Global climate change could radically alter the appearance of Bermuda, marine and coastal geologist Dr. Don Forbes said yesterday.

Ocean levels are expected to rise between nine centimetres and 88 cm by the year 2100, Dr. Forbes told The Royal Gazette.

"Our best guess is that the sea level will rise by a half metre - 48 centimetres," he said.

While rising water levels may not seem immediately shocking - as tides tend to rise and fall by similar amounts daily - Dr. Forbes said when you consider that the tides will be that much higher again and there may be storm surge and other wave activity giving the sea additional height and ferocity, the effects in terms of coastal erosion and costs of storm damage could be dramatic.

Dr. Forbes will be delivering lectures at the Bermuda Underwater Exploration Institute (BUEI) today and tomorrow as part of the museum's 2002 Explorer Lecture Series.

He told The Royal Gazette that scientists are now relatively confident global sea levels are on the rise but are less certain what the effects will be in different regions.

Sea levels are rising from combination of factors, he explained.

"We're seeing a melting of glaciers and icecaps in arctic lands like Greenland; glaciers are moving from frozen land to ocean," Dr. Forbes said.

"It's not clear yet if there is a net increase in melting in Antarctica.

"But this melting is combined with thermal expansion of the upper mixed level of the ocean."

As the air gets warmer, sea surface temperature too is rising, causing expansion due to decreasing density in the uppermost level of the sea which also adds to overall increase in volume.

The rate at which global seas are rising is not clear and seems to vary from region to region, but the overall phenomenon is of great concern to islands and coastal regions.

Dr. Forbes said there are particular worries about sea levels in low South Pacific islands such as Tuvalu where there is no land more than two to three metres above sea level.

While Bermuda is fortunate to have high ground, it is also compromised by its small land mass and dense population. And the changing global climate may also pose a threat to Bermuda's coral reefs, the most northerly reef structure in the world.

Depending of the degree of sea temperature change, Bermuda may see bleaching of the reefs as healthy coral dies off in warmer waters.

Reef death is would be costly to Bermuda as, in addition to offering beauty and protection from the sea, the coral reefs "grow" sand - a benefit to Bermuda that is absent in may coastal regions.

However, Dr. Forbes suggested that the rising tide of threat against Bermuda and other coastal regions can be managed, provided it is recognised and studied.

Dr. Forbes recently participated in a multidisciplinary study in Canada - where he works as a research scientist with the Geological Survey of Canada at the Bedford Institute of Oceanography in Halifax, Nova Scotia.

The research project used emerging technologies to study the effects of climate change on the Canadian province of Prince Edward Island (PEI).

Among other things, the study used a laser mapping technique to construct topographical models of how predicted sea levels will affect the Island - in both calm and storm weather.

Dr. Forbes said the Insurance Bureau of Canada was particularly interested in the research and many other regions are now inquiring about the study's applications - including CARICOM and Bermuda.

Part of managing the threat of higher sea levels will lie at the level of community planning and land development, Dr. Forbes said yesterday.

Coastal setbacks for developments need to be considered wherever possible as well as coastal fortifications, he said.

However, Dr. Forbes recommends natural coastal fortifications - protecting the health of reef barriers and planting mangrove forests - over simply pouring concrete along the coastline.

Bermuda's also benefits from overall economic strength, he added. Unlike many Island nations, Bermuda has resources at its disposal to direct toward protecting the environmental health of the Island.

In his lectures, Dr. Forbes will link storm damage Bermuda has already suffered during storms such as 1995's Hurricane Felix, to what the Island might expect in storms backed by higher sea levels.

Doors will open for the lectures at 6.30 p.m. and Dr. Forbes will speak at 7 p.m. Tickets for BUEI members are $10 and $12.50 for non-members.

Please call BUEI for ticket availability.