Reuters: Rapid rises in temperatures worldwide may overwhelm farmers’ efforts to keep up, say experts who want funds to breed new crops and freeze heat-resistant strains bred over past centuries. A Stanford University study to be published on Friday estimates that African growing seasons for the continent’s staple foods — maize, millet and sorghum — will be hotter in nine out of 10 years by 2050. Farmers can adapt by shifting growing times or using new varieties but the pace of change …