Magazine article The Spectator

Breaking the Ice

Magazine article The Spectator

Breaking the Ice

Article excerpt

The battle over whether Antarctica is warming reveals the bias that sustains the climate change consensus

Has Antarctica been getting warmer? To the frustration of many environmentalists, it's not an easy question. Manned weather stations have existed there for over 50 years, unmanned stations from 1980 onwards. Coverage is patchy both in space and time, with weather stations clustered in a few spots and records full of gaps from when sensors got buried in snow, breakdowns occurred or stations were closed. From 1982, satellites have measured the temperature over the continent but inaccurately, because of clouds and instrument inconsistencies.

So taking Antarctica's temperature involves considerable mathematical skill and leaves much room for statistical disagreement. The disagreement has just become a lot less polite, as several scientists exchanged the blogosphere equivalents of declarations of war. What started out as a difference over methods and results has descended into character assassination and accusations of duplicity.

Underlying all this, one side claims that Antarctica - a continent which holds 90 per cent of the world's ice - is warming significantly.

The other side claims this is not so. The battle has implications far beyond Antarctica. It has exposed a real problem of bias in scientific journals.

The story starts in 2009 when the prestigious journal Nature carried a cover story with an image of Antarctica glowing a warm pink.

The paper inside used a relatively novel statistical reconstruction method to combine the detailed satellite data with the more accurate, but sparse, weather station data. It concluded that most of Antarctica - and particularly West Antarctica - had warmed significantly since 1957. This was worthy of a cover story because it contradicted the previous understanding: that only the most northerly part of this ice continent, the slender Antarctic peninsula, was warming.

The paper's senior author was Eric Steig of the University of Washington. His work duly captured world headlines. Four days later, the editor of the famously pugnacious Real Climate blog, Gavin Schmidt, boasted that the sceptics were surprisingly silent. Mission, it seemed, accomplished: Antarctica was no longer an embarrassment to the global warming narrative.

He spoke too soon. The indefatigable Canadian climate analyst Steve McIntyre had already started to post analyses of the Nature paper at his blog, Climate Audit. He was joined by the engineer Jeff Condon, whose blog the Air Vent had, along with Climate Audit, played a crucial role in the release of the now infamous 'Climategate' emails from the University of East Anglia in 2009.

Within a few weeks, McIntyre and Condon, together with engineer Ryan O'Donnell, statistician Roman Mureika, economist Huston McCulloch and others, deconstructed Steig's results.

McCulloch soon discovered that an important factor - serial correlation - had been overlooked, which had the effect of making the warming trend look more statistically significant than it was. After this appeared at Climate Audit, Steig sent a correction to Nature, claiming he had found the error independently.

Mureika found that Steig's reconstructions were, mathematically, derived from only three underlying temperature sequences - too few properly to represent an entire continent.

McIntyre then showed that these sequences, claimed by Steig to be meaningfully related to important physical climate processes, resembled instead off-the-shelf mathematical patterns known as Chladni vibration patterns, and could be expected to arise irrespective of the claimed causes.

The blog workers were by now convinced that Steig's significant warming trend was an artefact of a mathematical method employed inappropriately. It smeared a trend from an area containing many recording stations over an area with few stations, specifically from the strongly warming Antarctic peninsula to the much larger West Antarctica - a region containing only two short-record manned stations. …

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