Understanding Our Earth, Part II
It was the wind that gave them life.
It is the wind that comes out of our mouths now
that gives us life.
When this ceases to blow we die.
In the skin at the tips of our fingers
we see the trail of the wind;
it shows us the wind blew
when our ancestors were created.
The ancient Greeks identified "Wind" or "Air" as one of the four basic elements of the cosmos. This "air" or atmosphere is essential to all life on land and in the sea. It is transparent, nurturing and is a global resource owned by no one and used by all. Most of the time we take it for granted and don't even notice it unless the air is dirty or the weather unpleasant. At present, the earth is the only known planet with an atmosphere capable of supporting life as we know it (at least for now).
LIFE AT THE BOTTOM OF THE OCEAN
We are bottom dwellers in an ocean of air. An ocean that extends up to about 1000 miles above the earth's surface and ebbs and flows with far more movement than any ocean of water. The eddies and currents are the winds that help shape the earth, it's weather, and it's inhabitants. Compared to the diameter of the earth this ocean of air is almost non-existent. A 1000 mile high, one inch square column of this thin membrane of air weighs only 14.7 pounds!
About 75% of the earth's air lies in the layer next to the earth (the troposphere) and only extends upward about 11 miles above sea level and about 5 miles at the poles. The next time you drive somewhere that is only about 10-11 miles away, think about how thin a layer we depend on for our survival. If you compare the earth to an apple, this lowest layer of air we depend on for our very breath is no thicker than the skin of that apple. This is the turbulent layer of air that is responsible for the distribution and control of water vapor (precipitation) and heat (temperature) that produces our weather and climates.
Climate is the sum total of weather events in a region. Air currents and wind are critical to our existence on the planet. Many terrestrial plant's reproduction cycles depend on the wind to spread their pollen and their seed. Wind picks up water, moves it, and drops it in the form of precipitation and is critical in the water cycle that sustains life on land. Wind evaporates water and cools the earth. Without wind, moisture would be limited to the oceans, and most of the world would be a desert. So while previous thought suggested that oceans and ocean currents were primarily responsible for our weather, it's the wind that drives the circulation of ocean currents. New studies analyzing data from the latest in satellite sensor measurements tell us that our atmosphere is moving a lot more heat than previously thought. At 35 degrees latitude, the atmosphere carries 78% of the total heat flow in the northern hemisphere, and 92% of the heat in the southern atmosphere. What this really means is our atmosphere is more important to climate than we thought, and therefore more important in determining the distribution of plants, animals, and humans.
The troposphere consists of approximately 78% nitrogen, 21% oxygen, with the final 1% made up of carbon dioxide and trace amounts of several other gases. The oxygen in our atmosphere that we rely on is mostly produced by the photosynthetic activity of green plants, green algae, and blue-green bacteria. They take in carbon dioxide and give us back oxygen; we take in oxygen and give them back carbon dioxide.
It is believed that our atmosphere originally began as mostly carbon dioxide with little or no oxygen and that plant life was primarily responsible for giving us the oxygenated atmosphere we depend on today. This atmospheric composition makes life possible and in turn the living organisms of this planet contribute to the delicate balance of gases that support life.
Carbon dioxide (CO2) plays a crucial role in two main processes…the greenhouse effect and the cycling of carbon among living systems.
The greenhouse effect is a natural process. Carbon dioxide traps the heat from the sun and warms the troposphere making the planet warmer. Without it life on this planet would not be possible. However, too much carbon dioxide produced from human industrial activities is building up and leading to global warming. There is new evidence that glaciers and ice caps are melting much faster than normal causing ocean levels to rise. A warmer planet could also have a major effect on food production, reduced water supplies (more evaporation), an increase in deserts, destruction of coral reefs, changes in distribution of forests, grasslands and other ecosystems. Maybe we should take a closer look at what we are doing to the planet.
Carbon dioxide is also part of the carbon cycle, which makes up the backbone of ALL organic compounds, and therefore all life. Plants take in carbon dioxide and turn it into sugars which are assimilated up the food chain by animals, who then release recycled carbon into the atmosphere as carbon dioxide to be used by plants to make sugars again. The carbon dioxide you breathe out this week will probably be part of the salad you eat next week. Remember that connection the next time you sit down to eat.
THE EARTH'S SUNSCREEN
The stratosphere is found in the next layer up from the troposphere and extends from 11 to 30 miles above the earth's surface. This layer contains 1000 times more Ozone than is found in the troposphere, and is known as the Earth's Sunscreen. Ozone is a molecule that contains 3 oxygen atoms (O3) instead of 2 oxygen atoms (O2) that is found in normal atmospheric oxygen that we breathe.
We have a kind of love-hate relationship with ozone.
We have a "love" relationship with ozone because of the unique nature of the molecule. This layer of our atmosphere absorbs about 99% of the harmful incoming ultraviolet (UV) radiation from the sun and prevents it from reaching the earth's surface. This filtering action allows life to exist on land and protects humans from sunburn, skin cancers, and immune system damage. So, even though most of the life on this planet could not exist without the presence of an oxygen rich atmosphere, it was the development of the ozone layer about 400 million years ago that allowed life to evolve onto land. Life in the oceans didn't really need that protection because the water reflected the UV rays. Unfortunately, human industrial activities are punching holes in the ozone layer letting in higher levels of UV rays, increasing the rate of skin cancers, cataracts, and immune system problems. Ozone depletion is one of the earth's most critical problems.
We have a "hate" relationship with ozone when it's in the troposphere, the layer we live in and breathe, because at ground level it is one of the major components of the photochemical smog that engulfs our cities. Ozone is highly reactive and erodes rubber, metals, buildings, and damages plants. Crop and forest damage has been reported in California and on the East Coast. Urban landscapers must plant pollution resistant trees and other plants. Ozone also plays a major role in such diseases as chronic bronchitis, emphysema, asthma, and lung cancer.
WITH EVERY BREATH YOU TAKE…
Every day you inhale about 21,000 quarts of air. With each breath you:
The oxygen you inhaled (which was once part of a plant) takes about 60 seconds to complete one circuit of your body, with about one-half of the new oxygen exiting the blood stream to nourish your body. This oxygen becomes part of a kidney cell, muscle cell, nerve cell, your DNA, part of a function, maintains the acid/base balance in your blood, feeds the brain, or becomes part of a thought. Oxygen is the final electron acceptor in the chain of events in the production of energy (ATP). Without oxygen, much energy would be locked up in the food we eat and unavailable to us. That life even exists is certainly a miracle in and of itself.
With every breath you take, remember your connection with the earth.
Air - the gaseous realm, the atmosphere, the planet's membrane. The inhale and the exhale. Breathing out carbon dioxide to the trees and breathing in their fresh exudations. Oxygen kissing each cell awake, atoms dancing in orderly metabolism, interpenetrating. That dance of the air cycle, breathing the universe in and out again, is what you are, is what I am.
-John Seed and Joanna Macy