Another Climate Change Catastrophe from the Mail

It seems that no Sunday is now complete without another pile of nonsense about climate change from David Rose in the Mail on Sunday (see my previous post here for example) and this week was no exception.

Rose has found a graph which he claims contains

…irrefutable evidence that official predictions of global climate warming have been catastrophically flawed.
The graph on this page blows apart the ‘scientific basis’ for Britain reshaping its entire economy and spending billions in taxes and subsidies in order to cut emissions of greenhouse gases.

Typically for Rose the whole piece is riddled with inaccuracies and distortions – for example he completely misrepresents the views of climate scientist James Annan and repeats the easily debunked myth that scientists in the 1970s were just as concerned about global cooling as global warming. But the main problem with Rose’s argument is more fundamental. The graph that he shows in order to support his argument simply doesn’t show what he claims it does. His “smoking gun” is not only not smoking, it is not even warm. Here is the graph in question

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The graph itself is genuine – it has been taken from the blog of climate scientist Ed Hawkins and shows projections of surface temperatures from climate models going back to the early 1950s and forwards to the mid 21st century with different certainty levels, and actual observations to date. Rose is wrong about the certainty levels they actually represent 50% and 90% but I’m betting that this is an innocent mistake because (as we will see) he just doesn’t understand statistical terminology very well.

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The Guardian’s Fred Pearce seems to be confused

The Guardian is not the first place one expects to see stories jumping on the “climategate” bandwagon, but they made a big splash this week with this story by Fred Pearce.

Phil Jones, the beleaguered British climate scientist at the centre of the leaked emails controversy, is facing fresh claims that he sought to hide problems in key temperature data on which some of his work was based.
A Guardian investigation of thousands of emails and documents apparently hacked from the University of East Anglia’s climatic research unit has found evidence that a series of measurements from Chinese weather stations were seriously flawed and that documents relating to them could not be produced.

The “evidence” which supposedly incriminates Jones seems to me to be rather flimsy, but my point is not to argue the rights and wrongs of the accusation. What I find a bit odd is that Fred Pearce seems to have rather changed his view of the hacked emails – after all he had previously published a piece with the headline “How the ‘climategate’ scandal is bogus and based on climate sceptics’ lies” with the sub-heading “Claims based on email soundbites are demonstrably false – there is manifestly no evidence of clandestine data manipulation” in which he wrote

Almost all the media and political discussion about the hacked climate emails has been based on brief soundbites publicised by professional sceptics and their blogs. In many cases, these have been taken out of context and twisted to mean something they were never intended to.

Of course people do sometimes change their positions on particular issues, there’s nothing wrong with that. So how long did it take Pearce to undergo this rather drastic conversion? Well the piece alleging malpractice based on evidence in the hacked emails was posted on the Guardian website at 21:00 on 1st February, whereas the piece claiming that the “climategate” scandal was bogus was posted at , er, 18:04 on the same day, less than three hours earlier.

Is it just me or does Fred Pearce seem to be somewhat confused?

Daily Mail spreading climate change misinformation again

Note: This piece has been updated on 15th December

The Daily Mail seems to have found yet more evidence to persuade its readers that they should be skeptical of man-made global warming. This piece by David Rose has two startling revelations – that both proxy data and an important diagram in an IPCC report were manipulated to make past temperatures appear cooler than they actually were, and that weather station data was also manipulated to show warming in recent times which may not have actually occurred. I don’t have time now to address the latter claim, but you can see a good summary here. However, I would like to address the question of the temperature data in some detail. Continue reading

AGW deniers in “statistically illiterate” shock

One of the most popular myths promoted by those skeptical about man-made global warming is that warming has stopped and, in fact, the trend has even reversed in recent years. This illusion largely stems from the fact that 1998 was an exceptionally hot year and 2008 relatively cool due to the respective el Niño and la Niña events of those years.
Despite the fact that the current decade is actually the hottest on record, that eight of the last ten years are among the twelve hottest ever and that ten years is in any case too short a period to represent a meaningful trend, this myth has been remarkably successful – it is not just the usual suspects who are promoting it, even the BBC seem to have been taken in.

Climate scientists and other interested parties have already attempted to correct this misapprehension based on science, unfortunately without much success, but now Associated Press has made an excellent contribution to the debate which demonstrates that the claims made by the deniers are nonsensical from a statistical point of view.

In a blind test, the AP gave temperature data to four independent statisticians and asked them to look for trends, without telling them what the numbers represented. The experts found no true temperature declines over time.

The AP sent expert statisticians NOAA’s year-to-year ground temperature changes over 130 years and the 30 years of satellite-measured temperatures preferred by skeptics and gathered by scientists at the University of Alabama in Huntsville.

Statisticians who analyzed the data found a distinct decades-long upward trend in the numbers, but could not find a significant drop in the past 10 years in either data set. The ups and downs during the last decade repeat random variability in data as far back as 1880.

Saying there’s a downward trend since 1998 is not scientifically legitimate, said David Peterson, a retired Duke University statistics professor and one of those analyzing the numbers.

Identifying a downward trend is a case of “people coming at the data with preconceived notions,” said Peterson, author of the book “Why Did They Do That? An Introduction to Forensic Decision Analysis.”

They also nailed the way the deniers have cherry picked the data to suit their agenda.

Grego produced three charts to show how choosing a starting date can alter perceptions. Using the skeptics’ satellite data beginning in 1998, there is a “mild downward trend,” he said. But doing that is “deceptive.”

The trend disappears if the analysis starts in 1997. And it trends upward if you begin in 1999, he said.

I doubt it will silence the deniers but we now know that on this particular question their arguments are both scientifically and statistically illiterate.

Hat tip: Climate Progress