Despite President George W. Bush's rejection of the Kyoto Protocol on climate change, the US administration is under mounting pressure from Congress to constrain the country's greenhouse-gas emissions.

On 1 August, a powerful senate committee called on the Bush administration to secure the participation of the United States in a revised Kyoto Protocol or other future binding agreement on climate change. The call was made unanimously by the Senate Committee on Foreign Relations.

And on 3 August, two influential senators, John McCain (Republican, Arizona) and Joseph Lieberman (Democrat, Connecticut), jointly announced that they would propose legislation later in the year to set mandatory limits on the United States' greenhouse-gas emissions.

The 19–0 vote by the foreign-relations committee surprised some observers, as several of its members, including Charles Hagel (Republican, Nebraska), have strongly criticized the Kyoto Protocol in the past.

Beating the gridlock: John Kerry hopes the United States will resume talks on carbon emissions. Credit: ALEX WONG/NEWSMAKERS: DAVID MCNEW/NEWSMAKERS

The resolution was proposed by John Kerry (Democrat, Massachusetts) as a non-binding amendment to a bill funding the Department of State. Its main goal is to bring the United States back to the negotiation table, Kerry says.

The resolution calls on President Bush to put forward a proposal at October's meeting in Marrakesh, Morocco, of the parties to the Kyoto accord in an attempt to secure the United States' participation in a revised protocol or other climate-change agreement.

A 1997 Senate resolution, which said that developing nations need to be included in any emissions treaty, should not cause the United States to abandon “its shared responsibility to help find a solution to the global climate-change dilemma”, the resolution adds.

Environmental groups praised the resolution, saying that it reflects growing momentum in the Congress for action on climate change. Elliot Diringer of the Pew Center on Global Climate Change, a group that encourages dialogue between industry and the public on the issue, notes that the resolution is the first time the Senate has declared that the United States should be party to a mandatory treaty on climate change.

But the Global Climate Coalition (GCC), which coordinates business opposition to mandatory controls of greenhouse-gas emissions, claims that the new resolution affirms Bush's opposition to the Kyoto accord. “The amendment effectively made the case yet again that any international approach to climate change must involve commitments from developing nations and must not harm American families, workers and communities,” says Frank Maisano, a GCC spokesman.

Almost 180 governments signed up to revised Kyoto rules in Bonn last month (see Nature 412, 365; 2001). But the United States — which emits about 25% of the world's greenhouse gases — rejected the agreement, saying it would unacceptably weaken the country's economy, and that the treaty should not exclude developing countries from binding reduction targets.