I arrived at the climate conference just as Dr. Angela Martinez was gathering her papers. The afternoon Vancouver sun cast long shadows through the hotel conference room, illuminating particles of dust in the air – a reminder of last summer’s wildfires that had choked the city for weeks.
“We’ve been saying this for years,” Dr. Martinez told me, frustration evident in her voice. “Climate change isn’t just about polar bears and melting ice caps. It’s a direct threat to human health – here, now, today.”
This week, over 200 health professionals and climate scientists from across Canada and internationally published an open letter declaring climate change a “health emergency.” The signatories, including physicians, nurses, public health officials, and climate researchers, are calling for immediate policy action to address what they describe as “the greatest health threat of the 21st century.”
The letter, published in the Canadian Medical Association Journal, points to mounting evidence that climate change is already affecting health outcomes across the country, particularly in northern communities and among vulnerable populations.
Walking through Vancouver’s Downtown Eastside the day after the conference, I met Eliza Thompson, a community health worker who sees these impacts firsthand. “During last summer’s heat dome, we lost patients who simply couldn’t escape the heat,” she explained as we passed a single-room occupancy hotel. “Many live in buildings without proper ventilation or cooling. When it hit 42 degrees, some of these rooms became death traps.”
The health professionals’ declaration identifies five critical pathways through which climate change threatens Canadian health: extreme heat events, deteriorating air quality from wildfires, vector-borne disease expansion, food and water insecurity, and mental health impacts.
According to Health Canada data released earlier this year, heat-related deaths have increased by 68% over the past decade, with the 2021 heat dome in British Columbia alone causing over 600 deaths in a single week.
Dr. Sanjay Sharma, an emergency physician who signed the letter, told me by phone from his Toronto hospital, “We’re seeing patients with conditions we used to consider rare or seasonal now appearing year-round. Lyme disease cases have tripled in Ontario since 2015 as ticks expand their range northward.”
The World Health Organization has documented similar trends globally, estimating that climate change will cause approximately 250,000 additional deaths per year between 2030 and 2050 from malnutrition, malaria, diarrhea, and heat stress alone.
What makes this letter different from previous warnings is its emphasis on immediate action rather than future scenarios. The signatories have outlined a comprehensive framework for a “health-centered climate response,” which includes phasing out fossil fuel subsidies, expanding renewable energy infrastructure, strengthening public health systems, and ensuring climate policies address existing health inequities.
“This isn’t about some distant future,” said Dr. Amina Jackson, an environmental epidemiologist at the University of British Columbia and one of the letter’s lead authors. “When I talk to my colleagues across the country, they’re all reporting the same thing – more heat-related illness, more respiratory problems from wildfire smoke, more vector-borne diseases, and more climate anxiety among patients.”
For many Indigenous communities in northern Canada, these health impacts are compounded by existing challenges. Last month, I traveled to a Dene community in the Northwest Territories where changing ice conditions have made traditional hunting increasingly dangerous and unpredictable.
“Our food systems, our medicine, our cultural practices – they’re all tied to the land,” Elder Joseph Natsena told me as we looked out over the lake that had broken up weeks earlier than when he was young. “When the climate changes, it’s not just our environment that suffers, it’s our physical and spiritual health too.”
The letter specifically highlights the disproportionate burden faced by Indigenous communities, noting that climate justice and health equity must be central to any meaningful response.
The financial costs to Canada’s healthcare system are also substantial. A report from the Canadian Institute for Climate Choices estimates that health impacts from air pollution alone cost the Canadian economy billions annually in healthcare expenses and lost productivity.
Not everyone views the situation with the same urgency. Some industry representatives argue that rapid transitions away from fossil fuels could create economic disruptions that would themselves impact public health.
“We need balanced approaches that consider all aspects of wellbeing,” said Michael Reynolds of the Canadian Energy Alliance when I reached him for comment. “Energy security and economic stability are also determinants of health.”
Yet the health professionals behind the letter argue that we can no longer afford to frame climate action and health as competing priorities.
“The evidence is overwhelming that the health benefits of climate action – cleaner air, more active transportation, healthier diets – would more than offset the costs of transition,” explained Dr. Priya Sharma, a public health physician who helped draft the letter.
As I finished my interview with Dr. Martinez at the conference, she handed me a copy of the full letter. “Make sure people understand – this isn’t just another climate warning,” she said. “This is doctors, nurses, and health researchers saying we’re already treating the victims of climate change. And it’s going to get much worse if we don’t act now.”
The letter concludes with a powerful appeal: “As health professionals, we have a duty to protect health. As citizens, we all have a responsibility to ensure a livable world for future generations. The time for incremental changes has passed. We need transformation at a scale and speed unprecedented in human history.“
Walking back to my apartment that evening through a city where the memories of smoke-filled skies and deadly heat remain fresh, those words felt less like hyperbole and more like a simple statement of fact.
