Twenty thousand school students are chanting 'climate action now!' and he is silent. He has been shouting the same thing for decades, first in scientific papers and then, with an increasingly urgent tone, in newspapers, televised debates and many rallies just like this one. Now he stands with a new generation taking up the fight, but he can't open his mouth to join them.
His voice is hoarse, but that's not the reason. He is scared of what will come out. He is scared he will say what he knows he can't say.
He can't say the Great Barrier Reef will be dead in their lifetimes, even if we cut emissions to zero today. He can't say the Australian government will probably keep opening up new coal mines, yes Labor too, because coal's economic value is just too tempting. He can't say that renewable energy won't be enough and we need to consider nuclear. He can't say we've probably already locked in two degrees of global warming, and natural tipping points could render all our efforts to cut pollution totally irrelevant.
Behind him a little girl, maybe eight years old, is holding a homemade sign. She has painted a blue and green Earth on brown cardboard in clumsy brushstrokes. The words read 'Look after our home'. Instead of a pole, the sign is taped to a tree branch. This small detail touches him, and he smiles, then the smile becomes a wince. He definitely can't say those things with her listening.
What he really wants to say, when it's his turn to step up to the microphone, is just one sentence. No, two sentences. 'I'm scared,' he wants to say. 'And I'm sorry.' He knows this wouldn't be helpful. He has read all the psychological studies about maintaining a careful balance between fear and hope so that your audience does not slip into paralysing despair.
He's been a climate scientist, a climate activist, a climate communicator. He's addressed Senate Inquiries and has run for Parliament. But now, looking at these kids, he doesn't have the energy to craft a compelling narrative that inspires collective action. He just wants to be honest. And he can't.
A few metres ahead of him, on a makeshift stage supported by green milk crates, a 14-year-old student is sharing her story. This is one of the girls who started the school climate strikes in Australia. The man looks at her, standing