A new study examined the climate effect of the mandated reduction of sulfur in ship exhaust emissions globally since 2020, and it suggests that the shipping regulation has reduced how much light is being reflected back into space, which has likely contributed towards the record warming over the last few years.International shipping, while invisible to most of us, has a large impact on climate and air quality. There are nearly 100,000 large ships within the global commercial fleet, accounting for over 90% of international trade.