Global warming of 2 ºC threatens African food production and Asian water supplies “in our lifetime”, hurting the poorest first, the World Bank said.

That increase may be reached in 20 to 30 years, while a 50 cm gain in sea levels may be “unavoidable” by 2050, the bank said last week in the report into how the poorest nations will be affected. The United Nations (UN) is seeking to keep warming to 2 ºC since the 1800s.

“In sub-Saharan Africa, food shortages will become more common,” Rachel Kyte, a bank VP for sustainable development, told reporters.

“In South Asia, shifting rain patterns will leave some areas under water and others without enough water for power generation, irrigation or drinking.”

The study builds on an investigation released by the bank in November that said the planet is set to warm 4 ºC by 2100. It increases pressure on policymakers to cut greenhouse-gas emissions blamed for warming the planet as envoys from more than 190 nations work to craft a new climate treaty by 2015.

“Climate change is a real and present danger that, if left unchecked, will undermine food security in the world’s hungriest regions within just 20 years,” Sasanka Thilakasiri, a spokesperson for development charity Oxfam said in a statement.

“If we can stop global temperatures from rising above 2 ºC, we can avoid the worst consequences.”

The concentration of carbon dioxide in the atmosphere passed 400 parts per million last month for the first time in millions of years, and the UN Environment Program has warned that current pledges to cut greenhouse gases by 2020 are not enough to keep the world below 2 ºC of warming.

In sub-Saharan Africa, droughts and heatwaves will leave about 40% of the land now used to grow maize unable to support the crop, the study said. Without measures to adapt to the changes, a 15 cm jump in sea levels and intensified cyclones may flood much of Bangkok within two decades, it said.

“In South-East Asia, the loss of coral reefs would reduce fishstocks, leave coastal communities and cities more vulnerable to increasingly violent storms and landslides and impact tourism,” Kyte said.

The bank’s spending to help nations adapt to the effect of climate change doubled in 2012 to $4.6-billion.

The report, prepared by researcher Climate Analytics in Berlin and the Potsdam Institute for Climate Impact Research, is the latest attempt by World Bank President Jim Yong Kim to make the institution a bigger partici- pant in the fight against global warming. The bank will “increasingly look at all its business through a ‘climate lens’,” it said in a statement.

Coal Lending
A physician by training who took over at the bank almost a year ago, Kim brought up Superstorm Sandy and the risk of more disasters at his first Group of 20 meeting of Finance Ministers in November.

In an April speech, he vowed to boost the lender’s contribution to easing the effects of global warming as part of a new goal to eliminate extreme poverty by 2030.

While the lender has expanded investment in renewables, it may not always be able to avoid funding polluting energy. As the bank studies offering partial guarantees for a lignite-fired power plant in Kosovo, Kim told a panel in April he could not refuse if the alternative was having people there “freeze to death.”

Kyte said the bank has helped fund “less and less coal in recent years” and it will only do so in “rare circumstances”.