The CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) today warned global leaders in agricultural development that “the world’s many cultures must adapt to the changing ... menu forced upon them due to climate change”. The warning is one conclusion of a Policy Brief on Recalibrating Food Production in the Developing World launched at the 2nd Global Conference on Agricultural Research for Development (GCARD2) in Punta del Este, Uruguay.
The Policy Brief summarizes a comprehensive report drawn up by 70 scientists from across the 15 centers of the CGIAR Consortium, including Bioversity International. The report identifies the many impacts of climate change on food production and, more so, the interactions among them. For example, while rising temperatures in some places may improve the productivity of bananas, a key research area for Bioversity International, conditions may also become more favourable for certain pests and diseases. Patterns of rainfall and water use will change too, with additional implications for yields.
The report points out that rising temperatures will be bad news for potatoes in many areas, because potatoes do better in cooler climates. Warmer winters, especially, may provide an opening for bananas in places that currently grow potatoes. Warmer weather can also reduce the time between planting and harvest for bananas, further increasing production. On the downside, pests and diseases thrive in warmer weather and may spread to areas that were previously free of them. Bananas are also very sensitive to water levels. They can survive quite extended dry periods and recover when water is again available, at the cost of lower yields, but that is better than other crops that succumb completely to droughts.
Can potato growers adapt to bananas and shift their diet to a new staple? There is little research on the topic, although the rapid adoption in the Old World of some New World crops, such as maize, after the voyages of Christopher Columbus, suggests that they can, if the benefits are clear.
Charles Staver, a banana expert based in Bioversity’s Montpellier office, warns that a 2-degree C increase in temperature will allow pests such as the banana weevil, which attacks the underground stem of the banana, to reproduce more quickly in the highland areas that produce most of the bananas in central and east Africa. That could mean more weevil generations per year, although the weevils too may be adapting. CCAFS is funding Bioversity to quantify this effect more directly.
“Losses could be 30% or more,” Staver says, “and nematode worms would also be a problem if temperatures increase.”
Tackling the threats posed by pests and diseases is largely going to require better crop management, although for some diseases, such as fusarium wilt, there may be opportunities to select more resistant types among the local varieties.
Staver notes that “new varieties from conventional breeding or genetic modification do not appear to be a solution in the next 10 years, and certainly not in the hands of small growers.”
Another approach to protecting crops against emerging or spreading pests and diseases is to grow mixtures of different varieties. An ongoing long-term project by Bioversity and partners has shown that diversity can protect crop yields against pests and diseases, especially when pest and disease pressure is high.
The CCAFS report also points out that trees can play an important role in adaptation to climate change at the same time as mitigating the effects by absorbing carbon. Trees also provide essential nutrition and opportunities for poor farmers to increase their incomes. Bioversity International research in Asia has documented how farmers are changing how they grow and use fruit trees, adapting to changes in growing conditions. And while deforestation for agriculture remains both a cause of and a response to climate change, Bioversity International research will help to prevent illegal logging in future.
“This report from CCAFS shows that climate change poses large and complex problems for agriculture,” said Emile Frison, Director-General of Bioversity International, who is in Uruguay for GCARD2. “It also offers several suggestions for ways in which research, like the work we’re doing at Bioversity, can prevent those problems turning into major crises.”
