A multicriteria decision analysis framework for developing and evaluating coastal retreat policy.

Managed retreat may be a necessity for coastal communities as sea levels rise due to climate change. Selecting the right policy decisions and timing is difficult given the vested interests of communities and stakeholder groups and requires careful balancing of the benefits and risks associated with each management alternative. State and federal agencies often employ single-objective optimization frameworks such as cost-benefit analysis to analyze coastal relocation alternatives, but such methods are limited in their ability to balance competing value considerations and stakeholder demands. The use of a multicriteria decision analysis (MCDA) methodology allows for such considerations to be quantified and evaluated, thereby improving planning and decision-making for coastal retreat policies. This paper provides a strategic MCDA framework to evaluate coastal retreat policy that could be leveraged by at-risk coastal communities. The MCDA is applied to a hypothetical coastal retreat scenario to visualize policy preferences and differing value considerations among stakeholders. This model can be used by government agencies to foster more sound, acceptable, and implementable coastal retreat policies and streamline the incorporation of this climate adaptation mechanism, which may be necessary for the near future. Integr Environ Assess Manag 2023;19:83-98. © 2022 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).

Cumulative environmental and employment impacts of the shale gas boom.

Natural gas has become the largest fuel source for electricity generation in the United States and accounts for a third of energy production and consumption. However, the environmental and socioeconomic impacts across the supply chain and over the boom-and-bust cycle have not been comprehensively characterized. To provide insight for long-term decision making for energy transitions, we estimate the cumulative impacts of the shale gas boom in the Appalachian basin from 2004 to 2016 on air quality, climate change, and employment. We find that air quality impacts (1200 to 4600 deaths; $23B +99%/-164%) and employment impacts (469,000 job-years ±30%; $21B ±30%) follow the boom-and-bust cycle, while climate impacts ($12B to $94B) persist for generations well beyond the period of natural gas activity. Employment effects concentrate in rural areas where production occurs. However, almost half of cumulative premature mortality due to air pollution is downwind of these areas, occurring in urban regions of the Northeast. The cumulative temperature impacts of methane and carbon dioxide over a 30-year time horizon are nearly equivalent, but over the long term, the cumulative climate impact is largely due to carbon dioxide. We estimate that a tax on production of $2 per thousand cubic foot (+172%/-76%) would compensate for cumulative climate and air quality externalities across the supply chain.

System-wide and Superemitter Policy Options for the Abatement of Methane Emissions from the U.S. Natural Gas System.

This work assesses trade-offs between system-wide and superemitter policy options for reducing methane emissions from compressor stations in the U.S. transmission and storage system. Leveraging recently collected national emissions and activity data sets, we developed a new process-based emissions model implemented in a Monte Carlo simulation framework to estimate emissions for each component and facility in the system. We find that approximately 83% of emissions, given the existing suite of technologies, have the potential to be abated, with only a few emission categories comprising a majority of emissions. We then formulate optimization models to determine optimal abatement strategies. Most emissions across the system (approximately 80%) are efficient to abate, resulting in net benefits ranging from $160M to $1.2B annually across the system. The private cost burden is minimal under standard and tax instruments, and if firms market the abated natural gas, private net benefits may be generated. Superemitter policies, namely, those that target the highest emitting facilities, may reduce the private cost burden and achieve high emission reductions, especially if emissions across facilities are highly skewed. However, detection across all facilities is necessary regardless of the policy option and there are nontrivial net benefits resulting from abatement of relatively low-emitting sources.