AFP

Paris, Nov 17: UN Chief Ban Ki-moon called on Saturday November 17, for urgent action on global warming, warning the world is on the verge of a catastrophe, as top scientists were due to issue a new report on climate change for policymakers.

"We all agree. Climate change is real, and we humans are its chief cause. Yet even now, few people fully understand the gravity of the threat, or its immediacy," the UN chief wrote in a commentary in the International Herald Tribune.

"I have always considered global warming to be a matter of utmost urgency. Now I believe we are on the verge of a catastrophe if we do not act."

Ban noted recent acceleration in the melting of glaciers and polar ice, and pointed out that the collapse of an at-risk Antarctic ice shelf could raise sea levels by up to six metres (18 feet), inundating costal cities New York, Mumbai and Shanghai.

"I am not scare-mongering. But I believe we are nearing a tipping point," wrote the UN chief.

Ban will preside over the presentation Saturday in Valencia, Spain of the UN Intergovernmental Panel on Climate Change's (IPCC) landmark report intended to help policymakers facing tough decisions on cutting pollution from fossil fuels, shifting to cleaner energy and bolstering defences against drought, flood, storms and other problems set to intensify through climate change.

He characterised the report's conclusions as "encouraging." "The over-arching message: we can beat this. There are real and affordable ways to deal with climate change," wrote Ban.