Melting polar ice cap bodes ill — very ill
I didn’t manage to get to it during the week, but don’t miss this Mike Davis essay over on Tom’s Dispatch. It’s about the seemingly obscure subject of "nonlinearity," a word that may just end up being featured prominently on humanity’s tombstone.
"Humanity, R.I.P. Should have payed attention to nonlinearity."
Specifically, it’s about a study — mentioned in Daily Grist last week — revealing that the Arctic ice cap is melting earlier in the summer, not fully re-freezing in the winter, possibly caught in an irreversible self-reinforcing cycle, and headed to final and complete disappearance by 2060.
This is some scary shit.
Scientific discussions of environmental change and global warming have long been haunted by the specter of nonlinearity. Climate models, like econometric models, are easiest to build and understand when they are simple linear extrapolations of well-quantified past behavior; when causes maintain a consistent proportionality to their effects.
In other words, the models we’re best equipped to build and understand assume that the future’s going to be basically like the past — or more specifically, that the rate of change in past years will continue in future years. But no:
… all the major components of global climate — air, water, ice, and vegetation — are actually nonlinear: At certain thresholds they can switch from one state of organization to another, with catastrophic consequences for species too finely-tuned to the old norms.
The disappearance of the Arctic ice cap could trigger such a change.
An ice-free Arctic Ocean has not existed for at least one million years and the authors warn that the Earth is inexorably headed toward a “super-interglacial” state “outside the envelope of glacial-interglacial fluctuations that prevailed during recent Earth history.” …
… “Outside the envelope,” moreover, means that we are not only leaving behind the serendipitous climatic parameters of the Holocene — the last 10,000 years of mild, warm weather that have favored the explosive growth of agriculture and urban civilization — but also those of the late Pleistocene that fostered the evolution of Homo sapiens in eastern Africa.
So, well, okay, we’re headed toward vastly wider climatic parameters, with much more extreme temperatures. But we’re pretty adaptable, right? Davis is not sanguine.
The demon in me wants to say: Party and make merry. No need now to worry about Kyoto, recycling your aluminum cans, or using too much toilet paper, when, soon enough, we’ll be debating how many hunter-gathers can survive in the scorching deserts of New England or the tropical forests of the Yukon.