Environmental Science and Engineering Seminar

The Pyrocene is reshaping the role of fire within the Earth System, with consequences for climate, air quality, and global biogeochemical cycles. From the preindustrial era to projections through 2100, changing fire regimes reflect competing influences of climate, land use, and human intervention. Yet the consequences of these changes for planetary health are far from straightforward: fire emissions can simultaneously threaten human health through air pollution while potentially supporting ocean ecosystems through nutrient deposition. This talk explores these contrasting impacts across the land–atmosphere–ocean continuum. The January 2025 Los Angeles fires illustrate the consequences of burning at the wildland urban interface, where combustion of vegetation and urban materials releases complex mixtures of aerosols and potentially toxic metals, threatening air quality and human health. Conversely, fires redistribute essential nutrients, including iron, phosphorus, and nitrogen, potentially stimulating marine productivity and influencing ocean carbon uptake. Together, these contrasting effects reveal that the consequences of changing fire regimes extend beyond the atmosphere, creating complex trade-offs for planetary health that must be understood to anticipate the impacts of future world with more fire.