What is climate change?
“Global warming is a greater risk to humanity than the war on terror, particularly in Australia where the stakes are high”: Al Gore, former US Vice President.
Climate change
Ten years ago we weren't sure about climate change, but today there is general agreement that our climate is changing. Today, pointers to the future of life on Earth are both unmistakable and locally significant. Countries around the world are seeing disappearing glaciers and thawing permafrost (the permanently frozen soils in countries near the poles), more lethal storms and floods, forest fires and extreme heatwaves.
The earth has warmed, on average, by about 0.7°C since 1910 with nine of the ten warmest years on record occurring in the past decade. There has been an increase in heatwaves, fewer frosts, and a warming of the lower atmosphere and ocean surface.
Australia will be significantly affected: our temperatures have increased by almost 0.9°C over the last hundred years, which is slightly more than the global average.
Using information gathered over the last 100 years, scientists can prove that the world has not been as warm as it is today for a millennium or more. And global warming appears to have accelerated during the past 30 years – this at a time when natural influences such as solar flares and volcanic eruptions (both of which cause changes in the atmosphere that reflect sunlight) should have reduced global temperatures.
Scientists studying the world's climate that report for the United Nations Intergovernmental Panel on Climate Change (IPCC) state global warming is linked to human activities.
Living in a greenhouse
People are changing the natural climate pattern by burning huge amounts of fossil fuels (coal, oil and natural gas), releasing billions of tonnes of carbon dioxide (CO2) every year. This process began centuries ago, but has increased sharply in the last century of industrial development.
While the "greenhouse effect", where our atmosphere controls the amount of the sun's radiation, is an entirely natural phenomenon, our emissions of gases such as carbon dioxide, methane and chlorofluorocarbons have created an atmospheric imbalance that exposes us to more solar radiation.
If current trends continue, increased carbon dioxide will probably be enough to raise global temperatures by around 2°C to 5°C by the end of the century, which will melt sea ice at the poles, raise ocean levels which will flood coastal towns and cities, alter local climate patterns, and change vegetation.
Effects on people and global economies that depend entirely upon our environment will be diverse and unpredictable. Diseases may flourish. Some crops may grow faster while others will be lost to drought. Dwindling water supplies will cause conflicts in many regions, and rising sea levels will create environmental refugees in numbers we cannot yet imagine.
As natural ecosystems such as coral reefs are affected, biodiversity is reduced. Some species will struggle to adapt and survive, and others will change in response to warming.
While forests and oceans absorb around half of the carbon dioxide we produce, research suggests that nature's ability to absorb ever-increasing levels of the gas could now be stretched to the limit.
What can we do?
In the view of the United Nations Intergovernmental Panel on Climate Change, the world needs to quickly become energy efficient and develop non-carbon-producing sources of energy, such as wind, solar, tidal, wave and geothermal. There is renewed and polarised debate about nuclear power as a substitute for traditional energy sources such as coal and gas.
The bottom line is that we will need to cut carbon dioxide emissions by 70 to 80 percent simply to stabilise atmospheric carbon dioxide concentrations, and thus control further rises in global temperatures.
How we do that involves every one of us, and begins with actions as simple as switching to low-energy light bulbs, reducing fuel use and turning the air conditioner thermostat up a degree or two. By reducing demand from power generators or energy sources that emit greenhouse gasses, we all play a part in reducing the problem.
