The Kyoto Protocol is a small step towards slowing global warming

On Wednesday February 16, 2005, some seven years after it was conceived, the Kyoto Protocol entered into force.

Under the protocol, developed countries are to reduce their collective emissions of six key greenhouse gases by at least 5 per cent by the period 2008-2012, with carbon dioxide emissions for most signatories measured against a base year of 1990.

Australia, along with the USA, has not ratified the protocol. In December, Environment Minister Ian Campbell announced that Australia was on track to meet its internationally agreed Kyoto target, which entails constraining emissions in 2008-12 to 108 per cent of their 1990 level.

It is entirely the role of government to determine whether to sign the protocol. However, the protocol represents just a small, first step towards slowing global warming. As it is only industrialised countries that have emission- reduction targets, the overall impact of the protocol would be reductions of significantly less than 5 per cent by the reporting period.

The harsh reality is, that if the world's commitment to tackling climate change were to finish with the Kyoto Protocol, by the end of the century we would have hardly made a dent in the level of carbon dioxide in the atmosphere.

Our climate has changed significantly over recent times. Global average temperatures have risen 0.6 degrees over the past century, while Australian average temperatures have risen 0.8 degrees, with a commensurate increase in the frequency of very warm days and a decrease in the frequency of frosts and very cold days. The Bureau of Meteorology recently announced that 2004 in Australia was another warmer than normal year: the tenth-warmest on record. Globally, according to the World Meteorological Organisation, 2004 was the fourth-hottest ever recorded, with the past decade the warmest since measurements began in 1861.

Just as climate has changed in the past, it will change in the future. Part of the future change will be caused by human activity. This is because about half of the carbon dioxide emitted by our activities is absorbed by the oceans and biosphere, leaving half in the atmosphere, where it has a lifetime of 50 to 200 years. Australia will be hotter in coming decades, with more extremely hot days and fewer cold days. By 2070, average temperatures are likely to increase by 1 to 6 degrees. In areas that experience little change or an increase in average rainfall, more frequent or heavier downpours are likely. Conversely, there will be more dry spells in regions where average rainfall decreases.

Even if we were to do the impossible and stabilise concentrations of greenhouse gases at today's levels, atmospheric temperatures would continue to climb, ultimately levelling hundreds of years in the future at about one degree warmer than now. To slow global warming, we will ultimately need to stabilise atmospheric concentrations. Substantial emission reductions will be required to achieve this.

Tackling climate change requires a combination of reducing emissions and adapting to the likely impacts.

The scientific evidence for global warming is compelling. The world should not allow global climate to continue to change at the rate that we are experiencing and are likely to experience in future as a result of human activity.