The Climate Book, Day 3
Day 3, of The Climate Book Posts: "All life is conjured from CO2."
Today, essay 1.2: "The Deep History of Carbon Dioxide"
Key excerpts:
1. At Earth's surface, with mere sunlight and water, CO2 is transformed into living matter through photosynthesis, leaving oxygen in its wake. This plant carbon then flows through animal bodies and ecosystems and back out into oceans and air as CO2 once again.
2. Life uses up 99.99 percent of the oxygen produced by photosynthesis, and would use it all if it weren't for the infinitesimal leak of plant matter into the rocks - as limestone or carbon-rich sludge that slumbers deep in the Earth's crust.
3. CO2 is not only the fundamental substrate of all living things on Earth and the indirect source of its life-sustaining oxygen. It's also critically modulates the temperature of the entire planet and the chemistry of the entire ocean.
4. Life on Earth crucially depends on maintaining a delicate balance of the movement of CO2 as it billows from volcanoes, stirs into the air and oceans, swirls through eddies of life and soaks back into the rocks again - this is called THE CARBON CYCLE.
5. Every mass extinction in Earth history is marked by massive disruptions of the global carbon cycle, the signals of which have been teased out of the rocks by geochemists.
6. In the End-Permian mass extinction, CO2 blasted out of Siberian volcanoes for thousands of years. The temparature increased by 10 degrees Celsius. In the aftermath, one could travel the world without seeing a single tree, the world's coral reefs were replaced by a bacterial slime, the fossil record went silent and the planet took nearly 10 million years to recover.
7. Now, humans are doing the exact same thing as those ancient volcanoes. We are immolating those same massive reservoirs of underground carbon NOT by mindlessly exploding it all through the crust like a supervolcano - INSTEAD by retrieving it from the deep and burning it all at the surface in a more diffuse eruption via fossil fuel consumption... at a rate TEN TIMES that of the ancient mass extinctions and those volcanoes that erupted for many centuries.
8. The climate doesn't know or care whether the excess CO2 in the atmosphere comes from a once-in-a-100-million-year volcanic event or from a once-in-the-history-of-life industrial civilization. It will react in the same way.
9. We have in the rocks an unmistakable warning - a fossil record littered with the tombstones of ancient apocolypses. If the rocks tell us anything, it is that we are pulling the most powerful levers of the Earth system, at our own peril.
