Leading climatologist Professor Stefan Rahmstorf has revealed at a UNSW public lecture that sea-level rises caused by global warming are higher than those published by the Intergovernmental Panel on Climate Change earlier this year.
Professor Rahmstorf, who is from the Potsdam Institute for Climate Impact Research, is being hosted in Sydney by UNSW's Climate Change Research Centre, led jointly by Professor Andy Pitman and Professor Matthew England.
Professor England warned that global warming being caused by burning fossil fuels, and the resulting carbon dioxide accumulation in the atmosphere, could lead to unpredictable, non-linear effects on climate.
"The combined effects of ocean warming and melting polar ice caps will weaken the overturning of the ocean's water, which is critical for absorbing carbon dioxide and buffering the effects of global warming," says England, who has pioneered scientific understanding of the Southern Ocean's relationship to climate change effects in the Southern hemisphere. "If the buffering effects of ocean overturning are greatly impeded or halted it could produce catastrophic climatic effects for the planet."
"Sea level rise is one of the most serious long term impacts of global warming," Professor Rahmstorf says. "The most recent information reveals that sea-levels are rising fifty per cent faster than levels predicted in the 2001 IPCC report.
"If global warming continues unabated, we could eventually see the melting of the massive ice sheets covering western Antarctica. This alone could cause global sea levels to rise by 5-7 metres and cause widespread devastation."
The combination of higher rainfall and higher sea-level rises in the Asia-Pacific region would create millions of climate refugees. The UN estimates that some 150 million people live less than one metre above the high-tide level and 250 million live within five metres. Potential consequences of climate change include increased flooding resulting in the loss of life and property, the destruction of coastal infrastructure such as bridges and the loss of beaches and damage to wetlands.
Professor England and Professor Stefan Rahmstorf have been invited to write a new comprehensive review of the risk of abrupt ocean change for a forthcoming issue of the prestigious journal Proceedings of the National Academy of Science (PNAS).
UNSW has recently supported the establishment of the Climate Change Research Centre via its 2007 strategic initiatives fund. Priority areas of research for the centre include climate extremes, predictability, oceanic change, and terrestrial-climate interactions.
Read more here: Recent climate observations compared to projections.