World will warm faster than predicted in next five years, study warns

Duncan Clark in the Guardian (UK): The world faces a new period of record-breaking temperatures as the sun's activity increases, leading the planet to heat up significantly faster than scientists had predicted over the next five years, according to a new study. The hottest year on record was 1998, and the relatively cool years since have led to some global-warming sceptics claiming that temperatures have levelled off or started to decline. However, the new research firmly rejects that argument.

The work is the first to assess the combined impact on global temperature of four factors: human influences such as CO2 and aerosol emissions; heating from the sun; volcanic activity; and the El Niño southern oscillation, the phenomenon by which the Pacific Ocean flips between warmer and cooler states every few years.

It shows that the relative stability in global temperatures observed in the last seven years is explained primarily by the decline in incoming sunlight associated with the downward phase of the 11-year solar cycle, together with a lack of strong El Niño events. These trends have masked the warming caused by CO2 and other greenhouse gases.

As solar activity picks up again in the coming years, the new research suggests, temperatures will shoot up at 150% of the rate predicted by the UN's Intergovernmental Panel on Climate Change. The research, to be published in a forthcoming edition of Geophysical Research Letters, was carried out by Judith Lean of the US Naval Research Laboratory and David Rind of Nasa's Goddard Institute for Space Studies. Lean said: "Our paper shows that the absence of warming observed in the last decade is no evidence that the climate isn't responding to man-made greenhouse gases. On the contrary, the study again confirms that we're seeing a long-term warming trend driven by human activity, with natural factors affecting the precise shape of that temperature rise."….

Altocumulus clouds shot by Fir0002, Wikimedia Commons, under the terms of the GNU Free Documentation License, Version 1.2