A SEA level rise of several centimetres could have devastating effects many metres inland, CSIRO researcher Kathleen McInnes told the climate forum.Dr McInnes' work involves looking at the effects of storm surges on the Australian coast under various climate change scenarios.She said parts of Melbourne and low-lying areas along the Victorian coast _ including land on which the Werribee sewage treatment plant is situated _ would be vulnerable to the consequences of global warming and a rise in sea levels.Without the greenhouse effect it is believed the earth would have an average temperature of minus 19 degrees, instead of an average of 15 degrees.However, Dr McInnes said the greenhouse effect was being enhanced by the increased release of carbon dioxide, methane and nitrous oxide resulting from human activity.She said the content of carbon dioxide in the atmosphere had "taken off" in the past 200 years, during which time it had increased from about 200ppm to about 380ppm.She said while the content of carbon dioxide in the atmosphere had fluctuated over time, levels now were "unprecedented in the last 800,000 years".Temperatures on Earth had increased in line with increases in carbon dioxide in the atmosphere.Dr McInnes said since 1900 the Earth had warmed by 0.74 degrees, with 13 of the past 14 years the warmest since 1880.She said as the result of the warming of the earth, sea levels were rising, mostly because of thermal expansion _ as the oceans warmed they expanded "like liquid in a thermometer".Over a longer time span she said melting of glaciers and polar ice could result in dramatic sea level rises.If Greenland ice was to melt entirely it was estimated that sea levels would rise by 7m.Sea levels are thought to have been stable for the past 6000 years.Scientific modelling suggests that the consequences of global warming for the Ballarat region could be rises in evaporation and the risks posed by bushfires and decreases in rainfall and run-off into water catchments.