Suchergebnisse

It is well established that a collapse or strong reduction of the Atlantic meridional overturning circulation (AMOC) would substantially cool the northern high latitudes. Here we show that there is a possibility that such cooling could be amplified under deliberate CO2 removal and result in a temporary undershoot of a targeted temperature level. We find this behaviour in Earth system models that show a strong AMOC decline in response to anthropogenic forcing. Idealized simulations of CO2 removal with one of these models indicate that the timing of negative emissions relative to AMOC decline and recovery is key in setting the strength of the temporary cooling. We show that the pronounced temperature-fluctuations at high northern latitudes found in these simulations would entail considerable consequences for sea-ice and permafrost extent as well as for high latitude ecosystems. ; The authors acknowledge funding from the Research Council of Norway (project IMPOSE, grant 294930) and the Bjerknes Centre for Climate Research (project LOES). J.S. has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 820989 (project COMFORT). The work reflects only the authors' view; the European Commission and their executive agency are not responsible for any use that may be made of the information the work contains. Supercomputing and storage resources were provided by UNINETT Sigma2 (projects nn9708k/ns9708k).