Fossil fuels are part of the slow carbon cycle (see fact box). Nature-based solutions are part of the fast, biological carbon cycle, meaning that carbon storage is not permanent. For example, carbon stored in trees can be released again by forest fires. Fossil emissions happen today, while their uptake in trees and soils takes much longer. The overall capacity of nature-based solutions is also limited, and is anyway needed to help remove the carbon dioxide that we have already released into the atmosphere.
