Tuesday, April 05, 2011

Sea rising 'at upper end of forecast'

From: The Australian

SEA levels are rising close to the upper end of predictions made in the Intergovernmental Panel on Climate Change's landmark 2007 report.

Oceanographer and climate scientist John Church, who is writing the chapter on sea level rises for the IPCC's 2013 update, said the world's oceans were on track to rise by between 60cm and 80cm by 2100. "There's no evidence to say that the IPCC has overestimated (the predictions)," Dr Church said.

The lower end of the prediction was a rise of about 18cm.

The pre-eminent climate scientist told the CSIRO's Greenhouse 2011 conference in Cairns yesterday the sea level rises were caused by a combination of factors.

"The largest contributions come from thermal expansion of the ocean and the melting of glaciers and ice caps," Dr Church said, noting that new research showed each contributed to about 40 per cent of the sea level rise.

Also contributing, he said, was the flow from the Greenland and Antarctic ice sheets.

He said it was urgent that Australia and the global community took action to reduce carbon emissions. "We don't have time to spare," he said.

He said sea levels were rising at about 3.2mm a year. In the 20th century, he said it was 1.7mm a year.

The CSIRO conference also heard dire predictions about the health of the Great Barrier Reef.

University of Queensland climate change researcher Ove Hoegh-Guldberg said that unless carbon emissions were dramatically curtailed within the next decade, the reef would die.

He said the reef would be killed by rising sea temperatures and the acidification of oceans due to rising carbon levels.

"We are going to get into a situation where reefs will no longer be able to sustain themselves," Professor Hoegh-Guldberg said.