[Marxism] Climate policy implications of nonlinear decline of Arctic land permafrost and other cryosphere elements

Greg McDonald gregmc59 at gmail.com
Mon Apr 29 14:36:32 MDT 2019


Arctic feedbacks accelerate climate change through carbon releases from
thawing permafrost and higher solar absorption from reductions in the
surface albedo, following loss of sea ice and land snow. Here, we include
dynamic emulators of complex physical models in the integrated assessment
model PAGE-ICE to explore nonlinear transitions in the Arctic feedbacks and
their subsequent impacts on the global climate and economy under the Paris
Agreement scenarios. The permafrost feedback is increasingly positive in
warmer climates, while the albedo feedback weakens as the ice and snow
melt. Combined, these two factors lead to significant increases in the mean
discounted economic effect of climate change: +4.0% ($24.8 trillion) under
the 1.5 °C scenario, +5.5% ($33.8 trillion) under the 2 °C scenario, and
+4.8% ($66.9 trillion) under mitigation levels consistent with the current
national pledges. Considering the nonlinear Arctic feedbacks makes the 1.5
°C target marginally more economically attractive than the 2 °C target,
although both are statistically equivalent.

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