Climate change cut global wheat and corn output by more than 3 percent over the past three decades compared to growth projections without a rise in temperatures, a study found on Friday. The impacts translated into up to 20 percent higher average commodity prices, before accounting for other factors, according to the paper published in the journal Science.

Crop yields rose over the period for example as a result of improvements in practices and plant breeding, and the isolated, negative impact of climate change was equivalent to about one tenth of those advances.

But that varied widely between countries with Russia, Turkey and Mexico more affected for wheat, for example.

The isolated impact of climate change on wheat and corn was a warning of the future food supply and price impact from an expected acceleration in warming, the paper said.