Judith Curry: Despite hysteric claims, IPCC models incapable of producing abrupt climate change

Judith Curry writes:

Admittedly there are numerous definitions of ‘abrupt climate change’, but the IPCC chooses a fairly trivial one: seemingly, the climate shift circa 2001 would qualify as an ‘abrupt’ climate change.

But the real issue is this. The IPCC approach, using highly damped deterministic global climate models, is incapable of producing abrupt climate change (beyond the melting of Arctic sea ice, which is not irreversible even on timescales of a decade).

The most scientifically interesting, and societally relevant topic in climate change is the possibility of abrupt climate change, with genuinely massive societal consequences (the disappearance of Arctic sea ice and regional forest diebacks arguably don’t qualify here). The IPCC has high confidence that we don’t have to worry about any of the genuinely dangerous scenarios (e.g. ice sheet collapse, AMOC collapse) on timescales of a century. These collapses have happened in the past, without AGW, and they will inevitably happen sometime in the future, with or without AGW. Are the IPCC overconfident in their conclusions on these also?

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3 thoughts on “Judith Curry: Despite hysteric claims, IPCC models incapable of producing abrupt climate change”

  1. The left has been crying wolf over the climate for decades – starting with the impending ice-age in the 70s that never occurred. The blame has always been placed on human activity for the purpose of imposing oppressive, freedom-killing laws on society. Enough!

  2. This is the point to hammer home. Long winded statistical analysis or deconstruction of scientific methodology, no matter how accurate, simply will not resonate with a significant portion of the voting public. They’ll always be won over by the just-in-case argument because “drastic times call for drastic measures.” We have to successfully make the comparison between the multi-meter sea level rise and ever-present super storm predictions and crazies on the street corner yelling “the end is nigh”. Anyone else remember Iben Browning’s 1990 earthquake prediction? Climatologist predicted disasters consistently fail to appear. If there are no drastic times, we need no drastic measures.

  3. Dr. Curry is wise to point out what our MSM conceal, that the IPCC’s own models don’t show the kind of problems that the SPM says should be addressed. And this is old news; scientists have reported that the Summaries have had no grounding in the reports for several iterations.
    More important, though, is that all the alarmist models have failed utterly. And if you start them at 1901, they fail against existing observations. If they can’t be jiggered to match existing data, they must not be used to project future conditions.

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