New research, led by scientists at the University of Leeds, has shown that global warming of only 2°C will be detrimental to crops in temperate and tropical regions alike, and that changes will begin to have marked effects on yields sooner than had been anticipated.

According to the scientists, yields could begin falling from the 2030s onwards.

Professor Andy Challinor, from the University's School of Earth and Environment led the study. Prof Challinor said, "Our research shows that crop yields will be negatively affected by climate change much earlier than expected… 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."

Challinor's study was published in the journal Nature Climate Change. The work will be used to form the upcoming Working Group II paper in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report, which is due for publication at the end of the month.

The last major IPCC report was released in September 2013, the first of four scheduled for release by the same time this year. The first report, released to coincide with climate talks between world leaders in Stockholm, showed that evidence of humanity's influence on the climate system is now apparent in most global regions and that this is threatening life on our planet.

The upcoming second report will consider the vulnerability and exposure of human and natural systems to the effects of climate change, as well as looking at future risks and the limits to adaptation measures.

Reacting to the findings of the 250 expert authors behind the first IPCC report, Environment Secretary Owen Paterson said, "I am rather relieved that it is not as catastrophic in its forecast as we had been led to believe [rather, its] something we can adapt to over time and we are very good as a race at adapting." He added that, "[Climate change] would also lead to longer growing seasons and you could extend growing a little further north into some of the colder areas. I think the relief of this latest report is that it shows a really quite modest [temperature] increase, half of which has already happened."

Speaking at the time, Lord Stern, author of a landmark report on the economic impacts of climate changed said that for anyone to underestimate IPCC's findings and the threat posed by climate change would be "absurd." Professor Kevin Anderson, Deputy Director of the Tyndall Centre for Climate Change Research warned that "His [Paterson's] view that we can muddle through climate change is a colonial, arrogant, rich person's view."

Leeds study reveals impacts of 'modest temperature increase'

As part of their study, Leeds researchers looked at the potential for climate change to affect yields of rice, maize and wheat. They said the dataset used to study potential impacts is the largest used to date on crop responses.

The study revisited earlier research from a 2007 IPCC assessment, though this time the Leeds researchers had more than double the amount of data available to inform their work. Scientists behind the 2007 research 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.

However, Challinor's team found that "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."

The professor warned that the updated research suggests that climate change will have a negative impact on crop yields from the 2030s onwards. The impact will be greatest in the second half of the century, when decreases of over 25 percent will become increasingly common, according to forecasts.

Professor Challinor said these statistics already account for minor adaptation techniques employed by farmers to mitigate the effects of climate change, such as small adjustments in the crop variety and planting date.

As a result, greater agricultural transformations and innovations will be needed later on in the century in order to safeguard crop yields for future generations.

"Climate change means a less predictable harvest, with different countries winning and losing in different years. The overall picture remains negative, and we are now starting to see how research can support adaptation by avoiding the worse impacts," Challinor concluded.