Natural Disasters on the Rise

In 2002, natural disasters caused approximately $85 billion in economic losses worldwide—up 36 per cent over the previous year. Last summer, parts of Europe experienced the worst floods in centuries, while Western Canada struggled through the most devastating drought in its recorded history.

Last year, the world experienced approximately 700 natural disasters—50 more than the annual average during the 1990s. The magnitude of the events that occurred and recent trends lend weight to the fact that such incidents are growing not only in number, but also in size.

Over the past decade, Canada has experienced many of its largest natural disasters, and experts believe that even bigger and more devastating ones are inevitable. While geophysical disasters, such as earthquakes, have remained relatively constant in this country over the past 50 years, weather-related disasters have skyrocketed. Climate change is projected to exacerbate this situation in future, as it is expected to increase the frequency and severity of some extreme weather events.

To examine this trend and help determine ways to mitigate its risks, a team of public- and private-sector partners, led by Environment Canada's Meteorological Service of Canada, formed the Canadian Natural Hazards Assessment Project. Key players include the Office of Critical Infrastructure Protection and Emergency Preparedness, the Institute for Catastrophic Loss Reduction, private insurance companies, emergency responders, academics, sociologists, and engineers.

After more than three years of collecting and analyzing data, the project team has written 20 technical papers on the subject, most of which will be published early this year in a special edition of the Journal of Natural Hazards. Also scheduled for release by this spring is a summary document for decision makers and members of the public.

The team's findings indicate that a combination of factors are behind this upward trend, not only in Canada, but also around the world. Chief among these is the fact that human beings have greatly increased their vulnerability to suffering some degree of loss from a hazardous event. This has occurred due to the many economic, socio-demographic, and technological changes that have taken place over the past 50 years.

For example, by exploiting our natural resources, humans have degraded the environment and destroyed natural buffers that help to reduce the impacts of certain hazards. Greenhouse-gas emissions from the burning of fossil fuels are changing our climate. The cutting of timber on hillsides is magnifying the impact of landslides. The draining of wetlands has amplified the effects of flooding.

Population growth and urbanization are also major contributors to our increase in vulnerability. Higher concentrations of people living in urban areas means that if disasters do hit, they affect a larger number of individuals. Urban sprawl has led to more development in high-risk areas, such as flood plains. Over-reliance on technologies, such as structures that divert floodwaters, has also encouraged development that might otherwise not have taken place—making the potential impact of a disaster even greater. Other factors include our aging population and our aging infrastructure, both of which are more susceptible to harm.

Data show that just over half of all Canadian disasters—whether natural or not—have been weather related, and that this percentage has increased drastically in recent years. Virtually all of the most expensive natural disasters this country has experienced fall into this weather-related category.

As in the rest of the world, floods are the main cause of the increase in the number of natural disasters in Canada, despite the fact that their impacts are largely avoidable. Snowmelt accounts for about 40 per cent of all floods in Canada, although they can also be caused or compounded by heavy rainfall, ice jams, glacier outbursts, coastal storms, tsunamis, cyclones, and hurricanes.

While some research suggests that a greater percentage of Canada's rainfall is occurring in heavy downpours, much responsibility for the upward trend in flood disasters is our own. Flooding in urban areas has been greatly exacerbated by extensive paving (which reduces the penetration of water into the ground), aging sewer systems that are less able to cope with larger loads, and the construction of roads, homes, and other structures on flood plains.

Forecasts can be useful in lessening the impact of flood events, but improved flood-plain mapping, land-use planning, and the use of structural defenses are even more effective. For example, the Red River Floodway, which was constructed in the 1960s to protect Winnipeg from flooding, has been used more than 20 times since—and saved an estimated $6 billion during the Red River Flood of 1997.

Drought is Canada's most expensive natural disaster in a cumulative sense. Over 40 severe events have occurred over the past 200 years in Western Canada alone, and a number have taken place in other parts of the country as well. Four of the six most expensive natural disasters in Canada's history were droughts—and all four took place within the last 25 years.

Droughts can be related to reduced streamflow, water levels, runoff, or soil moisture, but most are caused by disruptions in normal weather patterns that result in below-normal precipitation. They can be self-perpetuating, since areas experiencing drought add little water vapour to the local atmosphere. Droughts can't be predicted, but their impacts can be lessened through such efforts as water and soil conservation, grassland management, and forest-fire watches.

Although the only significant earthquake in Canada occurred off the East Coast in 1929, triggering a tsunami that killed 28 people, scientists predict that an earthquake in the Vancouver area is the most likely major disaster on our horizon. Since quakes occur where tectonic plates converge, only certain regions of the country are at risk: the West Coast, the St. Lawrence and Ottawa valleys, off the coast of Nova Scotia and Newfoundland, and certain parts of the Arctic.

Quakes are also unpredictable, but maps of their probability can be created using databases of past locations and magnitudes, and geotechnical models. These maps allow for the design of appropriate building codes, as well as the avoidance of development in potentially hazardous areas.

The findings of the Canadian Natural Hazards Assessment Project clearly indicate that mitigating the risks of natural disasters in Canada requires more than advancements in science and technology. It requires us to create a culture that is aware of disasters and their risks, and that considers them at all levels of decision making. It requires the implementation of non-structural steps, such as the preservation of the natural environment, public education, and the relocation of communities to areas that are not hazard-prone.

Most importantly, we must address the large gaps that exist in our understanding of the vulnerability of different regions of Canada by creating an interdisciplinary hazards community that involves both the physical and social sciences. By being aware of natural hazards and how the decisions we make affect our vulnerability, the human and economic toll they impose upon us can be greatly reduced.

  Home |  Air |  Atmospheric Science |  Climate Change |  Environmental Action |  Habitat |  Pollution |  Species at Risk |  Technology |  Water |  Weather |  Wildlife