The International Court of Justice is to clarify the obligations of states to act against global warming.

The window remains open for a few more days for governments around the world to make their words count. They have the opportunity to consider the proceedings of the International Court of Justice (ICJ), which is formulating a landmark judicial opinion on the responsibility of states for mitigating climate change.

Last year, the UN asked the ICJ – the UN's main judicial body in The Hague, Netherlands – for an advisory opinion on two issues. What are the obligations of states under international law to protect the climate system and the environment from anthropogenic greenhouse gas emissions? And what are the legal consequences for states that, by their actions or omissions, damage the climate system and the environment?

As an environmental policy expert and president of the global conservation NGO WWF, I call on scientists and citizens around the world to support the court. They must urge their governments to provide the ICJ with the evidence and arguments it needs to speak boldly about nature and climate protection. (Adil Najam, more at nature.com)