Sahel food shortage as studies show climate risk to crops

UN plea for food aid to the Sahel as scientific studies flag up climate change threat to food production

Pastoralist and farming communities in the Sahel have been hit by recurrent droughts (Source: Flickr/SOS Sahel UK)

Pastoralist and farming communities in the Sahel have been hit by recurrent droughts (Source: Flickr/SOS Sahel UK)

By Megan Darby

The United Nations is appealing for funds to fight hunger in the drought-hit Sahel, as scientific studies highlight climate change threats to food production.

Some US$100 million is needed to make 7.5 million vulnerable people in the African region more resilient against food insecurity, according to the UN. A call for donations in February brought in just US$16 million.

Recurring droughts, combined with migration from conflict zones, are making chronic food insecurity worse, warned UN regional humanitarian coordinator Robert Piper.

“If we are going to break out of this cycle of chronic crises across the Sahel region, emergency assistance to vulnerable farmers and pastoralists has to be considered a top priority,” Piper said.

“The best way to reduce tomorrow’s emergency case-load is to help households protect their assets today.”

Meanwhile, US scientists, writing in the journal Environmental Research Letters, have found that climate change “substantially” increases the risk global crop yields will fail to keep pace with rising demand.

Researchers from Stanford University and the National Center for Atmospheric Research (NCAR) put data on weather and crops into computer models of climate.

They found that over the next 20 years, the likelihood of natural climate shifts slowing growth in corn and wheat production was 1 in 200.

When human-induced climate change was factored in, the odds rose to 1 in 10 for corn and 1 in 20 for wheat.

“I’m often asked whether climate change will threaten food supply, as if it’s a simple yes or no answer,” said Stanford professor and study co-author David Lobell.

“The truth is that over a 10- or 20-year period, it depends largely on how fast the Earth warms, and we can’t predict the pace of warming very precisely. So the best we can do is try to determine the odds.”

Report: Climate change could worsen Sahel conflicts says UN

Global yields of corn and wheat have been rising by around 1% or 2% a year for the past few decades.

The UN food body predicts a further 13% increase in output by 2030.

At the same time, demand for crops is expected to rise rapidly as the population grows, people in eat more and biofuels are increasingly used for energy.

Lobell and NCAR scientist Claudia Tebaldi were studying the likelihood of climate change reducing yield growth by 10% or more – potentially a “dangerous scenario”.

“We can’t predict whether a major slowdown in crop growth will actually happen, and the odds are still fairly low,” said Tebaldi.

“But climate change has increased the odds to the point that organisations concerned with food security or global stability need to be aware of this risk.”

Earlier this year the UN’s Intergovernmental Panel on Climate Change (IPCC) warned large investments may be needed to ensure some vulnerable communities cope with changing weather patterns.

The part of its report focused on the global impacts of climate change revealed production of wheat and maize are likely to be negatively affected, while effects on rice and soybean yields were significant but smaller.
Wheat yields are vulnerable to ozone, but air pollution controls can help

Wheat yields are vulnerable to ozone, but air pollution controls can help

A separate study in the journal Nature Climate Change from MIT and Colorado State University highlighted an extra risk from air pollution.

Rising temperatures can increase production of ozone, the researchers found, which is known to damage crops.

Ozone pollution occurs when nitrogen oxides from motor vehicle exhaust, industrial and power station emissions react with volatile organic compounds in the air.

The effects vary by region and by crop. Wheat was found to be very sensitive to ozone, while corn reacted more to heat.

National and regional policies to cut air pollution could help limit the damage, the researchers found.

Under a pessimistic scenario, rates of malnourishment in the developing world increased from 18% to 27% by 2050. With stronger air quality controls, that increase was almost halved.

“An air quality clean-up would improve crop yields,” said lead author Colette Heald.

The results “show how important it is to think about the agricultural implications of air-quality regulations,” she added.

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