A newscaster from Kenya Television Network Local interviews Philip Thornton on the impacts of climate change on the African continent (photo credit: ILRI).

A new publication, Agriculture-Climate Letters, published by the Climate Change, Agriculture and Food Security program, this week highlight a paper published on the impacts of a 4ºC warmer world on African agriculture and food security. The lead author of the paper is Philip Thornton, an agricultural systems analyst with the International Livestock Research Institute (ILRI).

‘. . . The UK Met Office says a 4 degree [warmer] world is quite possible, and will plausibly be reached by 2070 or even 2060–in our children’s lifetimes. This will mean average temperature rises of a massive 15ºC in the Arctic, and 3-8ºC in the world’s most populated areas.

‘. . . Agriculture is highly sensitive even to a 2 degree scenario; a 4 degree world is beyond the bounds of both local and global knowledge, both modern and historical experience. . . .

‘A new paper, Agriculture and food systems in sub-Saharan Africa in a four-plus degree world, by Philip Thornton, Peter Jones, Polly Ericksen and Andrew Challinor, foresees profound effects. . . . [E]nsembles of models suggest average yield drops of 19% for maize and 47% for beans, and much more frequent crop failures. . . . Africa-wide, a massive 1.2 million km2 may be forced to flip from typical mixed farms, with both crops and livestock, into pure rangeland. . . .

‘Thus a 4 degree world calls for adaptive capacity in agriculture that is not just about increasing the resilience of current systems, but about completely new ways of farming and consuming. . . . Thornton and colleagues highlight four areas for immediate policy attention:

• supporting farmers’ own risk-management strategies
• strengthening basic data collection in agriculture
• investing seriously in genebanks
• improving governance of food systems so that poor people can get affordable food

‘. . . Rapidly urbanising populations will need to eat nationally and regionally grown food. If +4 degrees signals the end to half a millennium of Africans eating maize, will the 21st century usher in a new era of indigenous urban foods, be they free-range hamburgers or drought-resistant yamburgers?

Read the whole article at AgClim Letters: Hamburgers and yamburgers? Four-degree futures for food in Africa, 1 November 2010.

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Read the science paper by Philip Thornton et al. in the British journal Philosophical Transactions of the Royal [Society] Series A: Agriculture and food systems in sub-Saharan Africa in a four-plus degree world, 29 November 2010.

Kenya Television Network interviews Philip Thornton on the impacts of climate change to the African continent (photo credit: ILRI).

Bottom line implication: A 4-degree warmer world calls for adaptive capacity in agriculture that is not just about increasing the resilience of current systems but about completely new ways of farming and consuming.

The Guardian this week quotes agricultural systems analyst Philip Thornton, of the International Livestock Research Institute (ILRI), on the severe impacts that a 4ºC rise in temperature, now expected to occur within this century, will have on African livelihoods and food production.

'A hellish vision of a world warmed by 4ºC within a lifetime has been set out by an international team of scientists, who say the agonisingly slow progress of the global climate change talks that restart in Mexico today makes the so-called safe limit of 2ºC impossible to keep. A 4ºC rise in the planet's temperature would see severe droughts across the world and millions of migrants seeking refuge as their food supplies collapse.

'"There is now little to no chance of maintaining the rise in global surface temperature at below 2ºC, despite repeated high-level statements to the contrary," said Kevin Anderson, from the University of Manchester, who with colleague Alice Bows contributed research to a special collection of Royal Society journal papers published tomorrow. "Moreover, the impacts associated with 2ºC have been revised upwards so that 2ºC now represents the threshold [of] extremely dangerous climate change.". . .

'Rachel Warren, at the University of East Anglia, described a 4ºC world in her research paper: "Drought and desertification would be widespread. . . . There would be a need to shift agricultural cropping to new areas, impinging on [wild] ecosystems. Large-scale adaptation to sea-level rise would be necessary. Human and natural systems would be subject to increasing levels of agricultural pests and diseases, and increases in the frequency and intensity of extreme weather events."

'Warren added: "This world would also rapidly be losing its ecosystem services, owing to large losses in biodiversity, forests, coastal wetlands, mangroves and saltmarshes [and] an acidified and potentially dysfunctional marine ecosystem. In such a 4ºC world, the limits for human adaptation are likely to be exceeded in many parts of the world.". . .

'In sub-Saharan Africa, "the prognosis for agriculture and food security in a 4ºC world is bleak", according Philip Thornton, of Kenya's International Livestock Research Institute, who led another research team. He notes there will be an extra billion people populating the continent by 2050.

'"Croppers and livestock keepers in sub-Saharan Africa have in the past shown themselves to be highly adaptable to short- and long-term variations in climate. But the kind of changes that would occur in a 4ºC+ world would be way beyond anything experienced in recent times. It is not difficult to envisage a situation where the adaptive capacity and resilience of hundreds of millions of people could simply be overwhelmed by events," Thornton's team concludes. . . .'

Read the whole article at the Guardian: Climate change scientists warn of 4C global temperature rise, 29 November 2010.