Wildfire smoke lofted miles high could have an unexpected effect on Earth's climate

Researchers flying a NASA ER-2 into a New Mexico wildfire plume in June 2022 made the first direct measurements of five-day-old high-altitude smoke at about 14.5 km, finding unusually large aerosols (~500 nm) roughly twice the size of typical lower-altitude wildfire particles. The team attributes the particle growth to efficient coagulation in slowly mixing upper-tropospheric air and reports these larger particles increase outgoing radiation by about 30%–36% relative to lower-altitude smoke, producing a measurable cooling effect that current climate models do not account for. Co-authors warn the coagulated particles could also influence atmospheric circulation and jet streams, underscoring the need for more measurements to assess implications for climate projections and risk assessments.

Analysis

Researchers flew a NASA ER-2 into a New Mexico wildfire plume in June 2022 and made the first direct upper-tropospheric measurements of five-day-old smoke roughly nine miles (14.5 km) above the surface. Onboard instruments detected aerosols about 500 nanometers wide, roughly twice the diameter of typical lower-altitude wildfire particles, which the team attributes to efficient coagulation in slowly mixing upper-tropospheric air.

The study reports these larger particles increase outgoing radiation by about 30%–36% relative to lower-altitude smoke, producing a measurable cooling effect that current climate models do not represent. Findings were published Dec. 10 in Science Advances and highlight a quantifiable radiative impact from high-altitude smoke not captured in standard model parameterizations.

Co-author commentary flags potential knock-on effects for atmospheric circulation and jet-stream positions, but the authors emphasize insufficient data to determine directionality or magnitude of those changes. The result creates a concrete model risk and data gap: climate forcing and near-term weather projections may be biased until upper-atmosphere smoke processes are systematically sampled and incorporated into climate and risk models.

Key Decisions for Investors

• Monitor follow-up studies and model revisions closely because a 30%–36% increase in outgoing radiation from high-altitude smoke could alter near-term climate forcing assumptions and policy signals
• Consider increasing engagement with or allocating to firms that provide high-altitude atmospheric measurements and climate-risk analytics, as demand for refined inputs to climate and catastrophe models is likely to rise
• Reassess exposure to weather- and climate-sensitive holdings and implement stress tests or hedges for portfolio risk stemming from model uncertainty and potential shifts in atmospheric circulation such as jet-stream changes