Students around the world walk out to protest climate change ahead of U.N. summit

Students around the world are skipping school Friday and taking to the streets to protest global warming. Demonstrations in Madrid, Tokyo, and Melbourne are being billed as a "Global Day of Action" ahead of COP25, a U.N. climate change summit beginning in Madrid next week.

Outside the Houses of Parliament in London, young people from across Britain walked out of classrooms and onto the streets to protest against climate change, reports CBS News correspondent Imtiaz Tyab. They said they want politicians in the U.K. to make climate change a key focus of next month's general election.

The first protest of the day was in Sydney, Australia, where more than 150 wildfires are still burning and have left more than 5 million people in the city under a toxic cloud.

These strikes are part of a global movement started last year by Swedish teenager Nobel Peace Prize nominee Greta Thunberg. Since then millions of people around the world have joined the effort.

The U.N. warned this week that countries need to cut back their use of greenhouse gases dramatically over the next decade or face what they are calling a climate crisis.