Tag: ENSO

Carterist science meets its Cartergate

homer.jpgThe peer-reviewed rebuttal to last year’s infamous McLean, de Freitas and Carter paper which claimed that the El Niño Southern Oscillation could explain most recent warming (see Mother Nature’s Sons and Big Guns Brought To Bear), has been accepted for publication by the Journal of Geophysical Research (Comment on “Influence of the Southern Oscillation on tropospheric temperature” Foster et al, 2010). Co-author James Annan has the details (and full text of the rebuttal), but what is perhaps most remarkable is that despite being given the opportunity to reply to Foster et al’s comment — normal practice in these circumstances — McLean et al’s offering has failed to pass review and will not be published by JGR. Tim Lambert at Deltoid has more feedback, and draws attention to the comments by Prof Ove Hoegh-Guldberg at Climate Shiftswho demands:

The five things we want to know are:

  1. Will McLean et al. retract the paper (and will Bob Carter admit fault or even discuss the errors publicly)?
  2. Will the denial0sphere and the MSM give this story (a climate change scandal!) the same coverage it has recently showered on various IPCC hiccups?
  3. Will there be an investigation as Bob Carter himself and so many other skeptics have insisted on over and over again, usually in response to bogus and unsubstantiated allegations.
  4. Will Bob now reverse his policy positions and urge (vocally) politicians that may have been swayed by his bogus science to do the same? After all Bob, shouldn’t the science drive the policy?
  5. Will The Australian cover this pending scandal! A scientist behaving badly!

Those look like damned good questions to me. New Zealand’s science community has been reluctant to publicly criticise Carter — he was once a respected and influential scientist who encouraged many talented students to forge their careers in the earth sciences — but surely this display of academic turpitude puts him beyond the pale. What it says about de Freitas is probably unprintable. I encourage readers to remember the extravagant claims being made for this paper by Carter and de Freitas, and the uncritical acceptance of those claims by a pliable media. High time the boot was on the other foot.

[This song’s for Bob: h/t caerbannog in comments at Deltoid]

[Update 23/3: Skeptical Science explains the rebuttal here. Worth a read.]

Tipping and other points

During the Copenhagen kerfuffle a lot of interesting stuff hit the web: here’s something that deserves a bit more air – a Proceedings of the National Academy of Science (PNAS) special issue on tipping elements in the earth system, edited by John Schellnhuber, the director of the Potsdam Institute for Climate Impact Research in Germany.

Tipping elements (or points, as Malcolm Gladwell would have them) are changes that once started take on a life of their own, and can’t easily be returned to their original state. In the climate system that might be the rapid loss of an ice sheet in a few decades or hundreds of years, while regrowing it might take many thousands. The PNAS special issue deals with nine: dust production in the Bodélé Depression in Chad, ENSO, Arctic sea ice and ice sheets, the Atlantic Meridional Overturning Circulation, deep ocean hydrates (not shallow sea bed, Siberian methane) — David Archer dubs them a “slow tipping point”, the Amazon rainforest (no “Amazongate” here, just a confirmation that concern is justified), monsoons, oceans, and policy responses to the climate challenge. And the best thing is that all the articles are available online, free (click on the link above). Schellnhuber contributes an introduction, and the Potsdam press release also provides a good overview. For some introductory thoughts, check out Tim Lenton’s discussion here.

Another recent example of a real tipping point is the Pine Island Glacier in West Antarctica. Recent modelling suggests that the glacier’s grounding line retreated beyond a ridge in 1996, and is now free to retreat by several hundred kilometres inland. This could happen in a hundred years and result in the loss of half of the ice in the glacier — enough to raise sea level by 24cm. New Scientist reports:

Observations already show that the model severely underestimates the rate at which PIG’s grounding line is retreating, says Katz. “Ours is a simple model of an ice sheet that neglects some important physics,” says Katz. “The take-home message is that we should be concerned about tipping points in West Antarctica and we should do a lot more work to investigate,” he says.

Amen to that.

Big guns brought to bear

homer.jpgThe now infamous McLean, de Freitas and Carter paper in the Journal of Geophysical Research (see Mother Nature’s Sons) has attracted a damning response from some of the biggest names in climate science, including a strong Kiwi contribution*. A comment has been submitted to JGR by Grant Foster, James Annan, Phil Jones, Michael Mann, Brett Mullan, Jim Renwick, Jim Salinger, Gavin Schmidt, and Kevin Trenberth. McLean et al’s “analysis is incorrect”, “seriously overestimates” the link between ENSO and global temperatures, and their paper provides no support for any claim about recent global temperature trends. Here’s the abstract:

McLean et al. [2009] (henceforth MFC09) claim that the El Nino/Southern Oscillation (ENSO), as represented by the Southern Oscillation Index (SOI), accounts for as much as 72% of the global tropospheric temperature anomaly (GTTA) and an even higher 81% of this anomaly in the tropics. They conclude that the SOI is a “dominant and consistent influence on mean global temperatures,” “and perhaps recent trends in global temperatures”. However, their analysis is incorrect in a number of ways, and greatly overstates the influence of ENSO on the climate system. This comment first briefly reviews what is understood about the influence of ENSO on global temperatures, then goes on to show that the analysis of MFC09 severely overestimates the correlation between temperature anomalies and the SOI by inflating the power in the 2–6 year time window while filtering out variability on longer and shorter time scales. It is only because of this faulty analysis that they are able to claim such extremely high correlations. The suggestion in their conclusions that ENSO may be a major contributor to recent trends in global temperature is not supported by their analysis or any physical theory presented in that paper, especially as the analysis method itself eliminates the influence of trends on the purported correlations.

Looks to me like there’s no academic wiggle room for McLean, de Freitas and Carter. They got it very wrong. The big question now is how they managed to sneak the paper through peer-review. Meanwhile, claims that McLean et al shows “that most of the late 20th century global warming and cooling can be attributed to natural climate processes” will remain up at crank web sites, and Carter and de Freitas will consider their real work — to provide more propaganda for the denial machine — well done.

[* Brett Mullan and Jim Renwick are at NIWA, Jim Salinger’s now in the same department at Auckland University as CdF (which must make for interesting conversation over morning coffee), and Kevin Trenberth is a New Zealander.]