Climate change is listed by the World Health Organization (WHO) as an urgent health challenge for the next decade. 1 Anthropogenic global warming gives rise to extreme weather events and air pollution, in turn negatively affecting peoples' health. These greenhouse gas (GHG) emissions contribute to more than one-quarter of global deaths from heart attacks, strokes, lung cancer and chronic respiratory disease. 1 Furthermore, the WHO reports that climate change will result in an additional 250,000 deaths annually between 2030 and 2050 due to malnutrition, malaria, diarrhea and heat stress. 2 In Canada, more than 20,000 premature deaths each year are attributable to air pollution. 3 Children, the elderly and those with preexisting medical conditions are among the most vulnerable. 2 Health care is a major contributor to GHGs. In Canada, the health care system produces 4.6% of the national GHG emissions, which is comparable with that of the United Kingdom, Australia and the United States (3%-4%, 7% and 9%-10%, respectively). 3 These Canadian health care GHG emissions are a result of public hospitals (22%), prescribed drugs (21%) and physician services (13%). 3 Prescribed and nonprescribed pharmaceuticals together represent 25% of the total health care GHG emissions, the largest of any category. 3 Upstream economic activities, such as energy, pharmaceutical manufacturing or transportation, are responsible for 90% of these emissions. 3 Pharmaceuticals produce GHGs throughout their life cycle by means of manufacturing, procurement, transportation, packaging, disposal through incineration and the use of drugs themselves. Metered-dose inhalers (MDIs) and inhaled anesthetics are particularly carbon heavy, accounting for 4% and 2% of the UK National Health Service's (NHS) overall carbon footprint, respectively. 4 The hydrofluoroalkane propellants used in MDIs are potent GHGs, up to 3350 times worse than carbon dioxide (CO