by Perry McCarney

Created on: September 07, 2010   Last Updated: April 09, 2012

Simple fixes are highly desirable and we have a tendency to want them to be true. Unfortunately, they rarely are. Climate change is a global phenomenon impacting people in all regions of the planet. We know through experimentation that gaseous systems are more energetic the warmer they are. We know that certain gases entrap heat. While methane is far more capable of keeping significant amounts of the energy our planet receives from the Sun within our atmosphere, carbon dioxide does so to a lesser extent. Carbon dioxide impacts the global temperature more for the simple reason that there is far more of it in the atmosphere and human industry and land clearance practices are adding to that concentration continuously.

Carbon dioxide (CO2) is a vital component in photosynthesis; the process plants, phytoplankton and algae use to harness the Sun's energy to produce organic compounds. These organic molecules support most life as we know it, all but some of the oldest types of life: the extremophiles of the domain Archaea. CO2 also plays a significant role in the Earth's climate, a role that is not as clearly understood as we might think, after hearing it repeatedly being described as a greenhouse gas.

The current average amount of carbon dioxide in our atmosphere, including the air we breathe, is 0.038% or 380 parts per million on a per volume basis (ppmv). This varies depending on local events, downwind from slash and burn operations in a rainforest is typically higher, for example. But what is most significant are variations in CO2 levels that coincide repeatedly with global warming and cooling cycles, typically occurring over 70,000 year periods.

Scientists studying "fossil" air bubbles from ice core samples drilled in Antarctica have been able to obtain a continuous record of carbon dioxide levels for the past 400,000 years. That record shows CO2 levels ranging from 180 to 200 ppmv towards the end of periods of glaciation (ice ages) through to levels around 300 ppmv at the end of warmer, interglacial periods; a level that was reached in the middle of the Twentieth Century. Since then CO2 levels have continued increasing to the current 380 ppmv, a concentration level that the Earth has not seen in the last 400,000 years at least. Although recent studies on fossil bones has indicated that CO2 levels may have been considerably higher than now about 1.4 million years ago.

Nevertheless, we are currently in an unprecedented situation, no-one really knows what impacts

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