Overview

Fire is a natural part of global ecosystems that has shaped the landscapes humans live on today. However, human influences from land management and development practices and climate change have resulted in wildland fires that burn hotter, more frequently, over larger areas, or in some locations where fires had not typically been a part of the ecosystem. Fires transfer carbon between terrestrial pools and between the land and atmosphere through emissions of greenhouse gases (GHGs) and other gases and particles. Direct and indirect (i.e., climate change) human-driven changes in wildland fire regimes have the potential to increase GHG emissions at a scale that could inhibit global efforts to achieve “net-zero” GHG emissions in the coming decades. To inform land management and policy decisions, it is important to better understand future changes in wildland fires and their GHG emissions as well as effective management strategies that could limit potential GHG emissions and preserve ecosystems.

The National Academies of Sciences, Engineering, and Medicine convened a workshop on September 13–15, 2023, to identify opportunities to improve measurements and model projections of GHG emissions from wildland fires and discuss management practices that could be incorporated into current and future action plans. Workshop discussions sought to identify how tools and changes in land stewardship could inform and enhance strategies to limit wildland fire GHG emissions and associated threats to achieving net-zero emission targets.

Climate change is fundamentally changing ecosystems and their potential future fire behavior and effects. Many participants emphasized the importance of prioritizing reductions in anthropogenic GHG emissions to reduce wildland fire emissions driven by climate change. Costs of fire management strategies to reduce GHG emissions may compete with other government-funded priorities, and better tools may be needed to help decision makers consider effective investments.

A clear theme throughout the workshop was the importance of learning from historic and current practices of Indigenous peoples, reintroducing cultural burning and cultural land management practices, and including and elevating the leadership of Indigenous peoples in all stages of fire management. Engaging local communities who live in and manage ecosystems vulnerable to wildfire and benefit from land use is an important part of identifying and implementing appropriate intervention strategies.

Discussions were organized around three global biomes—temperate, Arctic/boreal, and tropical—where historical fire regimes and the carbon balance have been disrupted due to human-driven climate and land use changes. Many participants emphasized the heterogeneity in global ecosystems, fire regimes, and the associated management practices that are appropriate. For example, while there are potential opportunities to increase fire suppression in some ecosystems such as the northern boreal, in many other biomes, a legacy

of fire suppression may actually be contributing to the extreme fire conditions resulting in megafires (e.g., western United States).

Emission inventories are important tools for estimating GHG emissions from wildfires and ecosystem removals (i.e., uptake and sequestration) of carbon. Across ecosystems, there are limited data on all aspects of fire emissions, with important implications for GHG emissions. In particular, the impact of fires on soils, peat, and permafrost could be significant, given that such fires release to the atmosphere carbon that has been stored for decades to centuries. Participants also discussed tools and models that could help managers identify where fire mitigation strategies are climate-effective.

Discussions centered around the importance of regionally differentiated, ecosystem-appropriate mitigation strategies ranging from prescribed fires, fuel management, water table management, reduction in human ignitions, and targeted suppression, among others. Several participants recognized the co-benefits and trade-offs of different management approaches at local scales—for example, thinning in dry ecosystems can increase water availability and ecosystem health. There are opportunities to consider fuel reduction strategies that instead of burning, utilize biomass in ways that can benefit the bioeconomy, reduce fuel management costs, and reduce smoke and health impacts.

Moving forward, the challenge for decision makers and managers will be scaling up mitigation actions to have meaningful impacts while also considering trade-offs at large scales. As an example, implementing management strategies discussed at the workshop may mean shifting public acceptance of limited smoke from prescribed burning as an alternative to uncontrolled wildfire smoke. At the same time, local community concerns—for example, concerns about escaped prescribed fires in the wildland–urban interface—are important to address. Broadly, workshop discussions highlighted the wide range of available management solutions that would reduce GHG emissions and increase the resilience of vulnerable ecosystems.