As a result, they suggest that we should be aiming to limit global warming to near, or perhaps even less than the international target of 2°C. This conclusion is in sharp contrast to current economic models, which generally conclude that the economically optimal pathway results in a global surface warming around 3–3.5°C.
Current economic models mainly treat economic growth as an external factor. In these models, global warming and its impacts via climate change don’t significantly affect the rate at which the economy grows. However, several economic studies have concluded that this is an inaccurate assumption, with a 2012 paper by Melissa Dell and colleagues taking the first stab at quantifying the effects of climate damages on economic growth.
The new study by Frances Moore and Delavane Diaz of Stanford University calibrates the climate ‘damage functions’ in one of these economic models (DICE, developed by William Nordhaus at Yale) using the results from the Dell paper. They grouped the world into rich and poor countries, finding that while the economies of rich countries continue to grow well in a warmer world, the economic growth of poor countries is significantly impaired.
As a result, Moore and Diaz conclude that the economically optimal pathway could be very similar to the most aggressive scenario considered by the IPCC (called RCP2.6). In this scenario, human carbon emissions peak almost immediately and then decline until they reach zero around the year 2070.
Moore and Diaz find that if climate change does affect GDP growth in this way, then the best path for society would limit temperatures to between 1.6 and 2.8°C warming in 2100, with a best estimate of around 1.7°C warming.
Read more at Climate Change Could Impact the Poor Much More Than Previously Thought
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