The seas around New Zealand and Australia are likely to be the most seriously affected in the world by the continuing rise in sea levels, according to research on Tasmanian swamps.
Since the late 19th century the sea level in the southwest Pacific has risen about 20 centimetres with the fastest rate occurring in the early decades of the 20th century, says Patrick Moss of the University of Queensland.
Sea levels around the world rose at an average rate of 1.5 millimetres a year since 1880, but studies of tidal marshes in Tasmania show that, following a stable 6000 years, there was a rise of 4.2mm a year between 1900 and 1950, which was attributed to the end of a small ice age.
Dr Moss, who co-wrote the study in conjunction with scientists from the UK, New Zealand and Australia, said there was another jump in sea levels after 1990.
"The 1990s peak is most likely indicative of human-induced climate change."
The results of the study published in the journal Earth and Planetary Science Letters indicate the comparatively higher levels in the southwest Pacific are the result of melting ice in the northern hemisphere.
"It appears likely that the primary source of sea level rise in the southern hemisphere is the Greenland Ice Sheet, but also mountain glaciers in Alaska, western North America and the Canadian Arctic."
Dr Moss's study is largely based on sediment layers in core samples taken from salt marshes near Little Swanport in Tasmania.
He said the samples also provided physical evidence of the start of logging in Tasmania, when nuclear testing was at its peak globally and the introduction of unleaded petrol.