How this year's Edinburgh Fringe is tackling the serious subject of global warming

Alanna Mitchell, a science journalist from Canada, arrives at the Fringe with acclaimed play about ocean ecology

The Pianodrome auditorium is made entirely from old piano parts. Courtesy Pianodrome

Matt Winning has had a taxing build-up to this year's Edinburgh Fringe. The world's largest arts festival – which takes over the Scottish capital from Friday, August 2 until Monday, August 26 – is an important showcase for comedians. But Winning, who is an environmental economist by day and a stand-up comic by night, has spent the past month composing a hugely important report "about how we decarbonise Europe over the next 30 years", he explains, "while also trying to write a Fringe show".

At least his two careers now cross over, as the busy Scotsman introduced an original format to Edinburgh stages in 2017: the "storytelling lecture". Incorporating serious climate data with jokes, it proved to be a winning formula. Now, his new show, It's the End of the World as We Know It, is at the forefront of a major Fringe theme. The 72-year-old festival has always been a forum for important ideas and, this year, environmentalism is prominent: not only are there shows promoting green issues, but also whole venues.

Making its debut near Scotland's parliament building, Holyrood, is The Greenhouse, a pop-up theatre entirely constructed from recycled materials – and that includes its sets and props. It began two years ago, when Oli Savage of the theatre company BoxedIn saw a script about eco-­terrorism by his colleague Henry Roberts. "I started dreaming of creating a small programme of shows that could be performed in residency at a site-specific space at the Fringe," says Savage. "We began with a basic idea – we want the venue to not use any electricity. That meant having a clear roof, to allow sunlight in." Their original design used metal and Perspex, but it needed more support. "Luckily, we were able to collect some surplus timber last minute, and use that to create a new plan."

Meanwhile, a call was issued to like-minded theatre companies and performers: all Greenhouse shows should address the environment. "The responses we got were outstanding," says Savage, "from a blockbuster musical about sea-turtles called Shellshock! to an intimate two-hander called The Voices We Hear, discussing individual connection in the face of an environmental apocalypse."

Another upcycled venue is Pianodrome, a concert hall with an even narrower source of materials. It "is a 100-seater circular auditorium made entirely – seats, stairs, banisters, gangways, supporting structure – from piano parts", explains co-creator Tim Vincent-Smith. The artist and designer, who lives in Edinburgh, had been making furniture from found materials and discovered a surplus of unwanted pianos, then the idea bloomed.

This venue's line-up is a bit more eclectic, although each show has a musical theme ranging from jazz inspired by Scottish novelist Muriel Spark to an animated retelling of Aladdin. But the building itself sends a powerful eco message. As Vincent-Smith explains: "Pianodrome hopes to question our throwaway culture by saying, 'Look at this – all these pianos were on their way to the dump! Look at what can be done using a bit of hard work and imagination'."

Yet the Fringe is a curious contradiction when it comes to green issues. It may be forward-thinking in terms of its themes and venues, but the three-week festival also produces heaps of waste, particularly plastic cups and paper flyers. To offset that, this year, there are numerous sustainable initiatives. For example, Arts Council Wales is partnering with climate charity Size of Wales to help their 11 productions leave smaller footprints, while the Fringe collects surplus props for reuse.

These programmes all help, of course, but perhaps the most impactful initiative is to create a show that inspires others. That is exactly what Alanna Mitchell, a science journalist from Canada, has done. She arrives at the Fringe with acclaimed play, Sea Sick, about ocean ecology. It began as a book and lecture, detailing "my adventures as a journalist with marine scientists", she says, explaining that she undertook 13 journeys around the world in three years. The spin-off play was then commissioned, which surprised Mitchell, but the result has been effective. "People respond totally differently to the play than they do to the talks," she says. "The play is far more intimate, far more emotional. Many in the audience weep, usually out of relief at finding a way forward."

Shows like hers can be important, Mitchell says. "I think the science of climate disruption needs art to get the message through. Science can only take us so far. We need narrative to really understand it."

Winning has found that his new shows also resonate more than before. It is undoubtedly positive, if a bit ironic, considering comedy, for him, was originally an escape from a serious climate career. Despite that, he has loved the response. At first, he says, his audience aren't sure how to take such heavy subject matter, until they begin to see the humour in it. "They've been really shocked that I managed to do something funny on the subject," he says. "I love having conversations with people after shows … They hang about and ask questions. There's a level of engagement I didn't have before."

But, he admits, the underlying seriousness of it all can be tough for him to take. "Now I find it difficult to get away from," he says. Nobody ever said that saving the world would be easy.