Carbon emission reduction is top of the agenda at world climate summits, with green groups urging people to reduce their carbon footprints.
It is widely believed that carbon dioxide created by human activities is the main culprit behind global warming, so everybody should play their part to reduce the emissions and save our planet.
But what has carbon dioxide done to earth? Take a look at the numbers. The concentration of carbon dioxide in the atmosphere has increased from 280 parts per million (ppm) during the industrial revolution in the 18th century to 380 ppm in 2000 and there is no doubt the earth has warmed over the same period.
But Craig Idso and Keith Idso from the Centre for the Study of Carbon Dioxide and Global Change in the US say there is no compelling reason to believe that the rise in temperature was caused by an increase in carbon dioxide emissions. This is because data spanning a few hundred years is not enough to prove a link between the two.
Looking back at the earth's climate over the past 500,000 years, the scientists noted there had been seven big temperature transitions. During the same period, increases or decreases in carbon dioxide concentrations did not precede changes in temperature.
There were long periods when temperatures dropped and carbon dioxide concentrations remained the same.
