Greenhouse Gas

Found some interesting facts at The Unlikely Activist blog. Who would have thought that you create more gaseous carbon dioxide by weight than the weight of the gasoline you burn. For instance, every time I fill up my gas tank which holds 30 gallons which weighs about 180 pounds, I have just released 540 pounds of carbon dioxide into the atmosphere since my last fill-up. One fill-up lasts me about a week so on a yearly basis I, personally, have been responsible for releasing over 28,000 pounds or 14 tons of greenhouse gas into the atmosphere. Burning gasoline in the internal combustion engine actually takes oxygen out of the atmosphere and combines it with the carbon in the gasoline. This accounts for the extra weight. Water vapor is also produced as a by-product.

In defense of myself, I use my vehicle mainly for business and use public transportation whenever possible. But it makes one wonder how can the planet sustain this radical transformation in the gaseous composition of the atmosphere? Regardless of global warming, does it make any sense to radically alter the composition of the atmosphere which has stayed relatively constant for many millenia? The main gas in the atmosphere is nitrogen (78% by volume, 75% by mass). Nitrogen is very inert and doesn't react much. As such it is mainly "filler." Oxygen takes up 21% by volume, 23% by mass. Oxygen is highly reactive and is responsible for human energy production, forest fires and rust among other things. If the amount of oxygen in the atmosphere were to be substantially increased, wood would spontaneously combust all over the planet and there would be constant raging forest fires. If it were to be substantially reduced, on the other hand, we might not ever be able to get a fire going and would probably all freeze to death.

That leaves 1% by volume of the atmosphere to be composed of other gasses chiefly argon, an inert gas that takes up .93% by volume. This leaves only about .06% for all the other gasses that compose the atmosphere including the greenhouse gasses carbon dioxide and methane. So what's to worry? Carbon dioxide makes up only .03% of the atmosphere. So what if I personally am reponsible for an additional 28,000 pounds per year? Well, the reason is that carbon dioxide is very important to the earth's radiation balance because it traps radiant energy from the sun and reradiated energy from the earth in certain infrared wavelengths.  By so doing, it delays the departure of energy from the earth system into outer space, and this delay permits the lower atmosphere to maintain a reasonably stable and warm temperature.

The problem is that the amount of carbon dioxide in the atmosphere is increasing about .4% per year due to human activities such as my personal yearly release of 28,000 pounds from my vehicle's tailpipe. Carbon dioxide levels in the earth's atmosphere have about doubled in the last century, going up about 15 percent just in the last 40 years. This has resulted in global average temperatures having risen about 0.5° C in the last century (~1° F). They are predicted to rise another 3° C (~6° F) over the course of the next century. This could produce a number of unpleasant effects such as the polar ice caps melting with an associated raising of sea levels flooding low lying coastal areas, more and more violent storms, tornadoes and hurricanes and more floods and droughts.

There are mitigating factors, however. Higher ocean temperatures can increase the effectiveness of the oceans as a carbon sump. That is the oceans could absorb an increasing amount of carbon thus reducing the amount in the atmosphere. Deforestation can be followed by the increased photosynthesis associated with secondary vegetation which is often hyperactive in its photosynthetic activity. Finally, the earth's atmosphere itself is unstable producing Ice Ages from time to time from which we may only now be recovering. It's not unthinkable that global warming might tend to cancel out the effects of the next ice age. However, I reiterate: messing with the gaseous composition of the atmosphere is probably not prudent and moderating human activity so as to protect this rather fragile resource (only 10,000 km thick) is probably the best way to go.

Please go to see An Inconvenient Truth by Academy Award nominated star Al Gore and Who Killed the Electric Car? for more insights.