A built up of greenhouse gases in the atmosphere from human burning of fossil fuels can cause more powerful storms and raise the sea levels, exposing coastal land to increased erosion according to the experts. The rise in sea levels, pollution and damage to coral reefs make the coastline much more vulnerable to threats like tsunamis or storms.

World sea levels rose on average by 10-20 cm (4 to 8 inches) during the 20th century and an additional rise of 9-88 cm is expected by the year 2100, according to latest report by the U.N. Intergovernmental Panel on Climate Change in 2001.

Island nations like the Maldives, swamped by the tsunami, could literally disappear beneath the waves if seas rise. And in Bangladesh, 17 million people live less than one metre above sea level, as do many in Florida in the United States. One of the first risks for small islands is not that they will be submerged (by rising sea levels) but there will be no fresh water. Salt water would poison reservoirs of rainwater and purification equipment would be too costly.

The Intergovernmental Panel on Climate Change, a U.N. panel of 2,500 scientists, had stated in a report that average world temperatures would likely rise between 1.8 and 4.0 degrees Celsius in the 21st century. According to the Director of the U.N.'s International Strategy for Disaster Reduction (ISDR), new scientific evidence presented signaled temperature and sea level increases that would "very likely" make natural disasters more frequent and more intense. Few coastal ecosystems are robust enough to withstand freak waves like the ones that slammed into Asian nations from Sri Lanka to Thailand in 2004, killing more than 22,000 people, after a sub-sea earthquake off Indonesia.

Better weather tracking and early-warning systems could help mitigate the impact of heat waves, heavy rains, mudslides and drought, while climate-related hazards cannot be prevented outright. It’s likely that more heat waves and sea level increases could continue for more than 1,000 years even if greenhouse gas emissions -- released mainly by burning fossil fuels in power plants, factories and cars -- were capped.

But global warming, poorly planned coastal development and other threats over which humans have some control are weakening natural defences ranging from mangrove swamps to coral reefs that help keep the oceans at bay by providing a barrier and if they die many islands will be more vulnerable to cyclones.

According to Greenpeace "Coasts are under threat in many countries. Development of roads, shrimp farms, ribbon development along coasts and tourism are eroding natural defences in Asia." Damage to coral reefs was also making coasts more vulnerable to battering by the sea. An international report had showed that about 70 percent of the world's coral reefs had been ruined or were under threat from human activities, ranging from over-fishing to coastal pollution and global warming.

Replicating monitoring efforts strengthened after the deadly 2004 Indian Ocean tsunami could help address the "multi-hazards" expected to stem from climate change. International donors should be careful to ensure the world's poorest countries are ready for natural disasters linked to global warming according to the UN official. He stated that the aid ought to be well-coordinated to ensure houses, schools and hospitals are built away from landslide-prone areas, to protect coasts and farmlands and educate vulnerable people about ways to deal with natural disasters, he said.

Even simple measures such a shift in Bangladesh to raise ducks -- which can float -- instead of chickens, which drown in floods, could help according to the UN official. Efforts to plant drought-resistant crops in Cuba and India and to reinforce Costa Rican homes with storm-resistant bamboo were also good steps, he said.

The cost of an adequate initial ocean observing system would require a further investment roughly estimated at US$2 to 3 billion, involving: a stable network of satellites surveying vast extents of the surface of the oceans; fixed stations taking continuous measurements on the seafloor or as floats and buoys moored in the water column and at the surface; small robot submarine ocean monitors, some drifting with the currents, others motoring along programmed routes; marine animals ingeniously outfitted with electronic tags that equip them to capture and transmit data about the environments they visit; merchant marine and research vessels, opportunistically observing along their routes. Data analysis, integration with observations from the atmosphere and other sources, and assimilation into models then may produce insights and forecasts useful to the public and policy makers.

A continuous, integrated ocean observing system will return the investment many times over in safer maritime operations, storm damage mitigation, and conservation of living marine resources, as well as collecting the vital signs of the ocean that are needed to monitor climate change. The rapid pace of technological development is opening up entirely new approaches to ocean measurement, including biological and physical observations from fish and marine mammals. The potential for exploiting the merchant marine as platforms for monitoring ocean properties, although well demonstrated, offers tremendous opportunity for further development. Molecular biological techniques are transforming the way we identify species and interpret their evolutionary development; important opportunities exist for combining biological and physical data to better understand the linkage between marine ecosystems and ocean dynamics,” says David Farmer, Fellow of the Royal Society and head of the University of Rhode Island’s Graduate School of Oceanography.