You slide your finger across the screen, the red bird sitting in a slingshot is ready to fly - you tweak the angle and let go.

The bird soars across the sky and as you watch its progress on your phone you're probably not thinking about saving the planet. But that's about to change.

The developers of Angry Birds 2 and 10 other major mobile-games makers have committed to introducing environmental messages into their titles.

As well as the famous flying birds, popular games like Golf Clash, Subway Surfers and Transformers: Earth Wars are part of the project.

"There's something like three billion people with mobile phones and half of them are gamers," says John Earner, boss of Space Ape who make Transformers: Earth Wars.

"As an industry, we have a massive reach in comparison to other entertainment mediums.

"We feel like there is an opportunity and increasingly an imperative for us to do something."

A chance to inspire'

John helped organise a "game jam" - where games companies brainstorm new ideas - with the United Nations Environment Programme earlier this year.

It asked how games can educate and engage people on green issues, and inspire them to help save the planet.

Scientists are warning that the earth is now nearly one degree warmer than it was before widespread industrialisation.

The 20 warmest years on record have been in the past 22 years, with 2015-2018 making up the top four.

Sea ice has been reducing for decades and the Arctic Ocean may be ice-free in the summer as soon as the 2050s, unless something is done.

John accepts the developers' ideas "don't go far enough" but believes they are a good first step in putting environmental issues in front of a massive audience.

The 11 companies that took part have a combined audience of 250 million players.

Each will be introducing a new mode, map, themed event, story or art work into their game to share information and messages about environmental issues.

Angry Birds 2 players, for example, will soon be gathering seeds and planting trees in an upcoming in-game event and learning about the positive impact that can have in the real world.

"It's a big thing for us, we want to be a company with a purpose and this is one piece of that puzzle," says Ville Heijari, one of games developer Rovio's top bosses.

"It's fun to bring quirky, interesting, new and exciting gaming experiences to people - but then to also be able to have a positive impact on global issues, that's the icing on the cake."

The team at Rovio are fine-tuning that new experience but Ville says: "We're trying to make it feel like a common goal, all the players are in it together and that will give positive rewards to them."

Transformers: Earth Wars players will soon start seeing messages about renewable energy and be encouraged to take part in a UN green energy survey.

"Our ideas specifically don't go far enough," John admits. "But they're a really good start in measuring the problem and beginning to lay out the situation to a huge amount of people."

The United Nations has been working with games companies on green issues for some time through a scheme called Playing for the Planet.

"We're excited to see the gaming industry throw its weight behind global efforts to reverse the climate crisis," says Inger Andersen, boss of United Nations Environment Programme.

"The climate emergency needs all hands on deck. In reaching out to 250 million gamers, we hope to inspire audiences to take climate action."

John and Ville argue these small first steps can lead to bigger strides in helping educate people.

Part of that is convincing more games companies to get involved in future.

John explains: "What we've found is this experience is alleviating the fear some game companies have that somehow promoting an important message will negatively harm them by offending or upsetting players.

"If we could convince more in the game industry that you can afford to do this without harming your business, that would be an amazing first step.

"We all have a role, whether we like it or not, whether it's comfortable or not."

Ville says that while some will see initiatives like this in a negative light it is important games companies have values to stick to.

"Obviously we want people to be able to experience our games and our brands, but when we feel that something is the right thing to do then we are going to do it.

"Games really are an excellent platform for doing things like this and I think we will see even more activations like this."