News: The Oceans choking on Co2,...

Oceans choking on CO2, face irreversible changes

Sydney: The world's oceans are virtually choking on rising greenhouse gases, destroying marine ecosystems and breaking down the food chain - irreversible changes that have not occurred for several million years, a new study says.

       The changes could have dire consequences for hundreds of millions of people around the globe who rely on oceans for their livelihoods. "It's as if the Earth has been smoking two packs of cigarettes a day," said the report's lead-author Australian marine scientist Professor Ove Hoegh Guldberg.

       The Australia US report published in Science magazine on Friday, studied 10 years of marine research and found that climate change was causing major declines in marine ecosystems.

       Oceans were rapidly warming and acidifying, water circulation was being altered and dead zones within the ocean depths were expanding, said the report. There has also been a decline in major ocean ecosystems like kelp forests and coral reefs and the marine food chain was breaking down, with fewer and smaller fish and more frequent diseases and pests among marine organisms.

      "If we continue down this pathway we get into conditions which have no analogue to anything we've experienced," said Hoegh-Gulberg, director of the the Global Change in stitute at The University of Queensland. Hoegh-Guldberg said oceans were the Earth's "heart and lungs", producing half of the world's oxygen and absorbing 30% of man-made carbon dioxide. More than 3.5 billion people depend on the ocean for their primary source of food and in 20 years this number could double, the report's authors say.