Since the discovery by NASA satellites in the early 1970s that the layer of ozone over Antarctica has been in decline, encyclopedias worldwide have been updated with new terms such as greenhouse gas, ozone depletion and global warming, and many scientists have made it their life's mission to prove that the turmoil of the current is caused by global warming or climate change.
Others have made it their mission to disprove that and insist it is a regular cyclical event. This is what they call a hot potato issue! Both sides are accusing the other of so-called junk science.
The past few years have seen weather extremes, the likes of which have never before been recorded. For example, the Northern Hemisphere's summer of 2012 has seen record-breaking temperatures and unprecedented droughts. Could it be that we have more sensitive temperature monitoring instruments now? Whatever the reason, there is little doubt amongst climate scientists that greenhouse gases-many of them man-made-are the main cause of this rapid climate change.
What are greenhouse gases?
Greenhouse gases are those gases in the earth's atmosphere that play a part in the atmosphere's role of absorbing and emitting thermal radiation, but instead of maintaining the energy balance that supports all life on earth, these gases act like a greenhouse roof, trapping heat and raising the temperature of the atmosphere.
Starting with water vapor, which is a natural result of the masses of the liquid covering our home planet, we go into methane gas, nitrous oxide, carbon dioxide and ozone.
Water vapor is a greenhouse gas on its own, but it also amplifies the effects of other greenhouse gases. The warmer the air is, the more water vapor it can hold. More water vapor will mean more greenhouse heating, and the cycle continues.
Methane gas is created by the natural decomposition of organic matter; a large amount is produced as a byproduct of the beef cattle industry in the form of cattle flatulence and burps.
Carbon dioxide has many uses. For instance, in its frozen form it is known as dry ice. Carbon dioxide is also used extensively in fire extinguishers and is also present in the atmosphere naturally.
You may be most familiar with nitrous oxide from visits to the dentist, where it is used as a sleep-inducing agent. Also known as laughing gas, it might be the most abused of all greenhouse gases, as it induces a euphoria in the user that makes having all your wisdom teeth removed seem like a laughing matter.
Ozone, on the other hand, is no laughing matter. The ozone layer is very high up in the atmosphere and protects all living things from overexposure to ultraviolet rays emitted by the sun. These rays, most of which are absorbed by the ozone layer, are a direct cause of skin cancer, and dangerous ozone depletion can be caused by the greenhouse gas nitrous oxide as well as by chlorofluorocarbons (CFCs) and other compounds that rise up to the stratosphere.
Ground-level ozone, on the other hand, is very harmful, contributing to the creation of the irritants in smog. At this level, it also acts as a greenhouse gas because of its energy absorption abilities. Some of the main causes of the increase in ground-level ozone are emissions from carbon-fueled vehicles, electric utilities and industrial facilities.
Volcanoes and other natural sources
Natural emissions of greenhouse gases include volcanoes and hot springs. Explosions like Mount St. Helens and Pinatubo have made considerable contributions to accumulation of harmful greenhouse gases.
Not all greenhouse gases are manmade. This is a living planet, where organisms are born, grow and die, and in the process of their life cycle, they may be beneficial and sometimes harmful.