The Berkeley Earth Surface Temperature project today released some information about their research. Judith Curry, one of the co-authors, reports this here. The BBC has a story here, and the Economist reports it here.
These stories both play out as “the CO2-forced AGW model is confirmed,” which is a whole lot stronger than the actual results.
The BEP papers say that by re-analyzing existing temperature records, they get a close match to other temperature analyses of global average surface temperature for the last 200 or so years. This isn’t a big surprise: that fits what Wegman and others reported — agreement on warming over the last 400 years, but less clarity on temperatures 1000 years ago or more.
This is not in itself a confirmation of AGW.
I know I’ve said this before, but let’s just repeat: to confirm the CO2-forced AGW hypothesis, you need several steps:
- There must have been warming.
- That warming must be unusual.
- There must be a mechanism proposed for that unusual warming, and there must be a falsifiable way of confirming that mechanism.
- That mechanism has to be the result of human action.
- That human action has to be unusual release of CO2.
All we have here is confirmation of warming, the first step. This has been by far the strongest part of this chain and has been for a long time. It’s already well established — as I’ve said before, we know there’s been warming since the Little Ice Age — that’s how we know it was the Little Ice Age.
There is one fairly unusual aspect to this, that the authors have put on a big PR effort for papers that haven’t been peer-reviewed or published in the formal literature. Here’s something I wrote on Google+:
You’d be better off reading Judith Curry (one of the co-authors) on her blog: http://judithcurry.com/2011/10/20/berkeley-surface-temperatures-released/#comment-124946
The press embargo on this lifts today at noon Pacific time. I suspect there will be pretty widespread media coverage on this, with both sides of the debate spinning this to suit their purposes. I have had queries from several journalists, to whom I probably did not provide any usable sound bites. Lets see how it plays out.
Roger PIelke Sr wonders about site selection:http://pielkeclimatesci.wordpress.com/2011/10/20/comment-on-the-article-in-the-economist-on-rich-mullers-data-analysis/
Anthony Watts notes this is a PR press before peer-review, which is unusual: http://wattsupwiththat.com/2011/10/20/the-berkeley-earth-surface-temperature-project-puts-pr-before-peer-review/
As I was invited by The Economist to comment publicly, I would recommend rejecting Muller et al in the current form and suggest that it be resubmitted with meaningful and appropriate 30 year comparisons for the same time periods used by the Menne et al and Fall et al cited papers. I would be happy to review the paper again at that time.
I also believe it would be premature and inappropriate to have a news article highlighting the conclusions of this paper until such time meaningful data comparisons are produced and the paper passes peer review. Given the new techniques from BEST, there may be much to gain from a rework of the analysis limited to identical thirty year periods used in Menne et al and Fall et al.
Watts had been asked to review one of the papers, which was a follow-on to the site quality work he’s led over the last several years. He found some significant errors, and submitted his reviews just a few days ago; those errors weren’t corrected before the PR push.
Lesson: Be cautious about the reporting of a scientific paper that hasn’t been published yet, and be doubly cautious about how a paper is reported when it’s a politically sensitive topic.
Doug Keenan responds with some technical issues that I think are significant: http://www.bishop-hill.net/blog/2011/10/21/keenans-response-to-the-best-paper.html
Also, the decadal-oscillations paper makes it clear that an interpretation of their data could imply the human contribution to warming has been overstated.