In a ruling that came as a surprise to many legal experts, a court in the Netherlands today ordered the Dutch government to dramatically intensify its fight against climate change. The district court in The Hague ruled that by 2020, the Netherlands must cut CO 2 emissions by 25% from 1990 levels. Current government policies would lead to a reduction by just 17%.

The court ruled in a civil case against the government brought by an environmental group called Urgenda. (The name is a contraction of “urgent” and “agenda.”) The case framed global warming as a human rights violation that the Dutch government must do more to prevent.

Environmental groups hailed the ruling as a legal landmark that could inspire similar action elsewhere. But the court didn’t specify which measures the government must take to meet the target, and the verdict immediately triggered discussions about whether a 25% reduction in 5 years is feasible and whether it might hurt the Dutch economy.

The court acknowledged that it is has no scientific expertise in climate change—but it didn’t really need to, because the science itself was not on trial. The Dutch government did not dispute the international scientific consensus on climate change. The verdict (in Dutch) relies heavily on quotes, tables, and graphics from reports by the Intergovernmental Panel on Climate Change and other international bodies. The court adopted the growing consensus that drastic reductions in CO 2 emissions are necessary to prevent a temperature rise of more than 2°C—starting with a reduction between 25% and 40% by 2020.

The government had argued that the Netherlands cannot make such major cuts on its own, a line of reasoning that the court did not accept. That the Netherlands is responsible for less than 0.5% of global greenhouse gas emissions isn’t a valid argument either, it said. As the verdict put it:

“The State must do more to prevent the threats caused by climate change, given its duty to care for the protection and improvement of the environment. Effective control of the Dutch emission levels is a task of the State. In addition, the costs of the measures ordered by the court aren’t unacceptably high. The State cannot hide behind the argument that the solution of the global climate problem is not just dependent on Dutch efforts. Every reduction in emissions contributes to the prevention of dangerous climate change. As an industrialized nation, the Netherlands should be a frontrunner in this respect.”

The government had also argued that the issue belongs in parliament, not in the courtroom. Aware that its decision might smack of judicial activism, the judges responded:

“With this order, the court does not enter the domain of politics. The court must offer protection under the law, including in cases against the government. At the same time, the court must respect the government’s freedom to set policies, which is why judicial restraint is in order. This is a reason to restrict the order to 25%, the lower limit of the 25% to 40% norm."

Urgenda’s case was inspired by the book Revolution Justified, in which Roger Cox, a lawyer, argued that the legal community should become much more active in the fight against climate change, given that politicians seem unable to tackle the issue. (Click here for a TEDx Talk by Cox.)

The government, which was also ordered to pay Urgenda’s legal bills, estimated at €13,522, has not said whether it will appeal.