"Climatic changes also affect temperatures and regional climates, the conditions on which, for instance, in the continent of Africa, mosquitoes may spread from one region to another," Achim Steiner, executive director of the UN Environment Programme (UNEP) said on Friday.

The UNEP chief spoke ahead of Sunday's release in Copenhagen of the Fifth Assessment Report from the Intergovernmental Panel on Climate Change.

"Diseases will move as the world warms and we may in many parts of the world indeed see either the return or the arrival of diseases that in recent times have simply not occurred in those regions," he said.

That development, he said, will add "extra stress to the health infrastructure, the health system and ultimately the health and well-being of these populations in those countries".

Awareness of the link between climate and health has prompted environmental scientists to forge closer links with international bodies focused on health, Steiner said.

"That is why my colleague, Margaret Chan, who heads the World Health Organisation, convened a meeting in Geneva on climate change and health," he said.

"And her conclusion was that a climate agreement in Paris is not just only a climate change agreement, it is also a global health agreement, because clearly the connection between environmental change arise from global warming and greater health risk factors is very direct in many different respects," Steiner said.

World leaders are due to meet in Paris next year with the aim of producing a new pact on controlling emissions of greenhouse gases to take the place of the Kyoto Protocol. Besides the effect on climate, carbon emissions also cause direct damage to human health, according to the UNEP director.

Emissions of carbon and other pollutants are "responsible for approximately seven million premature deaths every year worldwide", Steiner said.

"That is more by far more than the combined premature deaths arising from HIV/AIDS and malaria combined."

"We need to, first of all, get a clearer scientific understanding on how these linkages (between climate change and health) are occurring, secondly to anticipate its impact and thirdly, to put in place the right policy and response measures," Steiner said.

There are, he said, "large economies such as Brazil which has taken significant steps in terms of, for instance, the main sources of greenhouse gases, carbon dioxide in this case arising from deforestation".

"Brazil has made a tremendous contribution by reducing deforestation, perhaps one of the most significant steps in moving away from a business as usual scenario that we had 10 years ago," Steiner said.

He also offered praise for Nicaragua, which he described as being "on the forefront of mainstreaming renewable energy technology in its power and electricity generator sector".

"We see in the Latin American region significant investments, for instance, in low carbon and building infrastructure efficiencies happening from Colombia to Peru," Steiner added.

"So I think what we are seeing in the year 2014 is a recognition that every country has an interest in acting on the threat of climate change, doing as much as it can within the means available to it domestically and counting on the international climate agreement and also green climate financing for funds to further assist countries in moving faster and more ambitiously," he said.

The 20th session of the UN Conference of the Parties on Climate Change, known as COP20, will be held from December 1-12 in Peru's capital.

The Lima gathering is supposed to produce a draft accord that can be signed next year in Paris.

"We have, in a sense, the choice now to make a judgment. We face an enormous risk that if we don't move into a low carbon future now that we would have lost that choice to even make it 20 to 50 years down the line," Steiner said.

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