Researchers will soon begin mapping the coastline around Halifax to help predict which areas are at risk of disappearing under water as an effect of global warming.

The mapping project will look at 1,300 square kilometres in and around Halifax Harbour.

"It's absolutely critical that we have the mapping that we can do predictive modelling with," said Stephen King, manager of environmental management services with the Halifax Regional Municipality.

"What are the most susceptible areas to the storm-surge sea-level rise?"

A United Nations report released last week said human activity was "very likely" the cause of global warming and that higher temperatures and rising sea levels would continue for centuries, regardless of reductions in greenhouse gas emissions.

Rising sea levels are the biggest threat posed to Nova Scotia, according to a report commissioned by the provincial government.

Called Adapting to a Changing Climate in Nova Scotia, the 2005 study presents a bleak scenario for what could happen in the province over the next 75 years. It says likely problems include:

• More frequent and intense storms.
• Storm surges likely to inundate areas never before flooded, including farmland.
• Less water available for consumption during dry periods.
• More mosquito-borne diseases, including malaria and West Nile virus.

Researchers will use LIDAR, a technique that fires laser beam pulses at the shoreline to produce a map of great accuracy. This will allow scientists to chart the impact of rising sea levels centimetre by centimetre, revealing which areas are most at risk.

The survey, expected to begin in March or April, will cover Halifax Harbour, its drainage basin and the East Petpeswick peninsula.

The provincial government is helping to cover some of the costs of the $250,000 mapping study.

The municipality has already developed draft guidelines for developers, but they have been delayed as staff try to get answers from this mapping project that will determine just how far buildings need to be back from the water line.