Category Archives: Climate science

Coverage bias and recent trends in global surface temperature, part 1

In retrospect, 2014 was an interesting year for climate watchers, and a turning point of sorts. That year, global mean surface temperature matched record highs for the instrumental period, without any assist from the El Nino weather pattern that usually accompanies such warm years.  That turned out to be a prelude to a record-smashing 2015. And 2016 may well provide an unprecedented third surface temperature record in a row, as the influence of  the current super El Nino will likely peak in the first half of this year.

But 20GMST 1990-201414 was also notable scientifically for the emergence of a previously under-examined scientific issue: namely coverage bias in observed surface temperature series, especially the HadCrut4 record issued by the UK Met Office.

This most widely cited temperature series does not account for missing areas, especially in high latitudes, likely leading to an underestimate of the overall rise in global temperature since the 19th century.

Not only that, but there is increasingly compelling evidence that the recent short-term slowdown in the surface temperature record was much less pronounced than previously estimated, if rapid Arctic warming is fully reflected, along with potential biases from the changing mix of sea surface temperature measurement sources in recent years.  Thus the discrepancy between very short-term and multi-decadal trends in the observations appears to have been exaggerated in prior estimates, including IPCC AR5.

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Open Thread #8

I’m working on two or three projects that are taking a little more time than I would like. But in the mean time, here’s a new thread for open discussion of climate science and related matters not discussed in other recent threads.

A first look at UAH 5.3

Readers here (and elsewhere) have noted the release of a new version of the UAH satellite-derived tropospheric temperature record by John Christy and Roy Spencer. As noted by Spencer on March 5, version 5.3 seeks to remove, or at least mitigate, a spurious annual cycle that was apparently exacerbated in the changeover from the older MSU sensors to the newer AMSUs back in 1998.

The new data set is now available, so I’ll show some graphs that highlight the differences between the two versions. But first I’ll give a brief background on the matter, including my role.

[Update, March 10: It appears that John Christy was first notified of the annual cycle issue in October 2008, although it is unclear whether he understood the implications at that time. ]

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Vaclav Smil on climate change: “No global warming in past ten years”

Smil at Q2CHere’s an astonishing segment from a  recent interview with futurist Vaclav Smil, conducted by New York Times environmental reporter Andrew Revkin. Smil claims that there has been “no global warming in the past ten years” and appears to suggest that we can safely ignore the problem of climate change because it won’t hit with “full force” any time soon, and its full impact is as yet unknown.

The interview came last Saturday at the Quantum to Cosmos Festival (Q2C)l in Waterloo, Ontario, a 10-day presentation of the Perimeter Institute for Theoretical Physics. Smil is a professor at the University of Manitoba in Winnipeg, and the author of 30 books, the most recent being “The Global Catastrophes and Trends: The Next Fifty Years.”

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Let the backpedalling begin

KHantemirovRM Fig 5 zoomThe latest battle over the “hockey stick” has taken quite a turn, one that may finally lay to rest all the  absurd claims of its demise made by contrarians (not to mention apparently libelous accusations of scientific malfeasance). In previous posts, we discussed climate blogger Steve McIntyre’s scurrilous accusations of “cherrypicking” against UK dendrochronolgist Keith Briffa, and summarized a a quick technical critique of McIntyre’s work by a dendrchronologist known as Delayed Oscillator.

Now comes new evidence that McIntyre’s accusations were completely false. And not only that, one of the Russian researchers who actually control the raw tree-ring data that McIntyre was mistakenly hounding Briffa for, has apparently confirmed that utilization of  a newer more complete Yamal data set has no substantial effect  on Briffa’s Yamal temperature reconstruction.

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“Delayed Oscillator” on divergence

Anyone who has blogged, or even just hangs around blogs more than they should, is familiar with the “pingback”. You know, it’s that automatically generated comment that signals that another blog has referred to a particular post. Yesterday, I got this “pingback” from a blogger called Delayed Oscillator (or “delayed.oscillator” as it is formatted there) and decided to follow it up.

And am I ever glad I did. DO (pronounced Dee-Oh), as I will call this blogger (I hope that’s OK!) has brought a welcome expert perspective to the discussion of the Steve McIntyre-Keith Briffa controversy, said by certain economists and business section editors to expose the global warming sham once and for all. In a two-part series of posts, DO shows why it “ain’t necessarily so” (to say the least).

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Climate “auditor” Steve McIntyre: Yamal like “crack cocaine”

By now, anyone who follows the climate blog wars knows that a new battle is underway over the standard temperature reconstruction popularly known as the “hockey stick”. Although it has been declared thoroughly shattered many times, apparently it must be attacked again and again.

Over the last few days, self-appointed climate “auditor” Steve McIntyre has made several insinuations concerning the work of UK dendro-climatologist Keith Briffa, focusing on the recently released Yamal series of tree-ring measurements. Along the way, he has once again rehashed an oft-repeated accusation that “cherry-picking” of proxy sites is endemic in the paleo-climatological community that he disdainfully calls the “Hockey Team”. But this time, McIntyre has outdone himself, comparing the repeated use of the Yamal tree-ring chronology in paleoclimatology studies to a “crack cocaine” addiction.

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