Tuvalu's tides divide scientists
Don Kennedy is raising money to build Tuvaluans a new settlement on a Fijian island.
What is causing the seas around the tiny Pacific nation of Tuvalu to rise? Sharon Mascall reports.
There is no doubt in Don Kennedy's mind. Tuvalu - located halfway between Australia and Hawaii in the South Pacific Ocean - is under threat. He has witnessed first hand the warnings that scientists have been broadcasting for years. The sea is stealing its shores.
"I grew up in Tuvalu as a child and left as a young man. When I lived there I had never heard of such things as hurricanes or king tides.
"Now the king tides go right up to the houses and they're becoming more frequent every year. In Tuvalu they used to say it was the hand of God and God will look after them. But now there is evidence of climate change. A few educated people are expecting catastrophe to happen."
Now based in Melbourne, Kennedy is determined to rescue his countrymen and women. He is raising money to build a new settlement on the Fijian island of Kioa - offering Tuvaluans a modern-day Noah's Ark.
He is also appealing to Australia, along with other industrialised nations, to intervene. "I have a feeling of rage and sadness that this is not through the hand of God but through the ignorance and greed of mankind," he says. "There is no doubt in my mind that the cause is global warming."
Australia is partly to blame, he claims. Emissions of carbon dioxide and other gases by industrialised nations are causing a greenhouse effect - where heat from the sun is trapped in the atmosphere and radiated back to Earth.
According to the Intergovernmental Panel on Climate Change - the IPCC - average global temperatures have risen by more than 0.7 degrees over the past 300 years. Most of the increase was registered in the past century.
"Most of the warming observed over the last 50 years is likely to be attributable to human activities," said the IPCC in 2001. The body - collating the expertise of thousands of scientists worldwide - also notes that oceans are expanding, ice sheets are melting and sea levels could rise by almost half a metre this century.
It sounds like an open-and-shut case. Cut emissions and global warming will stop. Sea levels will stabilise. Tuvalu will be saved. The science behind such conclusions reveals, however, that it is not that simple.
Firstly, global warming is not the only factor affecting sea levels in the Pacific.
Bill Mitchell, the manager of the National Tidal Facility in Adelaide, which is collecting data in the region, says the ebb and flow of the sea is not fully understood.
"It's very, very complex. You have to get a handle on the movement of land. There are changes in weather, barometric pressure and oceanographic processes such as currents."
Those oceanographic processes include the Pacific Decadal Oscillation, where a huge slosh of water moves around the ocean over a 10-year cycle.
The El Nino effect has also played a part. Interruptions to trade winds across the ocean have affected global weather patterns, making the sea rise and fall unexpectedly.
"The IPCC has done its best, considering the thousands of scientists who have contributed," says Mitchell, "but the truth is that scientists don't really know if they've got a handle on it."
Mitchell is not alone in recognising that complexity and uncertainty lie at the heart of an understanding of the issue.
"We are discussing uncertainty," says Roger Jones, a senior CSIRO scientist based in Melbourne who is contributing to the IPCC. "We are trying to be clear, we don't want to confuse people. Policy-makers need to make decisions and understand what we say."
So far, the IPCC's approach has been to publish a range of outcomes based on computer models. The models must accommodate margins of error and - in the case of Pacific sea levels - a lack of long-term data.
"The records are too short," says Mitchell. "Oceanographic processes take years."
On far-flung Tuvalu, sea gauges have been in place for just over 11 years - too short a time scale, he says, to draw accurate conclusions.
The use of computer models has drawn strong criticism from some quarters. Sonja Boehmer-Christiansen, the editor of the scientific journal Energy and Environment , says they are based on data that cannot be verified.
"The range of possibilities is quite large. The green lobby has gone for the most scary interpretation and the IPCC has not tried to stop it."
The outcome, she says, is that Australia is being "greenmailed" rather than "blackmailed".
"Some countries are trying to use global warming to access aid - but is it for the right reasons? I can understand poor countries wanting more money from rich countries but it's a shame if it's under false argument."
Other scientists reject the IPCC's findings altogether. William Kininmonth, a Melbourne meteorologist who is about to publish a book about climate change, believes that any shifts in global weather patterns are a natural phenomenon.
"The computer models are fundamentally flawed," he says. "The IPCC got it right in 1990 when they said there is a greenhouse effect but since then they've gone further off the rails.
"Climate change is something that has happened in the past ... Previous interglacial periods had higher sea levels and higher temperatures."
Unmoved by scientists' calls for more research into climatic variability and whether other factors could account for the plight of Tuvalu - erosion, sand mining, construction projects - Don Kennedy is still determined to take action.
"We can argue this until kingdom come - what they do and don't know. But look at the hardship of these people, do something to help them."
It's an argument that many scientists agree with, despite their reservations about the accuracy of conclusions and predictions.
"If we wait for another 100 years of research it could be too late," says Jon Barnett, a scientist at the school of Anthropology, Geography and Environmental Studies at the University of Melbourne.
"The Australian Government is playing the uncertainty card in order to do nothing."
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