Projected change in wheat yields for several European countries using a wheat growth simulation program called “EuroWheat”. The left bar (with an X) indicates the changes due to natural variability alone. The middle (black square) and right (black circle) represent the changes due to two climate models with CO2 increases to 435 ppm and 515 ppm respectively. Although these results were statistically significant, whether these changes would be fully realized at large scales is not so clear. (From: Hulme et al., 1999)