Comment on: Hsiang et al (2017) “Estimating economic damage from climate change in the United States.”
Here's the last sentence of the above paper's Abstract:
"By the late 21st century, the poorest third of counties are projected to experience damages between 2 and 20% of county income (90% chance) under business-as-usual emissions (Representative Concentration Pathway 8.5)."
Later on, the authors note:
"Importantly, for clarity, our approach holds the scale and spatial distribution of the U.S. population and economy fixed at values observed in 2012, since current values are well understood and widely agreed on."
In brief: the authors predict a whole lot of climate-caused misery in the US by the year 2100, given certain assumptions. For more details, the paper is available in full online.
Point #1: the authors don't explain what "Representative Concentration Pathway 8.5" is, except to say it's a "business-as-usual" emissions scenario. You can't really evaluate the paper without some idea of what RCP8.5 is and whether it's a likely scenario for global emissions trends.
Point #2: does it really make sense to assume no change in population distribution for the next 80 years, even if parts of the US become rather unpleasant places to live? Such an assumption might make the job of prediction easier, but it still has to be plausible.
Next: What is RCP 8.5?
Reference:
“Estimating economic damage from climate change in the United States.” By Solomon Hsiang, Robert Kopp, Amir Jina, James Rising, Michael Delgado, Shashank Mohan, D. J. Rasmussen, Robert Muir-Wood, Paul Wilson, Michael Oppenheimer, Kate Larsen, Trevor Houser Science 30 Jun 2017: 1362-1369.