Human
activity is also adding CO2 to the atmosphere
through deforestation. When tropical forests are clear cut,
the land is typically
converted to pasture. The original
forest and its soil have a much
higher carbon content
than the pastureland, so the process of burning the forest must result in a significant release of carbon to
the atmosphere.
Deforestation
is thought to be releasing about 2.2
gigatons of carbon every year into the atmosphere.