Building more homes may change weather, Prescott told

Roger Highfield:

Extensive house building projects demanded by the Government could lead to changes in the weather, a leading meteorologist warned yesterday.

John Prescott, the Deputy Prime Minister, has approved huge development plans across the relatively densely populated southern England, and yet no studies have been conducted into its impact.

Cities are potentially as big an influence on local rainfall and temperatures as more general, large scale changes in the climate, Prof Chris Collier, of the University of Salford, will tell the Royal Meteorological Society biennial conference at Exeter University on Thursday.

Canary Wharf-style developments and closely packed houses are of particular concern, said Prof Collier, who is president of the society. Hot air from factories, cars and people crammed into cities create "heat islands". This could make the centre of Manchester, for example, up to 8C warmer than surrounding rural areas.

Major building projects could change wind circulation, leading to an increase in rainfall in certain areas. "The heat island of London initiates convective showers. High rise buildings seem to have the same kind of effect as low hills," said Prof Collier.

Urban sprawl can also influence the weather, slowing wind speeds or changing the way pollutants are dispersed. Despite Mr Prescott's development plans for east and north London, the south Midlands and a belt from Lancashire to Yorkshire, the weather effects are still not fully understood.

"We really need to take account of the meteorological impact," Prof Collier said. "All those will have some impact on the weather. To what degree, we don't know. The studies have not been done."

The conference, which runs until the end of the week, is discussing issues including the future of weather forecasting, the possibility of cooking oil invading the atmosphere, and the observation that bad weather has shifted northwards in the past 40 years - creating more storms in north-west Scotland.

Meanwhile, Mr Prescott's plans to force councils to release more land for housing would just make "hot" markets "hotter" and prices more unaffordable, The Royal Institution of Chartered Surveyors said yesterday.

It criticised Mr Prescott's proposals to take into account house prices when deciding what level of house building was necessary. The surveyors said the Deputy Prime Minister's plans would have the opposite effect to what he intended. The proposal that councils should build up a 15-year pool of allocated land could jeopardise the regeneration of difficult, brown field sites, as these would be left aside while easier sites were developed.

The pressure to release more land would result in development "being targeted at over-priced hotspots that are already over-stretched", and lead to the inevitable take-up of green field sites.

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