A recent report by the CGIAR CCAFS initiative (Climate Change, Agriculture and Food Security) suggests that many regions in the tropics, especially southern Asia and sub-Saharan Africa, are facing widespread famine due to climate change. The CCAFS report, which was written together with ILRI (International Livestock Research Institute) identifies areas that are food insecure and particularly vulnerable to the impacts of future climate change.

This is one of the first, large-scale studies by agriculturalists that uses global climate models to pinpoint regions most affected by rising temperatures and other climate change consequences.

In the summary, the report concludes that:

"Length of growing period declines by 5% or more across a broad area of the global tropics, including heavily cropped areas of Mexico, Brazil, Southern and West Africa, the Indo-Ganetic Plains, and Southeast Asia."

"High temperature stress (above 30:C) will be widespread in East and Southern Africa, north and south India, Southeast Asia, northern Latin America and Central America. Length of growing period flips to less than 120 days in a number of locations across the tropics, notably in Mexico, northeast Brazil, Southern and West Africa and India."

Both are critical thresholds for certain crops and rangeland vegetation. For example, the yield of wheat decreaes by 1% per every day above 30 degrees. It is also the maximum temperature that beans can tolerate. 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.

"Africa and south Asia are clearly much more chronically food insecure regions than Latin America or China."

The report is extremely visual, and really relies on the power of global mapping exercises to get the important messages across. Its really well worth flipping through and looking at the different maps that really give a powerful overview of the projected effects climate change will have on global food security.

Some examples:

This figure shows the areas where annual maximum temperatures will flip from under 30 degrees celsius to above 30 degrees. Beans cannot tolerate temperatures above 30 degrees celsius. Crops such as wheat and maize suffer yield declines above this threshold temperature.

This figure shows the total number of malnourished children per square kilometer.

Read the full report.