It’s amazing that minuscule bacteria can cause life-threatening diseases and infections –- and miraculous that tiny doses of vaccines and antibiotics can safeguard us against these deadly scourges. It is equally incredible that, at the planetary level, carbon dioxide is a miracle molecule for plants -– and the “gas of life” for most living creatures on Earth.
In units of volume, CO2’s concentration is typically presented as 400 parts per million (400 ppm). Translated, that’s just 0.04% of Earth’s atmosphere -– the equivalent of 40 cents out of one thousand dollars, or 1.4 inches on a football field. Even atmospheric argon is 23 times more abundant: 9,300 ppm. Moreover, the 400 ppm in 2013 is 120 ppm more than the 280 ppm carbon dioxide level of 1800, and that two-century increase is equivalent to a mere 12 cents out of $1,000, or one half-inch on a football field.
Eliminate carbon dioxide, and terrestrial plants would die, as would lake and ocean phytoplankton, grasses, kelp and other water plants. After that, animal and human life would disappear. Even reducing CO2 levels too much – back to pre-industrial levels, for example – would have terrible consequences.
Over the past two centuries, our planet finally began to emerge from the Little Ice Age that had cooled the Earth and driven Viking settlers out of Greenland. Warming oceans slowly released some of the carbon dioxide stored in their waters. Industrial Revolution factories and growing human populations burned more wood and fossil fuels, baked more bread, and brewed more beer, adding still more CO2 to the atmosphere. Much more of the miracle molecule came from volcanoes and subsea vents, forest fires, biofuel use, decaying plants and animals, and “exhaust” from living, breathing animals and humans.
What a difference that extra 120 ppm has made for plants, and for animals and humans that depend on them. The more carbon dioxide there is in the atmosphere, the more it is absorbed by plants of every description –- and the faster and better they grow, even under adverse conditions like limited water, extremely hot air temperatures, or infestations of insects, weeds and other pests. As trees, grasses, algae and crops grow more rapidly and become healthier and more robust, animals and humans enjoy better nutrition on a planet that is greener and greener.