Editor’s note: This story was updated to correct a figure related to a cost estimate. We regret the error.
Smoke from Canadian wildfires traveled hundreds of miles along the U.S. East Coast this week and last week, forcing millions of people to breathe air laced with harmful pollutants.
The mix of pollution from these fires contains particles and gases that impede healthy lung and heart function. The levels of pollution New York City, Washington and many other cities experienced over the last few days led to an increased risk of asthma attacks, heart attacks, strokes, emergency room visits and hospital admissions. Even short-duration exposure to these chemicals in the air is associated with an increased risk of early death.
As the world warms, the amount of wildfire smoke pollution experienced this week could become the norm in the future. Drier air and soils, warmer temperatures and sustained high wind speeds combine into a perfect storm known as fire weather. During fire weather periods, a lightning strike, a carelessly discarded cigarette or a sparking power line is all it takes to ignite a fire that grows out of control. Humans actually start over 80 percent of wildfires in the U.S., contributing 5-10 percent to total fine particle pollution nationwide, a troubling statistic as people move closer and closer to wildlands.
Climate scientists predict that fire weather will become more common across the U.S. in the future, resulting in longer wildfire seasons, more intense fires and more smoke. Some studies indicate that wildfires could become the dominant contributor to harmful fine particles across the U.S. in the future unless we work quickly to make deep cuts in carbon emissions.
Wildfire smoke is just one of many ways that climate change is already affecting our health. Across the U.S., we’ve already seen dramatic public health consequences of extreme heat waves, destructive storms and expanded habitats for disease-carrying mosquitoes and ticks, and these climate-sensitive hazards are expected to get worse as the human influence on the climate grows. My research shows that climate change is expected to exacerbate dust exposure, smog and pollen too.
The wildfire connection is among the most studied and well-established links between climate change and human health in the scientific literature. Scientists have established each step of the causal chain: Climate change increases wildfire area burned, wildfire area burned increases air pollution emissions, air pollution emissions increase exposure levels and exposure levels lead to health outcomes. Each of these links stems from a peer-reviewed body of literature in climate science, ecology, atmospheric science and public health.
And yet, this clear climate-health connection is missing from the list of societal improvements the government considers when weighing the costs and benefits of reducing greenhouse gases.
The government uses a metric called the Social Cost of Greenhouse Gases to estimate the benefits of regulations that affect carbon emissions and compare them against implementation costs. This metric places a monetary value on the net harm to society associated with adding a small amount of carbon dioxide and other greenhouse gases to the atmosphere in a given year. The current value used across the government, $51 per ton of carbon dioxide emitted in 2020 (using a 3 percent discount rate), has enormous consequences for governmental decision-making. An underestimate, even by a few dollars per ton of carbon dioxide emitted, means that each carbon-reducing regulation appears less favorable when compared to costs.
The EPA recently provided an alternative and more comprehensive, yet still conservative, approach that incorporates scientific advancements recommended by the National Academies. Using the new approach, the Social Cost of Greenhouse Gases would be $190 per ton of carbon dioxide emitted in 2020, more than three and half times the existing government estimate. The difference is driven by a number of updates, including additional climate damage pathways and the discount rate for valuing future impacts. The new approach represents major progress in incorporating the health implications of climate change by more fully and transparently considering the effects of heat and cold on mortality. However, the new estimates still exclude mortality and illness from breathing wildfire smoke, as well as climate change-related increases in dust, smog, and pollen.
Wildfire smoke pollution is associated with over 6,000 premature deaths in the U.S. each year, in addition to 1,300-5,900 emergency department visits and 300-1,400 hospital admissions for asthma. The economic value of these damages is enormous — the 2018 California wildfires alone incurred $32 billion in health costs, $28 billion in capital costs and $89 billion in economic disruption. Scientists have estimated that the health consequences of wildfire smoke could be five times higher by the end of the century than they are today, with about 60 percent of that increase driven by climate change and the rest by population and economic growth.
Until we account for the disease and shortened lifespans ushered in by climate change — including from increased wildfire smoke exposure — the societal benefits from policies that reduce greenhouse gas emissions will be severely undervalued.
Susan Anenberg is the director of the George Washington University Climate & Health Institute and professor and chair of environmental and occupational health at GW Milken Institute School of Public Health.