Shall we follow one thing?

Researchers on the consequences of climate change"As humans, they are not adapted to this different climate"

A study by the US climate researcher Christopher Schwalm is currently being hotly debated. After this, we are currently on the way to a worst-case scenario for the climate. Air layers close to the ground could warm up by an average of five degrees Celsius compared to pre-industrial times. We talked to Elmar Kriegler about current climate scenarios, he is head of research at the Potsdam Institute for Climate Impact Research, his area is transformation paths.

Britta Fecke: A warming of five degrees by the end of this century, that is the worst scenario. How likely do you think this high temperature rise and the associated high increase in greenhouse gases are?

Elmar Kriegler: This very pessimistic scenario has been realized in the last ten years because a large number of coal-fired power plants have also been built. But in view of trends such as the increasing use of renewable energies and increasingly stronger climate policy - not only in Germany, but also in other areas of the world - the signs are good that things will not turn out quite as bad. However, it has to be said that there is only a difference of degree between the worst and the worst. If instead of five degrees in 2100 it will be 3.5 degrees - and that is what we will see if we continue the current trends, including in climate policy - then that will also be massive climate change and very bad. In this respect, it must be about doing significantly more than is being done at the moment.

(imago images / ZUMA Wire) Climate change and health - Bangladesh between heat deaths and cyclones
In the end it looked as if Bangladesh could defy cyclones and floods with dams and dykes. This hope has been fading since climate change has threatened not only the country but also health. But Bangladesh has always lived with water.

"Droughts, high temperature events, storms and floods"

Fecks: If you say it could only be three degrees, that will be just as bad, what do we have to expect if the temperature increases by three degrees?

Warrior: Not as bad, but very bad because the energy that is stored in the climate system due to the greenhouse effect is massive and enormous. The mean temperature will then rise, which then means significantly higher warming in our latitudes with all the consequences - droughts, high-temperature events, storms and floods. They are not distributed uniformly across the entire globe, but they are very different in the regions. There will be a massive change in our environment and our climate, which we as humanity have to pay for with many consequences, because we are not adapted to this other climate, but to today's climate.

Fecks: Even China is planning to phase out coal in the long term, and the Arab countries are also planning for the post-oil era. Isn't it a little too pessimistic to believe that coal-fired power generation will continue to prevail?

Warrior: Yes, the signs are very mixed. On the one hand, there is of course a lot of pressure in some regions, including Europe, but here in Germany too - and we just need to look across the border to Poland - we can see how difficult it is to get out of coal. In other countries, they are not at that point at all, but are even expanding coal - I'll mention Turkey and Vietnam, for example. In China, too, attempts are being made to curb coal expansion, but expansion is still taking place. That means that there must be a lot more political measures and, in the international climate negotiations, more efforts to approach coal and fossil fuels and not just look at the expansion of renewable energies, which is of course good. But if it is not accompanied by a drastic reduction in the use of fossil fuels, it will then only help the climate to a limited extent.

(dpa / Federico Gambarini) How the coal exit should succeed
The negotiations to phase out coal dragged on for many years. The timetable has now been set until the final phase-out in 2038. The lignite regions will have to change drastically - in the west and in the east.

Fecks: Using these fossil fuels is one thing. Is the thawing of the permafrost actually also factored in with these scenarios, because the methane that is released there - and it is much more than feared - is 24 times more climate-effective or climate-damaging than CO2?

Warrior: Yes, that's a good point - partly. The emission scenarios lead to global warming, and the warming itself then has an impact on methane, as you called it, in the soil, which then outgasses, we call this natural feedback on the climate system. That is not yet well understood. Some models take this with them. Whether the magnitude, i.e. the order of magnitude, is correct is another question, but the fear is that there are still a few surprises in store for us, that this feedback will then intensify climate change to an extent that has not yet been seen in is included in the invoices.

"We have already lost a lot of time"

Fecks: A warming of the air layer close to the ground by only 1.5 degrees Celsius is always mentioned in order to be able to control the consequences of climate change to some extent. What would we have to do to even reach this number?

Warrior: Yes, that is an important and very ambitious goal, and in order to achieve this goal we would have to have net zero CO2 emissions around the middle of the century. To put that into context: Today we are emitting around 40 billion tons of CO2 worldwide, and we would have to reduce this enormous amount of CO2 to zero in order to reasonably meet the 1.5-degree target. This also means for industrialized countries, which have to play a pioneering role there, that they have to achieve this even earlier than 2050 in order to then offset residual emissions in other countries. It's an enormous challenge, and that's why it's so important not to lose any more time. We have already lost a lot of time. 1992, the Framework Convention on Climate Change, 1997 the Kyoto Protocol, it was all almost 30 years ago, and this time, which we did not use, now hurts us very much, and in this respect there must really be no further hesitation. There are trends in climate policy, but they are still too weak. And especially, if I may say that, this sentence: Now that we have to focus on the COVID pandemic and a lot of thought is being given about which packages of measures can help to stimulate the economy again, it is all the more important that green transformation, to think about climate protection. This happens in Europe and in Germany to a certain extent, but if we look at other parts of the world, we see that this is not taken into account at all, on the contrary, more emphasis is placed on coal and fossil fuels.

Statements by our interlocutors reflect their own views. Deutschlandfunk does not adopt the statements of its interlocutors in interviews and discussions as its own.