LONDON -- In a clubby mid-rise on the River Thames, its lobby filled with models of container ships and oil tankers, a rather obscure United Nations group is gathering this week to make a momentous decision that will influence whether the world can meet its promise to limit perilous global warming.
The meeting of the International Maritime Organization, the U.N. body responsible for regulating shipping on the seas, opened on Monday, attended by delegates from 175 governments, who are set for a sharp debate over how ambitious they will be in slashing future greenhouse gas emissions from the maritime sector.
The shipping industry -- vital for trade, but fiscally conservative; international, but greatly influenced by a small number of magnates in a handful of countries -- plays an outsize role in climate change. It is traditionally a dirty sector, as most boats burn a heavy fuel oil.
About 90% of the world's trade travels by ship -- a ceaseless movement of 60,000 vessels plying their routes, moving 11 billion tons of goods each year.
Essentially, almost every import in a modern American home and garage arrives by boat -- cars, appliances, furniture, clothes -- and increasingly a lot of the food in the kitchen, too, like frozen burgers from Argentina or green bananas from Colombia.
Ocean transport contributes about 3% of humankind's greenhouse gas emissions. While that number might not seem like much, if the shipping sector were a country, it would be Germany -- and among the top 10 polluters.
At the IMO meeting, the United States is leading the charge by "high ambition" countries to hold future warming to 2.7 Fahrenheit -- to stave off dramatic sea level rise and other perils. The Biden administration is pressing the shipping sector to go green.
Countries such as Saudi Arabia and Russia, alongside China and Brazil, have generally advocated a slower approach -- either because they are major fuel exporters or a developing country opposed to measures that could hinder global trade. Also, change costs money -- by the shipper or the buyer.
Previously, the International Maritime Organization committed world shipping to a 50% reduction in warming gas emissions by 2050. That would be far too little, according to the current scientific consensus.
The Biden administration wants shippers to reach a 37% reduction in emissions by 2030; followed by 96% by 2040; and 100% by 2050.
The Americans said they were "cautiously optimistic" the International Maritime Organization would be more ambitious.
But some delegations are clearly opposed to high targets and want to set lower goals -- say, a 20% reduction in emissions by 2030. They also want the targets to be squishier -- "indicative checkpoints," for example, vs. "levels of ambition."
Senior U.S. officials, briefing reporters before the meeting, said the 2030 goals are achievable using "off the shelf" technologies.
Even so, those changes would be pretty dramatic.
One solution that seemed almost science fiction a few years ago may soon become commonplace, as cargo vessels are outfitted with "sails" mounted on their decks.
These won't be traditional canvas managed by ropes but could be giant kites, spinning rotors or telescoping hard sails -- think of a folding airplane wing -- that harness wind power to propel the vessel.
The first cargo ships are deploying these technologies on sea trials now.
The 235-meter Shofu Maru, a coal carrier running between Australia, Japan and North America, will test out its rigid sail and is expected to reduce emissions by 5 to 8% on the journey with a wind assist.
A French company called Airseas, which is piloting a huge kite called Seawing to pull a cargo ship along, traveling between France and the United States, claims it can reduce carbon emissions by an estimated 20%.
If new climate goals are adopted by the International Maritime Organization this week, we could also soon see voluntary speed limits out in the oceans.
Modern cargo vessels capable of doing 25 knots or more may be "slow-steaming" at half that speed.
Slower ships burn less fuel and emit less carbon dioxide. But slower ships also mean that to meet global demand for transport, the size of the shipping fleet will grow.
Other near-term technologies include better route planning, perhaps aided by artificial intelligence, and better design. One idea is to reduce the resistance between the ship's hull and seawater by using air bubbles. Experiments are underway.
To meet the 2040 and 2050 goals, the industry will need to transition to alternative shipping fuels, such as ammonia and green hydrogen. The new fuels will require massive investment -- new engines, new port infrastructure and a steady supply of fuels.
International Maritime Organization Secretary General Kitack Lim spoke with The Washington Post and other news outlets at the meeting. He said that in addition to technological fixes, the maritime industry must consider a carbon levy on ships that would fund action in the developing world. He called it "vital" to helping poorer countries, which also rely on shipping, ports and sea trade.
Whit Sheard, an expert in shipping emissions at Ocean Conservancy, an environmental group, said that shipping companies and the IMO "have been dragging their feet for too long."
John Maggs, president of the Clean Shipping Coalition, said the marine industry needs to set clear, hard targets to secure the financing and make the investments necessary to transform the industry.
António Guterres, secretary general of the United Nations, on Monday urged the International Maritime Organization to do more. "Humanity is in dangerous waters on climate. But the decisions you take over the coming days could help us chart a safer course," he told delegates in a video statement.
While Guterres acknowledged that "the industry has seen some progress," he said it "must move much faster to get on track and drive investment and innovation."