The United States on 12 Aug 2025 formally rejected the International Maritime Organization’s proposed “Net-Zero Framework,” which seeks to curb greenhouse-gas emissions from global shipping. A joint statement from Secretary of State Marco Rubio and the heads of the Commerce, Energy and Transportation departments called the plan a hidden tax that would raise costs for American consumers, energy producers and the domestic shipping industry. Washington warned it will “not hesitate to retaliate” against countries that back the measure and urged fellow IMO members to oppose it. The administration did not specify what form retaliation could take but said it would explore “remedies” to shield U.S. interests if the framework advances. The IMO blueprint, endorsed by a majority of members in April and slated for a decisive vote in October, aims to steer the sector toward net-zero emissions by 2050 and could include a global carbon levy on marine fuel. Ocean vessels carry roughly 80 percent of world trade and account for almost 3 percent of carbon-dioxide output. Several large carriers, including Maersk and Wallenius Wilhelmsen, have already pledged to meet the 2050 target. Tuesday’s move deepens the administration’s break with multilateral climate initiatives after its earlier exit from the Paris Agreement and months of tariff threats in other environmental negotiations. By walking away from the talks in April and now rejecting the plan outright, U.S. officials signal they will prioritize domestic economic considerations over new global emissions rules for shipping.