Early Environmental Articles
The Soil-Greenhouse Connection
Discussion Paper, Friends of the Earth(Sydney)
Prepared by Ted Floyd
When discussing the role of carbon and carbon dioxide in causing the Greenhouse effect little attention is paid to the importance of the soil as a major source of carbon.
The major Greenhouse gases and their relative importance are carbon dioxide 50%, chlorofluorocarbons 25%, methane 10%, ozone 10%, and nitrous oxide 5%. For carbon dioxide 75% is contributed by burning fossil fuels and 25% by destruction of vegetation.
It is obvious that the major source of carbon dioxide is fossil fuels but the destruction of vegetation is also a major source of greenhouse gases. In the minds of most people, the destruction of vegetation conjures up visions of forests being cleared by burning and all that beautiful timber going up in smoke and carbon dioxide. This is partially correct but what is not emphasised is the slower, less obvious process that occurs in the soil, where soil microorganisms break down soil organic matter and the end result of respiration by these microbes is carbon dioxide.
Balance exists as long as the ecosystem is not disturbed. Before I discuss some of the consequences of disturbing this balance I will try to emphasis just how much carbon is stored in soils.
In the following table the total amount of carbon stored in the various earth reservoirs is listed.
Reservoir 10x 15 g Carbon Stored
Living organisms 830
Soil surface litter 60
Surface water 728
excludes deep sea sediments and fossil fuels etc.
From this table it can be seen that the soil is a very large reservoir of carbon and for example there is nearly 2 x as much carbon in the soil than in living organisms.
Generally the ratio of carbon stored in above ground portions of an ecosystem to that stored below ground is dependent on the climate, mainly temperature. The colder the climate the more carbon is stored below ground. For example, tundra ecosystems have up to 90% of their carbon stored below the ground surface and 10% above ground level. A tropical rainforest may have 25% of carbon below ground surface and 75% above.
Grasslands can have a very high proportion of their carbon stored below ground. Up to four times their carbon can be stored below ground compared with above ground.
I hope I have shown that soil organic matter is important and though you can not see the organic carbon in a soil it is as important as the majestic tree which can be admired. When discussing the effects of destroying vegetation on the greenhouse effect, the important role of the soil must be considered.
We will consider a mature native forest that was in complete balance with carbon dioxide absorbed equaling carbon dioxide respired by animals and microorganisms. In this forest up to 75% of the carbon can be hidden away underground and 25% of the carbon stored above ground in the fine forest that we can see and walk through.
The foresters who love to chop down these trees also only see the fine timber above ground level. They argue that if they chop down these trees, they will grow again. Then the foresters argue that since trees are growing they absorb carbon dioxide and they are solving the greenhouse effect. Stop! Lets dig a little further into this argument.
In the native forest a large store of organic matter has built up. In the native forests the trees, bushes, grasses, etc. continually add organic matter (leaf litter) to this store. Similarly the soil microbes break this organic matter down. There was a balance. Organic matter added to the soil equaled organic matter broken down by microbes.
When the forest is cut down, the addition of organic matter to the soil is drastically reduced. The microbes are still there, they still continue to feed on the remaining organic matter. The difference now is that as the soil microbes break down the soil organic matter, little additions are made to this store from the cut down forest. The end result is the total store of soil organic matter decreases and this adds to the carbon dioxide released to the atmosphere, i.e. the greenhouse effect is exacerbated.
This effect of depletion of soil organic matter can last for many years after the cutting down of a forest. A study by the University of Western Australia showed that surface soil organic matter reached a minimum of 40% of original forest soil after 7 years of clearing. Even after 100 years the soil organic matter of a cleared forest was only 80% of the original forest.
Different farming methods can have a very important effect on the level of organic matter in a soil. Generally while land is under pasture and is not cultivated organic matter builds up, compared to cultivated land. When a crop is grown such as wheat, the soil is cultivated and generally the level of soil organic matter falls.
Usually when growing wheat a rotation is used where for some years wheat or similar crops are grown, then the land is placed under pasture, usually a mixture of legumes and grasses which is grazed by sheep or cattle.
The type of rotation has an important effect on the level of organic matter in the soil. If there is many years of wheat and a few years of pasture, the soil organic matter falls. It is important to have sufficient years of pasture in the rotation to maintain adequate levels of organic matter.
Falls in the level of organic matter during farming, will release carbon dioxide to the atmosphere and will be a contributing factor to the greenhouse effect.
The magnitude of this problem can be visualized from the following hypothetical example. A farm soil has in the top 10cm an average of 5% organic matter. After intensive farming the level of organic matter is reduced from 5 to 4%. From the decomposition of this organic matter 27,000 kg of carbon dioxide is released to the atmosphere. For comparison, the average Australian car produces 3,500 kg of carbon dioxide a year. Of course the opposite is true, i.e. if a good farmer increases the organic matter in the soil, carbon dioxide is absorbed.
