The Hot Air of Climate Change, Part 4

This is a multi-part series examining the current debate over "global warming", also known as "climate change".

As we examine the global warming arguments, we've found that it is extremely difficult if not impossible to accurately measure the global temperature over time; that there are a great many known climatic cycles which interact in extremely complex ways that have nothing to do with human activity; and that the Sun is known to have been getting warmer over the last few years, as seen by increasing temperatures on Mars.  But it doesn't seem completely unreasonable that we might be messing up the atmosphere, as anyone who has ever been to Los Angeles can attest.  So, our next question:

4. Does human activity contribute to global warming, and to what extent?

In 2004, it has been calculated that human activity released roughly 7910 million metric tons of carbon into the atmosphere - or, not quite 8 billion metric tons.  That is an almost unimaginably large number, and frequently you hear comparisons to an impossibly long coal-train that goes all the way around the world.  By human standards, it's a lot.

By the standards of the Earth, however, it's a drop in the bucket. Earth's atmosphere weighs 4.41 million billion tons.  Therefore, it's calculated that, each year, we are putting 6 ppm - that's parts per million - into the atmosphere.  In other words, out of every million pounds of atmosphere... we are adding 6 pounds of carbon.  That's .0006%.

Let's compare this to some other relevant percentages.  The FDA regulates how much rodent excrement, insect parts, mouse hairs, and other unpleasantness is permitted to be found in various foods.  Now, you might think they'd want to require its absolute absence, but that's not practical.  So, for example, we find that it is perfectly legal for peanut butter to contain an average of one rodent hair per 100 grams - that's about 7 tablespoons, or a bit less than half a cup.  In cornmeal, you're allowed one whole insect per 50 grams.

Not having a mouse conveniently to hand, we cannot determine what a single mouse hair generally weighs; but it is surely no less than 1/100 of a gram, which would make it twenty times as much, by percentage, as the carbon we're adding to the atmosphere.  And generally speaking, we don't consider our Skippy to be infested with mice.

You may be thinking, "It is unfair to compare the carbon we're adding to our atmosphere with mice in peanut butter!"  And you'd be absolutely right.  It's quite unfair - to the peanut butter.

Once the mouse hair is in the jar, it's not coming out until you spread it on your sandwich.  Not so with carbon in our atmosphere.

As attentive elementary students can relate, our planet has a fully functioning carbon cycle.  This means that, as we breathe oxygen and generate carbon dioxide, so do plants "breathe" carbon dioxide and release oxygen.  The more carbon dioxide there is in our atmosphere, the more lush we find plant growth becoming.

Of course, you can cast this in a very bad light - as witness this summer's rash of news articles about fast-growing, more potent poison ivy.  Nobody wants more poison ivy around, but it's absurd to emphasize the excessive growth of that one noxious weed, and completely ignore the exact same beneficial effect on the hundreds and hundreds of other useful, attractive, or edible plants that we are blessed with - all of which are working overtime to suck that CO2 out of the atmosphere just as fast as we can put it there.

Plants aren't the only natural action counteracting global warming.  Research shows that volcanoes have a tremendous effect too.  The 1991 eruption of Mt Pinatubo in the Philippines threw up to 26 million tonnes of sulfur dioxide into the stratosphere, where it became sulfuric acid aerosol - which causes cooling.  According to the Australian Commonwealth Scientific and Research Organization (CSIRO):