It is rare to see La-la-land lose its cool over a celebrity sighting.

But the presence of Greta Thunberg at the latest youth climate strike in Los Angeles caused an unusual fever of excitement.

True, some had come to genuinely protest about fossil fuels. But many confessed to being there primarily for a glimpse of the 16-year-old Swedish activist.

Image: Greta Thunberg speaks during a march in Los Angeles, California

Not that this was some idle fan worship - the young people who came see Greta view her as an inspiration that teenagers can make a real difference in the world.

They had skipped school in the hundreds to stand in the heat outside of LA's City Hall and add their voices to this noisy new global movement.


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Like Greta, who this week chastised her native Scandinavia that there was no time for "bragging" on climate change, the youth protest is ready to challenge some orthodoxies.

So a state like California, famed for its leadership on helping the environment, is still a legitimate target for protests over its high levels of oil production.

Greta has taken this message across America in recent weeks, adding her new-found star power to the local effort.

In California, she spent time with the actor and fellow climate activist Leonardo DiCaprio.

"There are few times in human history where voices are amplified at such pivotal moments and in such transformational ways - but Greta Thunberg has become a leader of our time," DiCaprio wrote on his Instagram.

As she joined a march through downtown Los Angeles, she did appear momentarily overwhelmed by the crush of attention from the crowd. It appeared organisers had somehow underestimated her popularity.

But she resumed her poise to deliver a short, powerful speech from the stage. Her voice has become an unmistakable clarion call for unity in taking action.

Helicopters battle big wildfire in California

She had no qualms about laying the blame for the wildfires that continue to rage across the state at the door of climate change. She was listened to in rapt silence.

The role she has taken up has brought her harsh criticism, derision and vitriol from those who deny the science. None of it has so far stopped her.

And spend a few hours standing in a crowd of people who have come to see and hear her - wearing their Greta shirts, waving their Greta banners - and one thing is very evident.

She has mobilised an army of young people to believe not only that their voices matter but also that this is a cause vital to their futures.

Whatever the debates about climate change, what she has unleashed cannot be put back in the bottle.

And the people leading this new fight are going to be around for a lot longer than many.