The journalist and author on the climate crisis and how the US and China will be key to averting disaster

David Wallace-Wells is the deputy editor of New York magazine. In July 2017, he wrote a long-form essay about the dire prospects for human civilisation caused by the climate crisis. It became the most read article in the history of the magazine and led to a book, The Uninhabitable Earth: A Story of the Future, which is being published in paperback in September.

The first line of your book states: “It is worse, much worse, than you think.” If you were sitting down to write the book again, would you be inserting another “much” into that sentence?

I still think the public aren’t as concerned as they should be about some of the scary stuff that’s possible this century. But I do think things have changed quite a bit. And I also think the politics have changed quite a lot. When I turned in the book in September, nobody had heard of Greta Thunberg. Nobody had heard of Extinction Rebellion. In the US, very few people had heard of Sunrise. And Alexandria Ocasio-Cortez had not even been elected.

In the United States, you have a climate crisis denier as president, yet areas of the country are experiencing frequent flooding, more forest fires and rises in average temperature of more than 2C. How do you explain this?

Actually, it’s quite striking how many Americans do believe climate change is happening. [Democratic presidential nominee] Jay Inslee says 75% of voters want action, compared with 63% 12 months ago – that is remarkable. There was a piece earlier this month in the New York Times about how for many young Republicans, it is their top issue.

There is a pervasive techno-optimistic view that we can just invent something and it will solve the problem

There seems to be a division in the US Democratic nomination race between candidates who advocate wholesale system change such as the Green New Deal and others who favour a more incremental progress because they claim that’s the only way to get laws passed. Which is the most effective approach?

The science demands a quite systematic response; incremental policy simply isn’t going to be adequate to avoid really terrible levels of warming. But ambitious legislation has to go through the Senate and I don’t think there’s a scenario where a Democratic president takes office in 2021 with more than 60 Democratic votes [a three-fifths majority].

On the other hand, the last few administrations have gotten quite creative in how to use what’s called “budget reconciliation”, which you can use to pass stuff through the Senate with only 51 votes [a simple majority] by defining legislation as essentially budget-based. That’s one reason why you see so many of the Democrats’ plans are essentially investment programmes.

Inslee has been more ambitious in putting forward details about how he would regulate the fossil fuel business but some of the other campaigns have basically just put forward a sort of Green New Deal or green Marshall Plan – a massive spending programme directed at green energy projects.

You’re hopeful that technologies like geoengineering and carbon capture will play a significant role in mitigating temperature rise. Some environmentalists and scientists argue that these unproven methods can’t bail us out, and that they give licence to the fossil fuel industry to carry on polluting…

I look at the science and say if we’re defining a comfortable world [as] staying below two degrees of warming, I just don’t think that there’s any way we can achieve that without a really quite dramatic amount of negative emissions.

But I’m also very mindful that there is a pervasive techno-optimistic view – especially among wealthy Americans – that we can just invent something and it will solve the problem.

The UN says we need to halve global emissions by 2030 to avoid catastrophic warming. We’re really deeply deluded about how quickly new technology can scale and can be deployed. We’re far from having a 747 flying on a zero-carbon fuel.

We can agree to decarbonise – rethink our agriculture, aim for a meatless diet and so on – but we don’t live in a global, centralised command-and-control economy. Every country has its own political interests. How do you make the world take collective action?

That’s harder than the technological problem. There are many cases of what I think of as climate hypocrisy, for example, Canada declaring a climate emergency and then the very next day approving a new oil pipeline.

Each individual nation could be quite aggressive in their decarbonisation and yet be living through the exact same climate that there would be if they took no action unless the rest of the world followed suit. No major industrial nation is on track to meet its commitments under Paris.

My own hope is that I see almost half of our global emissions being produced by two countries – the US and China. Maybe it’s naive, but I hope a cooperative pact can be reached between the two countries like the nuclear non-proliferation agreements that were made between the US and Russia in the cold war. The two nations remained rivals but were nevertheless jointly committed to protecting the planet from an existential threat.

If the US and China really took aggressive leadership on this issue, the collective action problem would become less important – the world’s most powerful countries have a way of bending the will of the less powerful.

We need to fight to make the world one we want to live in, rather than giving up hope before the fight is really over

Some environmentalists argue that we need to rethink economic growth – we need to reorient our expectations of the conveniences and luxuries of modern life…

I don’t yet have a firm perspective on this. My intuition is that we don’t need to abandon the prospect of economic growth to get a handle on climate change.

I look at the case of the US and I see that if the average American had the carbon emissions of the average EU citizen, the country’s emissions would fall by 60%. And I think most Americans would be happy with those lifestyles.

The American electricity grid loses two-thirds of all energy produced as waste heat. We discard something like 50% or 60% of all of our food. So we could achieve some quite significant emissions gains.

Do you still think of yourself as a journalist or have you morphed into an activist?

I do still think of myself as a journalist. And I don’t know how long that will last. I still feel like a chronicler of the story rather than a protagonist. I’m really heartened and excited by all of the new activist energy that we’ve seen over the last year.

Millennials are expressing doubts about having children because of the environmental crisis – they are concerned that their grandchildren and possibly their own children will be living in an inhospitable and volatile world. You have recently had a child…

My intuition is that we need to fight to make the world the one we want to live in rather than giving up hope before the fight is really over. The world is going to get warmer. Almost inevitably, there will be a lot more pain and suffering in it than we have now. But how much is really up to us.

At what point should panic set in? It’s plausible there’ll be four degrees of warming by the end of the century, which would mean mass migration from areas such as the Middle East and Asia to newly temperate areas such as Siberia and Greenland. That’s not a very smooth transition for human civilisation.

It seems hard to imagine. Yet we’re already seeing some fair amount of panic. The significant amount of human migration we’re seeing in the US coming from Central America, for example.

I am personally horrified by the way our politics are beginning to adjust to them. We need to be much more open-hearted and attentive to the suffering of those around the world rather than closed off and hard-hearted, which is how almost all of the countries of the west have been over the last decade to refugees.

We’re also seeing panic in the protest movements, which are essentially declarations that existing power structures and priorities are simply not sufficient to address this crisis in the terms that it demands.

• David Wallace-Wells will be giving a Guardian Live talk about the climate emergency at 7pm on Wednesday 11 September at Kings Place, north London. Tickets are £20 each or £27.50 with a copy of The Uninhabitable Earth (Penguin, £9.99). A booking fee of £1.26 applies