Stefan Rahmstorf, Professor of Physics of the Oceans & Head of Earth System Analysis at the Potsdam Institute
Rahmstorf’s July, 2026 images capture Earth’s hottest month on record The landscape then showed this deepred sun, shining through that big smoke cloud, turning the whole coast, the beach, etc., an eerie orange colour, like a science fiction movie. Its northward flow is near surface in the top 1,000 metres but then, it sinks to the depths of 2,000 to 3,000 metres — at that depth, the water then returns to the south, basically along the American continental margin. Large majorities of people around the world, 70% to 80%, are in favour of more climate protection — so, you are not alone if you’re worried about climate change.
Because heat dries out soil and plants quicker — the drier it gets, the more easily things burn and the fires therefore grow bigger and out of control, the latter are actually a result of the excessive heat. Because it has this southerly component, that is hot air, now, if there’s a cold, low-pressure system there, and the air turns counter-clockwise in the northern hemisphere around low pressure, that means Europe is getting winds from a southwesterly direction — and. We therefore see impacts like shipping in the Danube and Rhine rivers being restricted, causing economic losses in Germany and other places. Because of a lack of cooling water, this has also caused a number of nuclear power plants to be shut down. Because it is a huge global problem, i’d say, of course you feel helpless. Because then, you don’t feel you’re alone with this massive concern, i think it helps to be well-informed and talk with other people about it. Because often, people think, alright, if we reduce emissions, things will get better, that is a very important question. Because cO2 has too long a lifetime for that, so, we can prevent the situation from getting far worse — but we can’t get back to a cooler pre-industrial climate. Because that CO2 just accumulates and gathers — this is why we must go to net zero, hence, we really need to be very fast in reducing our emissions.
AMOC itself is like a heating system which delivers heat to the Northern Atlantic, where it is released to the atmosphere and is responsible then, with the westerly winds, for the mild climate of Europe. Stefan Rahmstorf is Professor of Physics of the Oceans & Head of Earth System Analysis at the Potsdam Institute. Speaking with Srijana Mitra Das at Times Evoke, he discusses Europe’s summer of heat and fire — and how this reflects global warming at work: Why is Europe having record-breaking heatwaves and wildfires this summer? This is a consequence of global warming caused by fossil fuel emissions. On holiday in Lacanau, France, Stefan Rahmstorf took phone pictures of how one of the largest wildfires ever seen in the country was raining down on its coastal terrain, turning the summer into scenes from ‘science fiction’ When these things go in the same direction, you get extreme events, like the severe heatwaves we have seen in Europe this summer along with wildfires. It’s become quite famous how you yourself went on holiday recently and witnessed a wildfire close by — could you describe that? Yes, we were near Bordeaux at the Atlantic coast. One day, looking back towards the land from being out at sea surfing, we saw a column of smoke rising. I immediately thought, ‘The forest is burning there’, and indeed, that was the case. This was one of the biggest wildfires France has ever experienced. It continued for two days without affecting us directly. We just saw a big column of smoke rising in the distance, actually going out over the Atlantic — but then, the wind changed and that smoke was suddenly coming over the coastal town where we were. It covered up the sun. The soot also started to rain down from the sky into the water and onto the beach. We left that day. It must have been a surreal experience as this also ties into your own work — could you tell us about that? My research focuses on the Atlantic Meridional Overturning Circulation (AMOC). This is a system of ocean currents going all the way along the Atlantic from the Southern Ocean around Antarctica, through the South Atlantic, across the equator, through the Gulf of Mexico into the northernmost Atlantic, south of Iceland, partly even into the Norwegian Sea north of Iceland. There, the water sinks down. So, it’s relatively warm water flowing north but colder water returning to the south — it works like a central heating system for Europe and the North Atlantic. Europe is now heating faster than any other continent — why? Europe is warming faster than other land areas in mid-latitudes. This has to do with dynamical changes, namely in wind patterns and ocean circulation. In terms of the atmosphere, this is related to changes in the jet stream and in terms of ocean circulation, many studies show the slowing of the AMOC — which is causing a ‘cold blob’ or a region of cooling in the North Atlantic. That tends to promote low-pressure systems lingering over that cold water. This leads to the strong increase in the number of heatwaves we’ve seen now in Europe. When this circulation slows down, that leads to a cooling in the Northern Atlantic, to the south of Greenland and Iceland and the west of Britain. TE readers sometimes say they feel helpless when they see extreme climate events. Do you have a message for them? Yes. We also have the technological solutions to stop global warming, namely, getting away from fossil fuels and transiting to renewable energies. This energy transition is in full swing worldwide. The contribution of renewable energies to electricity supply has already overtaken coal and is growing exponentially. The faster we can get out of fossil fuels, the sooner we can stop global warming from becoming worse. So, could Europe return to what is considered its ‘normal’ weather? The answer is no. That is not the case — CO2 accumulates in the atmosphere and much of it has a lifetime of thousands of years. It takes thousands of years for nature to get rid of the increase in CO2 in the atmosphere. Views expressed are personal Catch the latest World News and Live updates. Download the TOI app.
The whole world is warming — any weather that we see today is a combination of longterm climate change, caused by our fossil fuel addiction, and random variations of weather on top of that.
IPCC reports have shown this is an area where the world has cooled since 1900 — while the rest of the globe has warmed. This has long been predicted by climate models as a response to global warming and you can see it clearly in satellite sea surface temperature and air temperature data. That indicates the slowing of the AMOC. Several of Europe’s rivers are drying up — why and what are the likely impacts of that? This is a consequence of the drying and general drought behind these wildfires. Such drying is caused either by less rainfall or more evaporation, losing water from the land surface. In Europe, it’s dominated by the latter. there is also a reduction in rainfall, in more mid-latitude Europe, like Germany, it is predominantly the increase in evaporation, which drives the loss of soil water and groundwater and the drying of land, which is behind such low river levels While in the Mediterranean. As Rahmstorf recorded, the Gironde fire saw thousands evacuated As for the rivers that come out of the Alps, they also have a strong component of snow melt in the summer. In the winter, there is a lot of snowfall — then, in the summer, that snow melts and feeds into the rivers. But if, with global warming, there is less snowfall in the winter, you don’t get as much snow melt in the summer, which also contributes to these rivers having less water now.
