Perhaps it’s just hype surrounding the UN talks, but a new climate optimism seems to be in the air. The People’s Climate March on Sunday promises to be the largest event ever of its kind, engaging communities around the world. But the new climate optimism isn’t just a tree-hugging ‘another world is possible’ kind of optimism. This optimism wears a suit and tie. This optimism has business on board, or at least some business. The New Climate Economy report, launched this week, proudly concludes there’s no conflict between fighting climate change and growing the economy (and for that extra hopey changey thing vibe, it’s even Obama-endorsed). It’s about a new consensus for change.

We’ve seen similar promises before, of course. Madonna at the Live Earth concert in 2007 shouting “This is your last chance to show you care about the planet! I want the whole world to sing along!” We saw it around Rio, in 1992 as well as 2012. And it is hard to take seriously. If you’re optimistic about climate change, surely you’re lying to yourself, or someone else? Or you’re happy to forget the suffering of millions of people around the world. Or you’re just selling something. Journalists like Vox’s Brad Plumer or Vice’s Brian Merchant explicitly covering an ‘apocalypse beat’ are maybe striking a more accurate note.

But this is a new climate optimism for the post-2008 pre-2015 era. One packing for Paris, but leaving both the depression of Copenhagen and the rose-tinted specs at home. One rooted in a sense of how big and how bad the challenge is, but needing a sense of light at the end of the tunnel to move forward. Is it worth joining up to this great new hope? Are the doom-mongers the ones really with their heads in the sand?

“It’s certainly not saying that the pessimists are wrong. The pessimists are right.” James Murray, editor of Business Green and advocate of New Environmentalism, tells me. “We are clearly in a lot of trouble. I get depressed about it some days, you’d be inhuman not to. (…) But equally if you don’t focus on that wafer-thin possibility that we can get there” he pauses, “then you’re doomed.”

The new climate optimism is not about saying we have to be optimistic all the time. David Timms, Head of Campaigns at 10:10 feels we’ve moved on from a binary dispute over whether doom, on one hand, or hope, on the other, will motivate people. “We did occupy ourselves with this for quite a long time in the climate movement, I think unnecessarily.” Timms continues: “The best phrase is the Gramsci one – pessimism of the intellect and optimism of the will. It’s not a contradiction to have an honest and open appraisal of the science, be concerned about the consequences, but also be optimistic about the ability of people, if they choose to organise themselves, to bring those with power into line, and the optimism that humanity, if it applies its inventiveness and skill to problems, to overcome them.” To some extent, it’s about striking a balance, and appreciating the worth of applying a diversity of methods at once. 10:10’s It’s Happening campaign tries to get people sharing positive stories of action on climate change going right. But this wouldn’t work if there weren’t other groups, elsewhere, sounding a different note at the same time: “Different tactics work in different places. We see ourselves as part of a climate change movement. By itself, saying ‘isn’t a low carbon future exciting’ wouldn’t work.”

What’s driving this new optimism? Is it that we’ve finally recovered from the depression which followed Copenhagen? Or do we see some new hope in Paris? Is it because we are, finally, winning a public debate? Is clean tech actually living up to the hype? In some respects, the case for optimism is a moral one. When, last June, Ezra Klein offered 7 reasons America will fail on climate change, Grist’s Brentin Moc responded that this told those likely to be harmed by climate change they weren’t worth saving. Similarly, Timms feels there are a new group of campaigners wanting to argue mitigation is still plausible, and that a new optimistic discourse stems from that. But the case is more than ethics. As Mock argues, international cooperation is possible and has precedent, and solutions are there too, if you look. To Murray, just as pessimism about climate is evidence-based, we may have evidence-based optimism too. “We kind of are winning” he offers with a cautious smile, noting a range of cultural, economic, political and technological shifts. “Renewable energy records being set all the time. It’s not unfounded. Things are starting to happen, starting to roll.”

