The Greenhouse Effect
Greenhouse gases are gases in the atmosphere that absorb heat, and then radiate the heat back to the earth’s surface. This process of repeatedly absorbing and radiating heat creates a cycle which keeps heat in the earth’s atmosphere. This cycle is known as the greenhouse effect and has been in existence since the earth was formed. Greenhouse gases including carbon dioxide, water vapour, methane and nitrous oxide have always been present in the atmosphere, but human activities, particularly post Industrial Revolution, have meant an increase in the levels of these. It is this increased level of greenhouse gases in the atmosphere that is causing global warming and the resultant changes in weather patterns and the planet’s eco-systems.
Carbon dioxide emissions caused by human activity are the single most significant cause of the increase in greenhouse gas emissions. Roughly 60% of this carbon dioxide comes from burning fossil fuels to power our industry, heat our homes and power our transportation, which includes petrol or diesel powered cars, trucks, trains and airplanes. The problem also exists as a result of deforestation, because plants and trees store a great deal of carbon dioxide. When fossil fuels are burned, and forests destroyed, carbon dioxide is released into the atmosphere.
Because the rise in greenhouse emissions is caused by the actions of people, the actions of the same people can help to alleviate the problem by cutting down on our carbon dioxide emissions. This can be done by improving the insulation of buildings, traveling in more fuel-efficient vehicles, and using more efficient electrical appliances which all reduce energy use, and therefore reduce carbon dioxide emissions. Renewable energy sources such as solar and wind power can give us alternative energy sources which do not produce greenhouse gases and will help to reduce our overall carbon footprint.
Methane, which is the main component in natural gas, is not released into the atmosphere in the same quantities as carbon dioxide, but traps about twenty times more heat. Natural gas has very often been released during drilling for oil and gas, often being flared into the atmosphere as an unwanted by-product of oil production. Gas flaring is now illegal in many but not all oil producing countries. The problem being that many third world oil producers have no domestic gas networks, so no requirement for the produced gas and it then becomes cheaper to just flare it off. Methane is also released into the atmosphere during mining and other industrial processes. Industrial agriculture produces approximately 35 percent of human-caused methane emissions. A single cow can make up to 220 pounds of methane gas per year, while one mature tree absorbs as much as 48 pounds of carbon dioxide over the same period. Methane is generated in landfills as waste decomposes and in the treatment of wastewater. Landfills are the third-largest source of methane emissions in some countries and is also generated as a by-product from domestic and industrial wastewater treatment plants.
Recycling our waste can cut down the amount of waste we send to landfill and therefore help to reduce the associated methane release into the atmosphere. With beef and lamb being responsible for much of the agricultural release of methane, there is a trend to eat less meat, particularly red meat, and other dairy products so that the amount of meat production required in the market becomes less and in turn lessens the methane production.
Carbon dioxide has the reputation of being the greenhouse gas most responsible for global warming, but water vapour is actually the most abundant greenhouse gas in the atmosphere and the one with the biggest overall effect on heat retention in the atmosphere. As the atmosphere warms because of the increase in greenhouse gases, it is able to hold more water which is already the most abundant greenhouse gas. This creates a feedback loop which accelerates the global warming phenomena. It also creates more clouds, rainstorms and other symptoms of climate change.
Nitrous oxide is emitted during agricultural land use, industrial activities, combustion of fossil fuels, as well as during treatment of wastewater and the use of landfill sites for waste disposal. Although the presence of nitrous oxide in percentage terms is much lower than other greenhouse gases, the impact of 1 pound of the gas on warming the atmosphere is almost 300 times that of 1 pound of carbon dioxide. Nitrous oxide can be released into the atmosphere by the use of synthetic and organic fertilizers and other crop enhancing practices, as well as the management of manure, or burning of agricultural residues such as stubble left in the fields after harvest.
Emissions from nitrous oxide can be reduced by moving away from nitrogen based fertilizers or applying these fertilizers more efficiently, as well as modifying a farm's manure management practices. Nitrous oxide is a by-product of fossil fuel combustion, so reducing fuel consumption in motor vehicles or moving to electric vehicles can reduce emissions. Additionally, the use of catalytic converters to lessen the exhaust pollutants from passenger cars can also reduce emissions.
Global warming, or the heating up of our planet, is happening now. It is felt by many scientists that we can at best slow down the process, we are unlikely to be able to stop it unless we make major changes to our lifestyle. We can all see and feel the record temperatures we are experiencing and are aware of the wild fires engulfing large areas of forest or grassland which have seen no rainfall for months in some cases. Other areas are experiencing near drought conditions which will curtail the growth of food for both human and animal consumption.
The biggest polluters of the earth’s atmosphere are;
1. China, with its massive dependence on coal for energy, coal production in China has tripled since 2000 to nearly 4,000 million metric tons, which amounts to almost half of all global coal production;
2. USA, who have cut their coal usage for electricity generation but have increased their oil and gas dependence. This means that their carbon dioxide emissions remain high and their methane output has increased
3, India, state-owned Coal India has increased the country’s percentage of coal fired from electricity from 68% to 75%.
4. Russia, is the sixth largest coal-producing nation in the world, with coal production rising by 70% since the late 1990s, this despite a consistently high reliance on gas production
Only a concerted effort on the part of everyone from political leaders to the man in the street will help to halt global warming. Strange though, how the most powerful countries in the world are also the biggest polluters.