Managing Climate Expectations

It’s rather worrying, when you think about it, that the Himalayan glaciers may be completely gone by 2350, according to the IPCC. The only trouble is, nobody cares, because they erroneously claimed they’d be gone by 2035.

I’m becoming more and more concerned by the tendency of climate change cheerleaders to try to find worse and worse evidence of climate change. Consider a couple of recent posts at Realclimate.

First we have  Recent trends in CO2 emissions. The lead author is Corinne le Quéré who is an oceanographer, not an economist.

The argument is over the extent to which actual carbon emissions have exceeded the IPCC emission scenarios – the authors of the post seem to be keen to emphasise the overshoot. But these scenarios are purely designed to illustrate how atmospheric CO2 and other GHG levels might increase over the rest of the century and therefore how much warming might occur, if corrective action isn’t taken. They are guesstimates, with no basis in science, social or otherwise.

My personal opinion is that the scenarios have outlived their useful life, since the key determinant of future emissions will be the effectiveness of corrective action, not whether future economic growth is “fossil fuel intensive” or whatever.

In 2008, as discussed in the post, the actual emissions were higher than nearly all the IPCC examples. But towards the end of 2008, remember, the global economy fell off a cliff. The economic growth and hence emission levels in 2008 were clearly unsustainable. The Realclimate post also notes – rather than emphasises – that projected emissions in 2009 exceed the bulk of the scenario projections by less than was the case for 2008. No further projections are given.

Clearly, we can only determine how close the scenarios are to reality over a long period, and especially by taking account of the business cycle.

Why we’re even discussing the fit between the IPCC scenarios and actual emissions in a given year is beyond me.

It seems to me there is a dangerous tendency on the part of advocates for action to mitigate climate change to promote data showing the situation is worse than expected. This is unwise. It polarises the debate even more. Scrupulous objectivity is essential.

The worst example of “worse than expected” syndrome is the reporting of Arctic sea-ice, as I highlighted on here some time ago (subsequent posts are linked via the comments).

A number of commentators, such as Joe Romm [see Note], report the state of the Arctic sea ice on an almost daily basis (the NSIDC provides daily data, which I see now show the ice extent is now greater than in 2007 – perhaps we should revise our whole opinion on global warming!).

When I first started investigating the possible natural cycle in the Arctic sea-ice back in February, I noted:

“If I were a climate specialist about to make a song and dance over a particular piece of evidence for GW, I think I’d make pretty sure the phenomenon in question hadn’t happened before.”

I’m currently trying to collate my thoughts on the AMO – blogging has its plus side, but it’s pants for organising information – and I’ve come across a few tidbits in the IPCC’s latest report (AR4).  Here’s what the Technical Summary has to say (section TS.3.1.2, p.37):

The warming in the last 30 years is widespread over the globe, and is greatest at higher northern latitudes. The greatest warming has occurred in the NH winter (DJF) and spring (MAM).  Average arctic temperatures have been increasing at twice the rate of the rest of the world in the past 100 years. However, arctic temperatures are highly variable. A slightly longer arctic warming period, almost as warm as the present, was observed from 1925 to 1945, but its geographical distribution appears to have been different from the recent warming since its extent was not global.” [my italics]

As I said, notwithstanding the last desparate clause, which I don’t even recognise as a scientific statement (in my opinion the 1925-1945 warming was every bit as global), it’s happened before.

I know that even the Technical Summary of AR4 is not something you actually read, but you might expect commentators like Joe Romm to have browsed the thing.  Failing that, you’d have thought they’d at least look at the IPCC’s pictures.  Here’s one I haven’t posted on here before – check out the top panel in particular:

I say it again: claiming short-term changes in Arctic sea-ice extent “prove” GW is exceptionally foolish.  There may be a cycle – on top of the GW trend – which has overshot, which could mean a decade or more of sceptics saying the ice-melt – and hence GW – has “reversed”.  Hysterical climate change popularisers such as Joe Romm are becoming less part of the solution than part of the problem  (which reminds me that maybe I should try to get hold of Mike Hulme’s book, which I gather makes a similar point).

It should be a priority to understand (or debunk) the AMO cycle.  Which makes my attempts to raise awareness on the other Realclimate post I mentioned at the outset all the more frustrating.


Note: I originally started writing this post weeks ago – I just discovered it amongst my drafts.  It was at the exact point where I’ve written “see Note” that I was distracted by the question of where the precise dividing line lies between nationalism and racism, as illustrated by the case of Joe Romm.  Since then I’ve been much amused that the search parameters used to find my blog have included “Joseph Romm asshole”!  I feel myself under no pressure to pull my punches in the rest of this post.