"Global warming is a fact ... and Spain and southern Europe will be the worst affected in the short term by the phenomenon that is directly linked to the atmospheric emission of greenhouse gases," the minister told a news conference here, citing a recent UN report on the impacts of climate change.

Jose Manuel Moreno, a Spanish professor of ecology, told the same press conference that Mediterranean ecosystems are among the world's most sensitive and will be among those hardest-hit by global warming.

By 2070, between 16 and 44 million Europeans are projected to be suffering from water shortages as the region's rivers may lose up to 80 percent of their summer volume, said the professor, who coordinated a group of scientists who wrote the chapter on Europe in the report issued Friday in Brussels by the UN Intergovernmental Panel on Climate Change.

The chapter on Europe has not been released formally, but Moreno discussed data from it at the news conference in Madrid.

The sea level will rise dramatically in the coming decades, in Spain's case a rise of 0.4 of meter, resulting in a retreat of thecountry's beaches of 20 to 40 meters and putting 20 percent of thenation's coastal wetland at risk, Moreno said.