Climate change may have a profound effect on the world's ability to produce wheat — one of its staple crops — and adaptation efforts must take into account both the positive and negative effects of climate shifts, say wheat experts.
Production in some regions, such as India and Mexico, is predicted to be negatively affected by climate change, according to Thomas Lumpkin, director general of the International Maize and Wheat Improvement Center (CIMMYT).
But, in other regions, such as northern China, production may benefit from warmer winters.
'Both high temperatures and reduced rainfall will be more common, and wheat will be the most severely affected major crop,' Lumpkin told SciDev.Net on the sidelines of the 2012 Borlaug Global Rust Initiative (BGRI) Technical Workshop in China this month (1–4 September).
Despite several years of record South Asian harvests, global weather patterns appear to be changing, and regional food shortages may cause political upheaval, Lumpkin said.
Bangladesh has seen its wheat production area and yields reduce dramatically, as a consequence of a heat stress caused by climate change, and the current US drought has led to rising food prices, likely to stir up social unrest, according to Lumpkin.
'We already have evidence that high wheat prices in 2008 helped stimulate the 'Arab Spring' events in Libya, Egypt and Syria,' Lumpkin said.
Ravi Prakash Singh, head of CIMMYT's Irrigated Bread Wheat Improvement and Rust Research programme, agreed: 'Each country will need to invest more in agriculture, otherwise food shortages can lead to social unrest, as seen in recent years in some countries'.
Singh told SciDev.Net that climate change has already had both positive and negative effects on wheat production.
'For example, the 2011–12 South Asian wheat season was very favourable, and record wheat production occurred, to the extent [that there were] severe shortages of gunny bags for storing and transporting wheat in India,' Singh said. Such storage shortages were a big problem for the government, and it is likely a large quantity of wheat will be wasted, he added.
In contrast, this year, a delay and reduction in Indian monsoon rains has affected crops severely in rain-fed agricultural areas in South Asia.
Meanwhile, in China, warmer winter temperatures have enabled farmers in some areas to replace spring wheat with winter wheat.
'Warmer temperatures permit longer growing seasons and more crop productivity in northern China if irrigation and rainwater are available,' Lumpkin said. 'However, in some areas water use is already higher than sustainable,' he added.
Similarly, in southwestern China, warmer temperatures have extended growing seasons.
But these benefits may be offset by other impacts resulting from climate change, such as an increase in crop disease, scientists have warned.
'Diseases such as stripe rust, leaf and stem rust, fusarium head blight, and powdery mildew will be more severe,' Yuchun Zou, a senior wheat breeder of Crop Research Institute of Sichuan Academy of Agricultural Sciences told SciDev.Net.
Climate change will also bring more drought, he said, adding that breeding efforts should be aimed at adapting new wheat varieties to the impacts of climate change.
'To combat the effects of climate change we need integrated strategies,' Singh said. These include 'the development of high-yielding varieties that have more tolerance to drought and heat, but, at the same time, increased investment in grain storage infrastructure and more efficient irrigation systems to utilise water '.