Everybody but the anti-science disinformers have known for a long time that the Hadley/CRU (Climatic Research Unit) temperature data UNDERestimates — not OVERestimates — the recent global temperature rise. I’ve repeatedly written about how this data excludes “the place on Earth that has been warming fastest” (see “Why are Hadley and CRU withholding vital climate data from the public?” and “What exactly is polar amplification and why does it matter?”). So has NASA’s James Hansen (for years) among others.
The disinfomers — people like the Competitive Enterprise Institute — have been trumpeting yet more ass-backwards disinformation on this, spun from the Russian Institute of Economic Analysis (but debunked by Tim Lambert aka Deltoid and others). Now the Met Office has buried them with a new analysis, published Friday on their website:
New analysis released today has shown the global temperature rise calculated by the Met Office’s HadCRUT record is at the lower end of likely warming. The study, carried out by ECMWF (the European Centre for Medium-Range Weather Forecasts) with input from the Met Office, performs a new calculation of global temperature rise. This independent analysis is based on information from a wide range of sources. It uses all available surface temperature measurements, together with data from sources such as satellites, radiosondes, ships and buoys.The new analysis estimates the warming to be higher than that shown from HadCRUT’s more limited direct observations. This is because HadCRUT is sampling regions that have exhibited less change, on average, than the entire globe over this particular period. This provides strong evidence that recent temperature change is at least as large as estimated by HadCRUT. This conclusion is in contrast to a recently released study by the Institute of Economic Analysis (IEA) think tank based in Moscow. The IEA’s output is consistent with HadCRUT as they both confirm the global warming signal in this region since 1950, which we see in many other variables and has been consistently attributed to human activities.
Increase in mean near-surface temperature (°C) from (1989–98) to (1999–2008)
The lower figure is the ECMWF analysis which uses all available observations, including satellite and weather balloon records, synthesised in a physically- and meteorologically-consistent way, and the upper figure represents the same period from our HadCRUT record. The ECMWF analysis shows that in data-sparse regions such as Russia, Africa and Canada, warming over land is more extreme than in regions sampled by HadCRUT. If we take this into account, the last decade shows a global-mean trend of 0.1 °C to 0.2 °C per decade. We therefore infer with high confidence that the HadCRUT record is at the lower end of likely warming.
I would say, “Duh” but apparently even stuff that has been obvious in the scientific literature for a long time goes above the head of the antiscience crowd. How far back was this known in the literature? As Hansen just explained (again) — see NASA reports hottest November on record, 2009 poised to be second hottest year, Hansen predicts better than 50% chance 2010 will set new record:
As discussed by Hansen et al. (2006) the main difference between these analyses is probably due to the fact that British analysis excludes large areas in the Arctic and Antarctic where observations are sparse. The GISS analysis, which extrapolates temperature anomalies as far as 1200 km, has more complete coverage of the polar areas. The extrapolation introduces uncertainty, but there is independent information, including satellite infrared measurements and reduced Arctic sea ice cover, which supports the existence of substantial positive temperature anomalies in those regions.
Not exactly news.
For the sake of completeness, let me excerpt at length Deltoid’s 12/17 post, “Russian analysis confirms 20th century CRU temperatures”:
The latest story exciting the denialosphere is being put about by novelist James Delingpole and is based on an analysis (translated here) by a right-wing Russian think tank. Delingpole quotes from a news story:
On Tuesday, the Moscow-based Institute of Economic Analysis (IEA) issued a report claiming that the Hadley Center for Climate Change based at the headquarters of the British Meteorological Office in Exeter (Devon, England) had probably tampered with Russian-climate data.
The IEA believes that Russian meteorological-station data did not substantiate the anthropogenic global-warming theory. Analysts say Russian meteorological stations cover most of the country’s territory, and that the Hadley Center had used data submitted by only 25% of such stations in its reports. Over 40% of Russian territory was not included in global-temperature calculations for some other reasons, rather than the lack of meteorological stations and observations.
What the Russians are suggesting here, in other words, is that the entire global temperature record used by the IPCC to inform world government policy is a crock.
The problem here is the IEA report does not support the claims made in the news story. I’ve reproduced the final graph from the report below. The red curve is the temperature trend using the 121 Russian stations that CRU has released data for, while the blue hockey stick is from a larger set of 476 stations. I’ve put them on top of the CRU temperatures for northern extratropics. The red and blue curves agree very well in the period after 1950, thus confirming the CRU temperatures. Well done, IEA!
The red and blue curves do diverge in the 19th century, but the one that provides more support for anthropogenic global warming is the blue hockey stick. The red curve shows warming in the 19th century before there were significant CO2 emissions, so it weakens the case that global warming is man-made. If CRU (not HAdley as claimed in the Russian news story) have “tampered” with the data, it would seem that they must have been trying to make a case against AGW.
The IEA analysis is, in any case, misguided. CRU has not released all the station data they use, so the red curve is not the CRU temperature trend for Russia at all. If you want that, all you have to do is download the gridded data and average all the grid cells in Russia. You have to wonder why the IEA did not do this.
Since Russia is a pretty fair chunk of the land north of 30 degrees north, the CRU graph above is a rough approximation of the what the CRUTEM3 trends for Russia is, and you can see that it looks like the blue curve and not the red one.
That the anti-science disinformers would misrepresent an analysis that so utterly undermines their central point is no surprise. That anybody would continue to be duped by such ass-backwards crap remains a bit surprising.