Two UN agencies on Monday presented a new tool to map health risks linked to climate change and extreme weather conditions, enabling authorities to give advance warnings and act to prevent "climate-sensitive" diseases from spreading.

The World Metrological Organization and the World Health Organization presented their first joint "Atlas of Health and Climate," which pinpoints health problems like diarrhoea, malaria, dengue and meningitis that follow in the wake of sudden, but often foreseeable shifts in climate.

Using graphs, charts and bullet points, the atlas can be used as a guide for decision makers on how to prevent such diseases, WHO Secretary General Margaret Chan told reporters in Geneva, speaking alongside WMO chief Michel Jarraud.

The report "can help policy makers to make decisions," she said, pointing for instance to the more than 20 countries in Sub-Saharan Africa affected by bacterial meningitis, brought each year with a hot and dusty wind that blows across the so-called meningitis belt.

"In advance of the coming of the wind, ... this kind of information, allows us to do early warning" andprovide vaccines before the winds and the disease arrive, she said.

Jarraud meanwhile stressed how climate change was making advance warning ever more important in the cases of severe heat waves like the one that hit Western Europe in 2003 and the one that hit Russia two years ago, which he described as "unprecedented".

"These unprecedented heat waves, at the end of this century, might happen every five or every 10 years," he said, stressing that alerting the public, caring for the vulnerable and informing people how to act could save many lives in such situations.

Advance warning is also imperative in getting people out of harm's way in the cases of massive storms like Hurricane Sandy, which is currently threatening the East Coast of the United States, Jarraud said.