Asia accounts for 69-73% of the world's irrigated area. However, irrigation currently plays a relatively minor role in most of Africa, except in the contiguous irrigated area along the Nile basin and North Africa and South Africa . In India, long-term data  on the irrigated area shows that farmers adjust their irrigation investments and crop choices in response to medium-run rainfall variability . da Cunha et al.  report that farmers' income tends to be higher on irrigated lands in Brazil. In Bangladesh, farmers invest a part of their increased incomes in improving irrigation access . The severity of drought increases the likelihood of farmers adopting supplementary irrigation in Bangladesh . In Vietnam, irrigation improvement had the highest positive impact on crop yield among all farm-level adaptive practices . In South Africa, access to irrigation was one of the most important predictors of whether or not farmers would adopt a whole suite of other adaptation responses .
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Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report