STOCKHOLM (Reuters) - Greta Thunberg joined other young climate activists protesting outside the Swedish parliament on Friday for the first time since she embarked on a four-month overseas voyage to attend climate conferences in New York City and Madrid.

At the protest, taking place at the end of the school term in Sweden, activists presented a report card giving politicians an F for “failed” in tackling climate change at UN-led summits over the past decade and the verdict “Needs to try harder!”.

Thunberg, the 16-year-old Swede whose solo “School Strike for the Climate” outside parliament, begun in August 2018, swelled into the global Fridays for Future movement, took a low profile as other activists spoke.

“I would give them an F, actually. I know they did try, but they didn’t try hard enough,” activist Isabelle Axelsson, 18, told Reuters of politicians’ work on climate change this year.

Axelsson said she thought Fridays for Future deserved an A for effort, but added: “We haven’t accomplished convincing our politicians to act on climate, so I don’t think we should pass either, really.”

In 2020, weekly school strikes and larger protests aimed at persuading politicians to act would continue, she said.

Fridays for Future has seen millions of young people in more than 100 countries walk out of school on Fridays this year in support of Thunberg’s demands for urgent action from governments to curb carbon emissions.

After crisscrossing the globe by car, train and boat -- but not plane -- to demand action on climate change, Thunberg said as she was returning home from the COP25 climate summit in Madrid this week that she would take a break. [nL8N28N3GC]