International scientists have gathered in Japan for a week-long meeting centred on a grim climate change report that warned of floods and drought that could stoke conflicts and wreak havoc on the global economy.

A draft of their document, seen by AFP, is part of a massive overview by the Intergovernmental Panel on Climate Change (IPCC), likely to shape policies and climate talks for years to come.

Scientists and government representatives are meeting in Yokohama, south of Tokyo, to exchange ideas and release a full report at the end of the conference on March 31.

“We have a lot clearer picture of impacts and their consequences … including the implications for security,” said Chris Field of the United States’ Carnegie Institution, who headed the probe.

The work comes six months after the first volume in the long-awaited Fifth Assessment Report declared scientists were more certain than ever that humans caused global warming.

Rising greenhouse-gas emissions will “significantly” boost the risk of floods, with Europe and Asia particularly exposed, the draft says.

Temperature increase was also leading to the decline of renewable water resources, while the rising sea level was seen to displace “hundreds of millions” of coastal dwellers by 2100, according to the draft report.

Average yields of wheat, rice and corn were seen to fall, while demand for crops will likely rise sharply due to expanding population.

Poverty, migration and hunger are invisible drivers of turbulence and war, as they sharpen competition for dwindling resources, the report warns.

By reducing carbon emissions “over the next few decades”, the world can stave off many of the worst climate consequences by century’s end, says the report.