Pound for pound, carbon dioxide is not the worst global warming culprit. Carbon dioxide is climate change’s primary driver only because modern society produces so much of it. But humans put far more potent greenhouse agents into the atmosphere, too. Cutting smaller amounts of these super-warming chemicals is often easier than wringing carbon dioxide out of the economy — and can make a surprisingly large difference.

This is why it is a big deal that President Biden on Tuesday submitted to the Senate an international treaty on hydrofluorocarbons, known as HFCs. The accord requires a two-thirds vote to pass. On its merits, it should sail through unanimously.

HFCs have countless household and industrial uses — in refrigerants, insulation, fire suppressant, even bear spray. Produced to replace another class of chemicals that were eating up the ozone layer, HFCs themselves turned out to have a major drawback: They are hundreds of times more potent heat-trappers than carbon dioxide. International negotiators struck a deal in 2016 to amend the 1987 Montreal Protocol on Substances that Deplete the Ozone Layer, committing to reduce HFC use by more than 80 percent by mid-century, and with specific emphasis on the very worst compounds, such as extremely potent HFC-23, stocks of which should simply be destroyed.

Under the treaty, the United States alone would, over 15 years, cut its annual national emissions by the equivalent of 900 million tons of carbon dioxide — more than Germany’s total yearly carbon footprint. Altogether, the treaty would enable the world to avoid half a degree Celsius of warming, which is a massive difference.

Support for phasing out HFCs has been bipartisan. Seventeen Republican senators asked President Donald Trump to send the treaty to the Senate. Mr. Trump refused, but an unlikely group including the Natural Resources Defense Council, the U.S. Chamber of Commerce and FreedomWorks backed the accord. One major reason: U.S. companies such as Honeywell and Chemours have invested billions into developing HFC alternatives that they aim to sell here and in the scores of other countries that have adopted the treaty.

In December, despite Mr. Trump’s refusal to join the global agreement, senators of both parties forced through a national HFC policy empowering the Environmental Protection Agency to phase out these chemicals in line with the treaty’s stipulations. All that is left, then, is for the United States to formally ratify the accord. Doing so would be more than symbolic. It would encourage other countries to keep their end of the bargain. It would also enable U.S. companies to more easily market their HFC alternatives in countries that have formally accepted the treaty.

Senators often complain that presidents commit the country to international agreements, such as the Paris climate accord or the Iran nuclear deal, without consulting the Senate, the body that the Constitution gives the power to review treaties. Presidents fear, with reason, that partisanship has become so toxic that lawmakers would reject an important international accord merely to deny a win to a president of the opposite party. The Senate should show, on this crucial issue where there is broad consensus, that it can still do its job.