WMO’s Extreme Report

This week’s World Meterological Organisation’s report “The Global Climate 2001-2010: A Decade Of Climate Extremes,” attracted little publicity. This is probably a good thing as it is one of the most muddled and inaccurate reports I have ever read from an international organisation.It is about 'climate extremes' in the last decade which it claims are unprecedented. The WMO says that ten years is the minimum time required to detect decadal effects. Not many scientists would agree with that. Consider the extensive debate when it was noticed that the global annual average surface temperature had remained unchanging for a decade. Opinion was divided between those who said it meant nothing and those who thought it might be indicative of something. Yet the WMO thinks ten years enough to detect climatological weather effects with certainty. It seems to fit a recurrent pattern amongst some climate analysts that ten years is enough to see what you want to see, but not long enough to see what you don’t.The report also says that global warming accelerated between 1971-2010. This is obviously not the case. It has been established in the numerous analyses carried out of the various global temperature data sets that the late 20th century warming trend did not continue in the 21st century. The report places great store on the fact that the past decade has been the warmest of the instrumental (post-1850) period. So do we all, but the WMO fails to take into account the recent temperature plateau that extends far beyond a decade.This is another issue we have discussed many times here. Start and end points are crucial in such analysis. We have pointed out the fact that decadal bin-sizes are artificial as Nature does not know if a year has a zero at the end of it, and why did the WMO report stop its analysis of global temperature at 2010 ignoring two more valuable datapoints that solidify the temperature standstill this century.This rather confused section of the WMO report can be summarised in its own words, “The Earth’s climate fluctuates over seasons…” Evidently, the WMO authors confuse weather extremes with climate ones.No Clear TrendRegarding the extremes themselves there is a tension in the text that is quite apparent. It’s a desire to attribute the weather extremes in question to man-made climate change. One almost feels sorry for the authors having to say that no clear trend has been found in tropical cyclones and extra-tropical storms on the global level, while they admit that it is still difficult to quantify the degree and climate-change influence on a single observed event.Sometimes this underlying frustration comes out when the authors claim: “While climate scientists believe it is not yet possible to attribute individual extremes to climate change, they increasingly conclude that many recent events would have occurred in a different way – or would not have occurred at all – in the absence of climate change.”This is a complete misrepresentation of both climate scientists and the science. There are some scientists who believe this, but it is not a majority opinion and it has not been established even though a vocal minority of them claim it has.In reality, the 2011 IPCC SREX report pointed out that, apart from warmer nights, there is not a single weather event whose change in intensity or occurrence can be attributed to climate change. All extreme weather events so far observed are within the range of natural variability. Some, it seems, mistake events that are rare or haven’t happened before in our records, with events that are unexpected.Temperature: Stopped But Still RisingGiven the complex background to the WMO report one might have expected some of the few media reports about it, especially those penned by specialist reporters, to have reflected some of the subtleties. Not a bit of it.The Guardian carried a report by the “Climate News Network,” that began with the words, “If you think the world is warming and the weather is getting nastier, you’re right.” What followed was cherry-picked from the WMO’s Executive Summary. It repeats the claims of “accelerating global warming,” and “sea levels rose twice as fast as the trend in the last century.” There is a quote from the WMO Secretary General and only the WMO Secretary General. The fact that global annual average surface temperatures have not increased for 16-17 years is called by the Guardian, “the apparent slight slow-down.” The Climate News Network report, it distresses me to say, is a straight lift from the WMO press release with no context or analysis or awareness of official reports on similar topics issued in recent years.Not that the BBC is any better. It contains a sentence that might become an emblem for muddled climate change reporting: “Although overall temperature rise has slowed down since the 1990s, the WMO says the temperature is still rising because of greenhouse gasses from human society.”Even worse than the usual BBC confusion is Roger Harrabin’s use of the term “climate change doubters” for people who “emphasise the lack of movement in temperature throughout the decade.” Have we got nowhere in the almost decade-long debate about the shades of legitimate opinion about climate change and its causes?The recent global surface temperature standstill is one of the biggest challenges climate science faces at the moment. If Harrabin considers those who emphasise the reality of the 16-17 year standstill are “climate change doubters” he is going to have a very long list. Add me to it.Feedback: david.whitehouse@netzerowatch.com