and thus have a cooling effect. He also considered the thesis that warming is due to a specific reduction in sulfur emissions from ships to be speculative.

According to Latif, there are different effects on the number and strength of hurricanes: “It is expected that hurricanes will become more frequent due to the warm waters on the surface of the subtropical North Atlantic.” On the other hand, El Niño changes the profile of winds at altitude, reducing their number. “In general, there may be a completely normal hurricane season,” Latif says. He does not want to make short-term weather forecasts. “The weather is so messy that I don’t want to make specific forecasts. But as the weather gets warmer, extreme weather events often get more intense.”

© dpa-infocom, dpa: 230615-99-72500/5