The decarbonization of shipping is an ongoing goal to reduce greenhouse gas emissions from shipping to net-zero by or around 2050, championed by the International Maritime Organization (IMO). As of 2025 maritime transport emits 3% of global greenhouse gas (GHG) but that could rise to 10% by 2050. The IMO has an initial strategy that includes lowering, or limiting, the combustion of fossil fuels for power and propulsion to limit emission of carbon dioxide ; development of alternative fuels such as green ammonia, hydrogen, and biofuels to reduce reliance on fossil fuels, and adopting digital technologies to increase vessel efficiency; and reducing emissions by 40% by 2030. However in 2025 proposed IMO regulations aiming to reduce the GHG intensity of ship fuel, and the world's first global mandatory charge on GHG emissions, were blocked by the United States and Saudi Arabia.