Tanya Ronder's new play with the polar bears: 'We are literally decapitating the world with our actions'

Tanya Ronder's new play has been causing alarm at the box office, because theatregoers don't want to say its name. "That one with the polar bears," they say, or "the play that opens in September". This coyness is prompted by the play's title, "Fuck the Polar Bears".

"It seems like a weird double standard that theatre has completely put that boundary down in the last five years. Every play is riddled with swear words, yet there's still this weird taboo about it being in the title," says Ronder, who says the title was virtually the only element of the play she was sure about when she first pitched the idea to the Bush Theatre's associate director, Omar Elerian. It's a concise summation for a play about how we collectively choose to ignore climate change and how, like the play's protagonists, the married couple Gordon and Serena, we focus on first-world problems. Midway through the script, a stuffed toy polar bear belonging to their daughter Rachel goes missing, feeding into the play's motif.

"We all still use animals with our kids all the time," says Ronder. "We're on our knees going, 'Raa raa! Elephant goes whooor whool,' and yet no one's there going, 'Actually we're killing the animals off.'" Ronder was an actor for 14 years before she started adapting plays and you can still see that side to her. She uses hand gestures to mime along with her words and sound effects to create a full picture when she wants to emphasise a point. "Nothing's changed in our parenting in terms of the natural world… yet we are literally decapitating the world with our actions.

"There is no questioning the underpinning of that world, the world which says we have to make money. No one actually goes beneath that and goes, 'Well actually maybe we don't all need to be greedy cunts?'"

Her anti-capitalist stance will chime with anyone who's been following the Corbyn campaign and victory and how it's been derided by the right and members of his own party as unpragmatic fantasy. It turns out Ronder quite likes some of his policies. "There's loads I admire in him. Loads! And I love it that he's become this rock star out of absolutely nowhere. [There's] a swathe of people going, 'Corbyn's nuts, [the party] can't sustain power with him at the helm,' but then there are reams of youngsters going, 'Yeah, at last! Someone who's speaking truthfully and honestly. … People are really responding to it. It's just fantastic and it proved to me that not everybody wants to choose selfish options, but instead we are somehow collectively being herded in that direction and now it's really hard to turn the ship around."

Ronder was prompted to write the play when she read a news story about the CEO of an energy company who received a huge bonus. He was the inspiration for Gordon, the father and husband in the play.

"I could feel my judgement, my deep, nasty judgement about this man, who I had read about and then I thought, well, he's got to have a kid and a wife – well, not got to, but he's likely to have love in his life. Weirdly, I think Gordon's ended up being quite a sympathetic character in the play. I think you've got to give the devil the best lines."

Aside from reading about climate change, Ronder also met someone from British Gas who told her he had never met a climate change denier in his 15 years of working for the company. "I had assumed that all those guys [weren't convinced about climate change] but they all know. They all know, but they are squaring it with themselves."

Ronder was careful to scatter the facts sparingly, with lashings of humour, to avoid making the play seem worthy. "There were maybe a thousand [serious] things I wanted to put in, but I only had room for maybe three."

After switching from acting to adapting, Ronder worked on adapting plays for the next decade. This is her "first real original play", she says, slightly dismissing Table, which appeared at the National's Shed in 2013; that play, written by Ronder and directed by her husband, Rufus Norris, who now heads the National Theatre, followed the journey of a kitchen table (which, incidentally, was their kitchen table) through different families over 200 years.

"But Table was workshopped, so I could almost persuade myself that it was an adaptation. It wasn't: it was a new play, but it was really helpful to me to pretend it was an adaptation. This is the first one I've done without anybody else's influence," she says.

She tells me she kept a quote in her notebook for years: "Those who graft at words every day are those for whom words matter."

"I turn 50 this year and I am the slowest writer ever to (a) come to writing and (b) start saying what I actually want to say, and I will be really frightened on press day. I've carried around the tiniest flame really," she says, shielding a tiny invisible flame with hands. "My tiny writer's flame that I've brought into the world. It's not easy at all."

'Fuck the Polar Bears' by Tanya Ronder is at the Bush Theatre, London, until 24 October