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Do we need technical measures for CO2 removal to achieve the 1.5° target?

12 Oct 2018 | Source: GEOMAR Helmholtz Centre for Ocean Research Kiel

DFG Priority Programme Publishes Video on the Role of Negative Emissions

This week, the Intergovernmental Panel on Climate Change (IPCC) published the "Special Report on 1.5°C Global Warming" (SR1.5). The key message of the report is that limiting global warming to 1.5 degrees Celsius by 2100 instead of the 2°C upper limit set in the Paris Climate Convention would significantly reduce the major impacts of climate change. These include the loss of biodiversity on land and in the ocean, the intensity of extreme events such as droughts, heat waves and heavy precipitation, and not least global sea level rise.

To achieve the 1.5 degree target, however, it would be necessary to reduce man-made carbon dioxide (CO2) emissions by 45 percent compared with 2010 levels until 2030. By 2050 at the latest, emissions would have to be net zero. In addition, it would be necessary to remove 100-1000 gigatonnes of CO2 from the atmosphere during the 21st century. This corresponds to a quantity that mankind releases in 2.5 to 25 years at current levels.

In a new animated video, the Priority Programme "Climate Engineering - Risks, Challenges, Opportunities?", which is funded by the German Research Foundation (DFG), illustrates various measures with which such "negative emissions" could be realized. These measures include large-scale reforestation, the binding of carbon dioxide with the aid of artificial trees (direct air capture), the alkalinization of the oceans or the use of energy from renewable energy sources with simultaneous capture and storage of CO2 (Bio Energy with Carbon Capture and Storage, BECCS). "However, so far there is no experience regarding feasibility and sustainability with the removal of carbon dioxide from the atmosphere on a scale required to achieve the promised climate targets," says the coordinator of the Priority Programme, Prof. Dr. Andreas Oschlies from the GEOMAR Helmholtz Centre for Ocean Research in Kiel.

In the new video, the project therefore explicitly points out the side effects of the individual measures. "Even a seemingly natural process such as afforestation could cause considerable problems if executed on a large scale. Then it soon would compete with food production and could have unintended effects on the water cycle and ultimately on the climate," explains Professor Oschlies.

According to the expert for biogeochemical modelling of the Earth system, the problem is that techniques are already being discussed as solutions at national and international level before their long-term suitability has been proven. The DFG Priority Programme has set itself the goal of closing gaps in knowledge about the effectiveness and side effects of such climate regulation measures. At the same time, the participating researchers also want to stimulate public debate on the topic. "The new video should also contribute to this," says Professor Oschlies. Only one thing is already certain: without a drastic reduction in CO2 emissions, we will not even get close to the climate targets we have promised to aim for.