Climate change

Climate science and global warming

The evidence supporting the changes in global climate is strong, and contrary to what “climate sceptics” assert, it is supported by numerous peer-reviewed articles and reports from respected scientific bodies such as the Intergovernmental Panel on Climate Change,⁴ the US National Oceanic and Atmospheric Association,⁵ and the National Aeronautics and Space Administration Goddard Institute for Space Studies.⁶Figure 1,⁶* for example, shows the rise in global annual mean surface air temperatures since 1880. The average annual temperature in Canada has increased 1.30°C in the past 50 years. The change is greater at higher latitudes and in winter, such that the average annual temperature in the Arctic winter is projected to increase as much as 3°C to 4°C by 2020, and 5°C to 10°C by 2050.⁷ Associated changes of importance have included alterations to the hydrologic cycle, with a 12% increase in average annual precipitation in Canada in the past 50 years; increased intensity of storms and floods (due to warmer air holding more moisture); more periods of drought in many areas, including in central Canada; globally a rise in sea level; and a substantial loss of global biodiversity.

The Intergovernmental Panel on Climate Change states that the global increase in temperature is “very likely” (> 90% probability) owing to increases in the atmospheric concentration of greenhouse gases (GHGs), which are the result of human activity.⁴ The rate of increase of carbon dioxide emissions has steepened recently (Figure 2),⁸* such that the International Energy Agency⁹ believes we are now on a trajectory to a temperature increase of more than 3.5°C, a scenario that the World Bank describes as “devastating.”¹⁰ A 4°C world “would be one of unprecedented heat waves, severe drought, and major floods in many regions, with serious impacts on human systems, ecosystems, and associated services.”¹⁰ Canada’s total GHG emissions have risen 17% between 1990 and 2010, and in per capita terms, in 2010, we ranked third worst after Australia and the United States among developed countries¹¹ (at 15.2 tonnes of carbon dioxide per capita), with developing countries, including India and China, being well below us (1.6 and 5.8 tonnes of carbon dioxide, respectively).¹² Even if globally we were able to stabilize carbon dioxide atmospheric concentrations now, changes in climate and sea levels would continue for decades, and their attendant health effects would not be avoided because the climate system is slow to respond. Therefore, there are 2 aspects of intervention: adaptation (ie, interventions to reduce the inevitable effects of climate change) and mitigation (ie, the reduction of atmospheric GHGs by reducing emissions or increasing sequestration). Mitigation would be true primary prevention.

Health effects of climate change

Climate change has been described as the “defining issue for public health during this century.”¹³ In 2007, Dr Margaret Chan of the World Health Organization said the following: This century, climate change—a fifth horseman, a new threat of a magnitude unknown to human experience—will ride across our promising landscape of public health. It will ride on a collision course with all the fits and starts of our progress, sometimes fragile, sometimes fundamental.¹³

Direct effects on health include those resulting from severe weather events such as heat waves and intense storms. Indirect effects, in which the cause-effect pathway is more complex, include those that will result from increases in air pollution, increases in allergens, and changes to patterns of water-borne, food-borne, and vector-borne infectious diseases. In developing countries, increased threats to food and water security, as well as the profound effects of sea-level rise, will lead to the displacement of populations, creating climate-change refugees and the potential for resulting international conflicts.^7,14–16 In Canada, the approximately 150 000 people who live in the North⁷ will be affected severely and uniquely. With thinning Arctic ice, hunting for caribou and other traditional foods will become more dangerous and less successful; this will have dietary, sociocultural, and psychological consequences. There is also a concern about an increase of zoonotic and infectious diseases.^7,17,18

These health effects and attempts at adaptation are intertwined with other global problems, such as social determinants of health and health inequalities, population growth, and biodiversity loss.

