A latest study by University of Leeds found that even a two degree rise in global temperatures could lead to reduced yields in temperate and tropical regions sooner than previously thought.

Researchers said that the negative effects of climate change can be felt, beginning 2030.  The impact will be larger in the second half of the century, where 25 percent decrease in crop production will be increasingly common.

"... 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," Professor Andy Challinor from the School of Earth and Environment said in a press release.

For the study, the researchers created a new data set by analyzing results from over 1,700 published assessments that focused on the impact of climate change on crop yields of rice, maize and wheat.

"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 Challinor.

Researchers advise farmers to incorporate minor adaptation techniques to lessen the effects of climate change including crop variety and planting date. In the latter half of the century, greater agricultural transformations and innovations will be required to preserve 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," concludes Professor Challinor.

The finding is published in the journal Nature Climate Change. The study will also be published in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report. In the Fourth Assessment Report, researchers found that temperate regions like Europe and North America could resist a couple of degrees of warming without negatively affecting harvests.