For people living in Indonesia, the failure of a rice harvest can have serious consequences. Prices of this staple food are driven higher, making it impossible for poorer people to buy enough to eat. But while some families go hungry, others will manage to scrape by, and some may even benefit from the crisis. For the first time, researchers have assessed which nations and which groups of people are most at risk from climate volatility.

Syud Ahmed, from the Development Research Group at the World Bank in Washington DC, US, along with Noah Diffenbaugh and Thomas Hertel of Purdue University, US, combined global climate-model runs with statistical population data to assess the impacts on poverty of climate volatility for seven socio-economic groups in 16 developing countries from Asia, Africa and Latin America. They analysed the impact of one-in-thirty-year drought, flood and heat-wave events on each of the countries, focusing on two 30-year time slices: 1971–2000 and 2071–2100.

They found that all countries experienced increases in poverty rates after an extreme climate event, but some countries suffered more than others. In particular they showed that Bangladesh, Mexico, Indonesia, Mozambique, Malawi, Tanzania and Zambia are among countries with the highest shares of population that could enter poverty in the wake of extreme events.

What’s more Ahmed and colleagues found that urban labourers were likely to be the worst affected group. “Food is a major expenditure for urban poor and this group’s overall consumption falls with rising prices, which may push them below the poverty threshold of consumption,” Ahmed told environmentalresearchweb. By contrast, agricultural households tended to be less sensitive to climate extremes. “They are hurt by declines in agricultural productivity but the value of their farm output may rise due to higher food prices, increasing their incomes,” explained Ahmed, whose findings are published in Environmental Research Letters.

Using future climate-model runs Ahmed and colleagues discovered that the problem is likely to become worse in some countries and better in others. For example Tanzania currently experiences frequent extreme droughts, but in the future the intensity of these droughts is expected to decrease. “Tanzanian agriculture is almost completely rain-fed and thus highly sensitive to extreme dry spells,” said Ahmed. “Declines in the intensity of these poverty-inducing extreme-dry events would thus reduce the vulnerability of the population to be impoverished when a dry spell does occur.” Malawi, on the other hand, is expected to have more extreme-dry events in future, pushing greater numbers of people into poverty.

Understanding which countries are likely to be worst affected, and which groups of people are most vulnerable, will better enable people to prepare and perhaps mitigate the problem. For example, countries that are particularly vulnerable to extreme-dry events can focus on introducing better irrigation systems, or growing more drought-tolerant crops. In addition, governments and policy makers can try to improve a country’s infrastructure and economy to make people less vulnerable to extreme climate events.