Scientists in Denmark say global warming could create dead zones in oceans that would then be devoid of most marine life for up to 2,000 years. The scientists used computer modelling to simulate long-term climate change.

Under the worst-case scenario, the concentration of carbon dioxide in the air would triple by the end of this century, producing a temperature rise of up to seven degrees Celsius. The oceans would get warmer and water circulation would slow down. This would bring about a dramatic drop in oxygen levels in vast ocean tracts.

The project's lead scientist, Gary Shaffer of the Niels Bohr Institute at the University of Copenhagen, said there now had to be a question mark over whether future generations could look to the oceans as a major reserve of food.

(BBC, ABC, 26/01/2009)