This morning two very different kinds of harbingers brought us a message of climate doom. One was a colourful crowd of climate activists called Extinction Rebellion, who have been blocking traffic in London for the last two days, and who are today planning further “economic disruption” aimed directly at the city’s jugular: the tube and rail networks.

The other was less expected. Mark Carney, the governor of the Bank of England, along with the governor of France’s central bank, Villeroy de Galhau, has written an article for the Guardian warning banks and insurers that climate change threatens them too. In the wallet. Insurance claims from droughts and floods are bad for business. Then there’s the fact that governments are now taking carbon emissions seriously, which means companies that don’t adjust will likely be adjusted out of existence. And at a certain point, when climate catastrophe deepens, there will be a “Minsky moment” – a sudden collapse in asset prices, true economic disruption.

It feels like an important moment, this joining together of the solemn and besuited with the members of a group last seen supergluing their arses to the gallery glass in the House of Commons. It amplifies the message. Tackling climate change is, after all, about psychology. How should one talk about catastrophe? Make a problem too big and people will simply ignore it (just look at Brexit). Tell them it is too late, and the human instinct is to give up, rather than make vast efforts to save the scraps. And guilt doesn’t work on most people either – they are too wrapped up in their daily concerns. This is true of institutions too: David Cameron’s government was keen on green measures for a while, but only until something more important came along.

But there are certain milestones movements can hit, when it feels as if they are on their way. One is that they become cool. This happened to the modern feminist movement around the time Caitlin Moran’s book How to Be a Woman hit the shelves in 2011. It has gradually happened to climate activism too. Veganism is no longer something to sneer at. Celebrities who might have once tried to avoid looking too “hempy” now fall over themselves to burnish their climate credentials.

But an even more important milestone – when you know the movement has really picked up speed – comes when it directly threatens those in power. For feminism, again, this was #MeToo: the fear it has inspired among powerful men has done more for equality than decades of gentle awareness raising and women-friendly schemes. And now Carney is framing climate change in a language banks understand: as a threat to profits. It will add to other messages reaching the city. Five Volkswagen executives face up to a decade in prison for their role in faked diesel emission tests – a scandal that has also taken a chunk out of car sales. The investor Legal and General is cutting out companies they judge bad for the climate. For the planet, a turning point might just be at hand.

• Martha Gill is a political journalist and former lobby correspondent