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Carbon Brief Staff

Carbon Brief Staff

12.04.2011 | 10:00am
ScienceChristopher Booker argues that climate change has reversed itself. We check.
SCIENCE | April 12. 2011. 10:00
Christopher Booker argues that climate change has reversed itself. We check.

Christopher Booker’s latest piece in the Sunday Telegraph argues that climate change is “make-believe” and one of the “great fantasies”. He says belief that man’s activities are causing climate change is going through a “fantasy cycle”.

We fact-checked his scientific claims. First up, the suggestion that rather than being a response to greenhouse gas emissions, changes in the global temperature are the result of natural climate cycles:

“In the past few yearsâ?¦.[c]arbon dioxide levels continued to rise, but global temperatures failed to follow. Three times in the past 13 years – in 1998, 2006 and 2010 – they spiked upwards, thanks to periodic shifts in a major Pacific ocean current – the phenomenon known as “El Niño” – which brings warm water to the surface and boosts temperatures across the world. Each time it was trumpeted as “the hottest year ever”. But each time, as the ocean current reversed into “La Niña”, the spike was followed by an equally sharp cooling.”

The graph below shows the change in atmospheric temperatures since 1880, as measured by the four main temperature datasets. Some of the variation in temperature year-on-year has occurred as a result of the El Niño/ La Niña cycle. It is clear from this graph however that a 3-7 year cycle can’t account for the changes in temperature observed.

 

Graph _temp _rise 

2000-2010 has been the hottest decade on record, containing the majority of the hottest years on record.

Booker claims:

“In 2007, temperatures fell by 0.75C, more than the entire net rise recorded through the whole of the 20th century.”

It is not clear what source Booker is basing this claim on. (He doesn’t provide references in his columns.)

In early 2008, however, prominent climate sceptic website Watts Up With That (profiled here) claimed that NASA’s figures showed temperatures falling by 0.75Ë?C between January 2007 and January 2008.

The WUWT figures were cherry-picked – as you can see from the above graph, temperatures fluctuate all the time. The 0.75 degrees figure came from picking two moments in time which fitted the argument that temperatures were falling.

NASA’s figures actually showed that the average global temperature in 2007 was higher than that in 2006. At the time, NASA said that:

“The year 2007 tied for second warmest in the period of instrumental dataâ?¦. The unusual warmth in 2007 is noteworthy because it occurs at a time when solar irradiance is at a minimum and the equatorial Pacific Ocean is in the cool phase of its natural El Niño-La Niña cycle.” 

 

The NCDC recorded 2007 as the fifth warmest on record.

Booker goes on to imply that rising temperatures in 2010 could be attributed to El Nino, saying:

“After [temperatures] rose again to a new El Niño peak in 2010â?¦”

This is right as far as it goes – but only tells half the story.

In the first half of 2010 there was a “moderate to strong” El Niño which caused temperatures to rise. Booker does not mention that in the latter half of the year there was a dramatic shift to a moderate to strong La Niña – which has a cooling effect on the planet. The La Niña was in place by August. The Met Office called it “the strongest for more than 30 years”.

Despite this 2010 was one of the three warmest years on record. At the end of the year NASA said that:

“The record temperature in 2010 is particularly noteworthy, because the last half of the year was marked by a transition to strong La Niña conditions, which bring cool sea surface temperatures to the eastern tropical Pacific Ocean.”

Booker then moves onto some more cherry-picking:

“â?¦we were told, only three months ago, by the compilers of the two chief surface-temperature records – the UK Met Office, in association with Phil Jones of East Anglia’s Climatic Research Unit, and James Hansen of NASA – that 2010 was the “equal warmest” or “second warmest” year ever.”

As outlined by us in a recent profile there are actually four principal global temperature datasets. All of the four principal datasets agree that 2010 was one of the top three warmest on record (see here, here, here and here).

Booker goes on:

“Last week, however, with a new La Niña, it was reported that global temperatures, as measured by satellites, had fallen by 0.65C since March 2010, making the world cooler now than its mean over the past 30 years.”

March 2010 was particularly warm – the NCDC wrote that “combined global land and ocean average surface temperature for March 2010 was the warmest on record”.

Again, by cherry picking a moment in time when global temperatures happen to be particularly high, and then comparing to that moment, it is possible to argue temperatures are falling over a short time period.

Scientists know that it is unwise to draw conclusions about temperature trends over short time periods, as natural variability always causes fluctuations – precisely the kind of natural variability that Booker refers to when he talks about La Nina and El Nino, in fact.

To get around this, climate scientists who are studying the climate instead look at decadal trends. These long-term trends continue to show warming.

Booker’s argument here also appeared recently on the Watts Up With That website.

Booker concludes:

“Yet again the computer models, predicting that, thanks to rising CO2, the world should have warmed in the past decade by 0.3C, have proved hopelessly wrong.”

Evidence from the different datasets shows that temperatures have been rising since the 1880s. Since the 1970s the temperature has risen at about 0.16-0.17°C per decade (see here or here).

It is not clear where Booker has sourced the prediction that the world “should have warmed in the past decade by 0.3Ë?C”, but we may have missed it. Again, it’s difficult to pick apart his research methods when he doesn’t tell you where he’s getting the information from.

The IPCC project a temperature rise of 2-4Ë?C  by the end of the century, depending on different emission scenarios – but this rise will not necessarily take place at a steady rate.

The Met Office has for example clearly stated that short-term trends – which may cause increases or decreases in the rate of warming –

“are consistent with the modelsâ?¦ A 10-year decreased (or, indeed, increased) rate of global temperature rise is frequently seen in climate model predictions of global warming – driven by increasing greenhouse gasesâ?¦Recent trends therefore remain entirely consistent with predicted man-made climate change.”

We examined another of Christopher Booker’s recent articles here. Many of Booker’s claims in that article had also previously appeared on the sceptic website Watts Up With That.

Overall, it seems fair to say that Booker isn’t doing a great job of explaining climate science to his readers.

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