How Does Early Action to Cut Carbon Emissions Reduce Impacts from Climate Change?


Differential climate impacts for policy-relevant limits to global warming: the case of 1.5 _C and 2 _C (25 page pdf,Carl-Friedrich Schleussner, Tabea K. Lissner, Erich M. Fischer, Jan Wohland, Mahé Perrette, Antonius Golly, Joeri Rogelj, Katelin Childers, Jacob Schewe, Katja Frieler, Matthias Mengel, William Hare, and Michiel Schaeffer, Earth System Dynamics, Apr. 21, 2016)

Also discussed here: 1.5°C vs 2°C: Why half a degree matters (Newsletter, International Institute for Applied Systems Analysis, Apr. 21, 2016)

Today we review research using scenarios with global climate models that show the difference in impacts from limiting global warming to 1.5 deg C or to 2.0 deg C by taking action to reduce carbon emissions and how quickly this is done. Many authoritative sources from COP 21 in Paris indicated that unless cuts of the order of 50% are taken within a decade (2025) that the 1.5 deg goal will be breached and unless the cuts reach 100% by 2050 that the 2 deg goal is probably unachievable. The paper examines the consequences of taking action too slowly or to a less than acceptable degree.

The impacts affect the length of heat waves (lasting 2 months more for 1.5C or 3 months for 2C), water availability, sea level rise, coral reefs and reduced crop yields. Perhaps the largest impact, sea level rise, has the largest implications because the processes involved in melting ice sheets are so large and slow moving. Once the Greenland ice sheet begins to breakdown, sea level rises of 5-7 m are inevitable over centuries with warming over 2C and will accelerate beyond 2100, while early action to limit warming to 1.5C would limit the sea level rise to 40 cm. Clearly policy makers at both the international and national/subnational levels need to step up to the challenge and soon.

2 deg climate impacts

To see Key Quotes and Links to key reports about this post, click HERE

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