Graph of the Day: Projected Decline in Length of Growing Period in the Global Tropics, 2050

Areas that will experience more than a 5% reduction in length of growing period (LGP). LGP is defined by the average number of growing days per year, in which a growing day is one in which the average air temperature is greater than 6°C and the ratio of actual to potential evapo-transpiration exceeds 0.35 (Jones and Thornton 2008). The growing season begins once five consecutive growing days have occurred and ends once 12 consecutive non-growing days occur.

Areas where average annual maximum temperature will flip from under 30°C to over 30°C (Map 2.6). While this is the maximum temperature that beans can tolerate, rice and maize yields suffer at higher temperatures than this, as do other staple crop yields. Grazing vegetation will also suffer at such high temperatures and we could see switches in species with implications for palatability for livestock. Higher temperatures also affect food safety, for example milk storage, and disease transmission patterns, such as malaria. Significant areas of Latin America, Africa, and Southeast Asia are highlighted.

Mapping Hotspots of Climate Change and Food Insecurity in the Global Tropics [pdf]