To demonstrate that CO₂ warms the atmosphere,’ said Stanley, ‘we could empty two identical grain silos and fill one with air and the other with pure CO₂ gas piped in from the vodka plant. Then we would put an infrared heater inside each.’

‘Why use infrared heaters?’ asked Pamela his partner.

‘Because infrared radiation from the Sun passes through the atmosphere,’ said Norman. ‘Some is absorbed and the rest warms the Earth’s surfaces or is reradiated.’

‘Would the infrared heat the air?’

‘Indirectly. The metal wall of the silo will warm up and heat the gases by convection and circulation, like the atmosphere.’

‘The metal wall wouldn’t absorb and radiate like the ocean and land, would it?’

‘It could be similar.’

‘How long would you let the two silos heat up for?’

‘Maybe a week. Then we could compare the temperatures reached.’

‘Why did you go for pure CO₂? Air has only 0.045%?’ said Pamela.

‘I figured it would be easiest to see any difference with 100% CO₂ and then scale the results proportionally down to 0.045%. CO₂ would heat up more because it has 20% lower specific heat capacity.’

‘So what would this demonstrate?’

‘It could demonstrate Earth’s atmosphere containing more carbon dioxide would heat up more.’ 

‘Or not.’

‘Yes. It’s a fair test.’

Extracted from Animal Farm 2, by Martin Knox, available from Amazon.

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