The Story Of CO2 Is The Story Of Everything by Peter Brannen: When scorpions were the size of dogs

Carbon dioxide (CO2), writes Peter Brannen, is ‘the very stuff of life’. Without it, there would be no photosynthesis; without photosynthesis there would be no complex life on Earth. Organic carbon is ultimately made from CO2 and the basic building blocks of life are organic carbon. DNA is organic carbon.

CO2 is also the ‘principal control knob governing Earth’s temperature’. There needs to be just the right amount in the atmosphere to produce the conditions for life.

Brannen points out, ‘when CO2 has varied between 0.1 per cent and 0.018 per cent of the atmosphere, it has been the difference between alligators in the Arctic Circle on the one hand, and an Antarctica’s worth of ice burying North America on the other’. Brannen takes us on a grand tour of billions of years of history to prove his title, the story of CO2 is the story of everything.

The so-called Cambrian Explosion, more than 500 million years ago, produced what Brannen calls ‘nightmarish one-off experiments at the dawn of animal life’. In the Carboniferous Period, 150 million years later, there were ‘dragonflies the size of seagulls… scorpions the size of golden retrievers and millipedes the size of alligators’. Bizarre trees, known as lepidendrons, also thrived. With bright green trunks, they would become the coal to supercharge the Industrial Revolution.

The history of life on Earth has been punctuated by mass extinctions. The worst of them by far, sometimes known as the ‘Great Dying’, took place at the end of the Permian Period, around 250 million years ago. The result of volcanic eruptions in which ‘a planet-deranging amount of carbon dioxide’ came ‘billowing out of Earth’. Almost every living thing died, although enough survived to reseed the planet.

Brannen elegantly moves through the Earth’s epochs. The Middle Miocene was ‘the last time… when CO2 was as high as it might be again as soon as 2050’. The world was a different place. ‘A verdant Greenland… lived up to its name’, while turtles and parrots lived in Siberia. In the Pliocene Epoch, three million years ago, CO2 fell to 400 parts per million in the atmosphere. Level stayed below that amount until rising again in 2016.

The story heads towards ‘the CO2 Supereruption’ caused by our activities. We’re ‘emitting CO2 ten times faster’ than in the last mass extinction. At this rate, we’re not going to get a zero-carbon future or, as Brannen puts it, ‘likely even a livable one’.

His story of CO2 comes to a chastening conclusion. There is still time for us to save ourselves, but action is needed now.