Good farmers know there is many advantages in increasing the organic matter in a soil. The soil has a better structure, water infiltrates better, aeration is better and especially, soil erosion is reduced. Now it is important to maintain or raise organic matter so as to help in the global battle to reduce the greenhouse effect.
Basic Strategies-for Greenhouse Control Following extract is from a report to Friends of the Earth 1990. by Ted Floyd
1 Zero population growth Growth in population has long been recognized as disastrous for the world’s environment and also population stabilization is essential to prevent greenhouse warming. It was in 1968 that Paul Ehrlich wrote “The Population Bomb”. Many countries, especially poor countries with rapid population growth, have tried to control birth rates. Most schemes have failed and many poor nations have immense problems because of an expanding population.
The issues involved in controlling population growth in poor nations are complex. Generally it is difficult to ask poor people to have small families while they have no security for old age. There are many social and religious pressures that complicate the problems.
The difference between rich and poor nations should be emphasized. People in rich nations consume about 15 times more than people in poor nations. This means that in relation to greenhouse problems, one Australian causes the same problems as 15 people in poor nations. This would mean that population growth control is even more important in rich countries like America, Europe or Australia.
2 Steady state economy The increase of GNP (Gross National Product) is the aim of every country, spurred on by powerful politicians, influential economists and greedy businessmen. A country that has a low GNP is considered to be a failure, and all countries seem to be having a vigorous competition to “out GNP” each other.
The thought of having no growth in GNP is laughed at and people such as environmentalists who advocate a steady state economy are considered as belonging to the lunatic fringe. Despite all this more people are seeing the light, that the world’s ecosystems cannot sustain continued growth.
Basically, continued growth results in increased release of greenhouse gases. If growth in GNP continues, all other schemes to decrease greenhouse gases will fail.
Consider a 30/dyear growth rate in energy consumption. If we start at a total energy consumption of 100 units, in 9 years time total consumption will be about 130 units. Lets consider a 20% reduction of energy use (e.g. we achieve 20% savings by energy efficiency). We start with 100, reduce this to 80 by efficiency then continue to have a growth of 3%. With this growth rate we reach 130 units in 16 years.
This example shows that an initial 20% reduction of energy use will result in the same level of energy consumption in 16 years compared to 9 years if no initial reductions were made. If all these calculations confuse you then remember the simple fact that growth can not be sustained. If we make great reductions in energy consumption now, but continue to have a high GNP growth rate, we only delay by a few years inevitable disaster.
To achieve a stable GNP, or to reduce GNP will not be easy. Our whole economic structure relies on growth. Most individuals want more, most politicians promise more. All mainstream economic theories aim at providing more. Capital growth is necessary for large businesses and a company that fails to grow, will fail completely. Under present conditions; if Australia’s GNP fails to grow, our whole economy fails. As a matter of urgency economic structures should be developed for a steady state economy.
3 Reduced consumption of material goods Within our economy, activities that are energy intensive should be reduced, and worthwhile activities that are environmentally friendly and use little energy should be encouraged. There should be a shift from material goods to services. For example there should be increases in educational facilities, or artistic activities.
The major consumption of energy in our economy is in manufacturing and transport. These sectors should be looked at and ways of reducing our need of manufactured goods and transport should be encouraged.
Self-sufficiency has been the goal of many people who have moved to the country. People (often in communes ) in the country have tried to grow all their food and produce their energy by renewable means. Often they live a frugal lifestyle so that they have few material goods, and many of the goods they do have, they have made themselves. The concept of Bio-regionalism has also been proposed, where a district becomes as selfsufficient as possible.
This concept of self sufficiency has many attractive features. One important feature is that it reduces trade, i.e. transport of goods is at a minimum, so less energy is used and fewer greenhouse gases emitted. In general, self-sufficiency should be encouraged and trade with distant merchants should be reduced.
Durability of products is very important. In-built obsolesence should be discouraged. When energy and minerals are used to manufacture a product; all effort should be made to ensure the product will have a long and useful life.
Another important aspect is the ability to maintain a product. Products should be built so that they can be easily repaired and not thrown on the rubbish tip when they break down. Within the economy there should be shift a from the manufacturing sector to the repair industry.
Excessive packaging is a gross waste of resources and energy. Energy is used to manufacture, transport and dump packaging. Usually a plastic shopping bag has a fleeting life wrapped around some groceries and is then thrown on the rubbish dump where it lives an immortal life damaging our planet’s ecosystems for ever more.
Recycling should be encouraged . Recycling saves energy and resources and minimizes the problems of garbage dumps.
