The ongoing rapid retreat of Arctic sea ice is often interpreted as the canary in the mine for anthropogenic climate change. In a new study, scientists have now systematically examined the validity of this claim. They find that neither natural fluctuations nor self-acceleration can explain the observed Arctic sea-ice retreat. Instead, the recent evolution of Arctic sea ice shows a strong, physically plausible correlation with the increasing greenhouse gas concentration. For Antarctic sea ice, no such link is found – for a good reason.
When scientists try to attribute some observed climatic change to a specific forcing, they usually use complex climate models. The scientists at Germany’s Max Planck Institute for Meteorology (MPI-M), however, decided on a different strategy as they set out to identify the main driver for the observed sea-ice loss in the Arctic. Dirk Notz, lead author of the study that was now published in the journal Geophysical Research Letters [1], explains why: “Sea ice is so thin that it reacts very sensitive to the large natural fluctuations of weather and climate that prevail in the Arctic. Because these fluctuations are inherently chaotic, their specific timing cannot be reproduced by standard climate models. Such models therefore aren’t necessarily the best tool to examine if natural fluctuations did cause the observed sea-ice loss.”
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