Teen climate activist Greta Thunberg has told Sky News that the UK's pledge to produce net zero carbon emissions by 2050 is "actually doing more harm than good".
The 16-year-old Nobel Peace Prize nominee - who has inspired an international movement to fight climate change - urged politicians to act now on the issue or risk being viewed as "some of the greatest villains in human history".
In an interview with Sky News in Stockholm, Thunberg said many young people felt "sad, angry and scared" at the failure of adults - including politicians - to tackle the climate crisis.
"If they don't act now, then in the future they will be seen as some of the greatest villains in human history and we will not judge them easy," she said.
"But, I mean, they can still change that."
Asked if the UK's commitment to produce net zero carbon emissions by 2050 was a sign of progress, Thunberg replied: "That depends on what you define as progress."
She added: "They are being very proud of what they've accomplished but that's not nearly enough if they are to do their part.
"You could argue that is better than nothing but I think it's actually doing more harm than good.
"It sends a signal that we can continue like this for I don't know how many more years - 20 more years - and that we can continue like now, which is not good."
Prime Minister Theresa May announced a legally binding agreement last month to put the UK on the path to end its contribution to climate change in little more than 30 years.
It will mean the UK is set to become the first G7 country to legislate for net zero emissions.
A spokesperson for the Department of Business, Energy and Industry said: "We fully appreciate the urgency of tackling climate change, and we have listened to the independent expert advice of the committee on climate change who recommended the target of net zero by 2050.
"We are the first major economy to put such an ambitious target in law."
Thunberg, who is from Sweden, spoke in the UK's parliament earlier this year where she told MPs that her future and those of her fellow youngsters had been "sold".
She first staged a school strike over climate in front of the Swedish parliament in August last year and since then, millions of children around the world have followed her lead in what have become known as Fridays for Future.
The young activist continued to gain international attention after speaking at the UN Climate Talks in Poland in December and at the World Economic Forum in Davos in January.
Thunberg told Sky News that young people were taking action because "we are the ones who are going to live with this".
"Many children understand - more than adults - that it is our children at risk," she said.
"We also have enormous power. As a young person, you always have a natural instinct to rebel in a way and it's very useful in a situation like this."
Thunberg said anxiety among young people over the climate crisis was "a very big problem".
"Many people feel sad, angry and scared that nothing is being done and that in every bit of our everyday life, we are fuelling this crisis," she added.
"That is what I felt. I just kind of convinced myself. I was so desperate, I thought 'I have to do something'."
Thunberg insisted that children should not have to be staging protests and "the adults should take that responsibility".
"Of course, it's a big burden and in a way, we aren't forced to do this," she said.
"But since we know what is at risk, we know our future is being at risk - we feel like we must continue."
Thunberg said many young climate change protesters had voiced the message: "You are stealing our future. Why should we care about our future and educate ourselves if you don't care about our future?"
"I think that it is a very powerful message," she added.
"Many people feel guilty when children say that."
Professor Myles Allen, who co-authored a UN report on climate change, applauded the work of the school strikers but defended the UK's carbon target.
He said: "The rhetoric of climate emergency is clearly very powerful, it's clearly working, in terms of raising the agenda, but it is dangerous as well. I think we have to recognise the dangers.
"You could make an argument that the UK should be doing more because we, as a country, have actually put more carbon in the atmosphere per head of population than just about any other country in the world.
"But at least it is consistent with a global effort to limit warming to 1.5 degrees."