My third in the series, Earth, Air, Fire and Water, concerns a “element” that is absolutely necessary — Air. Without air any human would die in minutes. In a sense air is more necessary than earth and water (I covered water in my first diary — out of sequence, but timely.) What is air? Earth air is composed of 78% Nitrogen, 21% Oxygen 0.93% Argon, and around 0.04% Carbon Dioxide, plus various trace elements and compounds like Methane (See: en.wikipedia.org/....) In addition water vapor is maintained in changing humidity levels, producing clouds and precipitation in the forms of rain, snow, sleet, and hail, as well as making our planet warmer than it would be without it. Water vapor is a greenhouse gas (See: www.theguardian.com/...)! Weather occurs in air, our atmosphere, which allows life to actually exist on the planet.
The most important constituents of air from our point of view are oxygen and water vapor. Both are important in maintaining our life here on planet Earth, but of course oxygen is vital, as without it we will quickly die. In recent times increases in the small amounts of carbon dioxide and methane have altered the greenhouse effect, causing anthropogenic global climate change or more generally “global warming.”
Although oxygen is a good thing to have in the atmosphere from our (and all of life’s) point of view, a pure oxygen atmosphere would be very bad. Why? Because in a pure oxygen atmosphere many substances which would not burn as quickly under our 78% nitrogen atmosphere would easily burst into flames! (See: education.seattlepi.com/...) Oxygen supports combustion. Also pure oxygen can overload the physical system of the human body, leading to death. From our standpoint 21% oxygen is a good level, although it is a poison to anaerobic organisms and it is likely that early life forms were anaerobes (See: www.slate.com/...).
As Von Humboldt pointed out over 200 years ago, everything on earth is connected to a lesser or greater degree to everything else and so it is in reality very difficult to talk about “air” isolated from water, earth and fire. Fire is in fact maintained by the oxygen in our atmosphere, as nitrogen and especially carbon dioxide would easily snuff out a flame, while oxygen supports combustion. Water vapor forms clouds which produce rain, snow and hail, thus recycling water into streams, rivers, lakes and oceans. Water erodes rock and can pick up traces of impurities and toxins from the earth. Air also picks up particulates, radiation and gases, as well as pollen (as allergy sufferers like me all know too well!).
Weather happens in air. I find that since we stopped having thunderstorms of any consequences in my part of New Mexico for several years before I moved to the Pacific Northwest, I rather miss them. We have had a few minor ones here along Puget Sound, but nothing like the heavy thunderstorms I was used to in Tucson, Arizona, Gainesville, Florida, and Las Cruces, New Mexico. I can still smell in my mind the fragrance of desert plants as a thunder storm would sweep through the desert near the Chiricahua Mountains, or rumble through the Mesilla Valley. With thunderstorms often came violent winds, possible mesocyclones and hail. On a trip to the Big Bend region of Texas I once saw a wall cloud that moved swiftly toward our location, rapidly breaking in a violent thunderstorm with driving rain. At another point I just made it into Springer, New Mexico, as a massive storm dumped water in such quantities that by the time I parked my university truck, it was almost as deep as the bottom of my doors! A storm in the Sacramento Mountains, near Cloudcroft, New Mexico, made me worry that the cliffs along the road might come crashing down on my truck, but I survived. Still such experiences do tend to exhilarate as much as scare. They truly make you feel that you are really alive somehow.
The constant cycle in which water is drawn up into the air by evaporation, forms clouds and drops back to the surface is complicated by topography, the earth’s spin and the resultant winds. Hurricanes are fueled by warm water and eddies that start the spinning that leads to a major storm over the oceans.
Clouds are, of course, fascinating in their own right and there is in fact a very interesting book by Gavin Pretor-Pinney published in 2006 titled The Cloudspotter’s Guide (Penguin Perigee Books) for those who would like to take up cloudspotting as a hobby. In addition clouds and particulates in the atmosphere (including those from forest fires, volcanic explosions and dust storms) can result in spectacular sunsets which give photographers some very beautiful subjects.
However you think about air, it is obvious that it is vital. Try doing without it or having it polluted, as it has been in London, Los Angeles and Beijing, and you can quickly see the value of clean air. We breath the Oxygen, plants use the Carbon Dioxide (although not enough to stop global climate change) and Nitrogen is added to the soil by lightning (See: indianapublicmedia.org/…. The other planets that we have so far been able to study lack the balance of chemicals needed for Carbon-based life as we know it and we would die almost immediately if exposed to their atmospheres. Take a breath of fresh air and then realize how unlikely it is that you can do so in a universe where life may be common, but hardly universal.
As usual, all photos are by me.
See: Water! www.dailykos.com/…
Earth! www.dailykos.com/…
Fire! www.dailykos.com/...