| | | Greenhouse Gas - What Should You Know

From WikiVerde

Greenhouse gases, the greenhouse effect and global warming are terms widely used these days. What exactly do they mean? Greenhouse gases are chemical compounds or elements in the earth’s atmosphere that reflect some of the sun’s heat and trap the rest, keeping the heat passing through to the surface of the earth approximately regular. Infrared radiation is also absorbed by these gases.

Greenhouses gases are both naturally occurring, such as CO2, methane, water vapor, and nitrous oxide; and man made – like perfluorocarbons, hydrofluorocarbons and sulphur hexafluoride, which are emissions from certain manufacturing activities or gases used in products such as aerosol cans.

The green house effect refers to the capacity of these gases to absorb and hold heat. This ability varies; man made gases have a greater capacity for heat absorption, and nitrous oxide, for example, can take in 270 times more heat per molecule than carbon dioxide. We’ll come to global warming and its later.

Specific Greenhouse Gases

Carbon Dioxide (CO2)

^{A new, high resolution, interactive map of United States carbon dioxide emissions}

Carbon dioxide is discharged into the air when we burn fuel such as fossil fuels and wood, when we burn waste and during chemical processes in industries. It’s a heavy, stable, non-flammable gas, without colour or odour, and makes up a large part of the volume of the earth’s atmosphere. Let’s examine what is known as the carbon cycle. This greenhouse gas is breathed out by humans in addition to being produced by burning fuels.Plants absorb this CO2 during photosynthesis and expel oxygen as a byproduct. Deforestation is another reason for carbon dioxide increases and irresponsible, indiscriminate tree harvesting has lowered the planet's ability to remove the carbon dioxide in the air. While systems of nature like photosynthesis use up some carbon dioxide, our emission amounts are far more, and lead to an imbalance in the atmosphere, with the continuing increase of quantities of carbon dioxide and other greenhouse gases.

Methane

Human-caused methane emissions occur during the manufacture and transport of fossil fuels, such as natural gas, oil and coal mining. Naturally-caused methane emissions occur from sources such as livestock and organic decomposition. Like carbon dioxide, it is odourless and colourless, but it is flammable in nature. Methane, a simple alkane, is also known as swamp gas due to its prevalence in damp, marshy areas. Animals release methane naturally, with bacteria in their digestive systems that release the gas into the air.

Our contribution comes from mining for metal or coal, drilling for oil, rice cultivation and untended garbage that rots and releases the gas. Methane emissions have doubled since 1750, and are projected to do so again in another forty years. This gas stays in the air only for about a decade, but its heat holding capacity is twenty times that of carbon dioxide.

Nitrous Oxide

Nitrous oxide, also known as laughing gas, is a by-product of the burning of fuel and waste, and of manufacturing and agricultural processes. It is colourless, too, with a sweetish odour and has anaesthetic properties. In nature, nitrous oxide is discharged from certain soil bacteria, as well as from the oceans. Human activities such as the use of nitrogenous fertilizers, sewage treatment, and discharging of vehicle exhaust all contribute to nitrous oxide emissions, which take more than a century to dissipate.

Fluorocarbons

Fluorocarbons are basically synthetic organic compounds containing both fluorine and carbon, many of which move easily from the liquid to the gaseous state and vice versa. Hydrofluorocarbons, perfluorocarbons, and sulphur hexafluoride are man made and discharged during manufacturing. Although these gases replace ozone destroying gases like chlorofluorocarbons (which have been banned in America) and halon in refrigerators, air conditioners and aerosols, they add to global warming and are called High GWP (Global warming Potential) gases because of their pronounced greenhouse characteristics.

Make sure you prevent leaks of fluorocarbons from your appliances and use as little as possible by recycling them. And when you discard a fridge or an air conditioner, remove the gas so that it can be re-used, and so that you contribute to keeping fluorocarbon emissions down.

Why are Greenhouse Gases Bad?

In the past century and a half, ever since the industrial age began, greenhouse gas quantities in the atmosphere have risen by a hefty 25%, enhanced by massive fossil fuel burning. Human activities are pumping an increasing number of greenhouse gases into the atmosphere – carbon dioxide by burning wood, waste and fossil fuels; methane from the decay of organic matter and the production of fuels; and nitrous oxide from manufacturing and agricultural procedures.

Greenhouse Gases and Climate Change

As the amount of greenhouse gas emission increases, the temperature of the earth follows suit. This leads to weather changes and shifts in sea levels and land use patterns, causing unseasonable or freak weather and floods, etc.

Global Warming

Global warming is a phenomenon that many are concerned about these days. Our high emissions and resultant high concentration of greenhouse gases in the atmosphere are causing climate changes such as increased ocean temperatures, higher surface temperatures on the earth, Global warming will have far-reaching consequences on human, animal and plant health, ecology, farming and coastal areas. Already sea levels are increasing, there’s more water vapour in the air, ice is melting, and floods and droughts are more common.

As far as human health is concerned, many will suffer because of the increased heat, with cardiac problems, heatstroke, and so on. Due to the heat, there will also be an increased concentration of smoke particles and unpleasant-smelling gases. So the incidence of respiratory diseases like asthma and bronchitis is likely to increase.

How Do Greenhouse Gases Dissipate?

It generally takes years for such gases to leave the atmosphere, except for water vapor, but it does happen. Water vapour is removed by condensation and rain, snow, hail, etc., while methane quantities are reduced during chemical changes in the air. Some gases are absorbed by water on the surfaces of the oceans. Atmospheric carbon dioxide is lessened by forming carbonic acid, carbonates, and bicarbonates through reactions with sea water, as well as through photosynthesis. Halocarbons are dissipated by ultraviolet light, while nitrous oxide is involved in lightning during a storm.

Each of us should know enough about greenhouse gases to do our part in keeping emissions to a minimum. Let’s hand a clean, healthy earth over to our children!