Nutrition

As climate change dramatically influences the production and availability of staple food sources, it will have an equally stark effect on human nutrition. In South-East Asia, higher temperatures, episodes of flooding and drought, rising sea levels, warming seas and more frequent extreme events will alter the nutrition situation in various ways.

The impacts are likely to include significant declines in crop production, the nutritional value of staple foods, fishing catch, and livestock productivity. It may also contribute to changing patterns of crop and livestock disease and increased pests. In certain countries, cash crops, including coffee in Timor-Leste and tea in Sri Lanka, may also decline, affecting livelihoods and local economies.

The ecosystems that support food production will also suffer, with decreased pollinator populations and increased weeds, pests and fungus. Saltwater incursion in coastal areas, resulting from sea-level rise, is making arable land unusable. Low soil moisture, which adds to crop stress, will propel declines in yield.

These complex dynamics highlight the need for careful planning to adapt local agricultural production. For example, the rising concentration of atmospheric carbon dioxide (CO2), while generally a harmful driver of climate change, may offer a short-term boost to performance of crops such as wheat, rice and soybeans by increasing rates of photosynthesis and water use efficiency. That gain may be offset, however, as CO2 levels continue to rise. In addition, protein content may decline and yields may drop when air temperatures exceed 30°C. On top of that, current levels of ozone pollution globally are estimated to have suppressed wheat and soybean yields by 6-9%.

The sum of these challenges is a likely increase in the risk of undernutrition, including micronutrient deficiencies. It may go farther to reverse major gains in recent decades on stunting; one study forecasts an increase in severe stunting in South Asia of 61%. An additional challenge to tackling malnutrition in Asia is the dual burdens of undernutrition and obesity, at times occurring in the same individual, household and community. Lower crop production may trigger price shocks, forcing poorer households to reject more expensive foods, such as fresh fruits and vegetables, in favour of lower-cost, high-calorie products such as processed foods.