By now, most of the world has heard of the bushfires that are savaging the southern Australian state of Victoria. As I write this, 181 people are confirmed dead, a few thousand have been left homeless, and small towns have literally been destroyed. Not to mention the native wildlife that has been wiped out. The finger of blame is being pointed at firebugs but, although they may have worsened the situation, they did not cause it. Why do bushfires happen? Is there anything we can do to prevent them?
In the case of the Victorian bushfires, the 10-year drought and the unusually high temperatures have been big factors. One theory, as explained in the book "The Emerald Planet" by David Beerling, says that natural deforestation is occurring on Earth; forests are being destroyed by Mother Nature, and replaced by grassland. Here's how it works:
The death of trees in times of drought allows patches of grass and weeds to grow. These patches of grass provide a very flammable fuel in dry seasons; they are more flammable than the trees because of the way they process carbon dioxide. Bushfires, which arise due to the high-flammability of the grass, kill more trees, and allow more of these grasses to grow (these grasses recover very rapidly after burns). So, what we're seeing is grass usurping the dominance of forests by promoting fire. Nonflammable trees are gradually being replaced by highly-flammable grasslands, and this process is being aided by a gradual increase in greenhouse gases in the atmosphere. And just to top it off, it has been shown that smoke from burning forests acts to reduce rainfall by impeding cloud formation; the fires actually increase the severity of droughts - they cause climate change.
We often hear about natural selection and survival of the fittest when applied to the animal kingdom but, if this hypothesis is correct, natural selection is being played out in the plant kingdom with lethal and devastating consequences. It is believed that this trend of grasslands usurping forests has been happening over tens of millions of years - before man came on the scene. However, there is every possibility that man-made greenhouse gases are speeding up the process. This Darwinian war of attrition will inexorably lead to a stable state in which grasslands will completely replace forests. Reducing our greenhouse gas emissions will only delay the inevitable. And while all this happening, we humans - the self-proclaimed rulers of the planet - are left to watch helplessly and impotently as our houses and towns burn down, and as precious human lives are lost.
2009 is the International Year of Astronomy, and it also coincides with Charles Darwin's 200th birthday. Galileo and Copernicus showed that the Earth is not the centre of the universe, and Darwin showed us that humanity is just another species of animal, occupying a tiny limb on the tree of life. To me, these fires are a reminder of these sobering facts. However, although we are not the centre of universe, humanity and human nature are a product of nature - we are a part of the universe. To me, that is a source of inspiration.
