THE INTERNATIONAL Energy Agency (IEA) last week warned that global carbon dioxide emissions in 2012 were the highest ever. Yet international climate negotiations have floundered. Many Americans and their representatives in Congress still doubt climate change is a problem worth addressing. And as the developing world advances, its peoples are polluting more to obtain higher standards of living.

Forget for a moment the ideal or rational response; what’s the bare minimum global leaders could do? The IEA had some useful, if modest, suggestions.

An energy-gobbling world emitted 31.6 gigatons of carbon dioxide in 2012, the result of extracting and burning vast amounts of coal, oil and natural gas. Last month, the world reached another milestone that scientists and policymakers said they wanted to avoid — CO2 concentrations in the atmosphere that exceeded 400 parts per million. Scientists reckon that the last time concentrations were that high, the Earth was far warmer. Though the planet’s sensitivity to carbon emissions is still a matter of intense study, the IEA figures that, under policies in place now, the planet could warm between 3.6 and 5.3 degrees Celsius, mostly over the next hundred years. By contrast, world leaders have committed to limiting warming to no more than 2 degrees Celsius, the point past which the consequences could be very negative.

The IEA argues there are things that governments can do between now and 2020, at no net economic cost, at least to try to “keep the door open” to 2 degrees Celsius. Retrofitting buildings and constructing better ones could reduce emissions. More-efficient cars would help, too. These sorts of investments would also save consumers money over time. Phasing out the dirtiest coal-burning power plants would cut greenhouse emissions and other pollutants. So, too, would inexpensively reducing emissions of methane — itself a greenhouse gas — during oil and natural gas production. And, of course, countries should stop encouraging fossil fuel use by artificially lowering prices for the stuff, a problem here that’s much worse in other countries.

In the United States at least, those policies seem achievable, even without agreement among politicians on the scale of the climate problem. Bipartisan groups of senators have sought to pass an efficiency bill for years. The Environmental Protection Agency has been using its powers under the Clean Air Act to crack down on coal plants. Other federal regulations are addressing methane emissions. Washington’s policymakers should immediately follow through and pressure other nations to follow.

Then they should think about doing more than just the bare minimum.