Global shipping GHG emissions are rising
International shipping emissions had a year-on-year growth of 4.9 percent in 2021, rising to approximately 700 million metric tons of carbon dioxide (MtCO₂). This was higher than 2019 levels, and accounted for roughly 11 percent of total global transportation CO₂ emissions that year. Emissions from international shipping have risen almost 90 percent since 1990, owing to increasing seaborne trade and the growing number of ships crossing the world's oceans.While GHG emissions within the shipping industry have been on an upward trajectory, releases of sulfur dioxide (SO₂) have been falling since 2009 due to imposed limits on sulfur content in marine fuels. Stricter regulations were introduced by the International Maritime Organization (IMO) in 2020, lowering the upper limit of sulfur content to 0.5 percent (previously 3.5 percent). It is estimated that these new regulations could have reduced shipping SO₂ emissions by 77 percent that year, relative to 2019 levels.
