The major U.N. conference will test countries' ambition to limit global warming, which a landmark scientific report on Monday warned was dangerously close to escalating beyond the limits countries agreed on.
"I hope that this can be a wake up call, in every possible way," Thunberg said of the report, in an interview with Reuters.
"When these extreme weather events are happening, many say, what will it take for people in power to start acting? What are they waiting for? And it will take many things, but especially, it will take massive pressure from the public and massive pressure from the media," she said.
The U.N. report landed just three months before the Glasgow conference in November.
Thunberg, who has rallied youth to protest for climate action worldwide, had initially said she would skip the event out of concern that the uneven rollout of COVID-19 vaccines across the world would leave some countries unable to attend safely.
But Britain’s offer in June to vaccinate delegates assuages some of that concern, the 18-year-old Swedish campaigner said.
"I've said before that I wasn't going to go if it wasn't fair,” Thunberg said. “But now they say that they will vaccinate all the delegates that are going there. If that's considered fair and safe, then I will hopefully attend."
With wildfires ripping through Greece and Turkey this week, just weeks after deadly flooding swept through China and Germany and heatwaves baked the United States, Thunberg said people's awareness of climate change was increasing, but "very slowly".
But she said world leaders had ignored scientists' previous warnings about climate change and she did not expect them to match words with action in response to the latest U.N. report.
"I expect them to go out and have big speeches, or press releases, or posts on social media where they say the climate crisis is very important and we are doing everything that we can," Thunberg said.
"As it is now, nothing is changing. The only thing that's changing is the climate."
