Even with more ambitious measures to avoid emissions, climate neutrality and thus temperature stabilization can no longer be achieved. The Intergovernmental Panel on Climate Change (IPCC) points this out in its sixth assessment report. In addition to a faster reduction of emissions, a further building block is needed: unavoidable CO2 emissions must be removed from the atmosphere and stored in order to achieve "negative emissions" in this way. What exactly negative emissions are, how they...