, Salem, MA

May 23, 2013

Watson: Carbon dioxide in the air increases steadily

Brian T. Watson
The Salem News

---- — Early this month the chemical composition of the atmosphere, which for a variety of reasons changes constantly but very slowly, reached a mixture of gases that is considered to bode ill for the stability of climates across the globe.

Specifically, the amount of carbon dioxide in the atmosphere has climbed to a new high level that will increasingly affect the balances and equilibrium of many of the important soil, water, chemical, and weather patterns and cycles around the world.

The atmosphere is a relatively thin shell surrounding the earth. Most people, who rightfully perceive the sky as something “big,” are astounded to learn just how thin the sky — the lower atmosphere — is. To reach the upper atmosphere, where only a few light gases exist, we need travel through roughly only 60 miles of lower atmosphere.

Compare this 60-mile-thick layer to the diameter of the planet — 7,918 miles — and you can get a sense of what a narrow skin it is. And even though there are about 10,000 miles or more of diffused upper atmosphere gases above it — before “outer space” begins — it is the narrow 60-mile band that is important to us.

This band contains the oxygen, nitrogen, argon, carbon dioxide, water vapor, and about 15 other gases that constantly mix and circulate around the globe, creating or affecting the weather, microclimates, natural chemical cycles, and ecological processes that shape and support all natural (including human) life on the planet.

Alter the chemical composition of this band in any significant way and you’ll stimulate a reaction — some reaction — because all of the parts (gases, organisms, climate) are interconnected. This is science, but it’s not rocket science. It can all be grasped with mere common sense: alter the ingredients or their proportions in any soup recipe and you’ll change its taste or consistency or some other attribute.

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.

With the use of deeply drilled ice cores and analysis of ancient sediments, we can determine atmospheric CO2 quantities accurately for the past 800,000 years. We also have reliable techniques to estimate CO2 levels as old as 3 million years, which appears to be the last time that CO2 concentrations were as high as they are today.

The new quantity of 400 ppm is almost infinitesimal compared to the total gaseous volume of the atmosphere. Yet CO2 has an effective power all out of proportion to its percentage of the air. And understanding that man is rapidly increasing CO2’s presence is key.

This story is genuinely alarming, and you’d think citizens and leaders would respond strongly. But none of what I’ve described is visible, and the unraveling of ecological balances is occurring too subtly and gradually to compete with the powers that are resisting change.

A certain paralysis has set in too. After all, we are all dependent in innumerable ways on a status quo that is complex and finely braided. More and more, with our technologies, our lifestyles, our networks and infrastructures, and our growth-dependent economies, we have made of the world a terrible, stubborn, interlocking trap, and it is we who are caught.


Brian T. Watson is a Salem News columnist. Contact him at