BARCELONA, March 7 (Thomson Reuters Foundation) - Without
action to help farmers adjust to changing climate conditions, it
will become impossible to grow some staple food crops in parts
of sub-Saharan Africa, with maize, beans and bananas most at
risk, researchers said on Monday.
In a study of how global warming will affect nine crops that
make up half the region's food production, scientists found that
up to 30 percent of areas growing maize and bananas, and up to
60 percent of those producing beans could become unviable by the
end of the century.
Six of the nine crops - cassava, groundnut, pearl millet,
finger millet, sorghum and yam - are projected to remain stable
under moderate and extreme climate change scenarios.
"This study tells where, and crucially when, interventions
need to be made to stop climate change destroying vital food
supplies in Africa," said Julian Ramirez-Villegas, the study's
lead author who works with the CGIAR Research Program on Climate
Change, Agriculture and Food Security (CCAFS).
"We know what needs to be done, and for the first time, we
now have deadlines for taking action," he added in a statement.
For example, the study warns that around 40 percent of
maize-growing areas will require "transformation", which could
mean changing the type of crop grown, or in extreme cases even
abandoning crop farming.
Sorghum and millet, which have higher tolerance to drought
and heat, could replace maize in most places under threat.
But for 0.5 percent of maize-growing areas - equal to 0.8
million hectares in South Africa that now produce 2.7 million
tonnes - there is no viable crop substitution, the study said.
In a few places, the need to adapt to climate change is
already urgent, the researchers said. Those include pockets in
highly climate-exposed areas of the Sahel in Guinea, Gambia,
Senegal, Burkina Faso and Niger.
Banana-growing regions of West Africa, including areas in
Ghana and Benin, will need to act within the next decade, as the
land is expected to become unsuitable for bananas by 2025.
And maize-growing areas of Namibia, Botswana, Zimbabwe and
Tanzania also have less than 10 years left to change tack under
the most extreme climate change scenarios, the study added.
"If we don't do anything now, farmers are no longer going to
be able to grow certain crops in certain sites,"
Ramirez-Villegas told the Thomson Reuters Foundation from
"But we know there are several adaptation options ... with
which farmers should be able to carry on growing these crops for
a longer period of time than we project."
TIME 'RUNNING OUT'
Those options begin with shorter-term actions like improving
irrigation and weather information services for farmers, and
developing new varieties of maize and beans that can better
tolerate heat and drought.
Such measures are already underway in parts of Africa,
including the "Drought Tolerant Maize for Africa" initiative
that has released 160 varieties, benefiting up to 40 million
people in 13 countries.
But governments will still need to re-assess agricultural
and food security policies to see whether bigger transformations
are needed, such as switching to different crops or livestock.
If so, they will need to help farmers access markets or
build processing and storage facilities for new crops.
CCAFS researcher Andy Jarvis, a co-author of the paper
published in the journal Nature Climate Change, noted adjusting
national policies can take decades.
"Our findings show that time is running out to transform
African agriculture. This will require not only increased
funding but also a supportive policy environment to bring the
needed solutions to those affected," he said.
A separate study released on Monday, by researchers from
Brown and Tufts universities, suggested scientists have
overlooked how two important human responses to climate will
impact food production in the future: how much land people
choose to farm, and the number of crops they plant.
Looking at Mato Grosso, a key soy-producing state in Brazil,
they found a temperature rise of 1 degree Celsius was tied to
substantial decreases in crop area and double cropping,
accounting for 70 percent of the overall loss in production.
Only 30 percent was attributable to falling crop yield.
"If you look at yields alone, you're not looking at all of
the information because there are economic and social changes
going on as well," said Leah VanWey, professor of sociology at
Brown and one of the study's senior authors. "You're not taking
into account farmers' reactions to climate shocks."
(Reporting by Megan Rowling; editing by Ros Russell. Please
credit the Thomson Reuters Foundation, the charitable arm of
Thomson Reuters, that covers humanitarian news, women's rights,
trafficking, corruption and climate change. Visit news.trust.org)