May 23, 2011

Coastal Sea Levels Expected Set To Rise By 1 Meter

A report from the Australian Climate Commission has warned that "once-a-century" coastal flooding could become much more common and that the Earth's surface is warming rapidly, reports the AFP news agency.

Drawn from the most up-to-date climate science from around the world, the report said greenhouse gas emissions created by human industry was the likely culprit behind rising temperatures, warming oceans, and rising sea levels.

While climate scientists from Australian science body the CSIRO, the Bureau of Meteorology, and other academics, reviewed the report, some judgments, including on sea levels, were from its author, Will Steffen.

"I expect the magnitude of global average sea-level rise in 2100 compared to 1990 to be in the range of 0.5 to 1.0 meter," Steffen said in his preface to "The Critical Decade".

He said while this assessment was higher than that of the Intergovernmental Panel for Climate Change in 2007, which was under 0.8 meter, it was not inconsistent with the UN body which had said higher values were possible.

"We're five years down the track now, we know more about how those big ice sheets are behaving," Steffen told reporters. "In part we have some very good information about the Greenland ice sheet. We know it's losing mass and we know it's losing mass at an increasing rate.

"So that's telling us that we need to extend that upper range a bit towards a meter. Now there are commentators who say it should be even higher than that."

The commission report said a sea-level rise of a half-meter would have wide-spread impacts, with extreme inundations in coastal areas around Australia's largest cities of Sydney and Melbourne.

Steffen explains that in some instances, a one-in-a-hundred year event could happen every year. "The critical point is we have to get emissions turned from the upward trajectory to the downward trajectory by the end of this decade at the very latest. We have to make investment decisions this decade to put us on that long-term trajectory that minimizes the cost to our economy."

Australia has, in the last few decades, been prone to bush fires, drought and cyclones, illustrating the effects of higher global temperatures over land masses. In the last five decades the number of record hot days in Australia had more than doubled, increasing the risk of heat waves and bush fire weather, it said.

Chair of the Climate Commission Tim Flannery explained to AFP that evidence was becoming more convincing year by year that humans were changing the climate.

"In Australia we are seeing the impacts more clearly, we've seen the sea level rise that was predicted, we've seen the decline in rainfall continue particularly in the southwest of Western Australia, we've seen impacts on the Great Barrier Reef and so forth. This is the decade we have to act," Flannery told reporters.

Prime Minister Julia Gillard, who is struggling in the polls as she seeks to introduce a carbon tax to place a price on industry's production of greenhouse gas emissions, seized on the report. "We don't have time for false claims in this debate. The science is in, climate change is real," she said.


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