It sounds like the stuff of nightmares: increased heat waves in urban centres, droughts in areas already short of water, increased flooding risk in coastal regions and a rise in disease and illness.

Flooding is expected to increase in low-lying coastal regions around the world, a new climate change report warns. A resident paddles down a flooded street in Squamish, B.C., in 2003. (Richard Lam/Canadian Press)

These potential environmental disasters arise not from the imagination, but rather from the findings of a new UN-led report on the impacts of climate change.

When the Intergovernmental Panel on Climate Change in February released its summary of a first report on a changing Earth warmed by greenhouse gases, it predicted average worldwide annual temperatures would increase between 1.8 and four degrees Celsius over the next century and that sea levels would rise between 18 and 59 centimetres over the same time period.

It also called the proof of global warming "unequivocal" and said the root cause was "very likely" the result of human-produced greenhouse gas emissions.

The findings had an effect on governments and the public across the globe, but much of the talk that followed focused on how best to reduce greenhouse gases. And while the numbers were alarming, they were abstract enough to be open to interpretation on how climate change might actually affect the public.

Now, the second of four reports from the IPCC is making global warming a great deal more personal, predicting consequences worldwide and in the most vulnerable regions. The devil of climate change, it appears, is in the details.

The summary of this second report, titled Impacts, Adaptation and Vulnerabilities, was presented in Brussels on Friday, April 6, after another weeklong meeting of the IPCC.

It painted a grim picture of the future, particularly for the world's poorer regions.

It said up to 30 per cent of the Earth's species face an increased risk of extinction if average global temperatures exceed 1.5 to 2.5 C. Coastal regions will face heightened threats from flooding, severe storms and the erosion of coastlines, and areas suffering from water shortages will become even dryer, leading to increased risks of hunger and disease, the report predicted.

But it did not contain some information from earlier leaked drafts of the report, particularly sections linking the impacts around the world to each degree Celcius in temperature change. The report also said the influence of man-made global warming on the planet was only "likely," or up to 67 per cent certain, a softening of the report's expected stance.

The third IPCC report, detailing potential ways to mitigate climate change, is expected on May 4, and a fourth and final report, summarizing the first three reports, is expected on Nov. 17.

Many of the expected effects over the next 20 to 40 years can safely be predicted because of the slow response of the climate system to change, according to John Stone, a vice-chair with the IPCC's Working Group II, the team responsible for drafting both the summary and the report.

"While emissions have to be significantly reduced, there will be some impacts over the next two to four decades," Stone wrote in an e-mail to CBC News Online.

"Essentially, the history has already been written," he said.

The report goes into detail on specific regions at risk, warning higher temperatures could lead to water shortages effecting as many as 250 million people in Africa. Global warming could also severely threaten the ecologically rich Great Barrier Reef, melt snow on Africa's Mount Kilimanjaro and replace the eastern Amazonian rainforest with savanna.

For North America, the summary warned of increased risk of damage to forests from fires, pests and diseases. It predicted coastal communities would face heightened threats from flooding, severe storms and the erosion of coastlines. Cities that currently experience heat waves will see an increase in their intensity and duration over the next century.

It also predicted a short-term positive effect, as climate change would actually increase rain-fed agriculture in the next few decades in North America, as warmer temperatures would lengthen the growing season in some regions.

A polar bear plays on the ice near Churchill, Man. The giant predator faces possible extinction should rising temperatures in Arctic regions continue along predicted climate models. (Jonathan Hayward/Canadian Press)

Gordon McBean, president of the Canadian Foundation for Climate and Atmospheric Sciences and one of the review editors for the upcoming report, outlined for CBC News Online some of the impacts that could affect Canadian regions in particular:

• Worsening heat waves in major cities.
• Increased flooding from storm surges in coastal areas sensitive to sea-level rise, such as Charlottetown and the Fraser Valley delta in B.C.
• Water shortages in the Prairies, the result of rising temperatures increasing evaporation rates and affecting glacial sources of water.
• Lowering of the Great Lakes from evaporation, with implications for marine transportation, sewage and water-intake systems and marine ecosystems.
• Changes in the Arctic climate affecting the region's unique ecosystem, threatening many of the species in the North, particularly the polar bear.

A draft copy of the report's North American chapter, obtained by CBC News Online, estimated the annual cost of damage from weather-related extremes such as hurricanes, floods, droughts, heat waves and wildfires had reached "tens of billions of dollars in damaged property and economic productivity, as well as lives disrupted and lost.""

The draft report suggested North American vulnerability to the predicted changes would depend on the effectiveness and timing of adaptation. It said it would be necessary to centralize the response to climate-change issues in order to protect vulnerable groups, such as indigenous people and those with low incomes or who live in isolated areas.

One group that is particularly vulnerable to climate change is people living in Canada's Arctic regions.

While worldwide temperatures are expected to rise between 1.8 and four degrees Celsius over the next century, the rise in polar regions is expected to be more substantial, with some models predicting a rise of as much as 10 degrees.

"Climate change is exacerbated in higher latitudes," McBean said. "This was made clear in the Arctic Climate Impacts Assessment."

If many of the findings seem familiar, it's because the IPCC's Working Group II presented them in 2001, the last year the organization issued a similar impact assessment report.

The 2001 report detailed projected impacts such as increased mortality from heat stress, drought in the Prairies, the expansion of vector-borne diseases and the risk of flooding of coastal settlements.

Adaptation needed

Nations and the public alike will need to brace themselves for these changes, McBean said.

He outlined a number of actions Canadian cities can take:

• Coastal regions should strengthen and enlarge dikes against rising sea levels.
• Urban centres at risk of deadly heat waves could also add green space to mitigate the absorbtion of heat from materials such as concrete and asphalt.
• Prairie provinces facing water shortages might have to consider shifting farming to northern regions of the provinces, where conditions are likely to improve.

"We need a strategy that recognizes that the climate is changing," McBean told CBC News. "We need to have a strategy that rethinks the way we do things."

Up until now, most of the focus has been on reducing greenhouse gas emissions. Stone said both adaptation and emission-reduction strategies will be needed to ensure the predicted challenges of a century of climate change can be handled.

"What we have to develop is a portfolio of response actions," he said. "If we don't reduce emissions the impacts will be even greater. The longer we delay in reducing emissions, the greater will be the costs of the damages and the eventual costs of reducing emissions. In addition, we will be exposing ourselves to greater risks."

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