GOVERNMENTS like to cite external constraints—such as meeting the conditions for an international bail-out—when pushing through unpopular policies. But with measures to deal with climate change, the opposite prevails. Each round of intergovernmental talks on cutting emissions and compensating victims seems to achieve less than the one before. Meanwhile, according to a new study of 33 countries for GLOBE, a group of legislators from round the world, the number of new domestic environmental laws rose from ten a year in the early 2000s to 20 in 2012.

That figure is lower than the 30-odd laws recorded in 2009 and 2010, but the overall trend is a strong increase in legal activism. Last year Mexico passed a flagship law to guide all its climate-change policies: 31 of the 33 countries now have a basic greenery law. South Korea passed legislation setting up an emissions-trading scheme in 2015. Japan introduced a carbon tax and a new law to encourage denser, more energy-efficient cities. The study reckons that half the 33 countries made “substantial progress” in environmental legislation in 2012. In 2000 Western countries did more than poor ones. But in 2012 developing countries passed twice as many green laws as rich ones did.

Disclaimers and scepticism are in order. Defining what counts as a climate law is hard when so much affects the environment. The number of laws alone is not the crucial measure: some are comprehensive and others specific. Rules set by other layers of government may matter more than the national kind. And just because a law passes does not mean it will do any good.

Yet Sam Fankhauser of the London School of Economics, who helped write the study, says the rise in national legislation helps rebut the sceptics’ claim that it is self-defeating for a country to act alone on climate change. He also points out that many big countries still have a way to go. In so far as China and India, for example, still regulate emissions at all, they do it through the central-planning system (though the first draft of China’s flagship environmental law is due this month).

The study reveals the weak link between global action and domestic change. Holding a big climate conference prompts a flurry of laws a couple of years later (one reason why Mexico passed its new law). But by and large voters appear more willing to accept domestic environmental laws than international ones. If true, that is an indictment of years of green activism that has pushed for a global treaty first.