Climate activist Greta Thunberg, who has inspired a global movement against climate change, was declared the Time magazine’s Person of the Year for 2019. The 16-year-old is the youngest person to be chosen for the honour by the magazine in a tradition that started in 1927.

Before the announcement was made, Thunberg told a United Nations climate change summit in Madrid that the coming decade would define the planet’s future. The activist, who inspired millions of school students around the world to go on climate strike on Fridays, urged global leaders to stop using “creative PR” to avoid real action on the climate emergency. She added that summits on climate change seemed “to have turned into some kind of opportunity for countries to negotiate loopholes and to avoid raising their ambition”.

Greta Thunberg joined thousands of youngsters in Madrid last week to protest against the lack of progress in tackling climate change after making a nearly three-week journey across the Atlantic Ocean from the United States by a catamaran. In September, she had inspired four million people to join the global climate strike – the largest climate demonstration in human history.

“We can’t just continue living as if there was no tomorrow, because there is a tomorrow,” Thunberg told Time. “That is all we are saying.” Earlier this year, the activist was nominated as a candidate for the Nobel Peace Prize.

Announcing the decision on NBC, Time Editor-in-Chief Edward Felsenthal said: “She became the biggest voice on the biggest issue facing the planet this year, coming from essentially nowhere to lead a worldwide movement.”

In October, Thunberg had refused to accept an environmental award, saying the climate movement needed people in power to “listen” to “science” and “not any more prizes”. Thunberg was honoured at a Stockholm ceremony by the Nordic Council, which is a regional body for inter-parliamentary cooperation.