The only sustainable way to slow down climate change is to reduce CO2 emissions. So-called climate engineering is brought into play once more and once more in order to give the energy transition – which is progressing much too slowly – more time. This would release sulfate particles in the stratosphere, which reflect part of the solar radiation and cool the earth slightly. Such an intervention is naturally very controversial. On the one hand, there are voices that see relevant research as taboo because it pretends to be a simple solution to the climate problem and can have incalculable consequences. On the other hand, there is a risk that individual players will advance with their own technologies that have not been adequately researched.