Tuesday, May 11, 2010

We humans can't have a major effect on the atmosphere...

..or can we.

The Earth's atmosphere is a very thin layer of gas, relative to the planet itself. If we imagine the earth as being the size of a basketball(a diameter of a little more than 9 inches), the atmosphere would be about 1/100 of an inch. Moreover that atmosphere contains about 78% nitrogen gas, about 21% Oxygen, a little less than 1 percent argon- the rest is water vapour,CO2 and other gases such as methane.

So the actual gases responsible for the green house effect that traps heat in our atmosphere comprise about 1 percent of our atmosphere. So we don't have to change the composition of our atmosphere much to have an effect on it.

The total mass of our atmosphere is 15 x 10-18 Kg(15 000 000 000 000 000 000 Kg) or 30 x 10 -18 lbs.
These days, humans emit 26 gigatonnes or 26 x 10-9 tonnes of carbon dioxide into the atmosphere or about 2% extra carbon dioxide per year. The earth's environment absorbs about half of that( which is causing acidification of the oceans, among other problems). Of course, methane and water vapour also contribute to green house gases, and human activity produces them, too.

So we are making a massive change in the small quantity of gases that keep our planet at a habitable temperature. This current rate has been typical of the last ten years, so our atmosphere should have shown in the region of a 10 % increase in atmospheric CO2 in the last ten years. The WMO reports an increase of 1.8 ppm of CO2 per year over the last decade or 18 parts per million increase out of about 360 ppm. This seems low, and leaves the question, where has all the carbon gone? is it my math? On the other hand, the WMO indicates a 5%/annum increase in CO2- which means doubling in 20 years.

"If I had to choose between betraying my country and betraying my friend, I hope I should have the guts to betray my country."
-E.M. Forster