Maize Yields to Decline by up to 60%

By Richard Mann, Contributing Reporter

RIO DE JANEIRO, BRAZIL – A study to be published in May in the journal Agricultural Water Management simulated the potential impact of climate change on maize yields in Northeast Brazil. The Intergovernmental Panel on Climate Change (IPCC) has developed two possible climatic scenarios.

The most optimistic scenario foresees greenhouse gas emissions ceasing to increase by 2040 and a rise in average temperature in Brazil varying from 0.3ºC to 1.7ºC up to the year 2100.

However, in the most pessimistic one, emissions would continue to grow until the end of the century, and the average temperature in Brazil would be from 3ºC to 6ºC higher by 2100.

The projections suggest that climate change could affect maize yields in both scenarios, resulting in a decline in production of between 30 and 60 percent in the Northeast of Brazil.

The region is home to more than 50 million people, approximately 26 percent of which in semi-arid places where water is scarce. It is also one of Brazil’s most backward regions in terms of social indicators linked to poverty.

Minella Martins, an agricultural engineer at Brazil’s National Center for Monitoring and Early Warning of Natural Disasters, and leading author of the study, said: “We verified [that] in the worst case scenario crop losses may hit more than 60 percent by 2070.”

But she argues that there is still time to mitigate the situation if the crop cycle is lengthened and irrigation introduced during dryer periods.  “Considering the expansion of irrigated areas until 2030, our simulations indicate that losses will remain at less than 20 percent in the case of irrigated cultivars with longer crop cycles for all scenarios, except the most pessimistic ones,” said Martins.

“Irrigation and the development of new maize varieties would be essential to sustain productivity in adverse climate change scenarios,” she added.   According to the findings, maize yields in the South of the region would be most affected as several other studies have found that these areas are already facing more prolonged and more frequent droughts.

Agriculture in Northeast Brazil represents a significant source of income, with family farming responsible for 82.6 percent of jobs in rural areas and 50 percent of production value.  Since irrigation is likely to become central to the sustainability of maize productivity, it is crucial to evaluate future water usage demands, states Paulo Cesar Sentelhas, an agricultural engineer at the University of Sao Paulo’s Luiz de Queiroz College of Agriculture.