According to the Kyoto Protocol, biological carbon sinks can be used as a means of partially achieving national emission reduction targets. In this paper, I evaluate 1) the historical development of human impacts on the terrestrial carbon balance, 2) the resulting differences in baseline conditions in different parts of the world and for different nations, and 3) key aspects of the sustainability of accounting biological carbon sinks regarding the long-term development of the greenhouse effect.
Humankind has been influencing the greenhouse gas balance of the Earth for much longer than the past 100 to 150 years in a regionally highly differentiated manner. Forests play an important role as C sinks in most temperate zone countries today, but their sink strength results mainly from historical over-exploitation and thus should be regarded as “compensation” rather than a generic achievement of humankind in general, or forest management in particular.
Although accounting for biological C sinks for achieving national emission reduction targets appears positive at first sight, I conclude that this practice tends to obstruct problem solving, rather than fostering it. Considerations on the sustainability, ethics and efficiency and on the equitability of this accounting suggest that the two issues should be considered separately, without implying that forest protection would be of lesser importance, nor that biological C sinks would be of a marginal value.