Global Warming May
Not Be To Blame For
Rises In Sea Levels
KOROR, Palau (AFP) - Other phenomena than global warming could be to blame for the rising oceans which Pacific islands say are encroaching on their land, a scientist told South Pacific Forum officials Monday.
It was possible the Pacific Ocean was rising by up to two millimetres a year but the effect was wildly variable across the region, the director of Australia's National Tidal Facility of Flinders University, Wolfgang Scherer, said.
In some places such as Rabaul in Papua New Guinea rising volcanoes were causing land levels to rise while part of Australia was getting higher, causing the sea level to drop.
Climate change is one of the major themes of the 30th South Pacific Forum summit meeting on its second day in the northern Pacific island nation of Palau Monday.
Leaders have tended to blame global warming on the industrial world saying it has created an environment in which sea levels are rising, bringing flooding to low-lying atoll states.
Earlier this year, Kiribati claimed two of its islets in Tarawa had "disappeared" due to rising sea levels while Tuvalu, to the south, claims its coastline is sinking.
Scherer, who is part of a Pacific-wide sea level monitoring programme, said it was virtually impossible to identify any manmade effect in sea level change.
"You are playing a millimetre game with millimetre effects," he said, adding he would not want to speculate at this point on whether anything long-term was happening to the sea level.
The data was too little and too recent, he said.
However, he said it was clear that relative sea level rises in places like Kiribati may have nothing to do with the global situation but could be blamed on the use of freshwater aquifers under each atoll.
If such aquifers are over-used by the local population atolls can rise and fall, letting in more sea water to replace fresh ground water and flooding garden pits, giving the effect of sea level rises.
"The land itself is not stable, it is moving and often it is moving because of local issues."
He said the early data suggested the Pacific sea level might be rising by an average of two millimetres a year, but this was not uniform across the region and was often based on data less than 10 years old.
In Kiribati, data was showing the sea level fell by 21 millimetres while just to the north in the Marshalls islands the levels rose 2.9 millimetres.
"We are not finding places where the sea-level rise is very strong," Scherer said.
Scientists have little idea of what is happening to the land itself, whether it is rising or falling, and have no solid information on what the floor of the seabed is doing.
"The question is what is happening to the volume of the oceans, that is the real critical question ... and we are a long way from being able to do that problem."
While scientists cannot demonstrate any sea level rise or any relationship to manmade activities, Scherer said there was the possibility that global warming could speed up any increases.
"We cannot preclude the very definite possibility that the ocean may respond with an acceleration of sea level rise, even in the shorter term."