Theresa May has said seeing melting glaciers while on her walking holidays played a part in her push for the UK to be carbon neutral by 2050.

She was speaking on her way to the G20 summit in Osaka, Japan, where she will ask other countries to act.

It came as UK's new aim to reach net zero greenhouse gas emissions by 2050 became law on Thursday, making it the first major economy to set such a target.

All this week, Sky News has been setting out why the climate crisis is among the biggest challenges faced today by the human race.

The prime minister told reporters on the plane to Japan the retreat of a glacier on one of her walking routes in Switzerland had illustrated the need for action.


Image: Mrs May said she saw the retreat of glaciers on her walking holidays to Switzerland

She said writing the UK's net zero commitment into law was an "important contribution to make sure we're not contributing to climate change in future".

Mrs May and her husband Philip are keen ramblers, and she said the couple had been struck by the impact of climate change on their holidays.

She said: "Just as a small example of why this is important, as you know, Philip and I go walking, not just in Wales but also in Switzerland, and there's a particular place we go to where over the last decade you see the glacier retreating quickly.

"This has brought home to me the issue of climate change.

Image: Glaciers like the Swiss Alps' Great Aletsch are retreating and could almost vanish in the lifetimes of people born today, say scientists

"But the G20 represents 80% of emissions, so actually it's not just what the UK does, it's about what we can do together.

"So I'm going to be taking a message to the other leaders of them... following on the UK's lead and acting on this issue."

:: A New Climate is a special series of podcasts from Sky News Daily. Listen on Apple Podcasts, Google Podcasts,Spotify, Spreaker

It is the last G20 summit for Mrs May, who will leave Downing Street next month when a new Tory leader is installed.

Britain's move to net-zero carbon will require huge changes such as more renewable electricity generation, the phasing out of petrol and diesel cars and the cutting of beef and lamb consumption by 20%.

Energy and clean growth minister Chris Skidmore, who signed the legislation into law after it passed through the Commons and the Lords, said: "The UK kick-started the Industrial Revolution, which was responsible for economic growth across the globe but also for increasing emissions.

"Today we're leading the world yet again in becoming the first major economy to pass new laws to reduce emissions to net zero by 2050."

The net target replaces a previous goal to cut the country's emissions by 80% compared with 1990 levels by 2050, a target campaigners said did not go far enough.

Groups like Extinction Rebellion have been demanding much tougher action, saying it would be the only way to meet pledges made under the 2015 Paris climate agreement to try to limit a rise in global warming to 1.5 degrees Celsius.

Temperatures have already risen about one degree Celsius since pre-industrial times.

Scientists are worried further increases could place the world at a tipping point, beyond which parts of the planet could become uninhabitable and rising seas could drown many coastal towns and cities.