Researchers have shown that global warming of only 2 degree Celsius will be detrimental to crops in temperate and tropical regions, with reduced yields after 2030s.

Professor Andy Challinor, from the School of Earth and Environment at the University of Leeds and lead author of the study, said that their research shows that crop yields will be negatively affected by climate change much earlier than expected.

He said that the impact of climate change on crops will vary both from year-to-year and from place-to-place - with the variability becoming greater as the weather becomes increasingly erratic.

Due to increased interest in climate change research, the new study was able to create the largest dataset to date on crop responses, with more than double the number of studies that were available for researchers to analyse for the IPCC Fourth Assessment Report in 2007.

In the Fourth Assessment Report, scientists had reported that regions of the world with temperate climates, such as Europe and most of North America, could withstand a couple of degrees of warming without a noticeable effect on harvests, or possibly even benefit from a bumper crop.

"As more data have become available, we've seen a shift in consensus, telling us that the impacts of climate change in temperate regions will happen sooner rather than later," said Professor Challinor.

The researchers state that we will see, on average, an increasingly negative impact of climate change on crop yields from the 2030s onwards. The impact will be greatest in the second half of the century, when decreases of over 25 per cent will become increasingly common.

The study has been published in the journal Nature Climate Change.