We evaluate public health and climate impacts of low-sulphur fuels in global shipping. Using high-resolution emissions inventories, integrated atmospheric models, and health risk functions, we assess ship-related PM2.5 pollution impacts in 2020 with and without the use of low-sulphur fuels. Cleaner marine fuels will reduce ship-related premature mortality and morbidity by 34 and 54%, respectively, representing a ~ 2.6% global reduction in PM2.5 cardiovascular and lung cancer deaths and a ~3.6% global reduction in childhood asthma. Despite these reductions, low-sulphur marine fuels will still account for ~250k deaths and ~6.4 M childhood asthma cases annually, and more stringent standards beyond 2020 may provide additional health benefits. Lower sulphur fuels also reduce radiative cooling from ship aerosols by ~80%, equating to a ~3% increase in current estimates of total anthropogenic forcing. Therefore, stronger international shipping policies may need to achieve climate and health targets by jointly reducing greenhouse gases and air pollution.

Ship traffic emissions degrade air quality in coastal areas and contribute to climate impacts globally. The estimated health burden of exposure to shipping emissions in coastal areas may inform policy makers as they seek to reduce exposure and associated potential health impacts. This work estimates the PM 2.5 -attributable impacts in the form of premature mortality and cardiovascular and respiratory hospital admissions, from long-term exposure to shipping emissions. Health impact assessment (HIA) was performed in 8 Mediterranean coastal cities, using a baseline conditions from the literature and a policy case accounting for the MARPOL Annex VI rules requiring cleaner fuels in 2020. Input data were (a) shipping contributions to ambient PM 2.5 concentrations based on receptor modelling studies found in the literature, (b) population and health incidence data from national statistical registries, and (c) geographically-relevant concentration-response functions from the literature. Long-term exposure to ship-sourced PM 2.5 accounted for 430 (95% CI: 220–650) premature deaths per year, in the 8 cities, distributed between groups of cities: Barcelona and Athens, with > 100 premature deaths/year, and Nicosia, Brindisi, Genoa, Venice, Msida and Melilla, with tens of premature deaths/year. The more stringent standards in 2020 would reduce the number of PM 2.5 -attributable premature deaths by 15% on average. HIA provided a comparative assessment of the health burden of shipping emissions across Mediterranean coastal cities, which may provide decision support for urban planning with a special focus on harbour areas, and in view of the reduction in sulphur content of marine fuels due to MARPOL Annex VI in 2020.

This paper explores whether a Panama Canal Authority pollution tax could be an effective economic instrument to achieve Emission Control Area (ECA)-like reductions in emissions from ships transiting the Panama Canal. This tariff-based policy action, whereby vessels in compliance with International Maritime Organisation (IMO) ECA standards pay a lower transit tariff than noncompliant vessels, could be a feasible alternative to petitioning for a Panamanian ECA through the IMO. A $4.06/container fuel tax could incentivize ECA-compliant emissions reductions for nearly two-thirds of Panama Canal container vessels, mainly through fuel switching; if the vessel(s) also operate in IMO-defined ECAs, exhaust-gas treatment technologies may be cost-effective. The RATES model presented here compares current abatement technologies based on hours of operation within an ECA, computing costs for a container vessel to comply with ECA standards in addition to computing the Canal tax that would reduce emissions in Panama. Retrofitted open-loop scrubbers are cost-effective only for vessels operating within an ECA for more than 4500 h annually. Fuel switching is the least-cost option to industry for vessels that operate mostly outside of ECA regions, whereas vessels operating entirely within an ECA region could reduce compliance cost with exhaust-gas treatment technology (scrubbers).

Coastal wetlands sequester large amounts of carbon in their soils, effectively removing carbon dioxide from the atmosphere and acting as a carbon sink. In this paper, we estimate the economic value of carbon sequestered by wetlands in the Delaware Estuary. We estimate the value of the current stock of wetlands, the value of the historic loss of wetlands, and under a range of different scenarios the expected future loss. We use historical topographic maps and Land Cover inventories of the Delaware Estuary to measure the acreage of tidal wetlands in nine distinct time periods from 1778 to 2011. Using these data, we estimate an annual rate of wetland loss of 1.03km 2 . Coupling observed land cover change with exogenous factors including sea-level rise, population pressure, and channel dredging, we estimate changes in tidal wetland area under a range of future scenarios for our expected future economic loss estimates. Keywords carbon sequestration; blue carbon; tidal wetlands; ecosystem services; social cost of carbon 2

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