Signatories to the Paris climate agreement — every country in the world, unless and until the US drops out in 2020 — agreed to what is by now a familiar goal: “holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C.”
How important is that difference, though? How much worse would 2 degrees be than 1.5? Is it worth the extra effort — and it would be a truly heroic effort — to limit temperature rise to that lower target?
It’s been difficult to answer those questions, in part because they are value-laden and incredibly complex, but also due to a paucity of research. While there’s been a great deal of work done on the difference between, say, 2 and 4 degrees warming (which would be catastrophic), there’s been less modeling around 1.5 and no comprehensive comparison of 1.5 and 2.
Happily, a new study in the journal Earth System Dynamics tackles this directly. Over at CarbonBrief, Roz Pidcock has a great rundown on the study that gets into the background and some of the implications.
Best of all, the team at CarbonBrief (which you should really bookmark) has compiled the relevant comparisons in the study into a single clear, aesthetically pleasing graphic:
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