Nobody can see the earth from their window like the astronauts on the space station ISS. What Alexander Gerst sees there worries him: “Could just take the first pictures of Central Europe and by day, after several weeks of night overflights,” he writes. “Shocking sight. Everything is dried up and brown, which should actually be green. “
Gerst is not alone in this. In many regions the harvest is miserable. The risk of forest fires increases. Foresters fear for young plants that cannot cope with the drought. Ships can no longer be fully loaded because the water levels are falling. Power plants have to reduce their output because the water is too warm. Stress for people, stress for the environment and one anxious question: is this the exception or will it be the rule? The awareness of climate change is more pronounced than it has been for a long time.
Now a new study has re-fueled the debate. International researchers warn of a domino effect that could lead to hot periods.
The earth has warmed up by an average of 1.1 degrees since the 19th century, says Stefan Rahmstorf from the Potsdam Institute for Climate Impact Research (PIK). “Further evidence of climate change is the melting ice on the poles, glaciers and on Greenland, the warming of the oceans to great depths and the ever-increasing rise in sea levels.” Record heat months are already five times more frequent than in a stable climate would be expected. “There is overwhelming evidence that humans are responsible for almost all of global warming,” says Rahmstorf. The luminosity of the sun has decreased slightly since the middle of the 20th century. The hindered emission of heat into space by increasing greenhouse gases explains global warming, “which has been predicted to this extent for over 40 years”.
The air currents flow in large waves around the northern hemisphere at a height of nine to twelve kilometers. Warm air flows along the waves from the tropics or cold air from the north to Europe, explains Rahmstorf. Since the Arctic is currently warming more than the tropics due to climate change, the temperature difference between them will be smaller. Therefore, the jet stream more and more often remains in large loops and so weather conditions such as dry seasons, but also rain or cold waves, persisted longer.
So far, many researchers assume that global warming can be stopped at two degrees. An international team is now pointing out that even at temperatures below two degrees, various tilting elements could start a cascade of processes that in the long term could lead to four to five degrees Celsius warming and a sea level rise of 10 to 60 meters. According to PIK, long-term means “over centuries and perhaps millennia”. However, a lot of research is still needed to estimate the risk for the start of the cascade, emphasize the authors in the specialist journal “PNAS”. Commentators also point out that the study is quite vague.
These are components in the earth system that climate change can fundamentally change: For example, the permafrost in Russia or North America could thaw and release large amounts of carbon dioxide and methane in the process. The Amazon rainforest could give off more carbon dioxide than it absorbs. The Greenland ice sheet could completely thaw.
The focus is on the 2015 Paris Climate Agreement with the aim of limiting global warming to “well below two degrees”. However, the nations are still a long way from being on track, even if they managed to achieve the announced goals for saving CO2. The fact that US President Donald Trump wants to get out of the agreement has increased the ambition of many climate protectors and governments. In December, the next world climate conference will take place in Poland, which is supposed to adopt a rule book for the implementation of the Paris Agreement. But the climate diplomats are not on schedule – that’s why there is an additional meeting in Bangkok in September.
Germany is slipping towards embarrassment in terms of climate policy. His goal for 2020 of reducing CO2 emissions by 40 percent compared to 1990 can no longer be achieved without radical measures. In addition, Germany will soon miss EU targets and will have to buy its way from countries that emit less CO2 than they should. A commission is negotiating a schedule for the coal phase-out and is due to deliver by the end of the year. So far it looks bleak in traffic, where CO2 emissions have not decreased since 1990.
Farmers are at the center of the debate this summer. You are asking for a billion euros because of the huge crop failures – a decision will be made in the coming weeks. Environmentalists and Environment Minister Svenja Schulze warn that there should be no “business as usual” in agriculture. Factory farming and intensive cultivation of fields exacerbate the ecological imbalance. It is currently being discussed, for example, to what extent subsidies for farms should be tied to environmental requirements. However, an agricultural turnaround would mean a change not only for many farmers, but also for consumers – there would then no longer be masses of meat at dumping prices.