The Globe and Mail began an article on purported links between asthma and climate change with the following sentence. “America’s cities, blanketed with smog and climate-altering carbon dioxide, have become cradles of ill health and are fostering an epidemic of asthma.” Is this really the case?

According to the media, the conclusive results were in. Global warming is linked to higher asthma rates. “Global warming linked to high asthma rates,” (Globe and Mail, April 30) “Asthma linked to global warming, experts say,” (CTV News, April 30) and “Report Predicts Asthma Epidemic from Pollution.” (Reuters UK, April 29) The Canadian media chose to focus on the supposed link between climate change and asthma rates in preschool-age children.

Media reports were based on “Inside the Greenhouse- The Impacts of CO2 and Climate Change on Public Health in the Inner City,” by Paul R. Epstein and Christine Rogers of the Center for Health and Global Environment and Harvard Medical School.

What the Harvard Report Says:

The focus of the Harvard report is not the relationship between asthma rates (in children or adults) and increased levels of CO2 or global warming. It had a larger purpose. “This report examines the direct impacts of CO2, as well as climate change, focusing on urban centers; examining synergies between air pollution and climate change and connections between climate change and emerging infectious diseases – in particular, West Nile virus, a disease carried by urban-dwelling mosquitoes that presents new problems for public health and mosquito control authorities.” (Epstein, pg. 4)

The authors list 17 “key points.” These points combine a tremendous range of environmental factors and possible implications. Four are cited here to give the reader a better sense of the report.

  • Point four: “Fungal growth inside houses can affect respiratory health and insurance coverage.”
  • Point five: “Floods can drive rodents from their natural burrows into developed areas.”
  • Point 11: “West Nile virus in the U.S. is a new phenomenon — a mosquito-borne disease in urban areas; one not previously faced by public health and mosquito control agencies,” and
  • Point 13: “Severe and erratic weather – early and late snowstorms, ice storms and dense fog – present hazards for automotive drivers and pedestrians.”

The report concludes that rising carbon dioxide levels “in themselves” pose health hazards and suggests that local initiatives on individual, organizational, city, state and regional levels “can go a long way towards improving energy efficiency.”

The authors also suggest that a “clean energy transition” can become the “engine of growth for the 21st century, helping to alleviate poverty and initiate a more equitable, healthy and sustainable form of development.”

What the Media Say:

CTV reported that “The health of millions of children worldwide is threatened by global warming and air pollution,” and that there is a “health crisis” as a result of increased CO2 combined with pollution in the air. No conflicting viewpoint was offered for possible causes of increased asthma rates.

The Globe and Mail wrote of climate change fostering an “asthma epidemic.” This article cited one doctor with a conflicting view, who said that climate change may “play a part” in rising asthma rates, but indicated that other factors are also involved.


There are inaccuracies in the Harvard report itself:

  • The report says that CO2 levels are rising. This statement in itself is debatable.1
  • No data is given on the purported link between rising asthma rates and climate change or increases in CO2. No numbers of asthmatic children from different cities are given. There is no attempt in the report to account for other reasons for the increase, such as better diagnostic techniques in younger children.
  • The report uses numbers without footnoting the source. In a case study on the European Heatwave of 2003 the report notes that “35,000 people died from the direct results of heat.” No source is given for this highly questionable number.

There are inaccuracies in the way the media presented the Harvard report:

  • The amount of time explicitly devoted in the Harvard report to rising levels of asthma in children is miniscule and yet the media presented this aspect almost exclusively. The Harvard report is by no means devoted to exploring causes of asthma in children. It states only that the largest increase in asthma occurred in preschool-aged children (an increase between 1980 and 1994 of 160 percent). It is indeed worth asking whether the researchers ever intended to explain the causes of asthma in children, or whether they used this point to draw the media in. Television reportage was accompanied by photos of preschoolers in doctors’ offices using inhalers- certainly a more riveting audience hook than a general item on climate change.
  • Where the Harvard report frequently uses the words “may” “might” or “potential” to indicate the possible effects of climate change, the media did not. Media reports are therefore fundamentally inaccurate: “The following categories of diseases and other health impacts may (emphasis added) be affected by climatic conditions (Epstein, pg. 12) ” is a very different statement from “The following categories of diseases and other health impacts are (emphasis added) affected by climatic conditions.” The report said the former, while the media published the latter.
  • The Harvard report refers only to American cities, the media reported on a “worldwide crisis.”
  • The report is in fact a summary of other studies. The media reported it as if it were a set of new scientific findings, specifically on the relationship between asthma rates and climate.

Unrelated stories later in the same week on rising asthma rates will solidify a link between cities, pollution and asthma in Canadians’ minds that may or may not exist.

The media made no attempt to offer balanced articles on an already unbalanced report, in which many political and economic, as opposed to health or environmental, recommendations were made. It is not clear how changes in the economy toward using different energy sources will alleviate respiratory problems, nor is it clear how a “clean energy transition” will “help to alleviate poverty and initiate a more equitable, healthy and sustainable form of development.” Yet these are the conclusions of the report.

Readers should be aware of the inaccuracies and misrepresentation in the initial report, and the subsequent multiplication of inaccuracies in media reports.

Andrea Mrozek is a freelance writer and a former intern in the Toronto office of the Fraser Institute.


1“CO2 emissions have been pretty much stable over the past 30 years. From 1950 to 1974, CO2 emissions increased by a factor of 2.4 in Canada. But per capita CO2 emissions peaked in 1979 and have held steady ever since, despite economic growth. (Source: Marland, G., T.A. Boden, R. J. Andres (2000) “Global, Regional, and National CO2 Emissions.” In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn.)” From “Is Canada the World’s Biggest (per capita) Emitter of CO2?” CANSTATS, January 11 2003. Found online at Canstats

Leave a Reply

Your email address will not be published. Required fields are marked *