It was not until Paris in 2015 that scientists, environmentalists and politicians who recognised the genuine threat posed by global warming felt they could celebrate. Six years on, it seemed the world was taking the issue seriously.
However, despite this, carbon emissions are still rising and the nations of the world plan for this to continue for years to come.
The Cop26 climate summit in Glasgow is a chance to finally put humanity on a path to net-zero emissions, the point at which we will actually stop adding to the problem.
But will Glasgow be another Copenhagen? Will we have to wait another six years, as the wildfires, droughts and storms continue to grow, before real action is taken?
Or will world leaders recognise the direction of travel and that it is far better – both in terms of the economy and the climate – if action is taken sooner rather than later?
Alok Sharma, the Conservative MP who is Cop26 president, has now warned that “if temperatures continue to rise, we will step through a series of one-way doors, the end destination of which is climate catastrophe”, adding that actions by the G20 group of countries will be “make or break” for restricting global warming to 1.5C.
And in a speech today, Labour’s shadow business secretary Ed Miliband will warn of the dangers of Glasgow becoming “the greenwash summit”.
This is the decisive decade for efforts to stop dangerous climate change. To have any chance at all, it needs a good start.