Never mind mellow fruitfulness: autumn leaves refuse to go brown

Early morning mist rises in a wood at Woburn Abbey. The first shafts of muted sunlight strike the green leaves. It could be the start of a late summer's day.

Early morning mist rises in a wood at Woburn Abbey. The first shafts of muted sunlight strike the green leaves. It could be the start of a late summer's day.

In fact, this was happening yesterday, in the middle of what should be autumn. A handful of turning leaves, only visible on close examination, provide a clue to the true season.

The picture provides dramatic evidence of what is an extraordinarily late autumn, part of a thorough disruption of the seasons that is already taking place as a result of global warming. Already the traditional British winter has virtually melted away, while spring is getting steadily earlier.

Now scientific evidence has shown for the first time that autumn is getting later and later in Britain as the climate heats up.

Dr Tim Sparks, of the official Institute of Terrestrial Ecology, said that new research, presented at an international conference in Munich earlier this month, has shown that autumn in Britain is arriving two days later every decade.

By studying when leaves turn brown and fall it has found that the season has lagged by nearly a week since measurements began 30 years ago.

This year, he added, the unseasonably mild and wet weather had delayed it even further. "I am surprised at how green it is," he said. "And there are blackberries for picking as far north as Aberdeen."

At the same time, he said, research shows that spring is advancing even faster, arriving six days earlier every decade, as the world becomes warmer.

Butterflies like the red admiral and the comma are on average out and about two weeks earlier than they were in the 1970s, and last year the National Trust gardens in Cornwall were blooming so freely in February that they opened to the public early.

Eleven of the last 13 winters were officially classified as warm. Windermere, which used to freeze partially for 10 days each winter, has now been ice-free for a decade.

Putting the two trends together, Dr Sparks said, the research showed that the growing season has increased by 24 days over the past three decades, a dramatic change in the British climate.

And the stag at Woburn goes on dreaming in his green autumn.

* This week's weather is expected to continue mild in England and Wales.