In 1988, when the scientist James Hansen told a senate committee that it was “time to stop waffling so much and say that the evidence is pretty strong that the greenhouse effect is here”, those who took him seriously assumed that if they just persisted with emphasising that this terrible fact would eventually destroy us, action would be taken. Instead, the opposite happened: when confronted with the awful reality of climate change, most people tended to retreat into a panglossian vision of the future, or simply didn’t want to hear about it.

A lot of work has been done since to understand why climate change is so uniquely paralysing, most prominently by George Marshall, author of the book Don’t Even Think About It. Marshall describes climate change as “a perfect and undetectable crime everyone contributes to but for which no one has a motive”. Climate change is both too near and too far for us to be able to internalise: too near because we make it worse with every minute act of our daily lives; too far because until now it has been something that affects foreign people in foreign countries, or future versions of ourselves that we can only conceive of ephemerally.

It is also too massive. The truth is if we don’t take action on climate change now, the food shortages, mass migration and political turmoil it will cause could see the collapse of civilisation in our lifetimes. Which of us can live with that knowledge?

It’s not surprising, then, that some years ago climate activists switched to a message of optimism. They listened to studies that showed optimism was more galvanising than despair, and they began to talk about hope, empowerment, and success stories. They waited for some grand extreme weather event to make the final pieces fall into place. Maybe the submerging of New Orleans would be it; maybe some of the rich white people who were battered by Hurricane Sandy would use their privilege to demand action. Maybe Harvey or Irma – or now Maria – would cause us to snap out of our stupor. It hasn’t happened.

Instead what I think a message of optimism has done is create a giant canyon between the reality of climate change and most people’s perception of it. An optimistic message has led to complacency – “people are saying it’s doable so it will probably be fine” – and championing success stories has convinced people that the pathetic, threadbare action taken by governments so far is sufficient. I’ve lost count of the sheer number of politically engaged, conscientious people I’ve met who have simply no idea how high the stakes are.

It may be that if the time for a mass movement is not now, there won’t be one

The fact is, nobody knows how to solve the riddle of persuading the public to demand action on climate change. I certainly don’t have the answers. But I do think we need to contemplate that something is going disastrously wrong here – that perhaps it’s time to get back to the drawing board and rethink how we talk about climate change.

Two significant things have happened since that senate committee hearing in 1988: the first is the Paris agreement in 2015 to try to limit warming to 1.5C – research out this week shows this is still possible. The second is that major parts of the dominant global superpower have been decimated by two Katrina-dwarfing storms in less than a month. Circumstances have changed in the past 30 years: climate change is a material fact now, and we have a specific target to aim for, to limit the damage it will cause.

A new campaign could centre on the demand for governments to meet the 1.5C target, emphasising how dire the consequences will be if we don’t. People don’t need to imagine what climate change looks like any more: they can see it in the sea water that has enveloped the islands of the Caribbean, the drowning houses in Houston, the communiques from those who couldn’t escape, and prepared themselves to lose everything. In Britain we’ve seen floodwater inundate entire villages; a pub that became a thoroughfare for a swollen river. This is what catastrophe on our doorsteps looks like, and perhaps it’s time we link these images to climate change with as much gusto as the fossil fuel industry denies it.

Could the language of emergency work? It has never been tried with as much meteorological evidence as we have now, and we’ve never had a target as clear and unanimous as the one agreed in Paris. The one thing I know is that the events of the last few months have changed the game, and this is the moment to start debating a new way to talk about climate change. It may be that if the time for a mass movement is not now, there won’t be one.

• Ellie Mae O’Hagan is an editor at openDemocracy, and a freelance journalist