Based on many studies covering a wide range of regions and crops, negative impacts of climate change on crop yields have been more common than positive impacts (high confidence). (dotearth.blogs.nytimes.com)
Negative impacts of climate change on crop yields have been more common than positive impacts (some positive trends are evident in some high latitude regions). (metlink.org)
Temperature trends are therefore important for determining both past and future impacts of climate change on crop yields at sub-continental to global scales. (metlink.org)