Time magazine on Wednesday picked 16-year-old environmental activist Greta Thunberg as the "Person of the Year," making her the youngest-ever selection for the title.

The Swedish teen is credited for igniting a wave of youth protest on the issue of climate change, with students around the world engaging in school walkouts and rallies to demand that leaders take action.

The U.S. weekly magazine said in its cover story that although she is an ordinary teenage girl and is not the first to warn about the climate crisis, "By clarifying an abstract danger with piercing outrage, Thunberg became the most compelling voice on the most important issue facing the planet."

"The politics of climate action are as entrenched and complex as the phenomenon itself, and Thunberg has no magic solution. But she has succeeded in creating a global attitudinal shift, transforming millions of vague, middle-of-the-night anxieties into a world movement calling for urgent change," Time said.

Noting that she shows no interest in her own growing fame and summons the courage to speak truth to power, Thunberg "became the icon of a generation," it added.

In traveling around the world as a high-profile activist, Thunberg has notably avoided the greenhouse gas emissions of air travel.

She sailed to New York from southern Britain on a zero-emissions yacht to attend the U.N. Climate Summit in September, and opted for yacht travel again in crossing the Atlantic Ocean to Spain to attend the 25th session of the Conference of the Parties on climate change, dubbed COP25, in Madrid this month.

Scientists link global warming to more frequent droughts and floods as well as melting glaciers and rising sea levels, among other effects impacting human life around the world.

For this year's feature, Time introduced four new categories to highlight influential people in sports, entertainment, business and public service. Its additional picks were, respectively, the U.S. women's soccer team, pop singer Lizzo, Disney CEO Bob Iger, and the officials who reported and testified about U.S. President Donald Trump's alleged abuses of power in dealings with Ukraine.