Clearer skies over Europe as fog halved in 30 years

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Europe has become less foggy over the past three decades, according to scientists who have examined weather records across the continent. Fog, mist and haze have become less frequent and have contributed, they calculate, to between 10% and 20% of the warming trend during that period. The change is down to reduced air pollution, the scientists think. Robert Vautard at the Atomic Energy Commission in Gif sur Yvette, France, and colleagues, looked at the number of "low-visibility" events, where visibility fell to under 8km. They found a 50% drop since the 1970s, which they call a "massive decline".

Europe has become less foggy over the past three decades, according to scientists who have examined weather records across the continent. Fog, mist and haze have become less frequent and have contributed, they calculate, to between 10% and 20% of the warming trend during that period. The change is down to reduced air pollution, the scientists think.

Robert Vautard at the Atomic Energy Commission in Gif sur Yvette, France, and colleagues, looked at the number of "low-visibility" events, where visibility fell to under 8km. They found a 50% drop since the 1970s, which they call a "massive decline".

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Fog, mist and haze block sunlight, and the team reckons the clearing of the air could have contributed around 10-20% of the European warming trend over the period. Europe has warmed by 0.5C a decade — more than predicted by climate change models.

Writing in the journal Nature Geoscience, the scientists describe how they analysed data from 342 weather stations, and found "a massive decline of low-visibility occurrence throughout Europe", which they say "represents a real change". They link the decrease to lower sulphur dioxide pollution that has come about through efforts in Europe to curb air pollution.

Dave Britton of the UK Met Office said. "That makes sense. Clouds form around particles and dust in the air, so cleaner air brings clearer skies." Fog, mist and haze are essentially clouds that form at ground level, he said. "Go back to the 1950s and the big pea-soupers in London came from the amount of crap that people were putting out of their chimneys from coal fires."

The decline in low-visibility events has slowed since 2000, the research shows.

Article Continues: http://www.guardian.co.uk/environment/2009/jan/16/pollution-climatechange