Fruits of global warming

In early summer this year, that sweet sun-loving fruit from the lands of vines and olive trees grew on a branch in Kent, part of the first-ever commercial harvest of apricots in the UK. Sainsbury's has just marketed them in 250 stores. You think climate change isn't happening? The Sainsbury's apricots, with the Union flag on the punnets, say otherwise.

The harvest was a small but notable progress point in the shift that climate change is likely to bring to a world in which, among much else, we may see fruits and plants from hotter climates flourishing in British orchards and gardens.

There is no doubt that the climate is now warming steadily in Britain, as well as in the rest of the world. Since 1900, the average UK temperature has risen by about 1C, and the growing season has lengthened by about a month. Currently, the temperature is rising by between 0.15C and 0.2C per decade, but the rate itself will increase, and by the 2020s the climate will be nearly another full degree warmer than the average of 1961-1990.

According to the UK Climate Impacts Programme, very hot and dry summers of the sort Britain experienced in 1995 will strike in one in three years by the 2050s. Maximum temperatures in southern counties, such as Berkshire, which now reach about 34C (93F), will start to exceed 40C (104F). By 2080, South-east England could become on average 5C (9F) warmer in summer, making it as hot as Bordeaux.

Enter the apricots - forerunners, perhaps, of much more to come. Members of the rose family, and closely related to plums, peaches, cherries and almonds, apricots are by no means native to Britain. Their original home was China; they are believed to have been brought to the Mediterranean basin by Alexander the Great in the 4th century BC. They have flourished in southern Europe and the Near East, and in regions with similar warm climates, such as California and Australia.

Their key characteristic is early ripening, so they require fairly high temperatures in spring and early summer. Although apricots have long been grown in Britain in a warm corner of a cottage garden or on a sheltered south-west-facing wall, they have never till now been cultivated on a commercial scale.

But the 2005 harvest from Kent was substantial - about 1,200kg (filling 3,000 punnets) from an apricot orchard of 1,800 trees planted three years ago. Sainsbury's was surprised by the quality. "They were much bigger than I would have expected," says the company's product technologist, Theresa Huxley. "The colour was superb, a beautiful dark orange with a beautiful sheen; I thought they'd be quite pale. They had a very rich, perfumed, aromatic apricot taste, quite stunning. I think they should be one of our premium brands."

Because so few insects are present to pollinate trees during the British winter and early spring, the growers worked with two self-pollinated varieties. But without the warmer seasons, the enterprise would not have stood a chance. "We know summers are getting warmer, and we thought it was worth trying," Huxley says.

Sainsbury's isn't stopping at apricots. It has a project, under wraps for the moment, to grow kiwi fruit in Britain. Kiwis at present flourish in countries such as Chile, New Zealand, Greece and Italy, but Huxley's department is trialling a variety, which they think will also grow well in Kent.

And next, why not warm-weather nuts? There appears never to have been a commercial harvest of almonds in Britain, but Mark Diacono, a landscape consultant with a farm going organic near Honiton in Devon, is aiming to produce one.

On his 16 acres on the banks of the river Otter, Diacono has planted orchards with a difference. "I had to find a niche, so I went for a mix of old fruits that have been forgotten and new fruits that have never been tried." His "forgotten" fruits include quinces and mulberries, and almonds head the list of his new varieties.

"With the climate changing, it seemed a possibility," he says. After research and a deal with a French supplier, early this spring he planted 100 almond trees. "It will be next year before we know if we will produce them properly, and perhaps 2008 before they are fully productive, but I'm confident," he says.

He has a market lined up too, being a friend of the chef Hugh Fearnley-Whittingstall. "Climate change is obviously a serious worry, but while governments dally about the causes and possible solutions, farmers and smallholders are entitled to be entrepreneurial about the opportunities it presents," Fearnley-Whittingstall says. "I love the idea of English almonds being a West Country seasonal treat - for the time being, at least. If Mark can grow them successfully, and organically, I'll be first in line to grab a share."

Perhaps the strongest evidence of how the climate has already changed in Britain, in terms of growing things, is a wine grape: the pinot noir. This is the grape of classic red Burgundy, of Beaune, Vosne-Romanée and Chambertin. It needs far more sun than the hardy white grapes that have been the backbone of the nascent English wine industry over the past five decades.

No one ever envisaged the pinot noir growing in England. Yet for several years now, it has been growing successfully on the south-facing chalk slopes of the North Downs near Dorking in Surrey - 25 miles from central London - at Denbies, the largest vineyard in Britain, producing a powerful, perfumed and delicious (if expensive) version of Burgundy, English style.

The owners of Denbies attribute their success with it directly to the changing climate. Yet not everything about growing new fruits in a warmer world will be plain sailing, warns Phil Hudson, chief horticultural adviser of the National Farmers' Union. "We should remember that what is predicted is not only warmer weather, but also more variable and extreme weather," he says. "And there is the potential not only for new and exotic fruits and plants, but for new and exotic fruit and plant diseases." He also thinks that achieving the quality consumers expect may be difficult, while some produce, such as citrus fruits, are unlikely ever to flourish in Britain.

Finally, he points out that the water supply is likely to fall. "Yes, we will have new produce, but we should not forget that climate change will bring risks as well as opportunities."