About Air

“The Philips Nature Encyclopaedia” explains that all living things are made up of molecules based on carbon. The carbon atoms come originally from the carbon dioxide in the atmosphere and enter the living world by photosynthesis in green plants, algae and some bacteria. These primary producers are the starting point of a cycle of consumption, decay and respiration in which carbon atoms are incorporated into complex organic compounds and then released from these compounds.

Oxygen gas is returned to the atmosphere from the living world by green plants and cyan bacteria, which give out oxygen during photosynthesis. 

That life on earth is supported by an extraordinary thin shell of atmospheric oxygen at an altitude of only 20 kilometres. The earth is the only planet in the solar system having an atmosphere capable of supporting any life at all. In fact, the evolution of life was intimately linked with the evolution of the atmosphere, most crucially 2000 million years ago, when plants began producing free oxygen.

During the first half of the Earth’s existence, only trace amounts of free oxygen were present. Then green plants evolved in the oceans and they began to add oxygen to the atmosphere as a waste gas.

The addition of large amounts of oxygen was very important for the further evolution of life because of the role that ozone plays in protecting plants and animals from lethal ultraviolet radiation. Due to the early ozone layer being very thin and close to the surface, living organisms had to rely on alternative protection, and could only develop under about 10 meters of water.

As oxygen increased to 1 percent of the atmosphere, the required depth of protective water became only 30 centimetres (12 inches) and complex multi-cellular marine life -forms could develop. The atmosphere continues to evolve but human activities – with their highly polluting effects- have now overtaken nature in determining the changes.

According to Yvonne Baskin in “The work of Nature”, the major greenhouse gases are water vapour, CO2, methane, nitrous oxide, and manmade molecules known as chlofluorocarbons. With water vapour excluded, all of the trace gases together make up less than a tenth of 1 per cent of the atmosphere.

She explains that without naturally occurring levels of water vapour and Co2 in the air, for instance, the earth would be colder by about 33 degrees centigrade, making it inhabitable for all.

She tells us that over the past 250 years, as modern industrial societies developed, CO2 levels have risen from about 270 parts per million to more than 350 parts per million and are continuously rising.  She explains that this is due to largely increased burning of coal, oil, and other carbon rich fossil fuels, as well as the cutting and burning of forests. In addition, methane levels from sources such as rice paddies, landfills, and the guts of cattle and sheep, have more than doubled since 1750 and are gradually rising.

She alerts that about one-fourth of the human contribution to rising trace gas levels comes from deforestation, and most of that gas is CO2 released into the air from soils and vegetation when trees are cut and burned. Land clearing also releases significant amounts of methane and nitrous oxide, especially when trees are burned. Ploughing the cleared land for crops over time can release 25 percent of the carbon stored in soil organic matter. Nitrogen fertilizers applied to these fields lead to further emissions of nitrous oxide. Putting cattle on the land or flooding it for rice paddies increase the emission of methane.

She tells us that the rise in global CO2 levels shows up on a chart in a steadily rising wave. This wave reflects seasonal patterns in photosynthesis as the terrestrial biosphere inhales huge amounts of CO2 during each spring and the summer, and then exhales it in a burst of microbial decomposition in fall and winter. At the rate the biosphere breathes, an amount equivalent to the total CO2 in the atmosphere passes through green plant communities on land every seven years.

In her opinion the carbon that plants pull from the air may be returned to the atmosphere quickly, as microbes or animals that consume fruit, leaves, algae, and other plant material “burn” the carbon compounds to fuel their life processes and breathe CO2 back to the air as a waste product.

She explains that methane is second only to CO2 as the most important human –generated greenhouse gas. Although it exists at atmospheric concentrations 175 times lower than CO2, a molecule of methane is twenty as effective in absorbing and trapping radiant heat. Intensive livestock grazing in temperate and tropical grasslands and flooding of large areas for rice cultivation are believed responsible for doubling atmospheric methane over the past 250 years. 

She points out that nitrous oxide is a very long-lived greenhouse gas whose production has nearly doubled in the past century. Automobile exhausts and the burning of nitrogen-loaded fossil fuels such as coal generate some of the rising tide of nitrous oxide, but a major portion of it comes from the microbial breakdown of ammonium or nitrates in the soil.

She concludes that the production of nitrous oxide is particularly steep in agricultural areas where high rates of nitrogen fertilizer are applied to the soils and in ecosystems like temperate forests where, ironically, acid rain and dry deposition deposit high loads of nitrogen pollutants.

Yvonne Baskin explains that terrestrial plant communities influence climate processes both directly and indirectly. Vegetation generates surface conditions, such as roughness and albedo, at the boundary between the earth and air and determines evapotranspiration rates, influencing regional rainfall, temperature patterns, and air currents. Both plants and soils serve as sources and sinks for greenhouse gases, such as carbon dioxide, methane and nitrous oxide, that change the heat- trapping properties of the atmosphere, indirectly influencing the global climate. Major realignments of the earth’s vegetation zones, driven either by human land-use changes, such as deforestation, or by a warming climate, affect both the surface properties of the earth and the gas exchange between biosphere and atmosphere and climate in a continuous push pull between living things and the atmosphere. Even without the warming effect of green house gases, human – driven build-up of carbon dioxide in the atmosphere will influence plant growth and alter key physiological processes, such as transpiration, that also have a profound effect on regional temperature and rainfall.

