What humans have been doing — especially in the last 250 years — is adding carbon dioxide to the air. As we have multiplied, created machines, cleared lands, built buildings and pavement, and burned the fossil fuels of wood, coal, natural gas, and oil, we have steadily released increasing amounts of CO2 — a waste byproduct of combustion — into the atmosphere.
For a while, this was not a problem. During the early Industrial Revolution, the relatively clean atmosphere could absorb and cope with CO2 pollution. But today, after decades of intense, growing CO2 emissions, after the loss of many square miles of greenery, and in the face of enormous new emissions from developing countries, the atmosphere is being stressed and overwhelmed beyond its ability to either digest or shed its CO2.
Now here’s the hard part to grasp. At best and at worst, the amount of CO2 in the atmosphere is tiny. Most of the air is composed of nitrogen, oxygen, and argon. About 78 percent is nitrogen, 21 percent is oxygen, and 1 percent is argon. That’s about 100 percent already, before adding in trace amounts of hydrogen, helium, neon, krypton, xenon, radon, and carbon. The carbon can be in the form of methane, carbon monoxide, or carbon dioxide.
The total amount of carbon (in various forms) in the atmosphere is roughly four one-hundredths of a percent. The carbon dioxide portion of the air today equates roughly to 400 parts per million. That is in fact the threshold just reached. And it is rising at an increasing rate — now at 2 ppm per year.
At the start of the Industrial Revolution, CO2 comprised roughly 280 parts per million. So man is on the way to doubling the amount of this gas in the air, and therein lies the trouble.
Carbon dioxide is a “greenhouse gas,” and it acts as an insulating blanket around the earth. Today, it prevents the planet from shedding enough heat to maintain an equilibrium of temperatures. Although the temperatures of the earth’s climates have varied over long, geological time, man’s copious fossil fuel emissions are altering the planet’s atmospheric composition and climate equilibriums at a rate far faster than would any current natural events.