Wednesday, July 13, 2016

Trump's energy plan poses climate threat to U.S. economy - by Robert Kopp, Rutgers University

Expected number of days in a typical year with highs above 95°F under the Trump Trajectory. (Credit: Rasmussen et al., 2016, Author provided) Click to Enlarge.
Two years ago, I co-led an analysis of several key climate-change-related risks facing the United States.  Our team used state-of-the-art climate and economic models to assess multiple scenarios for the current century.

These scenarios, developed by the international climate modeling community, include a high-emissions future with expanded fossil fuel use and a low-emissions future in which, consistent with the aspirations of the Paris agreement, emissions go to zero in the second half of this century. Comparing the highest and lowest scenarios – let’s call them the Trump Trajectory and the Paris Path – provides a sense of the risks Donald Trump’s energy policy poses to our country and the planet.

Using the high  scenario as a proxy for Trump’s policy, what changes could we expect?

Carbon dioxide concentrations in Earth’s atmosphere will average about 404 parts per million (ppm) this year.  While the Paris Path would keep them from rising above 450 ppm, the Trump Trajectory would elevate them over 550 ppm in the 2050s and – if policies consistent with rapid expansion of fossil fuel production were maintained – over 900 ppm in the 2090s.

By the middle of the century, climate models indicate that global mean temperature would likely be about 0.5°-1.6°F warmer than today under the Paris Path, but 1.6-3.1°F warmer under the Trump Trajectory.  The models also show that, by the last two decades of this century, temperatures would have stabilized under the Paris Path, while the Trump Trajectory would likely be about 4.4-8.5°F warmer.

Sea-level projections by the Intergovernmental Panel on Climate Change (IPCC), by our researchgroup and by others indicate that global average sea level at the end of the century would likely be about 1-2.5 feet higher under the Paris Path than in 2000.  Emerging science about the instability of the Antarctic ice sheet suggests it might be around three to six feet higher – or even more – under the Trump Trajectory.  And, due to the slow response of the ocean and ice sheets to changes in temperatures, the Trump Trajectory would lock in many more feet of sea-level rise over the coming centuries – quite possibly more than 30 feet.

A continued rise in greenhouse emissions would also lead to a dramatic expansion of Americans’ exposure to extreme weather.

Over 1981-2010, the average American experienced highs above 95°F on about 16 days in a typical year.  Based on our analysis of global climate model projections, the Paris Path would keep the likely number of such extremely hot days to about 22-31 in a typical year.  Under the Trump Trajectory, they would likely increase to 27-50 days by the middle of the century and 46-96 days by its last two decades.

By the middle of the century, Pennsylvanians would likely experience about as many extreme heat days as South Carolinians do today; Coloradans nearly as many as today’s Californians; and Californians about as many as today’s Texans.  And by the end of the century, the Trump Trajectory would make extremely hot and humid days similar to the worst of the 1995 Midwest heat wave – which killed over 700 people in Chicago – an annual occurrence in the eastern half of the country.

Read more at Trump's energy plan poses climate threat to U.S. economy

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