The 44th president posted an image on his Instagram page showing him meeting the 16-year-old Swedish teen in his Washington office.
The former president, who is seen wearing a white buttoned down shirt with no tie and business slacks, gives Thunberg a fist bump.
‘At just 16 years old, GretaThunberg is already one of our planet’s greatest advocates,’ Obama writes in the caption.
‘Her age might have something to do with it. With full knowledge that her generation will bear the heaviest burden of climate change, she’s unafraid to believe that progress is possible – and fight for real change.
‘She’s an example of why Michelle and I started the Obama Foundation – because we believe in a future that’s shaped by the courage and hope of young people like Greta.’
Obama’s Instagram post with Thunberg went viral within minutes, generating hundreds of thousands of likes.
The former president has 24.4 million followers on Instagram. Obama, though, is far more influential on Twitter, where he has 108.5 million followers – the most of anyone.
Thunberg first made headlines last year when she refused to go to school, opting instead to demonstrate outside Sweden’s parliament and to demand action on climate change.
Sweden had just experienced one of its hottest summers ever – one that included wildfires and heat waves.
Her one-person protest, in which she is seen in Stockholm holding up a sign that called for a ‘school strike for the climate,’ ignited a nationwide movement in Sweden thanks to social media.
She has also been nominated for a Nobel Prize.
Thunberg, who refuses to fly because of the aviation industry’s large carbon footprint, arrived in the United States last month after crossing the Atlantic Ocean on a ‘zero-carbon yacht’.
Thunberg was in Washington, D.C. on Friday to participate in a march led by schooldren who were ‘striking’ – playing hooky – for the planet
Thunberg thanked a few hundred kids who showed up near the White House but had no ultimatum for the U.S. government
President Trump is a global warming skeptic who has called it a ‘hoax’ and claimed China invented the climate change hypothesis in order to weaken the U.S. economy
She is leading a worldwide student-led strike calling for urgent action on climate change – just days before the United Nations convenes a summit on the topic.
The strike is scheduled to take place this Friday.
Thunberg on Tuesday called for action, not praise, from U.S. lawmakers as she joined other youth leaders in kicking off two days of meetings and speeches on Washington’s Capitol Hill.
‘Please save your praise. We don’t want it,’ Thunberg told the Senate Climate Change Task Force.
‘Don’t invite us here to tell us how inspiring we are without doing anything about it because it doesn’t lead to anything.’
Democratic Senator Ed Markey, chairman of the task force, called the growing number of young protesters the new ‘X-Factor’ in politics, and said their passion could play a significant role in next year’s U.S. presidential elections.
‘2020 is going to be a referendum on climate change,’ Markey told a news conference on Tuesday.
‘It will be a referendum between Donald Trump and a whole new Green New Deal direction.’
The Green New Deal is a non-binding congressional resolution Markey co-sponsored with Representative Alexandria Ocasio-Cortez, a fellow Democrat, that aims to transform the U.S. economy away from fossil fuels within a decade.
Republican lawmakers and Trump administration officials have pilloried the plan as fantasy.
President Trump, one of the few world leaders who openly question the science of climate change, has made a priority of rolling back Obama-era climate protections he says are not necessary and hurt the U.S. economy.
Anaiah Thomas, a 17-year-old climate activist and member of U.S.-based youth movement Zero Hour, told the senators they need to take an urgent approach to climate change and support proposals like the Green New Deal.
‘What’s most important is to decide to take action today. Not in five years. Not gradually. Not tomorrow,’ she said.