Scenario-based studies in the Great Lakes-St. Lawrence basin conducted over the past 15 years (see Section 15.2.1) have indicated consistently that a warmer climate would lead to reductions in water supply and lake levels (Cohen, 1986; Croley, 1990; Hartmann, 1990; Mortsch and Quinn, 1996; Mortsch, 1998). Observed low-level events have been rare during the past several decades, but when they have occurred (e.g., 1963-1965, 1988), conflicts related to existing water diversions and competing stakeholders have led to legal challenges and political stress (Changnon and Glantz, 1996).
In 1998-1999, dry and record warm weather combined to reduce ice extent and lower water levels (Assel et al., 2000). In November 1998 and again in spring 1999, cargo limits were placed on ships travelling through the Great Lakes and the St. Lawrence Seaway when water levels fell by more than 25 cm. Some commercial ships ran aground. Lower water levels significantly increased the distance between docks and waters at some tourism facilities and marinas. Recreational boaters had access to fewer waterways. In addition, hydroelectric facilities are very dependent on water flows and have expressed concern about maintaining production (Mittelstaedt, 1999). These observed impacts are similar to the impact scenarios described earlier. The reduction in ice cover did provide some offsetting benefits by reducing the need for icebreakers during the winter and spring (Assel et al., 2000).
Water resources management, ecosystem and land management, and health concerns are highlighted in the Great Lakes-St. Lawrence Basin Project (GLSLB) and the Toronto-Niagara Region Study (TNR). The former is a binational exercise that used analogs and model-based scenarios to assess impacts and adaptation responses. Reduced lake levels continue to be projected, leading to potential conflicts over water regulation and diversions, water quality, and rural water use (Mortsch et al., 1998). The TNR exercise is in its initial stages. Within the GLSLB region, the TNR represents a highly urbanized area that has a significant impact on surrounding agricultural and forest landscapes. Urban influences on land use, air quality, and human health will be a major focus. In addition, concerns about vulnerabilities of the built environment (transportation and energy infrastructure, etc.) have been identified as high-priority research questions (Mills and Craig, 1999).
There also have been studies of alternative scenarios for lake-level management. Decision support systems can facilitate this process (Chao et al., 1999).
Severe winter storms combined with a loss of power can have devastating consequences, even in a highly developed region such as Ontario-Quebec and the northeast United States. In January 1998, a severe winter storm struck; instead of snow, some areas accumulated more than 80 mm of freezing raindouble the amount of precipitation experienced in any prior ice storm. The result was a catastrophe that produced the largest estimated insured loss in the history of Canada. The same storm ran across northern New York and parts of Vermont, New Hampshire, and Maine in the United States (see Table 15-5). The basic electric power infrastructure, with its lengthy transmission lines, was severely damaged, stranding some residents and farmers without power for as many as 4 weeks. Almost 5 million people were without power at some point during the storm, and consideration was given to evacuation of Montreal. In Canada, there were 28 deaths, and damages were US$2-3 billion (CDN$3-4 billion) (Kovacs, 1998; Kerry et al., 1999). The same storm caused 17 deaths in the United States, as well as damages exceeding US$1 billion in New York and the New England statesone-third of which was from losses to electric utilities and communications (DeGaetano, 2000). Combined Canadian and U.S. insured losses stood in excess of US$1.2 billion as of October 1, 1998. Total Canadian insured and uninsured economic losses were approximately US$4 billion (CDN$6.4 billion).
The ice storm produced more than 835,000 insurance claims from policyholders in Canada and the United States. This was 20% more claims than were created by Hurricane Andrew, the costliest natural disaster in the history of the United States.
The event served as a grim learning laboratory for the insurance and disaster recovery communities. It revealed the wide spectrum of insured and noninsured losses that can materialize from a single natural catastrophe, including:
Ice storms occur regularly in North America, although severe and prolonged damage is rare. Several urban centers are vulnerable to major storms, including Minneapolis, Winnipeg, Chicago, Detroit, Toronto, Buffalo, Montreal, Boston, and even New York. Many communities are not prepared for an extreme winter storm, particularly combined with the loss of electric power. In the 1998 storm, total losses exceeded insured losses by a substantial margin. The event also raised questions about the connection between such events, the El Niño phenomenon, and global climate change.
Other reports in this collection