Wildfires in boreal forests release large quantities of greenhouse gases to the atmosphere, exacerbating climate change. Here, we characterize the magnitude of recent and projected gross and net boreal North American wildfire carbon dioxide emissions, evaluate fire management as an emissions reduction strategy, and quantify the associated costs. Our results show that wildfires in boreal North America could, by mid-century, contribute to a cumulative net source of nearly 12 gigatonnes of carbon dioxide, about 3% of remaining global carbon dioxide emissions associated with keeping temperatures within the Paris Agreement’s 1.5°C limit. With observations from Alaska, we show that current fire management practices limit the burned area. Further, the costs of avoiding carbon dioxide emissions by means of increasing investment in fire management are comparable to or lower than those of other mitigation strategies. Together, our findings highlight the climate risk that boreal wildfires pose and point to fire management as a cost-effective way to limit emissions.

Climate change is intensifying fire regimes across boreal regions, and thus both burned area and carbon emissions from combustion are expected to increase significantly over the next several decades. Fire management through initial suppression of fires is effective at reducing burned area, but limited work has addressed the role that fire management can play in reducing wildfire carbon emissions and their impacts on climate change. In this work, we draw on historical data covering fire and fire management in Alaska to project burned area and management outcomes to 2100. We allow management to both respond to and impact variations in annual burned area and carbon emissions, while keeping decadal-average burned area at or above historical levels. The total cost of a fire is calculated as the combination of management expenditures and the social cost of carbon emissions during combustion, using the Social Cost of Carbon framework. Incorporating the tradeoff between management expenditures and burned area, we project that by 2100, increasing management effort by 5-10 times relative to current expenditures would minimize combined management and emissions costs. This is driven by the finding that the social costs of carbon emissions greatly exceed management costs unless burned area is constrained to near the average historical level. Our analysis does not include the many health, economic, and non-CO2 climate impacts from fires, so we likely underestimate the benefits of increased fire suppression and thus the optimal management level. As fire regimes continue to intensify, our work suggests increased management expenditures will be necessary to counteract increasing carbon combustion and lower overall climate impact.

Focusing on 23 greening measures, this paper systematically compares the greening efforts of the busiest container and cargo ports in the United States (US) and the European Union (EU). We move beyond accounts for general environmental differences between the EU and the US to examine how specific environmental decisions are shaped by the effects of regulatory characteristics in each region. We identify systematic variation in number and type of port greening measures adopted in the two regions. We demonstrate that differences in the number and type of measures adopted reflect the level of policy making with local policy making playing a more important role in the US compared to the EU, thus proposing a pathway through which the form of regulatory approach could influence content and extent of regulation. The EU adopts regulation that is broader in scope while US ports are more likely to address problems affecting local populations.

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