We start The Sustainable Hour no 345 with the words of the United Nations’ leader Antonio Guterres as he urges world leaders to declare a climate emergency for their countries:

“I call on all leaders worldwide to declare a state of climate emergency in their countries until carbon neutrality is reached,” the Secretary-General told a global Climate Ambition Summit over the weekend.

The summit included leaders of more than 70 countries – including the British Prime Minister, the President of France, of China, Korea, Japan, India, the European Union, the Prime Ministers of Denmark, Norway, Sweden, Finland, Holland, Italy and Germany, and many more.

“Can anybody still deny that we are facing a dramatic emergency?” Guterres asked via the live-streamed video-transmission of his opening remarks at the summit.

This was a peak moment for the Climate Emergency Declaration movement which has been five years in the making. It started with volunteers collecting signatures in the streets of both Geelong and Melbourne. Darebin City Council in Melbourne was the first local government in the world to declare which inspired a torrent of local, state and even some national goverments across the world to do the same, while excited volunteers kept track of the exponentially growing number of global declarations on a shareable spreadsheet.

After a slow start, a tipping point was gradually reached, and four years down the track, almost 2,000 local government authorities worldwide had declared a climate emergency in their municipality. In the United Kingdom, close to 500 councils have declared a climate emergency, and 90 per cent of the population there live in a jurisdiction which has declared.

And our language changed. Oxford Dictionaires named ‘climate emergency’ Word of the Year in 2019, and whether or not one has “declared” took on a whole new meaning. To declare, became a thing everyone can do.

On Saturday 12 December 2020 – five years after the global Paris Agreement – the movement reached the top, the head of the United Nations.

This is one of those moments where an editor-in-chief runs into the editorial room of hard-working journalists nearing the deadline and shouts, “We have breaking news! Whatever you are working on, drop it! Put everything aside and clear the front page!”

It didn’t happen in any editorial rooms that w...