Key Takeaways:
- PM2.5 exposure due to wildfire-related air pollution contributes to health issues, often lasting months to years.
- Effects can show up long after exposure and even in areas without fires due to pollution travelling long distances.
- El Niño events reduce improvements in heart disease and injury-related mortality, eroding longevity gains.
- These trends may have implications for insurance and actuarial models.
Climate change is negatively impacting human health by increasing the risk of death, disease and other health crises, according to the World Health Organization (WHO). A 2023 WHO Fact Sheet estimates there will be 250,000 additional deaths annually between 2030 and 2050 due to climate change impacts on disease and coastal flooding.
Many Americans have already been experiencing negative health outcomes due to climate change. In a consumer survey conducted by The Society of Actuaries (SOA) Research Institute to gauge the public’s experiences with climate risks, 53% of respondents reported that extreme weather had impacted their health. Nearly a quarter said it impacted existing chronic conditions and 15% reported it caused long-term injury and/or chronic conditions.
The SOA Research Institute has studied two natural phenomena that have intensified due to climate change: El Nino weather events and exposure to wildfire smoke. Researchers found that both types of climate-related events have lagging effects on the health landscape in the U.S., which may slow the progress of people living longer, also known as mortality improvement.
Health Risks Due to Wildfire-Related Air Pollution
Most wildfire-related deaths result not from the flames themselves but from the health effects of wildfire-related air pollution. According to The Impact of Wildfire-Related and Environmental Air Pollution on Morbidity, breathing in fine particulates that are less than 2.5 micrometers in size (PM2.5) impacts many diseases. When PM2.5 exposure occurs alongside extreme heat, the delayed health impacts are significant, accounting for 2.3% to 8.6% of overall disease prevalence for the conditions studied. In other words, 2 to 9 of every 100 cases of the conditions studied are due to the effects of wildfire-related air pollution coupled with heatwaves, which rivals and often exceeds the impacts of COVID-19 and its aftermath.
The health effects of wildfire-related air pollution can persist for months or sometimes years after exposure. Respiratory conditions rise immediately, while circulatory and mental health issues peak months later, reflecting the difference between short-term airway inflammation and longer-term systemic and neurological effects.
The study also found that wildfire-related air pollution doesn’t affect everyone equally. Communities with less access to health care, more chronic health problems, and greater social and economic challenges tend to get sicker when exposed to wildfire-related air pollution than people in better-resourced areas.
An accompanying SOA Research Institute study on the effects of wildfire-related air pollution on mortality cites a finding by the U.S. Environmental Protection Agency that wildfires have accounted for up to 40% of annual PM2.5 emissions. This impacts the prevalence and severity of health conditions, especially cardiovascular and respiratory diseases, increasing mortality in the medium to long term.
Additionally, the study found that wildfire frequency and burned area within a state are poor indicators of air pollution–related mortality. One reason is that PM2.5 from wildfires can travel long distances, increasing mortality even in states that did not experience fires directly. The health effects of PM2.5 often emerge months or years after exposure, creating a disconnect between when wildfires occur and when their health impacts are detected.[^1]
Big Impacts From El Nino
El Nino events are also associated with a slow-down in mortality improvements, particularly for cardiovascular and injury-related deaths. The SOA Research Institute report, Climate Anomalies’ Enduring Impacts on U.S. Mortality and Health Landscape, finds that circulatory death-rate improvement worsens significantly, with an estimated cumulative loss of about 4.8 percentage points in improvement over five years. The study also uncovers a 5.0% loss in mortality improvements from external causes, including accidents and trauma.
The study shows that heart disease drives most of the increase in circulatory deaths linked to El Nino. For external causes, transportation accidents and medical or surgical complications are the main drivers of higher risk.
Findings also indicate that the long-term mortality burden falls primarily on middle-aged and older adults. Impacts on circulatory-related diseases are most pronounced among people ages 50 to 80, while deaths from external causes peak among those ages 35 to 44. Although the immediate effects of the event at year zero are relatively modest, the consequences compound over the years that follow, driving long-term deterioration of mortality trends.
The report finds that under intensified El Nino Southern Oscillation (ENSO) variability, mid-century to end-of-century projections show material erosion of U.S. life-expectancy gains. Predictions under higher-emission scenarios show losses exceeding the entire mortality improvement achieved in the early 21st century, with circulatory disease being one of the largest drivers of these projected losses.[^2]
Implications for the Insurance Industry
The effects of increased climate risks, such as those posed by El Nino and wildfire-related air pollution, create an increasingly complex environment for the insurance industry to navigate. These and other extreme weather events could exacerbate existing uncertainties in health care utilization, premium pricing, and regulatory policies. As a result, insurers may need to adapt how they assess risk, design benefits, and engage with stakeholders.
For example, the Climate Anomalies’ Enduring Impacts on U.S. Mortality and Health Landscape study suggests that life and health insurers can use ENSO forecasts to anticipate claims volatility, stress-test capital, and adjust solvency buffers and reinsurance coverage in response to expected increases in morbidity and hospitalizations. ENSO-related uncertainty can also be reflected in benefit pricing, reserving assumptions and reinsurance design. In addition, insurers may find value in exploring parametric triggers for catastrophe or stop-loss coverage. Regulators and actuarial bodies may consider the use of climate-adjusted mortality improvement assumptions in valuation and solvency frameworks.
Similar challenges are expected from wildfire-related air pollution, particularly when combined with extreme heat, which may further increase claims volatility. These risks are unlikely to be evenly distributed, reflecting differences in geographic factors and social determinants of health. At the same time, ongoing uncertainty from medical cost trends underscores the need for actuaries to explore new methods of measuring risk and developing appropriate contingency loadings.
Together, these studies reveal that climate-driven events are not merely short-term disruptions. They can lead to lasting health effects and weaken long-term mortality improvement trends. The findings emphasize the potential value of integrating climate considerations into modeling, pricing, reserving,and capital planning to better manage both health and financial outcomes.
To learn more, visit the SOA’s Catastrophe and Climate and the Mortality and Longevity strategic research pages.
- The SOA Research Institute studies, The Impact of Wildfire-Related and Environmental Air Pollution on Morbidity and Modeling the Impact of Wildfire-Related Air Pollution on Mortality, provide valuable evidence on wildfire-related PM2.5 health and mortality impacts, but data limitations and complex relationships warrant caution and further research on long-term effects.
- A limitation of the analysis in the SOA Research Institute report Climate Anomalies’ Enduring Impacts on U.S. Mortality and Health Landscape is its national scope; future research could incorporate higher-resolution health data. Also, extending the framework to a global basis could enable comparative insights into ENSO’s impacts. Additionally, the projections in the report are based on model outputs that do not yet fully represent updated climate simulations which could provide a more realistic assessment of ENSO-related health risks.
Published Jul 8, 2026 10am EDT / 7am PDT / 3pm BST / 4pm CEST