By mid-century, climate change may have outrun the ability of Africa's farmers to adapt to rising temperatures, threatening the continent's precarious food security, warns a new study.
Growing seasons throughout nearly all of Africa in 2050 will
likely be "hotter than any year in historical experience," reports
the study, published in the current issue of the British-based
journal Global Environmental Change.
Six nations - Senegal, Chad, Mali, Burkina Faso, Niger and
Sierra Leone - are especially at risk because they will face
conditions that are today unknown anywhere in Africa.
As a result, even the hardiest varieties of the continent's
three main crops - maize, millet and sorghum - currently under
cultivation would probably not tolerate the conditions forecast for these countries in four decades.
'Urgent measures' needed
A trio of researchers led by Marshall Burke, a professor at
Stanford University's Program on Food Security and the Environment, said urgent measures must be taken to stock seed banks and develop new varieties to stay a step ahead of Africa's shifting agricultural map.
"When we looked at where temperatures are headed, we found that for the majority of Africa's farmers, global warming will rapidly change conditions beyond the range of what occurs anywhere in their country," he said.
The study is based on a mid-range projection from the UN
Intergovernmental Panel for Climate Change (IPCC) that forecasts an increase in average global temperatures by 2100 of 2.8 degrees Celsius (5.0 degrees Fahrenheit) over pre-industrial levels.
More recent research, however, suggests that the impact of
global warming could be even worse. MIT climate modellers, averaging 400 possible scenarios, have calculated that Earth's surface temperatures will jump 5.2 C (9.4F) by century's end in the absence of rapid and massive measures to slash greenhouse gas emissions.
"This is not a situation like the failure of the banking system
where we can move in after the fact and provide something akin to a bail-out," said co-author Cary Fowler, head of the Global Crop Diversity Trust.
"If we wait until it's too hot to grow maize in Chad and Mali,
then it will be too late to avoid a disaster that could easily
destabilize an entire region and beyond."
African nations to face 'unprecedented climates'
Over 40% of Africa's population lives on less than a
dollar a day, and 70% of these poor are located in rural
areas and thus largely dependent on agriculture for survival.
The authors note that "adverse shifts in climate can cause
devastating declines in human welfare, and have been implicated in everything from famine to slow economic growth to heightened risk of civil conflict."
Burke and colleagues found that while most African nations will face unprecedented climates by 2050, they could anticipate future needs by stockpiling seeds from neighbouring countries with similar conditions today.
By mid-century, for example, local varieties of the staple maize in Lesotho - which has one of Africa's coolest climates - will be wilting in the heat.
Varieties that thrive in hotter climes grown in Mali today may well be adapted to Lesotho's future needs, and so should be set aside. But that still leaves the six most vulnerable countries without any apparent solution.
"For these nations, there is a much smaller potential pool of
foreign genetic resources in which to seek heat tolerance, at least
within Africa," the authors caution. – (Sapa, June 2009)
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