Carbon dioxide in the atmosphere

The combustion of fossil fuels adds more carbon dioxide to the atmosphere. Carbon dioxide added to the atmosphere in one place will, over time, spread throughout Earth’s atmosphere. Plants act as carbon sinks because, as they grow, they remove carbon dioxide from the atmosphere. The decomposition or combustion of plants returns the carbon they are storing into the atmosphere. Human activity is adding carbon dioxide to the atmosphere more quickly than it is being removed by natural processes.