Performance artist Bryony Kimmings doesn’t hold back. If something is troubling her then it invariably finds its way out in the open and into her work. Her early theatre shows, including Sex Idiot and 7 Day Drunk, took audiences on a freewheeling tour through the perils of early adulthood. Love, desire and STIs. Anxiety, alcohol and the drive to create good work. They were whirlwind one-woman shows, brimming with creativity, rammed with zany props and mad detours, and – despite all the doubts and fears contained within them – glowing with a childlike sort of optimism.

Later shows would see Kimmings pull other people and their concerns on to the stage. In Credible Likeable Superstar Role Model, Kimmings and her nine-year-old niece created and performed a powerful critique of the hyper-sexualisation of tween culture. She and her then partner Tim Grayburn explored the devastating impact of depression in Fake It ’Til You Make It. As her profile grew, there followed an ambitious musical about cancer at the National Theatre (A Pacifist’s Guide to the War on Cancer) and I’m a Phoenix, Bitch, a ragingly powerful solo show about postnatal depression and the breakdown of Kimmings’s relationship and mental health.

Now the 44-year-old artist is deeply worried about the climate crisis – and she’s not just creating a show about it. She’s upending her life. Three years ago, after getting together with projection artist and self-taught ecologist Will Duke, Kimmings left Brighton with her young son Frank and moved to rural East Sussex. The family is surrounded by farmland. They have huge polytunnels and water butts, 25 fruit and nut trees and their own chicks and ducks. Within the next two years, they fully intend to get a farming co-op off the ground (it normally takes around 10 years, but Kimmings isn’t one to hang around).

Raging … Bryony Kimmings in I’m a Phoenix, Bitch in 2018. Photograph: Tristram Kenton/The Guardian

As we talk over video call, Kimmings is just as personable on screen as she is on stage and quick to develop an intimate rapport with her audience of one. Her sentences splinter as her mind races off in different directions. There’s always another book to reference, an anecdote or silly impression to squeeze in; a different part of herself to reveal, laugh at and offer up for inspection.

Bog Witch is Kimmings’s first devised theatre show in five years. Part of that is down to logistics. The show was a commission from Soho theatre – a long-time champion of Kimmings – which wanted her to headline the opening of their new 960-seat theatre in Walthamstow, east London. Only the building work kept getting delayed. Before all those delays, the show was going to be called Soil and Water. Kimmings laughs ruefully about this rather earnest starting point: “Luckily, we had more time to think about it. When we first moved out here, we were quite worthy. If you don’t have a solar panel then who are you? I’m glad we didn’t make the show then.”

Some way into the devising process, Kimmings and her long-term collaborators decided to change the title and position it firmly as a mainstream comedy: “It had to be a standup show because I feel like that’s where it’s the most populist. That’s where we’ll get the most bums on seats.” And the butt of the joke? Kimmings. Always Kimmings. “In all my shows, I will always try to be the stupidest person in the room. Because that’s the clown way of doing things. Nobody in here is going to make a mistake as big as my mistake. I’m the clown. Laugh at me. Because then everyone feels less bad about themselves.”

‘I always try to be the stupidest person in the room’ …Kimmings with her niece Taylor in Credible Likeable Superstar Role Model. Photograph: Linda Nylind/The Guardian

Gradually, Bog Witch evolved into a comedy about Bryony Kimmings, the most reluctant and unlikely ecowarrior you’ve ever encountered: “It’s the story of being a terrible climate activist. Of not wanting to move to the countryside. Of wanting to try to find something to fill the void. The hole in my soul that wouldn’t go away. It’s about asking the audience: do you feel like there’s something wrong too?”

It’s all part of Kimmings’s resolve, which started in earnest during the pandemic, to only make work about the climate crisis. On top of her work in theatre, Kimmings is also developing an eco horror movie called Little Red Hen. “It’s set in an eco homestead that is the only place in a rural community that is equipped to survive eco collapse. So all the other villagers, who have never helped this place before, descend on it during the emergency. It’s a slasher movie, too. When the end comes, who do you want to bring into the new dawn?”

She’s hoping the film will be “camp” and “gory” and, most importantly, a bit of a laugh: “I’m desperate to make climate stories that are really funny. Engaging. Solution-based programmes and pieces of theatre.” She’s also got a primetime BBC drama in the works, The Rapture, which started filming this summer. Based on Liz Jensen’s bestselling novel and starring Ruth Madeley, the show follows a juvenile inmate in a mental health institution and her newly disabled psychotherapist, who have to figure out a climate conspiracy together.

Freewheeling … Kimmings in 7 Day Drunk in 2011. Photograph: Murdo MacLeod/The Guardian

All of Kimmings’s latest work aims to cultivate hope rather than despair: “It’s a tough sell. Nobody wants to know about climate change for lots of reasons and some of that is because it’s just not fun. It’s bleak. And what I’ve realised from hanging around with all these farmers and permaculturalists is that there’s so much good stuff happening. There’s so much good going on out there. All of this is not a sealed deal.”

In the past, Kimmings’s shows were often created with the intention of spurring the audience into action. With Bog Witch, she says: “I want to create a fucking great night out and equip the audience with some tools and coping mechanisms. But we’re not being too bold with this one. All we will say is that seeing Bog Witch might make you want to engage with the climate crisis. Dipping your toe in isn’t going to kill you.”

Optimism runs through our conversation, although she struggles to feel hopeful about the theatre industry as a whole. “I love the world of performance art. I love the creativity and experimentalism. But there’s not much going on right now and that’s not because there aren’t brilliant artists. It’s because the courses have closed and the festivals have closed. An entire movement of art is scrabbling around trying to find opportunity and I find that very sad.”

Kimmings believes it’s harder than ever to make a living in theatre. “It doesn’t pay enough. There isn’t enough work, especially for people like me. The funding is going down. It isn’t sustainable for family life. It doesn’t have social hours. Looking at this year on the spreadsheet of earnings, and then looking at TV, it’s a no-brainer that I work in TV.”

Yet something keeps pulling Kimmings back to the stage. “Theatre is my love.” She’s not sure she likes straight plays – too fake, too staged – but on those rare and special times when theatre really works? “When that happens and you’re in a room with other bodies, there’s nothing like it. It’s like church. The awe. The connection.” For Kimmings, that’s what drives her stage work. “It’s always about that exchange. It’s never about my feelings. I’m a mirror for your feelings. As far as I’m concerned, you go to the theatre to see yourself.”

• Bog Witch is at Soho Theatre Walthamstow, London, 9-25 October