Physicians working in hospitals see the mountains of medical waste generated each day. Meanwhile, the climate crisis challenges the medical system to reduce its contribution to greenhouse gas emissions. Globally, healthcare systems contribute as much carbon dioxide as the airline industry. In Canada, healthcare accounts for 4.6% of our total emissions. The problem is urgent, but potential solutions are both easier and more complex than many might think. Guests on this episode are advocates in the climate and health space. Dr. Samantha Green is the co-author of the CMAJ article, Five Things to Know About Metered Dose Inhalers and their Impact on Climate Change. She's a family physician at Unity Health Toronto and the climate and health lead at the University of Toronto's Department of Family and Community Medicine.In the article, she and her co-authors point out that pressurized metered-dose inhalers (pMDIs) are an important contributor to greenhouse gas emissions.  Dr. Green says measurements done in the United Kingdom by the National Health Service found that MDIs contribute 3.1% of the entire health system's carbon emissions. One MDI contributes the equivalent of driving 290km by car.Meanwhile, dry powdered inhalers (DPIs) and soft mist inhalers (SMIs) are effective available alternatives with lower environmental impact. Dr. Green encourages physicians to make the switch for eligible patients and explains how her clinic has created resources to facilitate the prescribing change.Addressing such low-hanging fruit of climate action in the healthcare system is important but, according to Dr. Andrea MacNeill, reducing waste, changing prescriptions, and recycling are the tip of the iceberg. What’s really needed is profound systemic change. Dr. MacNeill argues that emissions are driven by a system focused on providing the most complex and carbon-intensive care. “New healthcare funding seems to go into very complex resource-intensive treatments that modify very advanced disease processes. And I would suggest that we need to shift that focus upstream and start to think, okay, could we have prevented this from ever happening? And in many cases, the answer to that is yes,” says Dr. MacNeill.Along with a focus on prevention, Dr. MacNeill argues healthcare systems need to put pressure on the supply chain, which accounts for the bulk of emissions. In England, the NHS is demanding that vendors match the NHS's climate target to decarbonize by 2030. Links to resources discussed on the episode:Inhaler Toolkit for PhysiciansCascadesPlanetary Health Lab