In our society there should be a shift away from the ever expanding consumption of material goods. All material goods require resources and energy to manufacture. Some activities that should be encouraged are; arts, crafts, sports, continuing education, visits to museums, art galleries, libraries, and national parks. If more money was spent on these activities instead of on manufactured goods less energy and resources would be consumed.
Carbon dioxide emissions during manufacture of basic products
kg C02/kg product
Steel 2.4 Aluminium 20.0 Paper 1.4 Glass 0.9 Bricks 0.2 Cement 0.8
4 Individual environmentally friendly actions The energy consumption of all products should be considered. Is it necessary to own clothes dryers, dishwashers, electric blankets, automatic garage doors, large deep freezers. electric can openers, kitchen garbage disposal units, heated water beds, pillow-massagers, infrared lamps, heated towel rails the list goes on. Usually these products are of dubious benefit. They all consume energy, add to greenhouse gases and can be easily done without. Energy is not only necessary to operate these gadgets but considerable energy Is consumed during manufacture distribution and dumping.
People should live close to work and amenities and either ride a bike or walk to work. It may cost more to live close to work, but you could sell your car and save money which can be spent on dearer housing.
When going on holidays, leave the caravan behind, forget about the petrol guzzling 4-wheel drive car and sink the power boat.
In your sports and hobbies use your own energy not fossil fuels. Throw away trail- bikes, powerboats and racing cars.
When buying products, we should consider their durability. It would be wise to spend a little extra to buy a product which will last longer.
Fashions should not be highly regarded. Especially for clothes, we should buy long lasting products that can be wom for years and not fashionable rubbish that is worn for a season and then eaten by moths while it gathers dust in the wardrobe.
A look should be taken at the home garden. Should there be large expanses of lawn that require regular watering, mowing, edging, fertilizing and toxifying, with insecticides, herbicides, mitacides etc? Should exotic flowers and bushes be grown that need extra water and fertilizers? A natural Australian bush garden can be estabrished that doesn’t need mowing, fertilizers and excessive watering.
Battery operated gadgets should be used sparingly. To manufacture batteries, considerable energy and many other resources such as heavy metals are used. A major problem is the disposal of flat batteries. The heavy metals in batteries cause a serious environmental problem when the old batteries are dumped on rubish tips. In the home, mains powered radios and cassette recorders should be used. Solar powered calculators are now very economical. Children should not be given battery powered toys. They are expensive to buy and exorbitantly expensive to run.
Individuals should explore different activities that they could pursue, that will give them pleasure but will not consume vast amounts of energy or other resources. Time and money saved by not consuming vast amounts of energy can be spent on less polluting activities.
One could learn a craft, learn to play a musical instrument, or take up painting. A saving of $1000 in your fuel bill could be spent on a beautiful painting. Bushwalking is a very enjoyable pastime, especially if you catch a train to the mountains and leave the 4-wheel drive monster at home.
Continuing education would be a most fulfilling pastime that would use little energy. There are now available many adult courses on every conceivable subject. People could discover how to educate themselves by learning how to use libraries and other sources of information.
It would be wise, so as to save energy and to save your sanity, to turn the TV off and read a book. The TV not only burns electricity but it pursuades us to race out and buy the latest, fashionable electric toothbrush.
5 Reduction In Personal Consumption Every product we buy, all the goods we consume, need energy in their manufacture and distribution. Old goods that have become rubbish need energy to dispose of at the garbage dump. The more we consume, the more energy is used and the more greenhouse gases are released.
Many environmentalists are questioning the need for this excessive consumption. Ted Trainer in’his book “Abandon Affluence” ( 2 ) argues that to solve environmental problems affluent people have to give up their ever increasing want to consume more. Also, Trainer argues, excessive consumption in rich countries prevents poor countries from raising their living standards.
Recently there has been a widespread interest in green consumerism. This is good but does it go far enough? There should also be red consumerism, red as for stop, danger, don’t buy.
Excessive consumerism has been looked upon by many religions as an evil. The bible has many passages warning against seeking wealth and goods, though this has had little effect on dampening the quest for wealth by Christian nations and people. Some eastern religions have had much more success in advocating a simpler lifestyle.
It is hard for an individual to voluntarily consume less. Our success in society is judged by the value of the goods we own. Manufacturers keep on dreaming up new goods to make, whether we really want them or not. Advertisers fool us into thinking that worthless junk is absolutely necessary. Salesmen lie to us as they take our money. Politicians can only promise us more, they do not have the wisdom to realize that we do not need more.
Individuals who finally make the decision that they do not want more, will find it is fairly simple to reduce their level of consumption. The process is usually gradual but as time passes people will find that there are many goods and products that they do not need. The hardest part is usually to make the initial decision and to develop a commitment to succeed.
Article published in Ecology Action (Australia)