2 The carbon connection

The development of life on a dynamic Earth was associated with major changes in the composition of oceans and atmospheres, and carbon-based life played a key role in this. The section above discussed how greenhouse gases in the atmosphere have a major effect on the mean temperature of the Earth, through the greenhouse effect. Once again, carbon in the form of carbon dioxide plays a major role. This section will explore more fully the role that the element carbon plays in the life of the planet by following two trails: first, the trail that carbon atoms follow as they cycle through different parts of the Earth, and then the carbon trail produced by human activity.