The dark night of the shoal  

The ABC reports on a scientific study on the impact of global warming on fisheries - Climate change to cause dark night of the shoal.

Climate change will cause key species of fish to migrate towards the poles, badly depleting many commercial fisheries, scientists say. "The impact of climate change on marine biodiversity and fisheries is going to be huge," said study lead author William Cheung, of the School of Environmental Sciences at the University of East Anglia, eastern England.

The research team used a high-powered computer model, based on knowledge of 1,066 species of fish, their habitat and climate change, to predict what might happen by 2050 according to three scenarios for global warming.

Warmer water will lead to "large-scale redistribution" of these species, with most of them moving towards the poles, shifting on average by more than 40 kilometres per decade, they said.

Arctic Norway will benefit from an increased catch, but in sub-polar regions, the tropics and semi-enclosed seas, "climate change may lead to numerous local extinction," hitting developing countries most of all, the paper warned.

Part of this trend will be offset by colder-water species that venture into a warmer habitat.

In the North Sea, for instance, stocks of Atlantic cod may fall by more than a fifth as the species heads towards chillier waters. On the other hand, the European plaice, a more southerly fish, could increase in the North Sea by more than 10 per cent.

In the United States, there would be a fall of up to 50 per cent in today's cod fisheries on the east coast. Some species will face a high risk of extinction, including the striped rock cod in the Antarctic and the St Paul rock lobster in the Southern Ocean.

DIRE warnings of future devastation sparked by global warming have not been dire enough, climate scientists warn.

Just over a year ago, the Nobel-winning Intergovernmental Panel on Climate Change published a report warning of rising sea levels, expanding deserts, more intense storms and extinction of up to 30 per cent of plant and animal species.

But recent studies suggested the report significantly underestimated the potential severity of global warming over the next 100 years, a senior member of the panel warned yesterday.

"We are basically looking now at a future climate that is beyond anything that we've considered seriously in climate policy," said Chris Field, a co-ordinating lead author of the report.

Fresh data showed that greenhouse gas emissions had grown by an average of 3.5 per cent a year from 2000 to 2007, Professor Field said at a meeting of the American Association for the Advancement of Science.

That was "far more rapid than we expected" and more than three times the 0.9 per cent growth rate in the 1990s, he said.

Professor Field, of Stanford University, said it appeared that most the growth was "because developing countries like China and India saw a huge upsurge in electric power generation, almost all of it based on coal".

Complicating the problem was that higher temperatures could thaw the Arctic tundra, releasing nitrous oxide, which was 300 times more potent as a greenhouse gas than carbon dioxide. ...

Recent studies have shown that global warming is reducing the ocean's ability to absorb carbon by altering wind patterns in the Southern Ocean. Faster winds blow surface water away, causing water with higher concentrations of carbon dioxide to rise to the surface.