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Last Updated: Wednesday, 28 March 2007, 16:35 GMT 17:35 UK
Reading peat's carbon contribution
By David Shukman
BBC science correspondent

Peat bog. Image: National Trust
Climate is affected by a complex interplay of factors
I can feel the peat springing beneath my feet. I'm on the National Trust's High Peak Estate in Derbyshire and I'm walking over a landscape that's suddenly a cause for concern.

The peat is a uniquely fragile soil and it's vanishing, which matters because peat is a huge store of carbon.

My guide, the National Trust's Carl Hawke, produces the startling fact that Britain has an astonishing 15% of all the world's peatlands.

Looking out towards the hazy horizon, it seems as if there's nothing wrong with them - mile after mile of moss and grass rolling over the hills.

But soon I'm led to the edge of a deep gully. What began as a small stream has torn an ever wider path through the landscape, and now it's an ugly gash, a pattern repeated countless times on this estate and many others.

We scramble down through the mud as Carl explains why the gullies matters.

Car-equivalent carbon

While the peat is sodden, it locks away the carbon inside. But when it's exposed to the wind and sun, it starts drying out which triggers an abrupt transformation - the peat switches from being an absorber of carbon to being a massive source of it.

Gulley on bog. Image: National Trust
Special dams can keep bogs wet and prevent degradation

Calculations show that the eroded peat on this one estate emits as much carbon dioxide every year as 18,000 family cars doing an average mileage.

With us is a researcher from the University of Durham, James Rowson. He has spent long months out in the cold, measuring the emissions of carbon dioxide. He shows me how the gas surges off the drying peat.

There are signs of hope. We stumble over the rough landscape to a series of small dams.

The National Trust is trying a variety of techniques to keep the peat sodden. The dams create small pools which allow the peat to settle and grasses and mosses to recover.

I am among optimists - Carl and James believe the erosion of the peat can be halted, even reversed. But it will take a big effort - as many as 25,000 of the little dams will be needed on the High Peak Estate alone.

There are lots of factors influencing our future climate. Who'd have thought that one of them would be the fate of peat bogs?

Why gases given off by peat bogs could be a problem

'Preserve peat bogs' for climate
28 Mar 07 |  Science/Nature

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