Part of the knottiness of this issue is how we see technology. Faith in technology is, for good reasons, often dismissed as reductive, obscuring politics, or hype to sell us someone else’s idea of the future. But you don’t have to buy into the myth of a silver bullet to believe in the power of technology for positive change, and you can be aware of the dangers of technology whilst also appreciating its benefits. Moreover, a belief in the ability of humans to organise their inventive energies to particular goals, and do so fairly, is different from the belief that if you sit around long enough, some superhero will turn up. Timms argues: “You create your own luck.” He looks up to an office wall covered in last year’s It’s Happening stories, pointing out they only occasionally showcased new technologies, choosing to focus on the uptake of technology instead. A new see-through solar panel is awesome, but it’s building a school from them that will really get us celebrating. There’s also only one example of a product an individual might buy amongst his many case studies. Consumption is part of this story, but only a small part.

For Murray, however, the sustainability industry could take a page from the book of tech marketers. He recalled his experience covering IT: “You immediately got how these companies were able to create hype, buzz, excitement, and spent money to do that, because they knew it was essential for the roll out of their technologies.” There are negatives involved in such a roll out, but “in a 20-30 year time period, they’ve transformed the world. Those companies and entrepreneurs almost made what they had inevitable, and the green tech companies are only starting to work out that this is what is needed. They haven’t got that bullish optimism, they haven’t got those heroes, they haven’t got those corporate warrior king people that, whatever you think of them, made things happen.” But this is not a model of power everyone will subscribe to. Or find hope in. If we’re creating a new, bright green world, shouldn’t we all be involved in imagining what it looks like? Murray says he’d personally prefers more democratic models, but worries there isn’t time. “The pace at which things have to happen, the scale of the challenge means you want the Chinese state, and you want Google saying here’s millions of dollars.”

There is a way in which some of this climate optimism feels slightly borne out of desperation, and problematic for that reason. “I don’t think people can sustain themselves in long-term political struggles without some sense that we are going to win eventually” Timms notes. He also argues climate change is different from, for example, feminism or civil rights, invoking the idea of a ticking climate clock, referring to the sometimes problematic milestones that get applied like 2 degrees warming, or 350ppm. “I used to do civil liberties stuff and a movement forward was a movement forward, you could win battles. But with climate change, you are doing it against time. You’ve got to get there by a particular moment. And sometimes that can feel very debilitating, because you are trying to get there at a particular speed, so just making progress isn’t enough, and that’s really different.” As a long term advocate of opening up science policy, Andy Stirling has argued in the context of geoengineering that we make bad decisions when we are scared. Similarly, Amanda Machin warns in her book Negotiating Climate Change, the idea of a ticking clock of climate change too easily becomes a way to limit debate in climate change. This not only leads to the top-down control Murray refers to but, she suggests, worse decision-making. There is a way in which climate optimism can be applied to close down debate, just as pessimism might. It’s all very well saying here’s a new, hopeful consensus, but what if you disagree with those who’ve framed this debate? What if you don’t like the look of the particular vision of a bright new green future on offer?

And how do scientists feel about all this? Sarah Perkins, a climate scientist at the University of New South Wales, says she doesn’t necessarily find her work researching climate change an emotional experience: “Not while I’m working on it. When I do my work, it’s more about getting it done properly. Effectively. Correctly. Making sure I’ve used the right tools, the right data, the right methods. But it’s when the results are published, what gets me, what makes me emotional is when I stand up and say this is a problem, we need to do something about this, and nobody cares.” Perkins recently took part in an art project – Scared Scientists – which stressed that the biggest fear many scientists have over climate change is that we won’t take action. And yet Perkins says she has hope too: “I get that people feel overwhelmed by the situation. Because how can one person make a big difference? I sometimes feel that way too. My work does worry me, the results do worry me.”

She offers the analogy of skin cancer: “You see a mole and think oh I’ll leave it. But the longer you leave it, the more risky it is. That’s what the IPCC is saying. Come 2100, if we’ve not touched any reduction targets, we’re screwed, we’re going to get that cancer and we’re going to die. However, if we do change, that’s where the good news story starts to come in. There is this cancer on your back, but we’re not there yet, there is still hope. We can make it be not as bad as those projections.” It seems as if the new climate optimists are, in essence, simply trying to open up that space of hope so we act before it gets too risky. If you don’t like the particular images of hope they offer, maybe the trick is to try to get involved and offer some of your own too. Similarly, those offering visions for the future need to make them open. As Timms says, we make our own luck. We make our own hope too.”