A report on the Earth’s cryosphere (ice and snow, including the polar oceans) by a group of leading scientists highlights the urgent need to limit global temperature increase to 1.5°C because of the devastating and potentially irreversible societal impacts from issues such as sea-level rise, loss of water resources and fisheries.
The ‘Cryosphere 1.5° Report’ was released at the UN Climate Change meeting COP25 in Madrid this week, and brings together the results of the IPCC (Intergovernmental Panel on Climate Change) Special Reports on 1.5° (2018) and on the Ocean and Cryosphere (2019). It also includes newer research which will not be reflected by the IPCC until its next full Assessment Report in 2021, keeping up to date with fast-moving cryosphere science.
The report, which was authored and reviewed by over 40 IPCC and other leading cryosphere scientists, describes the 1.5°C level as an “outer guardrail” for the planet due to the growing threats across the cryosphere, from the poles to tropical high alpine regions.
One of the key messages of the report is the increase in anticipated permafrost carbon emissions due to “abrupt thaw” events. These will need to be treated as an additional large “country of Permafrost” in terms of extra human emissions. This, in combination with much greater projected sea ice declines, will in turn speed up permafrost thaw and increase the Greenland ice sheet melt, raising sea levels globally.
The reports executive summary states: “We see far greater risk of massive irreversible sea-level rise (SLR) at 2°C, on a scale of 12-20 meters or more in the long term.” It also highlights the combined stress placed on polar ocean fisheries by acidification – which is occurring faster in cold polar waters than anywhere else, with signs of shell damage already observed in more corrosive polar waters; and describes a future with almost no glaciers outside the Himalayas and poles by 2°C, compounded by snow loss harming water supplies.
Plymouth Marine Laboratory Biological Oceanographer, Dr Helen Findlay, who was at the climate talks in Madrid and a Scientific Editor of the report’s section on ‘Polar Ocean Acidification, Warming and Freshening’ said: “Whilst there is more to learn about the response of species to ocean acidification in the Polar Oceans, the science is clear that if we do not drastically reduce emissions and stick to the target of 1.5°C global temperature levels, we will be knowingly putting at risk the organisms, species and ecosystems that society relies on for food, health and climate regulation."
Martin Sommerkorn coordinated the polar chapter of the IPCC SROCC: “The level of ambition to limit emissions that we currently see is in no way commensurate to the threat,” he said, noting especially the “Production Gap” report released last week by the Stockholm Environment Institute, Climate Analytics, UNEP and others showing that planned fossil fuel production by 2030 is 120% greater than would keep the planet within 1.5°C; “The polar regions are already losing ice, and further losses have severe and long term global consequences.”
Pam Pearson, Director of the International Cryosphere Climate Initiative which coordinated the report, said: “There is a great need, at this end stage of the Madrid climate talks and as countries head home, for decision makers to be aware of the level of risk we’re facing if we wait until it’s too late to prevent or at least slow these cryosphere dynamics. We all need to treat 1.5°C as the real guardrail.”
The report can be accessed at the following link: http://iccinet.org/cryosphere15/