Maritime Shipping's Impacts on Air and Water Quality
EM – February 2021: This month, EM examines the maritime shipping industry's impacts on climate, air quality, water quality, and the broader ocean ecosystem.by Bryan Comer
Ships are critical to global trade, transporting about 11 billion tonnes of cargo annually.1 To do this work, the global maritime shipping sector emits approximately 1 billion tonnes of carbon dioxide each year, making it responsible for nearly 3% of global emissions, according to the International Maritime Organization (IMO).2 Ships have become more efficient over time, and yet the global shipping sector's greenhouse gas (GHG) emissions grew around 10% from 2012 to 2018, with methane emissions growing a staggering 150% over that same period, reflecting a trend toward liquefied natural gas (LNG)-fueled ships that emit low levels of sulfur oxides and nitrogen oxides, both of which are regulated, but high amounts of unregulated methane.3 The coronavirus pandemic has mitigated some of the damages done by ships, but not for long. The United Nations Conference on Trade and Development predicts that maritime emissions will fall 4.1% in 2020 but will expand 4.8% in 2021.4
In addition to climate pollution, ships contribute to air pollution, water pollution, and noise pollution. They are also a vector for aquatic invasive species. Ocean-going vessels are responsible for the introduction of more than 50 non-native species to the North American Great Lakes since 1962, including zebra and quagga mussels, which scientists think are partly responsible for the devasting harmful algal blooms that plague the Great Lakes every summer because they preferentially feed on other, non-toxic phytoplankton.5
This issue examines the maritime shipping industry's impacts on climate, air quality, water quality, and the broader ocean ecosystem. Three articles focus on shipping's impacts on the aquatic environment and two on air emissions.
Continue reading the full February 2021 issue of EM.