World's most important crops hit by global warming effects

A A A

Global warming over the past quarter century has led to a fall in the yield of some of the most important food crops in the world, according to one of the first scientific studies of how climate change has affected cereal crops.

Rising temperatures between 1981 and 2002 caused aloss in production of wheat, corn and barley that amounted in effect to some 40 million tons a year - equivalent to annual losses of some £2.6bn.

Although these numbers are not large compared to the world-wide production of cereal crops, scientists warned that the findings demonstrated how climate change was already having an impact on the global production of staple foods. "Most people tend to think of climate change as something that will impact the future, but this study shows that warming over the past two decades has already had real effects on global food supply," said Christopher Field of the Carnegie Institution in Stanford, California.

The study, published in the journal Environmental Research Letters, analysed yields of cereals from around the world during a period when average temperatures rose by about 0.7C between 1980 and 2002 - although the rise was even higher in certain crop-growing regions of the world.

There was a clear trend, showing the cereal crops were suffering from lower yields during a time when agricultural technology, including the use of chemical fertilisers and pesticides, became more intensive. The study's co-author, David Lobell of America's Lawrence Livermore National Laboratory in California, said that the observed fall in cereal yields could be clearly linked with increased temperatures during the period covered by the study.

"Though the impacts are relatively small compared to the technological yield gains over the same period, the results demonstrate that negative impacts of climate trends on crop yields at the global scale are already occurring," Dr Lobell said.

The two scientists analysed six of the most widely grown crops in the world - wheat, rice, maize, soybeans, barley and sorghum. Production of these crops accounts for more than 40 per cent of the land in the world used for crops, 55 per cent of the non-meat calories in food and more than 70 per cent of animal feed.

They also analysed rainfall and average temperatures for the major growing regions and compared them against the crop yield figures of the Food and Agriculture Organisation for the period 1961 to 2002.

"To do this, we assumed that farmers have not yet adapted to climate change, for example by selecting new crop varieties to deal with climate change," Dr Lobell said.

"If they have been adapting, something that is very difficult to measure, then the effects of warming may have been lower," he said.

The study revealed a simple relationship between temperature and crop yields, with a fall of between 3 and 5 per cent for every 0.5C increase in average temperatures, the scientists said.

Latest stories from i100
Have you tried new the Independent Digital Edition apps?
iJobs Job Widget
iJobs General

Recruitment Genius: Account Manager

£20000 - £35000 per annum: Recruitment Genius: This full service social media ...

Recruitment Genius: Data Analyst - Online Marketing

£24000 - £35000 per annum: Recruitment Genius: We are 'Changemakers in retail'...

Austen Lloyd: Senior Residential Conveyancer

Very Competitive: Austen Lloyd: Senior Conveyancer - South West We are see...

Austen Lloyd: Residential / Commercial Property Solicitor

Excellent Salary: Austen Lloyd: DORSET MARKET TOWN - SENIOR PROPERTY SOLICITOR...

Day In a Page

Isis in Iraq: Yazidi girls killing themselves to escape rape and imprisonment by militants

'Jilan killed herself in the bathroom. She cut her wrists and hanged herself'

Yazidi girls killing themselves to escape rape and imprisonment
Ed Balls interview: 'If I think about the deficit when I'm playing the piano, it all goes wrong'

Ed Balls interview

'If I think about the deficit when I'm playing the piano, it all goes wrong'
He's behind you, dude!

US stars in UK panto

From David Hasselhoff to Jerry Hall
Grace Dent's Christmas Quiz: What are you – a festive curmudgeon or top of the tree?

Grace Dent's Christmas Quiz

What are you – a festive curmudgeon or top of the tree?
Nasa planning to build cloud cities in airships above Venus

Nasa planning to build cloud cities in airships above Venus

Planet’s surface is inhospitable to humans but 30 miles above it is almost perfect
Surrounded by high-rise flats is a little house filled with Lebanon’s history - clocks, rifles, frogmen’s uniforms and colonial helmets

Clocks, rifles, swords, frogmen’s uniforms

Surrounded by high-rise flats is a little house filled with Lebanon’s history
Return to Gaza: Four months on, the wounds left by Israel's bombardment have not yet healed

Four months after the bombardment, Gaza’s wounds are yet to heal

Kim Sengupta is reunited with a man whose plight mirrors the suffering of the Palestinian people
Gastric surgery: Is it really the answer to the UK's obesity epidemic?

Is gastric surgery really the answer to the UK's obesity epidemic?

Critics argue that it’s crazy to operate on healthy people just to stop them eating
Homeless Veterans appeal: Christmas charity auction Part 2 - now LIVE

Homeless Veterans appeal: Christmas charity auction

Bid on original art, or trips of a lifetime to Africa or the 'Corrie' set, and help Homeless Veterans
Pantomime rings the changes to welcome autistic theatre-goers

Autism-friendly theatre

Pantomime leads the pack in quest to welcome all
The week Hollywood got scared and had to grow up a bit

The week Hollywood got scared and had to grow up a bit

Sony suffered a chorus of disapproval after it withdrew 'The Interview', but it's not too late for it to take a stand, says Joan Smith
From Widow Twankey to Mother Goose, how do the men who play panto dames get themselves ready for the performance of a lifetime?

Panto dames: before and after

From Widow Twankey to Mother Goose, how do the men who play panto dames get themselves ready for the performance of a lifetime?
Thirties murder mystery novel is surprise runaway Christmas hit

Thirties murder mystery novel is surprise runaway Christmas hit

Booksellers say readers are turning away from dark modern thrillers and back to the golden age of crime writing
Anne-Marie Huby: 'Charities deserve the best,' says founder of JustGiving

Anne-Marie Huby: 'Charities deserve the best'

Ten million of us have used the JustGiving website to donate to good causes. Its co-founder says that being dynamic is as important as being kind
The botanist who hunts for giant trees at Kew Gardens

The man who hunts giants

A Kew Gardens botanist has found 25 new large tree species - and he's sure there are more out there