UN scientists are set to deliver their darkest report yet on the impacts of climate change, pointing to a future stalked by floods, drought, conflict and economic damage if carbon emissions go untamed.
A draft of their report, 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 will meet in Yokohama, Japan, from Tuesday to hammer out a 29-page summary. It will be unveiled with the full report 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.
It predicted global temperatures would rise 0.3 to 4.8 degrees Celsius this century, adding to roughly 0.7 C since the Industrial Revolution. Seas will creep up by 26 to 82cm by 2100.
The draft warns costs will spiral with each additional degree, although it is hard to forecast by how much.
Warming of 2.5 C above pre-industrial times – 0.5 C more than the UN’s target – may cost 0.2 to 2.0 per cent of global annual income, a figure that could amount to hundreds of billions of dollars each year.
Jacob Schewe of the Potsdam Institute for Climate Impact Research in Germany said many scientists concurred that recent heatwaves and floods were evidence of climate change already on the march – and a harbinger of a future in which once-freakish weather events become much less rare.
Among the perils listed in the draft are increased flooding and drought, rising seas, hunger and species loss.
Poverty, migration and hunger are invisible drivers of turbulence and war, as they sharpen competition for dwindling resources, the report warns.
“Climate change over the 21st century will lead to new challenges to states and will increasingly shape national security policies,” its draft summary says.
“Small-island states and other states highly vulnerable to sea-level rise face major challenges to their territorial integrity.
“Some transboundary impacts of climate change, such as changes in sea ice, shared water resources and migration of fish stocks, have the potential to increase rivalry among states. The presence of robust institutions can manage many of these rivalries to reduce conflict risk.”
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.