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.