VAPOUR trails from jet planes are creating artificial clouds and blotting out the sun. Fumes are polluting the atmosphere we breathe - and some scientists claim air traffic is the biggest threat to global warming.

By Richard Cornwell

VAPOUR trails from jet planes are creating artificial clouds and blotting out the sun. Fumes are polluting the atmosphere we breathe - and some scientists claim air traffic is the biggest threat to global warming. PAUL GEATER and RICHARD CORNWELL investigate environmental impact, in day four of our special series.

THE impact of planes on our environment is complex, according to Dr Keith Tovey, a reader in environmental sciences at the University of East Anglia in Norwich.

The release of carbon dioxide high in the atmosphere helps to accelerate the greenhouse effect - and the effects are much greater if it is released into the upper atmosphere.

Dr Tovey said: “If CO2 is released at ground level it can be absorbed to some extent in plants and in water, but high in the atmosphere it gets straight to work in the greenhouse effect.”

And other particles released by planes also reacted with the air high in the atmosphere.

“All school children studying science know that rain should be neutral in the PH scale, but with carbon being released high in the air it is now coming down as slightly acidic,” he said.

However the existence of planes could have the opposite effect as well - the contrails created by high-flying planes absorb light and reduce the affects of bright sunlight.

Dr Tovey said: “This is a phenomenon that has been described as 'global dimming' and it can have quite an effect on the atmosphere. In the immediate aftermath of 9/11 when there were no planes flying over America for three days, the temperature across the country was estimated to be a degree higher than it would have been because the skies were clear.

“I certainly would not recommend that as a method of combating global warming but it does make the whole issue of the impact of flying more complex.”

But Dr Tovey pointed out that the carbon dioxide created by planes had a much more serious effect on the global climate.

He said: “At present the impact of flying is relatively small, only contributing a few percentage points of the total CO2 to the atmosphere. But by 2030 that will change, especially if the demand for flying continues to increase and as more work is put into saving energy on the ground.

“Now is the time to look for alternatives to flying where possible.”

Dr Tovey said short-haul flights often had less damaging alternatives.

“Everyone flying from Norwich to Paris will create 150 kilogrammes of carbon dioxide. The same journey by train to London and then Eurostar will create 25 kilogrammes - and that won't be at the high level,” he said.

Researchers at the University of Dundee have been using satellite images to track the paths of planes across large areas of Europe - watching as blue skies turn to white within hours, robbing communities of their sunshine.

Closer to home, residents in Felixstowe - which last year had a bumper year of more than 3,800 hours of sunshine - say on some clear mornings, blue sky can be turned white as if its is cloud-covered in just a few hours, thanks to sometimes more than a dozen contrails expanding to miles wide and joining up.

On one day last week Evening Star weather man Ken Blowers glanced up at the sky to see 48 contrails, in various parts of the sky over Ipswich at the same time. He said: "Some of the trails are a mile wide when they spread out.”

On an autumn day last year he counted 72 planes crossing the sky above Ipswich.

Ken added: “Clacton sector is the busiest airspace in Europe. There are 5,000 aircraft movements in the UK every day, including take-offs and landings."

Photographs taken by the Dundee Satellite Receiving Station show vapour trails covering the whole of Ireland within a few hours, large swathes of Britain, and much of Spain.

Scientists are locked in a furious debate over whether vapour trails are making global warming worse.

Some experts believe the trails have little impact because they can be swept away by high-altitude winds and fade quickly, but others fear the growth in long-haul, high-altitude, contrail-forming plane journeys could mean more contrails lasting longer, blotting out skies and trapping heat inside the earth's atmosphere.

One aspect scientists are still researching is whether the blotting out of the sun by vapour trails could stop the sun's rays causing skin cancer.

WEBLINK: www.newscientist.com

www.royal-met-soc.org.uk

www.sat.dundee.ac.uk

What do you think of the effects of the planes' contrails? Write to Your Letters, Evening Star, 30 Lower Brook Street, Ipswich, IP4 1AN, or e-mail EveningStarLetters@eveningstar.co.uk

Tomorrow our Air Fair campaign will focus on Stansted - the third busiest airport in the country - and its plans to expand which will have a huge impact on Suffolk's skies.

AIRLINES are quick to defend their environmental record - and no airline is keener to distance itself from claims of damaging the planet than Ryanair.

Environment minister Ian Pearson hit the headlines recently when he branded Ryanair "the irresponsible face of capitalism" for its attitude to the environment. But the company insists that by operating modern jets at near capacity that it is taking an environmentally-responsible stance in providing a service demanded by millions of people.

And it is anxious to avoid any threats of government tax increases aimed at driving passengers to other forms of transport.

In a statement the company said: “Ryanair proves that air transport can be environmentally friendly whilst continuing to deliver huge economic benefits in terms of the lowest cost air travel for consumers, increased tourism, regional and social cohesion, job creation, inward investment, etc.”

Ryanair, along with other budget airlines is a member of the European Low Fare Airlines Association (ELFAA). John Hanlon, Secretary General of ELFAA said the low-cost airlines run modern planes which are fuel efficient and reduced emissions:

“Latest statistics from ELFAA members reinforce the low fares airlines' position as the most environmentally-friendly sector of the industry,” he said.

“Ongoing investment in new aircraft reduced the average fleet age amongst ELFAA members to just 3.9 years at December 31 2006! This remarkable result led to minimised fuel burn and CO2 emissions per passenger kilometre.”