London and Yokohama - Global warming was depleting fresh water and crops, destroying coral reefs and melting the Arctic, the UN said yesterday in a report that concluded that the world was ill-prepared to face many new threats.

Climate change had brought “key risks” that endangered lives and health worldwide, including storm surges and coastal flooding worsened by rising sea levels; infrastructure destruction and the disruption of power networks, communications and health services by extreme weather; and the depletion of crop production due to droughts and floods, the UN’s Intergovernmental Panel on Climate Change (IPCC) said.

“If you look around the world today, people, cities, businesses and nations aren’t prepared for the climate-related risk we face now,” Chris Field, the US professor who co-chaired the 309 scientists drafting the report, said.

“The climate changes that have already occurred have been widespread and have really had consequences. It’s not the case that climate change is a thing of the future.”

The report is designed to guide global legislators as they devise policies to reduce heat-trapping emissions and make their infrastructure, agriculture and people more resilient to a warmer world.

It aims to influence climate treaty talks among 194 nations that are working to devise an agreement next year to rein in global warming.

“The IPCC is a bell tower,” Field said after the report’s release. “It is trying to allow the world to climb up to a high point so that it can see far and clearly into the future and to let people make smart decisions for their own purposes to use science to build a better world.”

The researchers documented how climate change affects everything from retreating glaciers in east Africa, the Alps, the Rockies and the Andes to the bleaching of corals in the Caribbean Sea and Australia’s Great Barrier Reef. Mussel-beds and migratory patterns for salmon are changing off the US West Coast, grapes are maturing faster in Australasia and birds are flying to Europe earlier in the year.

One of the panel’s starkest findings concerns water availability and food production.

Where seven years ago, researchers were less certain about the potential damage to staple crops, in the study, they said global wheat and maize production were already being negatively affected by warmer temperatures, with yields of wheat declining by about 2 percent per decade and those of maize by 1 percent.

Total soya bean and rice yields are largely unchanged.

Since 2007, “several periods of rapid food and cereal price increases following climate extremes in key producing regions indicate a sensitivity of current markets to climate extremes”, the panel wrote. – Bloomberg