Adapting to Climate Change: An Introduction for Canadian Municipalities

Toronto's Heat-Health Alert System

This example illustrates how an adaptation measure can be based on existing program models and successfully integrated with similar programs.

Toronto developed its heat alert system proactively- before being crippled by a major heat wave- largely based on past disastrous heat wave experiences in Chicago (1995) and in Philadelphia (1993), both of which killed hundreds of urban residents and hence, were an impetus for implementing the Toronto Heat-Health Alert.

The City of Toronto has developed and implemented two extreme weather alert plans: Extreme-Cold Weather Alerts (in 1996), and Heat-Health Alerts (in 2001). These plans are designed to protect the City's most vulnerable populations—the elderly, children, medically at-risk persons, and the homeless—from extremes of heat and cold.

Typical summer daytime temperatures in Toronto vary between 17 and 20ºC, though temperatures often can exceed 26ºC. Between May and September, Toronto experiences on average 9.5 days over 30ºC (averaged from 1961-1990). However, between 1995 and 2005, Toronto experienced an average of 16.1 days per year above 30ºC. Some global climate change models estimate that temperatures in the Toronto area will rise between 2 and 5ºC in the next 100 years. This implies that Toronto will experience more frequent heat waves.

Before the Heat-Health Alert system was introduced, Heat Warnings were issued using one-day forecasts of a humidex of over 40ºC. The City identified a need to improve on this system, and developed the Heat-Health Alert system in partnership with the Toronto Atmospheric Fund and the University of Delaware. Using 46 years of meteorological data provided by Environment Canada and 17 years of mortality data, researchers identified which meteorological conditions coincide with an increase in the number of excess deaths. The Heat-Health Alert system relies on computer modelling of various weather factors, including humidex, apparent temperature (a measure of human discomfort due to combined heat and humidity), cloud cover, wind direction and speed, and air mass. Simply described, this method looks at the relationship between different air masses and climate conditions, and health (in the form of mortality).

The model predicts when the probability of excess mortality due to certain oppressive air masses rises above expected thresholds. When the conditions are such that it could potentially rise above 65 per cent, the Toronto Medical Officer of Health issues a Heat Alert. When the probability rises above 90 per cent, an Extreme-Heat Alert is issued. The variables associated with the oppressive air masses are tracked by the Heat-Health System, which is able to predict a heat alert or extreme-heat alert up to 48 hours before the event is expected.The City of Montreal is implementing a similar extreme heat alert plan. Heat alerts are issued when the temperature rises to 33ºC for three or more consecutive days, or when temperatures remain above 25ºC for two consecutive nights. Alerts are issued through the media and various community agencies, and response measures undertaken are similar to Toronto's.

At the beginning of the summer, the City of Toronto issues information about hot-weather risks and vulnerable populations to its partners and the media. The City also posts fact sheets on its Web site and distributes pamphlets. When a Heat Alert is issued, there is a city-wide response. Measures taken include:

• Contacting local media to inform the public that a heat alert has been issued.
• Contacting community agencies (more than 800 are involved) to inform them of the alert and ask them to take appropriate action. For example, shelters are asked to ease their curfew rules to allow people to stay inside during the day.
• Distributing bottled water through the Red Cross to vulnerable people at the places where they are likely to gather.
• Distributing Toronto Transit Commission (TTC) tokens to the homeless so they can reach cooling centres through community agencies that have out-reach programs.
• Operating a 12-hour heat information line to answer heat-related questions from the public and requests to check on seniors. (This helpline is operated by the Red Cross.)
• Staffing a Toronto Emergency Medical Services vehicle with a specially trained Community Medicine Program Paramedic, and ensuring the vehicle has emergency medical and other equipment to provide in-home medical and environmental assessments for persons at risk of developing heat-related illness.

In the event of an Extreme-Heat Alert, the City opens designated cooling centres at various public locations, such as civic centres. Some centres are open 24 hours as long as the Extreme-Heat Alert is in effect. As indicated, many of these activities are carried out in partnership with community services and agencies. Even the Toronto Animal Services provides information on how to help animals cope with hot weather.

The main benefit of the program has been an increase in awareness of problems related to extreme heat, and the partnering of various departments of the City of Toronto and non-governmental organizations and other local groups.

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