Most of us are now accustomed to the fact that the main purpose of the Kyoto Protocol is to devise ever more bizarre and complex ways for developed countries to avoid reducing emissions at home. Even so, to include sinks in the CDM is probably the worst possible way for developed countries to evade their obligations. Sequestration in biological sinks, such as forests, is temporary. Their ability to take up and store carbon varies unpredictably and uncontrollably over time in response to many natural and human induced variables, including climate change.
Sinks can easily become sources.
It was rash to allow forests to be used as sinks by Annex I countries. I countries have to make up for unpredictable changes in their own sinks. Proponents of sinks in the CDM have yet to put forward adequate proposals to guarantee developed country responsibility for any impermanence of CDM sinks projects. It is hard to estimate the uptake and storage of carbon by biological sinks with any degree of accuracy, and certainly without expensive and extensive monitoring. Reliably estimating sinks will be difficult even in highly developed countries with fairly accurate baselines.