Vulnerability of Waterborne Diseases to Climate Change in Canada: A Review

Abstract

This project addresses two important issues relevant to the health of Canadians: the risk of waterborne illness and the health impacts of global climate change. The Canadian health burden from waterborne illness is unknown, although it presumably accounts for a significant proportion of enteric illness. Recently, large outbreaks with severe consequences produced by E. coli O157:H7 and Cryptosporidium have alarmed Canadians and brought demands for political action. A concurrent need to understand the health impacts of global climate changes and to develop strategies to prevent or prepare for these has also been recognized. There is mounting evidence that weather is often a factor in triggering waterborne disease outbreaks. A recent study of precipitation and waterborne illness in the United States found that more than half the waterborne disease outbreaks in the United States during the last half century followed a period of extreme rainfall. Projections of international global climate change scenarios suggest that, under conditions of global warming most of Canada may expect longer summers, milder winters, increased summer drought, and more extreme precipitation. Excess precipitation, floods, high temperatures, and drought could affect the risk of waterborne illness in Canada. The existing scientific information regarding most weather-related adverse health impacts and on the impacts of global climate change on health in Canada is insufficient for informed decision making. The results of this project address this need through the investigation of the complex systemic interrelationships between disease incidence, weather parameters, and water quality and quantity, and by projecting the potential impact of global climate change on those relationships.

Determining Canadian water utility preparedness for the impacts of climate change

“…The summary findings of the leading international body for climate change assessment -comprised of thousands of scientists from all corners of the globe -are that warming of the climate system is unequivocal, that atmospheric concentrations of carbon dioxide, methane, and nitrous oxide have increased to unprecedented levels and that human influence on the climate system is clear (IPCC, 2013). Outcomes of global warming conditions as projected by world climate change models include longer summers, milder winters, increased drought, and more intense precipitation (Charron et al, 2004). Relatedly, studies of precipitation and waterborne illness in North America have found significant associations between extreme precipitation events and rates of gastrointestinal illness (Curriero et al, 2001;Harper et al, 2011).…”

Avoiding dangerous climate change

“…There is also the possibility of true surprises, events not yet currently envisioned [66]. However, in the case of true surprises, it is still possible to formulate 'imaginable conditions for surprise'-like rapidly-forced climate change, since the faster the climate system is forced to change, the higher the likelihood of triggering abrupt nonlinear responses (see page 7 of [27]).…”

“…Schneider et al (1998) [66] took this a step further, defining 'imaginable surprises'-events that could be extremely damaging but which are not truly unanticipated. These could include a large reduction in the strength or possible collapse of the North Atlantic thermohaline circulation (THC) system, which could cause significant cooling in the North Atlantic region, with both warming and cooling regional teleconnections up-and downstream of the North Atlantic; and deglaciation of polar ice sheets like Greenland or the West Antarctic, which would cause (over many centuries) many meters of additional sea level rise on top of that caused by the thermal expansion from the direct warming of the oceans [61].…”

“…[79], [20], [66], [39], [56], [11], [34]). In the discussions among authors in the AR4, one classification scheme for uncertainties includes the following categories: lack of scientific knowledge, natural randomness, social choice, and value diversity [23].…”

Monitoring Recreational Waters: How to Integrate Environmental Determinants

“…Moreover, during rainfall some bacteria such as E. coli would be quickly carried away by runoff waters and would have less chance to interact with the soil matrix [66]. Furthermore, studies have shown positives associations between rain events and waterborne disease outbreaks [67][68][69].…”