The Global Warming Statistical Meltdown

Continuing to rely on climate-model warming projections based on high, model-derived values of climate sensitivity skews the cost-benefit analyses and estimates of the social cost of carbon. This can bias policy decisions. The implications of the lower values of climate sensitivity in our paper, as well as similar other recent studies, is that human-caused warming near the end of the 21st century should be less than the 2-degrees-Celsius “danger” level for all but the IPCC’s most extreme emission scenario.

This slower rate of warming—relative to climate model projections—means there is less urgency to phase out greenhouse gas emissions now, and more time to find ways to decarbonize the economy affordably. It also allows us the flexibility to revise our policies as further information becomes available.

http://online.wsj.com/articles/judith-curry-the-global-warming-statistical-meltdown-1412901060

Climate Science is not Settled

Any serious discussion of the changing climate must begin by acknowledging not only the scientific certainties but also the uncertainties, especially in projecting the future. Recognizing those limits, rather than ignoring them, will lead to a more sober and ultimately more productive discussion of climate change and climate policies. To do otherwise is a great disservice to climate science itself.

http://online.wsj.com/articles/climate-science-is-not-settled-1411143565

The Global-Warming Debate: Matt Ridley Responds

As for the hockey stick, Mr. Plait repeats long-discredited defenses of the graph, including the suggestion that other selections of data have confirmed it. Surely he knows (if only because it is in my article) that these confirmations rely on including Tiljander’s lake sediments or bristlecone pines, but that if you leave these now-debunked data sets out, then the effect vanishes. Please read Climate Audit to verify this. Here’s a quote:

“As CA readers are aware, the ‘big news’ of Mann et al 2008 was its claim to have got a Hockey Stick without Graybill’s bristlecone chronologies (camouflaged as a ‘no-dendro’ reconstruction). CA readers are aware that this claim depended on their use of contaminated modern portion of the Tiljander sediments and that the original claims for a ‘validated’ no-dendro reconstruction prior to 1500 fell apart, even though no retraction or corrigendum to the original Mann et al (PNAS 2008) has been issued.As we learned (from an inline comment by Gavin Schmidt in July 2010), Mann et al have conceded that these claims fell apart, but did so using a “trick” (TM- climate science.) Instead of acknowledging the false assertions at the journal in which the assertions were made (PNAS), they acknowledged the failure of the no-Tiljander no-bristlecone reconstructions deep in the Supplementary Information of a different paper (Mann et al, Science 2009) – a trick for which the term ‘Mike’s PNAS trick’ is surely appropriate (though the term ‘Mike’s Science trick’ also merits consideration.)”

http://blogs.wsj.com/ideas-market/2013/07/09/the-global-warming-debate-matt-ridley-responds/

Michael Crichton on consensus

I want to pause here and talk about this notion of consensus, and the rise of what has been called consensus science. I regard consensus science as an extremely pernicious development that ought to be stopped cold in its tracks. Historically, the claim of consensus has been the first refuge of scoundrels; it is a way to avoid debate by claiming that the matter is already settled. Whenever you hear the consensus of scientists agrees on something or other, reach for your wallet, because you're being had.

Let's be clear: the work of science has nothing whatever to do with consensus. Consensus is the business of politics. Science, on the contrary, requires only one investigator who happens to be right, which means that he or she has results that are verifiable by reference to the real world.

http://wattsupwiththat.com/2010/07/09/aliens-cause-global-warming-a-caltech-lecture-by-michael-crichton/