Disaster at sea: global warming hits UK birds
By Michael McCarthy Environment Editor
30th July 2004
Hundreds of thousands of Scottish seabirds have failed to breed this summer in a wildlife catastrophe which is being linked by scientists directly to global warming.
The massive unprecedented collapse of nesting attempts by several seabird species in Orkney and Shetland is likely to prove the first major impact of climate change on Britain.
In what could be a sub-plot from the recent disaster movie, The Day After Tomorrow, a rise in sea temperature is believed to have led to the mysterious disappearance of a key part of the marine food chain - the sandeel, the small fish whose great teeming shoals have hitherto sustained larger fish, marine mammals and seabirds in their millions.
In Orkney and Shetland, the sandeel stocks have been shrinking for several years, and this summer they have disappeared: the result for seabirds has been mass starvation. The figures for breeding failure, for Shetland in particular, almost defy belief.
More than 172,000 breeding pairs of guillemots were recorded in the islands in the last national census, Seabird 2000, whose results were published this year; this summer the birds have produced almost no young, according to Peter Ellis, Shetland area manager for the Royal Society for the Protection of Birds (RSPB).
Martin Heubeck of Aberdeen University, who has monitored Shetland seabirds for 30 years, said: "The breeding failure of the guillemots is unprecedented in Europe.” More than 6,800 pairs of great skuas were recorded in Shetland in the same census; this year they have produced a handful of chicks - perhaps fewer than 10 - while the arctic skuas (1,120 pairs in the census) have failed to produce any surviving young.
The 24,000 pairs of arctic terns, and the 16,700 pairs of Shetland kittiwakes - small gulls - have "probably suffered complete failure", said Mr Ellis.
In Orkney the picture is very similar, although detailed figures are not yet available. "It looks very bad," said the RSPB's warden on Orkney mainland, Andy Knight. "Very few of the birds have raised any chicks at all."
The counting and monitoring is still going on and the figures are by no means complete: it is likely that puffins, for example, will also have suffered massive breeding failure but because they nest deep in burrows, this is not immediately obvious.
But the astonishing scale of what has taken place is already clear - and the link to climate change is being openly made by scientists. It is believed that the microscopic plankton on which tiny sandeel larvae feed are moving northwards as the sea water warms, leaving the baby fish with nothing to feed on.
This is being seen in the North Sea in particular, where the water temperature has risen by 2C in the past 20 years, and where the whole ecosystem is thought to be undergoing a "regime shift", or a fundamental alteration in the interaction of its component species. "Think of the North Sea as an engine, and plankton as the fuel driving it," said Euan Dunn of the RSPB, one of the world's leading experts on the interaction of fish and seabirds. "The fuel mix has changed so radically in the past 20 years, as a result of climate change, that the whole engine is now spluttering and starting to malfunction. All of the animals in the food web above the plankton, first the sandeels, then the larger fish like cod, and ultimately the seabirds, are starting to be affected."
Research last year clearly showed that the higher the temperature, the less sandeels could maintain their population level, said Dr Dunn. "The young sandeels are simply not surviving."
Although over-fishing of sandeels has caused breeding failures in the past, the present situation could not be blamed on fishing, he said. The Shetland sandeel fishery was catching so few fish that it was closed as a precautionary measure earlier this year. "Climate change is a far more likely explanation."
The spectacular seabird populations of the Northern Isles have a double importance. They are of great value scientifically, holding, for example, the world's biggest populations of great skuas. And they are of enormous value to Orkney and Shetland tourism, being the principal draw for many visitors. The national and international significance of what has happened is only just beginning to dawn on the wider political and scientific community, but some leading figures are already taking it on board.
"This is an incredible event," said Tony Juniper, director of Friends of the Earth. "The catastrophe [of what has befallen these] seabirds is just a foretaste of what lies ahead.
"It shows that climate change is happening now, [with] devastating consequences here in Britain, and it shows that reducing the pollution causing changes to the earth's climate should now be the global number one political priority."