Gauteng Smallholder May 2016 | Page 17

CO2 EMISSION Help to save the planet ~ plant a tree A s a land-owner, do you realise that you, too, can play an important role in reducing atmospheric carbon dioxide? Leading climate scientists report that the atmospheric concentration of carbon dioxide has increased by 40% since pre-industrial times. More than half of this increase has occurred since 1970, and of all greenhouse gases in the atmosphere, carbon dioxide plays the most significant role in global warming. Naysayers will hasten to point out that the eruption of a major volcano, such as Mount Helens, Krakatoa, Mount Erebus or Vesuvius, or the eruption of the volcano in Iceland that caused the closure of airports throughout Europe and North America, singly and rapidly spew out vastly more carbon dioxide than humans will ever Plants, being largely carbon themselves, and even the earth, can remove vast quantities of CO2 from the air. All it needs is a little help from landowners, who should be planting trees and crops produce in their cars, planes, power stations etc. But those events, being natural and on a vast scale, are not preventable. Gases in the earth's atmosphere are necessary to trap the heat of the sun, which makes conditions on earth suitable for plants, animals and human habitation. However, with the rise in carbon dioxide temperatures on earth have risen and have caused the climate to change. This affects the rainfall, what types of plants grow where and has also increased the frequency of violent storms. Scientists have come up with various ways to capture and store CO2, otherwise known as carbon sequestration, but these are not accessible to ordinary citizens. However, for those of us involved in agriculture, no matter how small our land, the most promising systems for carbon sequestration in soil combine crop rotation and low or no inputs of pesticides, herbicides and chemical fertilisers. And here's the good news: carbon sequestration is taking place on your plot right now, through the process of photosynthesis. In daylight, plants assimilate carbon by absorbing CO2 through their leaves. They chemically separate the two oxygen atoms from the 15 www.sasmallholder.co.za carbon atom and release the oxygen back into the atmosphere while absorbing the carbon atom into their own structure (plants are largely made up of carbon). The carbon that remains as plant tissue is then consumed by animals or humans or is added to the soil as litter when plants die and decompose. Continued on page 17