Global ethical and economic perspectives

The global maldistribution of cause and effect raises ethical concerns. There will be substantial health effects over time within Canada and other developed nations; by the 2080s, deaths related to higher temperatures and poorer air quality attributable to climate change could account for 1% to 2% of the total deaths within Canadian cities.¹⁹ However, by far the larger effects will be in developing countries, whose historical contribution to GHGs has been low.¹⁶ The World Health Organization estimates that climate change now results in 150 000 deaths per year, mostly in these developing countries, owing to climate-sensitive conditions, including malaria, malnutrition, gastroenteritis, water stress, and flooding from intense storms and sea-level rise. Climate change will increase the health differential between rich and poor nations. Moreover, developing countries lack the adaptive capacity, including public health systems, to avoid the health effects of climate change.

There is also a convincing economic argument for mitigation. The financial benefits of strong and early action to reduce GHG emissions far outweigh the economic costs of delaying action.²⁰ Also, there are “health co-benefits” to green strategies such as using green energy to reduce emissions of air pollutants. Active transportation strategies that promote aerobic activity and eating lower on the food chain (which reduces GHG emissions through less meat production, which is carbon intensive) are important in the public health battle against obesity, cardiovascular disease, and diabetes.

Role of family physicians

It is reasonable to reflect on the 4 principles of family medicine²¹ as a way to steer our individual and collective actions in relation to climate change.

Role of professional organizations

Medical organizations can also be models for addressing climate change. For example, the College of Family Physicians of Canada showed leadership in 2009 by switching to renewable energy for its offices.

The health care sector in Canada contributes approximately 10% of the gross domestic product and is responsible for 2.1% of GHG emissions.³⁰ Although many hospitals have engaged in sustainable practices, more needs to be done. The Canadian Coalition for Green Health Care³¹ is an organization, supported by a number of hospitals, environmental organizations, and health care associations, that encourages health care institutions to follow more sustainable practices. In the United Kingdom, the National Health Service, whose emissions account for 25% of total public sector emissions and 3.2% of total carbon emissions, has taken considerable steps to reduce its carbon footprint.³² The Climate and Health Council³³ in the United Kingdom supports sustainable initiatives among health professionals in their various roles.

In 2009, before the United Nations Framework Convention on Climate Change in Copenhagen, Denmark, a joint statement on climate change was issued by the College of Family Physicians of Canada, the Canadian Medical Association, and the Royal College of Physicians and Surgeons of Canada.³⁴ This was an unprecedented coalition. We encourage the formation of an ongoing coalition of medical organizations to promote the health “angle” in the need to address climate change in Canada. Nationally we face a huge struggle in reducing GHGs, as the National Roundtable on the Environment and the Economy suggests: Canada stands at a decision point for achieving its 2020 greenhouse gas reduction target. The analysis demonstrates a large gap between Canada’s emissions trajectory and the federal government’s target of 17 per cent below 2005 levels by 2020. Further, we show that the cost of achieving the Canadian climate policy target is high owing to the short time frame remaining to meet the target, a lack of coordination by governments, and the growing emissions from some economic activities. It is getting harder, not easier, to achieve Canada’s climate policy goals the longer time goes on.³⁵

Internationally and within Canada

Internationally, the outcomes of the 2011 United Nations Framework Convention on Climate Change in Durban, South Africa, were hopeful, in that all countries, including the United States and developing nations such as India and China, agreed to work toward legally binding and transparent carbon dioxide reductions, as well as to establish a fund to address inequity by transferring appropriate capacity and technology from developed to developing nations. However, no immediate action was endorsed. Canada won 6 Fossil of the Day awards (awards distributed by members of the Climate Action Network to countries they believe “block” progress in climate-change negotiations),³⁶ and its role was described as “shameful.”³⁷ A strong health lobby composed of both medical and nongovernmental organizations was present at the Durban meetings, as a health focus became more prominent. In the future, it is hoped that Canadian physicians will be able to join our voices with this emerging movement both in Canada and internationally,³⁸ as Dr Chan stated in a 2007 speech: “The health sector is not in a position to mitigate climate change in a direct and substantial way. But health is in a strong position to give the policy debate some compelling evidence-based arguments.”¹³

Climate change is a health issue. As such, it should be our responsibility as family physicians to, individually and collectively, speak in a credible, educated, and united voice to our patients, communities, and government organizations about mitigating and adapting to the effects of climate change.