The Canberra Times

Fog, mist and haze in Europe had declined over the past three decades, a trend that might have stoked regional warming and, ironically, could be linked to better air quality, a study published yesterday said.
From 1978 to 2006, temperatures in parts of Europe rose above the global land average, with prominent increases in the north, centre and eastern parts of the continent.

As much as 20 per cent of Europe's warming during this time, according to the study, can be pinned on a reduction in fog, mist and haze, which because they are white reflect solar radiation and thus keep the ground cool.

In eastern Europe, the decline in fog, mist and haze could account for 50 per cent, the paper believes.

The authors, led by Robert Vautard, of France's Atomic Energy Commission, pored over data from 342 weather stations around Europe.

They found that over nearly 30 years, the number of days categorised as having restricted visibility fell by half. These categories were determined by ranges of visibility at 2km, 5km and 8km.

The phenomenon is closely linked to falling levels of atmospheric sulphur dioxide (S02), a by-product of burning oil and coal that causes notorious ''acid rain'' that damages forests and lakes.

The temperature rise has been especially perceptible in eastern Europe, where the end of the communist system closed down innumerable sources of coal pollution.

However, the SO2 clean-up is now largely tapering off.

This means the fog reduction will probably stop and ''the warming trend in Europe will not be so large in the coming years'', Mr Vautard said.

According to the United Nation's paramount authority on global warming, the Intergovernmental Panel on Climate Change, the global average temperature rose 0.74 degrees Celsius from 1906 to 2005, and the pace in the past 50 years was double that of the first half-century.

A blanket of fog could reduce local temperatures by some 2 degrees, according to figures quoted in the new study. AFP