terça-feira, junho 16, 2009

Gelo fundido no tecto do mundo

The effects of climate change are dramatically illustrated at the world's "third pole", so-called because the mountain range locks away the highest volume of frozen water after the north and south poles.

The 1956 photograph of the Imja glacier, then one of the largest glaciers at an altitude of around 5,000m, shows a layer of thick ice with small meltwater ponds. But by the time Byers took his shot in 2007, much of the glacier had melted into a vast but stunning blue lake. Today, the Imja glacier, which is just 6km from Everest, continues to recede at a rate of 74m a year - the fastest rate of all the Himayalan glaciers.

Nepal's average temperature has increased by 1.5C since 1975. A major UN Environment Programme report last year warned that at current rates of global warming, the Himalayan glaciers could shrink from 500,000 square kilometres to 100,000 square kilometres by the 2030s - a prediction supported by the rate of retreat seen in Byers' pictures.

Imja is one of 27 glacial lakes in Nepal classified as potentially dangerous. If the moraines which dam the lake are breached, thousands of lives in the most densely populated Sherpa valley in Nepal are at risk from flooding and landslides.

Himalayan glaciers also feed into major Asian river systems including the Ganges, Indus, Mekong and Yangtze. If glacial meltwaters turn to a trickle, widespread droughts will threaten the 1.3 billion people that depend on water flowing in those rivers.

Captured On Camera: 50 Years Of Climate Change In The Himalayas