That is from a new paper by R. Warren, et.al. The model does cover uncertainty, quadratic damages, and other features to steer it away from denialism. At the end of the calculation, however, for a temperature rise of three degrees Centigrade they still find a mean damage of 2% of global gdp, and a range leading up to three percent of global gdp in terms of foregone consumption. That is plausibly one year's global growth.
If I understand them correctly, and I am not sure I do: "These give initial mean consumption discount rates of around 3% per year in developed regions and 48% [!] in developing ones." And what are the non-initial rates? I just don't follow the paper here, but probably I do not agree with it. Perhaps at least for the developed nations this is a useful upper bound for costs? And it is not insanely high.
Again, better than previous projections.
As I said in the title of this post, these are "Claims." But overall I would say that the new results are slanting modestly in the less negative direction, though I am not sure that the headlines of the last two weeks are equally encouraging.