We read IPCC, we read Wallace-Wells, we read Scranton. We think we’ve built a thick enough hide. But a while back a reader of Grist’s pointy Umbra column asked for “the full list of climate tipping points.” I could barely read Eve Andrews’s (Umbra’s) response, in which she confirms the question is “inherently, existentially, and unavoidably upsetting,” defines what a tipping point is, and then hits us. IPCC 2018 identifies four: “the ice sheets of West Antarctica and Greenland; the El Niño and La Niña cycle; the circulation of water throughout the Atlantic Ocean; and the Southern (Antarctic) Ocean’s ability to absorb carbon.” Umbra’s ensuing essay discusses the scariness of tipping points, the uncertainties around how many degrees, and the semantics (it’s more than that of course) of hopelessness versus hopefulness. In the end, she offers this view, one that flushes me with dread and hope equally:
The “tipping point” that I believe we should look out for is the one at which we have no idea what’s coming, and we can’t possibly prepare for it. And make no mistake, some communities are already reaching something very close to that reality. We’re currently at 1 degree C of warming, but barring some swift and comprehensive change, our business-as-usual policies and practices have us on track for as much as 3.5 degrees C. In my mind, that means the tipping point we should all be looking out for is the one that tips the scales in the direction of timely and aggressive slashing of carbon emissions.