Mark Redstone stood sweating in a crowd of commuters waiting to cross Euston Road. Only nine o'clock, and already too hot.

A few minutes later he was trudging through back streets, keeping to the shade and looking forward to getting to his air-conditioned lab. At his building he took the lift to the top floor, feeling guilty that he wasn't getting his usual exercise by climbing the stairs. He paused outside the company's entrance, lifting the hem of his shirt to give the 'London Bio' brass sign the morning's ritual polish.

He strode along the line of fume hoods to his office at the far end of the lab, exchanging greetings with the half-dozen staff scattered around the benches. The air was deliciously cool, and carried a faint smell of its chemical history. He felt at home.

'Morning, Mark,' said Joanne, the company's administrator. 'Before you sit down, you need to have a word with Rosie. She's puzzled.'

'What about?'

'My guess is it's about science. That's all I could understand.'

'Ho, ho. OK, I'll go along.'

He stepped back into the lab and made his way to the window wall, where Rosie was staring at a collection of glass apparatus which was illuminated by a bright desk lamp.

'Hi,' she said. 'Bad news, isn't it?'

'What is?' His heart sank. Was she referring to London Bio's main programme, designing a skin cream that would cure migraines?

'The wildfires, and the deaths across Europe. So many places with temperatures over 40C.'

'Ah,' Redstone said, releasing a deep breath. 'Yes, awful. You know anyone affected?'

'Not directly. You?'

'My son Graham, in California. No fire in his area at the moment, but…'

'Oh dear. I hope he'll be OK.'

'Thanks. So, Joanne says…'

'Yes,' she said. 'Look at this.' She gestured at a large glass beaker, containing light brown sludge surrounding an irregularly shaped white translucent lump,

'What is it?'

'The brown stuff is wet sand and silica, from a column I was using. But the white solid is a mystery. What's more, it keeps growing.'

'What else was in the column?'

'I was purifying my amazing new catalyst. Nothing else.'

'Why the lamp?'

'It simulates sunlight. I was using it to test a sample of the skin cream, to make sure it's stable when users go outside. Happened to be next to the column.'

Redstone peered at the mixture. He tugged at his chin. 'I wonder…'

He took a box of tapers from a drawer, lit one, and thrust the glowing tip into the beaker. It briefly flamed.

'Oxygen!' Rosie said.

'I suspect you're making a polymer. Looking at it, maybe polymethyl methacrylate – Perspex. The process would be a bit like photosynthesis. Look.' Redstone scribbled a couple of chemical equations on a piece of paper.

'Are you saying my catalyst, sunlight and wet sand will pull carbon dioxide out of the air?'

3/3/2025