Michael Mann is an Idiot (again)

A friend recently pointed me to an article at Inside Climate News : Many Scientists Now Say Global Warming Could Stop Relatively Quickly After Emissions Go to Zero –  with the understandable comment “The game-changing, optimistic assertion in the headline is not discussed until the last eight paragraphs of the article (???)!!! And little ink is spent explaining it. Dunno why.”

Well, let’s see.

The article does say that “The idea that global warming could stop relatively quickly after emissions go to zero was described as a ‘game-changing new scientific understanding’ by Covering Climate Now, a collaboration of news organizations covering climate.” And the article linked to does, in turn, refer to two interviews with Michael Mann – one on the CBS News show 60 Minutes and  a companion interview in The Guardian, the latter of which I guess can be taken as the root source of the claim.

According to the Guardian:

 Using new, more elaborate computer models equipped with an interactive carbon cycle, “what we now understand is that if you stop emitting carbon right now … the oceans start to take up carbon more rapidly,” Mann says. Such ocean storage of CO2 “mostly” offsets the warming effect of the CO2 that still remains in the atmosphere. Thus, the actual lag between halting CO2 emissions and halting temperature rise is not 25 to 30 years, he explains, but “more like three to five years”.

Well if Mann said that he’s a scientific idiot. The idea that the oceans will “start to take up carbon more rapidly” if we stop putting it in the air is manifestly ridiculous. The oceans don’t care where the carbon comes from, and the rate of ocean uptake at any time is a function only of the current concentration and other atmospheric conditions at that time – not of their rate of change. Also, there is no way that ocean storage of CO2 “offsets the warming effect of the CO2 that still remains in the atmosphere”. Absorption into the ocean may actually reduce atmospheric CO2, but if it does so fast enough then the effect won’t just be to stop global warming but to reverse it (though the effects of the consequent ocean acidification may in that case be even stronger than in the earlier predictions).

And even if there is some correct science behind Mann’s garbled nonsense, he’s a political idiot for bringing it up in the context of this interview – for at least two reasons.

First, suggesting the possibility of a rapid reversal of global warming completely undermines his claim that another four year delay in shutting of the CO2 tap would be catastrophic.

And secondly, his idiotic claim on 60 Minutes that  “There’s about as much scientific consensus about human-caused climate change as there is about gravity” is undermined by his assertion that “research over the last decade has overturned” the previous consensus that even if all CO2 emissions were halted overnight, global temperatures would keep rising and heatwaves, droughts, storms and other impacts would keep intensifying “for about 25 to 30 years” (as Sir David King, the former chief science advisor to the British government, said in 2006). It is manifestly clear that large swathes of climate science are definitely NOT “settled” in anything like the same sense as that of gravity and to claim that they are is just to unnecessarily invite challenges to those parts where we do have some certainty – either about some of the actual facts themselves, or about our lack of certainty about how bad some other facts might be. (Whatever anyone may speculate, we certainly don’t know that there is anything that will mitigate the harmful effects of spewing GHGs. So we must stop. And, since we don’t really know how long we have, we must do so as soon as possible.)

I’ve always had doubts about Mann. From when his sloppy temperature studies had to be re-done by Richard Muller’s Berkely Earth Temperature Study and when foolish emails about data adjustment used language which virtually demanded charges of fakery and tampering. Unfortunately the most prominent advocates for anything are often not the most credible.

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