Some people have proposed geo-engineering as a solution. One way to do that is by deliberately enhancing greenness; a strategy that on its face seems far less outrageous than other proposed climate manipulations aimed at diverting sunlight from the earth:

Two U.S forest Service researchers optimistically estimated in 1190 that the nation could sequester more than 56 percent of its own carbon emissions in new wood by planting trees on virtually all “economically marginal and environmentally sensitive pasture and croplands and non-federal forest lands. 

The air is directly affected by what is done on the soil and vegetation therefore farming procedures must be changed.

She tells us that researchers are studding and putting into practice a system that they believe can work in order to prevent further ecological destruction -ecological restoration is a notion that degraded lands can be restored to a fully functional and self-sustaining condition and that the ecological damage can be undone and natural landscapes recreated.  

Some improvements have been verified in prairies where ecologists have put this system into practice. The structure and water holding capacity of the soils have improved dramatically.  

The author tells us that multi-crop agriculture has also been put into practice. The question for researches is weather multi crop systems involving only two or three species can achieve the same yield as monocultures without sacrificing the sustainability that diversity provides. Studies so far show that the right combination of species in the right setting can consistently yield more together then the same species grown singly on the same plot. Not only do multi-crop systems often match the output of monocultures; more important, they may provide steadier yields through good and bad years while requiring fewer artificial resources to defend or nurture them. 

This strategy involves combining a cereal grain with a nitrogen-fixing legume, such as inter-planting rows of corn between rows of clover. The clover supplies nitrogen, provides living mulch, protects soil and water, and creates habitat for insects that prey on crop pests.

Plant diversity in a field not only lowers the risk of complete crop failure but also preserves a level of natural pest control that helps reduce losses to insects. It can also help sustain productivity by preventing soil deterioration. In any multi-crop system, of course boosting output depends on picking the right combination of species.

Researches say that by practising organic farming many harmful situations can be avoided. Organic farming consists in a production system, which avoids or excludes the use of synthetically compounded fertilizers, pesticides, growth regulators, and livestock feed additives.

This system relies upon crop rotations, crop residues, animal manures, legumes, green manures, farm organic wastes, mechanical cultivation, mineral-bearing rocks, and aspects of biological pest control to maintain soil productivity, to supply plant nutrients, and to control insects, weeds and other pests.

Sustainable Agriculture is also being put into practice. It is a philosophy based on human goals and on understanding the long - term impact of our activities on the environment and on other species. Use of this philosophy guides our application of prior experience and the latest scientific advances to create integrated, resource conserving, equitable farming systems. These systems reduce environmental degradation, maintain agricultural productivity, promote economic viability in both short and long term and maintain stable rural communities and quality of life.

According to researches the first aspect of sustainable agriculture is the understanding that a respect for life, which protects its various forms, and recognizes their right to exist, is not only desirable but also necessary to human survival. A second aspect requires that the farming system does not put life in jeopardy; its methods do not deplete the soil or the water, or place farmers in situations where they themselves are depleted, either in numbers or in the quality of their lives.

 According to researches sustainable agriculture is:

• Environmentally sound

• Economically viable

• Socially acceptable

Today, action is occurring at every level to reduce, to avoid and to better understand the risks associated with climate change. Many countries have prepared greenhouse gas inventories; and many are actively pursuing programs and policies that will result in greenhouse gas emission reductions. Changing our live styles, choosing to use environmental friendly materials can be our contribution to help prevent further destruction.

Some measures are being put into practice such as:

Controlling the Greenhouse effect by:

Reforestation

Many researches believe that replanting forests can recycle as much as 2 billion tons of carbon dioxide per year.

Revolution of new types of cars

Researches tell us that fossil fuels contribute to a large amount of greenhouse gases in the atmosphere. Cutting the fossil fuel use can help greatly in reducing global warming. In their opinion there is a way to do this by making a revolution of the transportation that we use everyday.

They say that solar, electricity, hydrogen or other renewable fuels can power cars.

World population

Researches say that the rate of population growth in the undeveloped countries is three times faster than in the developed countries. With this increase in population, there will also be a demand of food. This will lead to an increase of cattle rising and farming area. The amount of methane released will consequently rise.

They say that not only will there be an increase in methane, the quantity of lumber demanded will also rise (as a result of furniture or other construction needs). 

Phasing out the use of the CFCS

Researches tell us that by eventually phasing out the use of chlorofluorocarbons, we can get rid of a gas that contributes an estimated 10 percent to global warming. Substitute chlorofluorocarbons with other safer chemical compounds, or restrain from using it or products made using it will help contributing to the phasing out of chlorofluorocarbons.

Other energy sources

Researches defend that we need other sources of energy, renewable sources of energy such as the sun, the wind, or hot springs. Shifting from fossil fuel to these sources would reduce carbon dioxide emissions another 700 million tons.

According to them, another option of a new fuel worth considering as part of a defence against greenhouse warming is hydrogen. It is one of the cleanest burning fuels available. When electricity is passed through water, the water molecules split into hydrogen and oxygen. The hydrogen gas that results can, like natural gas, be piped to where it is needed to produce heat, power slightly modified vehicles or other industrial uses.

They believe that besides developing alternative sources of power, another step we can take is to use the fuels we have more efficiently. Building automobiles that use less gasoline is a step. Insulating our homes so that we can heat and cool them more efficiently is another. On a global basis, if the industrialized nations can use fuel twice as efficiently as in the past, scientists estimate they can reduce carbon dioxide emissions by 1.5 billion tons.