Is global warming really happening?

Source: Image courtesy of NASA

Around the world scientists, politicians and business leaders are debating about the existence, extent and cause of global warming.

One view maintains that global warming is not occurring and we are merely witnessing natural weather patterns.

As humans only recently began keeping records of the weather in the last few hundred years, we know much less about how the weather varies over thousands, hundreds of thousands, or hundreds of million years.

In this view, it is therefore possible that a few unusually hot or cold years or changes in weather patterns may be entirely natural.

A second group does acknowledge that global warming appears to be happening, but challenges the belief that humans are responsible.

This group maintains that we are undergoing a long-term change in the weather; however this is caused by changes in the sun, the earth and much larger natural events than a few hundred years of pollution released by humans.

Finally, there is a growing group who believe that humans are directly contributing, if not actually causing, changes in global weather patterns.

This group believes that our choices of where we live, the pollution we release into the natural environment, and our direct impact on the environment - removing tree cover for farming, diverting rivers for our own water needs and emitting heat from our industries - are forcing up global temperatures and changing weather patterns.

Regardless of the cause or whether this is a short-term or long-term variation in the earth’s temperature, there are clear indications that the earth is heating up.

According to the Australian Greenhouse Office publication 'Climate Change: An Australian Guide to the Science and Potential Impacts ', "the 1990s were the warmest decade and 1998 the warmest year of the millennium".

When charting meteorological (weather) records since 1910 there is a trend to warmer annual mean temperatures across Australia.

The Bureau of Meteorology has reported that 2005 was the hottest year in Australia’s recorded history, and the second warmest year globally since records have been kept.

Studies of retreating glaciers and sea, ice global ocean currents, and winds have also indicated that significant climate change is in progress.