The changing face of Britain's skies

Driven by climate change, the 21st century will see a dramatic shift in the nation's feathered population with many species either arriving for the first time or leaving for good. Michael McCarthy reports

If you're a bird-lover and you want to see nesting snow buntings in the mountains of Scotland, or pintail ducks breeding in the fens of East Anglia, go now; their time here is limited. Research shows that British and European birds face a potentially disastrous future thanks to climate change during the coming century.

Three-quarters of the breeding birds of Britain and Europe are likely to decline in number as the climatic range in which they can comfortably exist – their "climate space" – shrinks with global warming, says a study by the Universities of Durham and Cambridge, in association with the Royal Society for the Protection of Birds (RSPB).

The picture is grim. With eight British breeding species, from the snow bunting and the pintail to the Scottish crossbill and the arctic skua, the shift is likely to mean extinction by the century's end (or before), as climate suitable for them ceases to exist in the British Isles.

With another group of similar size, including the red-throated diver and the dotterel, the distribution will shrink to a tiny fraction of the present range – less than 5 per cent – making the birds so rare they will be teetering on the edge of disappearance.

A third group of about 25 species, which includes many familiar waders, gulls and game birds, as well as woodland species, is also at risk. Its demise would shrink the British breeding range significantly; the birds are likely to vanish from many parts of the UK.

Thus redshanks, lapwings, curlews and snipe, all wading birds, are likely to cease nesting in all or most of southern England, as will common woodland birds such as the treecreeper. Red grouse, now bred and shot on moors in north Wales, northern England and Scotland, will probably vanish from the first two of these areas as the century progresses, and survive only north of the border.

The astonishingly detailed, species-by-species predictions are in a huge, innovative mapping project which outlines the future faced by 450 British and European bird species in a world of rising temperatures, published today as A Climatic Atlas of European Breeding Birds. The original and ingenious approach has been to work out the theoretical "climate space", or "climate envelope" in which each of the birds is able to flourish.

It is calculated using the parameters of how cold the winter is over its breeding range, how hot the summers are, and how much moisture is available. This is presented as a map. Then, using the supercomputer climate models which are the basis of present global warming predictions, the researchers have worked out how each species' climate space is likely to move as the warming takes hold over coming decades, and the parameters defining it alter.

A new, and mostly dramatically different, series of maps shows that a typical bird's climate envelope shifts significantly by the end of the century from where it is today.

The remarkable conclusion is that, for the average bird species, the potential distribution by 2100 will shift nearly 550km (340 miles) north-east, equivalent to the distance from Plymouth to Newcastle. And what follows is that the average European bird's distribution will be reduced by a fifth, and overlap its present range by only 40 per cent.

The predictions have been made with the main computer model of the global climate used by the Met Office's Hadley Centre for Climate Prediction and Research. The basis has been a moderate scenario of future greenhouse gas emissions drawn up by the Intergovermental Panel on Climate Change (IPCC), which suggests a rise in global average temperatures of just under 3C by the century's end. (This is in the middle range of IPCC predictions, which go from 1.4 to 6.2 degrees by 2100, depending on the amount of greenhouse gas emitted between now and then.)

The predictions for each species cannot be precise, because factors other than climate can ultimately determine range, such as habitat availability and direct efforts at conservation. But the general thrust of this seven-year research project is crystal clear: the climate space available for 75 per cent of Europe's breeding birds is likely to shrink, with their numbers consequently likely to decline in the worst cases to extinction. This dire conclusion has drawn calls for urgent action to combat climate change from the authors of the Atlas, Professors Brian Huntley, of Durham University, and Rhys Green, of Cambridge University, and the RSPB, with Dr Yvonne Collingham and Dr Steve Willis, of Durham.

"Although the details both of future climatic changes and of species' responses to these changes remain uncertain, the potential magnitude of both is clear, and is such that the adaptation measures necessary to conserve European biodiversity only can be achieved through urgent international action," Professor Huntley said.

Professor Green said: "Climatic change and wildlife's responses to it are difficult to forecast with any precision, but this study helps us to appreciate the magnitude and scope of possible impacts, and to identify species at most risk and those in need of urgent help and protection."

Mark Avery, the RSPB's director of conservation, added: "We must heed the wake-up call and act immediately to curb climate change. Anything above an average of 2C risks catastrophic impacts for wildlife."

Scotland is likely to be particularly hard-hit by the range shifts, with iconic Scottish birds of mountain, forest and loch severely reduced in range and thus number. Six Scottish extinctions are forecast: snow bunting, Scottish crossbill, great skua and arctic skua, Leach's petrel and common scoter (a duck). The osprey, the fish-eating hawk which has returned to the Highlands in the past 50 years, is also predicted to vanish, but there is less confidence in this prediction because of difficulties in mapping its present climate space correctly.

Some compensation for the potential losses may come in the shape of new birds colonising Britain from the continent as their climate space shifts north. About 20 species fit into this category, each a British birdwatcher's dream, ranging from the serin, a small relative of the canary, to the spectacular cinnamon-coloured hoopoe, and from the scops owl to the black kite.

But although the disappearance of a bird's "climate space" from Britain is considered likely to lead to the disappearance of the species, there is no guarantee that the climate space of a species new toBritain will mean the birds will actually come here. We can only hope.