Of all the fraught issues raised by the climate crisis, tipping points–or, more recently, “tipping cascades”–are the most fraught. Pessimism can be self-fulfilling–it comes to that.
And yet there is the truth, which isn’t looking particularly good. Which is why I recommend The Tipping Points at the Heart of the Climate Crisis, which was published a while ago in The Guardian. It’s the best simple overview to the state of tipping point science I’ve seen, and its both up to date and judicious. No “doomsterism” here, but not false comfort either. Rather, simple quotes, as for example when Ricarda Winkelmann of the Potsdam Institute for Climate Impact Research tells us:
‘The 2016 agreement committed most countries to limit warming to 1.5 to 2C . . . Winkelmann argues that 1.5C is the right target, because it takes into account the existence of the tipping points and gives the best chance of avoiding them. “For some of these tipping elements,” she says, “we’re already in that danger zone.”’
I particularly appreciated the straightforward manner in which Michael Marshall, the author of this piece, dealt with the debate about 2018’s “Hothouse Earth” paper, which was itself a tipping point. After its publication, the extent of our danger was palpably clearer. Straightforward like so:
“In 2018, researchers including [Tim] Lenton and Winkelmann explored the question in a much-discussed study. “The Earth System may be approaching a planetary threshold that could lock in a continuing rapid pathway toward much hotter conditions – Hothouse Earth,” they wrote. The danger threshold might be only decades away at current rates of warming.
Lenton says the jury is still out on whether this global threshold exists, let alone how close it is, but that it is not something that should be dismissed out of hand.
“For me, the strongest evidence base at the moment is for the idea that we could be committing to a ‘wethouse’, rather than a hothouse,” says Lenton. “We could see a cascade of ice sheet collapses.” This would lead to “a world that has no substantive ice in the northern hemisphere and a lot less over Antarctica, and the sea level is 10 to 20 metres higher”. Such a rise would be enough to swamp many coastal megacities, unless they were protected.”