Air takes heat for the climate

The atmosphere is the great leveller when it comes to determining global climate. Scientists have found that it plays a much greater role in redistributing heat from the tropics to the poles than do the oceans.

The analysis by Kevin Trenberth, a senior scientist, and colleague Julie Caron, at the National Center for Atmospheric Research in the US, has resolved a longstanding mismatch between observations and calculations.

They found that the atmosphere redistributes as much heat as would be produced by 5 million of the world's biggest power stations.

"This new analysis makes the observations more consistent with the most stable global climate models and gives us confidence that the models are on target," Trenberth said.

With no movement of heat around the globe, the tropics would be far hotter and wetter while high latitudes would be frozen solid.

The atmosphere and oceans help even out the Earth's temperatures, primarily during each hemisphere's winter.

The two scientists reanalysed satellite data gathered between February 1985 and April 1989 for the Earth Radiation Budget Experiment. This revealed that the atmosphere handles 78 per cent of the total heat transport in the northern hemisphere and 92 per cent in the southern hemisphere at the 35-degree latitude mark.

These results, published in the Journal of Climate , are very close to the best climate models operated by the Hadley Centre in the United Kingdom and the NCAR.