Heat wave in the sea: take the extreme water temperatures seriously – knowledge

When more rain clouds roll over Germany over the long weekend, quite a few are likely to look enviously at southern Europe. It’s more than 35 degrees warm in Andalusia right now, and isn’t it already great for swimming in Mallorca? Nothing against some sun and sand, but it’s remarkable how little attention is paid to the negative consequences of such heat waves. The fact that processions are already going through some Spanish towns to ask for rain is worth a side note at best in many reports.

This applies even more to what is happening in the seas. The globally averaged surface temperature oceans at 21.1 degrees Celsius was never as high as this April. Many climate researchers are also amazed that the record has now lasted for several weeks.

Many effects of warming on the oceans are still unclear

The fact that the warming of the oceans has so far received little attention is in stark disproportion to the importance of what is happening. 89 percent of the heat that accumulates on earth as a result of climate change is absorbed by the oceans. More than 60 scientists recently had it like that accounted for in a comprehensive study. In contrast, the atmosphere and landmasses together receive only seven percent of the excess heat. Heat waves, droughts, other extreme weather on land: all these consequences of global warming represent only a fraction of what the oceans absorb.

But what happens in these also affects people. It has long been clear that warmer seas lead to more severe storms, or that marine heat waves can also intensify those on land. In addition, a number of species in the sea are already fleeing high temperatures – if they can flee, greetings to all corals. This is already threatening the livelihoods of many fishermen.

Not all of the effects of global warming on the oceans are understood. For example, it is unclear whether the rise in water temperatures will slow down the Gulf Stream, which is so important for Europe, or whether other ocean currents could also be fundamentally disrupted. The treacherous thing is that it could already be too late once you have understood such connections. Because the oceans behave much more slowly than the atmosphere, so they also react to climate protection measures with a delay. An experiment on a huge scale is taking place in the world’s oceans. It’s better not to assume that things will go smoothly.