Smoky summers are now the norm in Canada. Over the past summer, wildfires burned approximately 4.5 million hectares, more than 33,750 people were evacuated and millions were exposed to hazardous air pollutants, which even exacerbated tensions between Canada and the United States. These impacts were modest in comparison to 2023, the most destructive wildfire season in Canadian history, which caused short- to long-term economic consequences that could reach several billion dollars. The ongoing El Niño may lead to another destructive wildfire season next year.Climate change is making the hot, dry conditions that favour wildfires more common and lengthening the wildfire season. New research by colleagues and me estimates how climate change will influence the economic costs of Canadian wildfires as well as the global burden of their carbon dioxide emissions over the 21st century. The scale of future wildfire impacts depends on the choices that we make today about fossil fuels.Future wildfire costs for CanadiansWe used a new boreal wildfire-vegetation model that accounts for the complex interactions between weather, forest growth, lightning and human ignitions, and suppression. We compared a world without human-caused climate change to possible futures with differing levels of greenhouse gas emissions and degrees of climate change. We found that limiting global warming to 2 C above pre-industrial temperatures (as set out by the 2015 Paris Agreement) would keep the burned area, number of Canadians exposed and the costs of wildfires comparable to what we have experienced in recent decades. On the other hand, high greenhouse gas emissions and rapid climate change could expose an additional 180,000 Canadians to wildfire each year by the end of the century. However, it’s important to note this only includes people living within 50 kilometres of a fire and not the much wider reach of wildfire smoke. Additional costs of fire suppression, lost timber and lost opportunities for outdoor recreation could reach up to $870 million each year by the end of the century. Our estimate is conservative because we did not account for costs of evacuation, property and infrastructure damage, business interruption, and, in particular, smoke-related health impacts, which are currently estimated at $19 billion per year.The burden of these impacts is disproportionately placed on Indigenous communities and younger generations. In our projections, approximately 78 per cent of exposed communities are primarily Indigenous, although they represent only 17 per cent of the communities included in our study. This is consistent with longstanding inequities. The generation born in the 2020s could experience nearly three times the lifetime wildfire exposure of the generation born in the 1960s in a high-emissions future.The global burdenConsequences extend beyond Canada as these wildfires emit large amounts of CO2. For example, emissions from Canadian wildfires in 2023 were comparable to the annual fossil fuel emissions of several large nations, surpassed only by India, China and the U.S.. This creates a feedback loop in which climate change intensifies wildfires, which in turn worsens climate change and its impacts. We estimated the global burden of CO2 emissions from Canadian wildfires attributed to climate change using the social cost of carbon. This quantifies the worldwide damages caused by emitting CO2 and includes heat-related morbidity and mortality, crop failure and sea level rise. In a high-emissions future, we found that the additional worldwide damages from Canadian wildfire CO2 emissions could reach up to $50 billion per year by the end of the century, over an order of magnitude greater than the direct costs of wildfires to Canadians.We need to do more than respondPart of this problem is due to wildfire management: better emergency response, resilient infrastructure, science-based forest management and supporting Indigenous-led cultural burning can reduce impacts. The Canadian government is committing more to management, including $317 million over five years for additional firefighting aircraft and $48 million over five years for Parks Canada wildfire preparedness. Read more: Canada’s aerial wildfire-fighting plan is a start — but it is not yet a strategy However, these investments are small in comparison to the projected direct costs of wildfires due to climate change from our study (between $100 and $870 million per year at the end of the century). More importantly, they do not address the root cause of the problem: our continued reliance on fossil fuels is driving climate change and intensifying wildfires. Canada is far off track to achieve its climate targets, and expanding fossil fuel infrastructure while rolling back climate policies only increases the burden that wildfire management needs to address.Our research shows that less warming means fewer people exposed to wildfire and lower costs both in Canada and worldwide, and every fraction of a degree matters. Protecting Canadians from worsening wildfires cannot rely on wildfire management alone — it requires a rapid transition away from fossil fuels.Sian Kou-Giesbrecht does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.