Soaring carbon emissions will amplify the risk of conflict, hunger, floods and mass migration this century, the UN's expert panel said today in a landmark report on the impact of climate change.
Left unchecked, greenhouse gas emissions may cost trillions of dollars in damage to property and ecosystems, and in bills for shoring up climate defences, it said, adding the impact would increase with every additional degree that temperatures rise.
"Increasing magnitudes of warming increase the likelihood of severe, pervasive, and irreversible impacts," a summary said, in a stark message to policymakers.
The report is the second chapter of the fifth assessment by the Intergovernmental Panel on Climate Change (IPCC), set up in 1988 to provide neutral, science-based guidance to governments.
The last overview, published in 2007, unleashed a wave of political action that at one point appeared set to forge a worldwide treaty on climate change in Copenhagen in 2009.
But a global consensus failed to emerge as the developing world and developed world squabbled, with big polluters like China insisting it was up to rich countries to take the lead, arguing they could not be expected to sacrifice growth.
And in the United States, President Barack Obama's attempts at passing climate change legislation have been stymied in Congress, where some Republicans remain unconvinced of the scientific case for warming and argue that mitigation efforts are an unnecessary block on economic growth.
The new document, unveiled in Yokohama after a five-day meeting, gives the starkest warning yet by the IPCC of extreme consequences from climate change, and delves into greater detail than ever before into the impact at regional level.
It builds on previous IPCC forecasts that global temperatures will rise 0.3-4.8 degrees Celsius (0.5-8.6 degrees Fahrenheit) this century, on top of roughly 0.7 Celsius since the Industrial Revolution.
