The UN's International Maritime Organization (IMO) votes this month on sweeping new rules to impose a global price on shipping emissions, but US threatens adoption, reports Bloomberg.

The draft Net-Zero Framework, backed by many IMO members in April, would require ocean-going vessels to reduce emissions and pay for excess greenhouse gases. The rules would take effect in 2027, with payments starting in 2029.

But the US condemns the plan as a "global carbon tax on Americans" and warned of tariffs and other penalties if adopted. Oil-producing nations including Saudi Arabia, Russia and Iran also oppose the measure.

Ships failing to meet emissions targets must buy "remedial units" at US$100 or $380 per ton of CO2-equivalent, depending on the level missed.

Bloomberg cited estimates that penalties could reach $20,000 daily for high-methane vessels. The IMO expects the framework to generate $11 billion to $12 billion annually by 2030, with some forecasts reaching $300 billion by 2035.

Revenue will fund the IMO Net-Zero Fund, rewarding ships using low-emission fuels. The EU, which already enforces its own emissions rules, supports the IMO plan and has pledged alignment through its FuelEU Maritime Regulation.