One of the first concrete breakthroughs of the COP26 meeting were made when 90 countries joined a US-EU led initiative to slash emissions of the potent greenhouse gas Methane with 30% from 2020 levels by 2030.

According to Reuters the new initiative will be formally launched on Tuesday.

Methane is the main greenhouse gas after carbon dioxide. It has a higher heat-trapping potential than CO2 but breaks down in the atmosphere faster – meaning that cutting methane emissions can have a rapid impact on reining in global warming.

China, Russia and India, countries in the top-five methane emitters, have not signed on to the pledge.

Commenting on the undertakings made so far at Cop26 Philippe Sands, law professor at University College London and environmental activist tweeted: ‘Is it binding in law? Does it have effective enforcement and dispute settlement mechanisms? Let us see the hard details.’

Sands said to Al Jazeera: ‘We need targets, taxes and treaties, not statements of aspiration.’