Oliver Geden is a visiting scientist at Max Planck Institute for Meteorology. He heads research group EU/Europe of foundation science and Politics and is lead author in 6th Status report of IPCC World Climate Council.
When world IPCC IPCC publishes its special report on 1.5 degree target in October, debate will largely be in familiar tracks. Researchers warn of consequences of climate change. Environmental associations are urging greater efforts in climate protection. But one thing is going to be new: re will be a debate about technologies with which CO2 can be pulled out of atmosphere again. Climate politicians and environmental associations see danger that a discussion of so-called negative emissions will give impression that one can essentially carry on as before. Finally, ejected CO2 could be captured later. On or hand, climate research is convinced that world will no longer come without such technologies.
The facts are clear: mankind has been continuously emitting more greenhouse gases since Earth Summit in Rio de Janeiro 1992. It is already foreseeable that world will leftover its emissions budget. If humanity wants to limit global warming to 2 degrees, budget would probably have been exhausted in mid-2030s, for 1.5 degrees already around 2020. We'll have to get out of atmosphere again later. For 2 degrees deficit is up to year 2100 at about 500 billion tonnes, for 1.5 degrees at 800 billion tonnes. For comparison, human race is currently about 40 billion tonnes per year.Policy does not manage to reduce global CO2 emissions
Climate politicians and environmental associations ignore issue of negative emissions so far. The necessary sizes appear unrealistically high. And technologies are questioning climate policy success story, according to which climate agreement of Paris 2015 was a turn of times and renewable energies have since been on a unstoppable triumphant march. Some also reject Negativemissions technologies as geoengineering.
For three reasons, negative emissions are problematic. First, after decades of insisted to meet fixed CO2 budgets, researchers and policymakers now seem to be acceptable at once to carbon debt. Secondly, in no country in world is issue of negative emissions on agenda so far. and thirdly, even if politics were to take issue seriously, it would have trouble finding even semi-mature technologies that could cope with this enormous task.
It is tempting to think that it is okay to overspend issue budget as long as future generations repay debt. Climate scientists have been applying this mechanism in ir models for ten years. As emissions have continued to rise, volume of planned negative emissions has also increased. Many climate researchers are irritated by fact that politics does not manage to reduce global emissions, but also does not want to talk about CO2 extraction technologies. At same time, it is adopting ever stricter climate targets, last 1.5 degrees at Paris climate summit. In IPCC special report, negative emissions will refore play a major role.Date Of Update: 14 June 2018, 12:02