Wild sheep on a remote Scottish island are shrinking, and new research suggests that they're global warming's latest warning. But is climate change really to blame for the dip in this mouton célébré's size?
According to Tim Coulson and colleagues at Imperial College London, Soay sheep on the Outer Hebridean island of Hirta shrank by two kilos over the 25-year long study. And it's not because they've discovered the Atkins diet: Professor Coulson says that climate change is shortening Europe's harsh winters, allowing the puny sheep that would normally perish in the cold to survive. 'The Soay sheep provides another example of how far-reaching and unpredictable the effects of climate change can be', he remarks in the Times.
While there's no doubt that Europe's winters have become markedly warmer since the '70s, allowing the sheep to shrink, not all scientists are as sure as Professor Coulson that climate change is pulling the strings. This 2007 study by Dr Anastasios Tsonis, for example, points the finger at natural variability rather than greenhouse gas emissions. The North Atlantic Oscillation, the northern hemisphere's weather-maker, has simply been stuck in 'positive' (a.k.a. winter-warming) mode since the 1970s, he suggests.
'The standard explanation for the post 1970s warming is that the radiative effect of greenhouse gases overcame shortwave reflection effects due to aerosols', notes Dr Tsonis. 'However [our models suggest] an alternative hypothesis, namely that the climate shifted after the 1970s event to a different state of a warmer climate, which may be superimposed on an anthropogenic warming trend', he concludes.
So: William Blake's 'Little Lamb' can still thank the mild and the meek for its existence - but not necessarily climate change.