To understand the climate, we have to first understand time, argues Ian Plimer.
We are all environmentalists. Some of us underpin our environmentalism with political and romantic idealism, others underpin it with emotion, others have a religious view of the environment, some underpin their environmental view with economic pragmatism and many, like me, try to acquire an integrated scientific understanding of the environment. An integrated scientific view involves a holistic view of the Earth and considers life, ice sheets, oceans, atmosphere, rocks and extraterrestrial phenomena which influence our planet.
Geology is about time, changes to our environment over time and the evolution of our planet. Geology is the only way to integrate all aspects of the environment. Past climate changes, sea level changes and catastrophes are written in stone.
Time is a beautiful but misunderstood four-letter word. Most of us can't fathom the huge numbers that geologists and astronomers use, hence most of the community has little knowledge of geology. History and archaeology are rarely integrated with natural geological events. There is little or no geological, archaeological and historical input into discussions about climate change.
It is little wonder then that catastrophist views of the future of the planet fall on fertile pastures. The history of time shows us that depopulation, social disruption, extinctions, disease and catastrophic droughts take place in cold times and in warm times life blossoms and economies boom.
Climate has always changed. It always has and always will. Sea level has always changed. Ice sheets come and go. Life always changes. Extinctions of life are normal. Planet Earth is dynamic and evolving. Climate changes are cyclical and random. Through the eyes of a geologist, I would be really concerned if there were no change to Earth over time. In the light of large rapid natural climate changes, just how much do humans really change climate?
The Earth's climate is driven by the receipt and redistribution of solar energy. Without this, there would be no life on Earth. Despite well-documented linkages between climate and solar activity, the Sun tends to be brushed aside as the driver of climate on Earth in place of a trace gas (CO2), most of which derives from natural processes. The CO2 in the atmosphere is only 0.001 per cent of the total CO2 held in the oceans, surface rocks, air, soils and life.
Although we are in one of the many warm periods between ice ages, there is a significant amount of ice remaining in the polar regions. Polar ice has been present for less than 20 per cent of geological time, life on Earth for more than 80 per cent of time and liquid water on Earth for 90 per cent of time. Planet Earth is a warm wet volcanic greenhouse planet, which is recovering from glacial times and is naturally warming. Cooling has also occurred in the current interglacial times. Earth has warmed and cooled on all time scales, whether they be geological, archaeological, historical or within our own lifetime. The key questions are: How much of this warming can be attributed to human activity?
If we humans are warming the planet now, how do we explain alternating cool and warm periods during the current post-glacial warming?
Before we can hope to understand present climate change, we must understand how climate has changed in the past. We know that there have been past climate changes which have been extreme and rapid yet we do not understand all the drivers of these past climate changes. Although we know that there are a large number of variables that influence climate, there are probably variables that have not yet been discovered. Some of the known variables have a huge effect on climate, others have a slight effect, but combinations can have an unpredictable effect.
We cannot view planet Earth as a simple scientific experiment where, by …