Solutions For 9780131905429 Chapter 3.3 Problem 5A

On land, the major exchange of carbon with the atmosphere results from photosynthesis and respiration. Forests act as a major carbon store because carbon dioxide () is taken up from the atmosphere and used to produce the carbohydrates, fats, and proteins that make up the tree. When forests are cleared, and the trees are either burnt, this carbon is released as carbon dioxide into the atmosphere far more rapidly than it is being removed and this imbalance causes atmospheric carbon dioxide concentrations to increase. In addition by clearing forests, we reduce the ability of photosynthesis to remove from the atmosphere, also resulting in a net increase. Because of these human activities, atmospheric carbon dioxide concentrations are higher today than they have been over the last half – million years or longer. Then, increase the atmospheres ability to hold heat. It has been called as “green house gas”.