Worsening heat waves could kill thousands of people in North American cities unless governments put in place better warning systems and other protective measures, says a major UN report on climate change.

The report by the Intergovernmental Panel on Climate Change won't be released until next month but its contents were described by Gordon McBean, a scientist who has seen it.

The report will say the vulnerability of specific regions depends on the effectiveness and timing of adaptation strategies -- a point also made by former environment commissioner Johanne Gelinas in her last report before being fired recently.

A heat wave in August 2003 killed 35,000 people in Western Europe and a similar tragedy could occur in North America "unless we take counter-measures,'' said McBean, president of the Canadian Foundation for Climate and Atmospheric Sciences.

Protective measures would include warning systems, architectural changes, protection of green space, and community programs to monitor the well-being of people living alone.

The UN study will identify coastal areas sensitive to sea level rise and cite Charlottetown as an example of a city vulnerable to increased flooding and storm surges, McBean said.

It will outline the risk of water shortages on the Prairies and of a sharp drop in Great Lakes water levels that could interfere with navigation.

The study will also highlight the risks to infrastructure in the North and in coastal areas, said McBean.

"The major railway line that connects Halifax with the rest of Canada runs along about a foot above sea level along the Bay of Fundy.

"We should be now doing the investments to make those critical transportation facilities less vulnerable by moving them inland.''

So far, Canada's debate about climate change has focused almost entirely on how to reduce greenhouse emissions, and some environmentalists have resisted talking about adaptation thinking it implies surrender on the emissions issue.

But scientists say a certain amount of warming is inevitable regardless of how much emissions are cut. That's largely because the oceans absorb heat gradually, delaying the effect of past emissions.

"All of the good work we hope is done on protocols and all that kind of stuff will actually have no impact on that at all (in the near term),'' said McBean.

"It will have an impact showing up by mid-century and particularly in the latter part of the century.''

He said there is an urgent need for more research to guide adaptation strategies in specific sectors and regions.

Most such research in Canada has been co-ordinated by the Canadian Foundation for Atmospheric Sciences, which received $110 million from the previous Liberal government.

The money has now been allocated, and no new funding has been received from the new Conservative government, said McBean.

"So far, at least in a public way, the missing ingredient in our national strategies has been on the question of adaptation policies, said McBean.

"We have not had an active federal strategy, a nationally co-ordinated strategy on adaptation."