If you had to predict who would save the world, city lawyers may not instantly spring to mind. So many people were surprised last week when US lawyers launched a strike against global warming.

Attorney-generals from eight states and lawyers from New York City filed a lawsuit demanding cuts in emissions from the five major power companies that they say belch out about 10% of the nation's carbon dioxide (see http://www.nature.com/news/2004/040719/full/040719-12.html). The move is an unmistakable dig at the Bush administration for shirking strict curbs on greenhouse-gas emissions in favour of voluntary reductions.

Much of the lawsuit is sheer showmanship from the ambitious legal team behind it. When they get their day in court, they may struggle to win a guilty verdict. It may be tough to prove that a few companies should shoulder the blame for their share in a global problem, or that the modest cuts the lawsuit seeks would help.

But the trial signals that the fight against global warming in the United States is far from over. Lawyers and policy-makers in individual states are willing to take the issue into their own hands—even if President George Bush is sitting on his. And the states can force the federal government to deal with issues where activists have failed.

The Regional Greenhouse Gas Initiative, for example, is an effort by nine northeastern and mid-Atlantic states to build a system to cap greenhouse-gas emissions. California, meanwhile, is developing legislation demanding curbs in carbon dioxide from vehicles. Such initiatives could drive a change in national policy simply by showing that it can be done, or because companies reined in by conflicting state laws may turn to the federal government for clarity.

Many environmentalists would like to see the heads of power plants squirm in the dock, and may get their wish. Some experts predict an imminent wave of lawsuits against greenhouse-gas producers, much like those against the tobacco industry, from people claiming damages for property or loved ones lost to floods or droughts.

But acrimonious court battles are not the best way to resolve issues that affect the future of the planet. Negotiation, legislation and regulation are. State lawmakers should unite and act where the federal government has not; scientists and activists should support them.