Assessing the Potential for Future Managed and Unmanaged Carbon Sequestration

It is expected that over the next 100 years the productivity of terrestrial ecosystems will be increasingly driven by frequent extreme weather events, set against unprecedented increases in air temperature and the concentration of key trace gases in the atmosphere. These changes will drive a myriad of feedbacks between the biosphere and the atmosphere that are expected to alter the ecosystem functions that control productivity and carbon sequestration, resulting in unmanaged changes in carbon cycling through terrestrial ecosystems. However, management of terrestrial ecosystems is being undertaken with the aim to slow the rate of rise in Ca. The extent to which these unmanaged and managed changes in carbon sequestration in terrestrial vegetation will mediate against rising Ca is highly uncertain with estimates ranging from 10% to 60% over the next 100 years (Fig. 2.2). In Section 2.6 we will assess the potential for both unmanaged, as a consequence of global change, and managed carbon sequestration in terrestrial ecosystems.

Unmanaged (500 Pg C)

Managed (20 Pg C)

Unmanaged (150 Pg C)

Fig. 2.2. The (a) upper and (b) lower limits of both unmanaged (global change-driven) and managed changes in the carbon sequestration capacity of the terrestrial biosphere summed for the next 100 years, relative to predicted CO2 emissions over the same period. Predicted CO2 emissions of 1500 Pg C over the next 100 years are from IPCC scenario IS92a, a mid-range scenario of rising Ca. The upper limit of unmanaged carbon sequestration is predicted from both CO2 and climate change effects on terrestrial carbon cycling by the TRIFFID model of Cramer et al. (2001), and the lower limit is from Gruber et al. (2004). The upper (maximum theoretical potential) and lower (actually achievable) limits of managed carbon sequestration are from Cannell (2003).

Managed (20 Pg C)

Unmanaged (150 Pg C)

Fig. 2.2. The (a) upper and (b) lower limits of both unmanaged (global change-driven) and managed changes in the carbon sequestration capacity of the terrestrial biosphere summed for the next 100 years, relative to predicted CO2 emissions over the same period. Predicted CO2 emissions of 1500 Pg C over the next 100 years are from IPCC scenario IS92a, a mid-range scenario of rising Ca. The upper limit of unmanaged carbon sequestration is predicted from both CO2 and climate change effects on terrestrial carbon cycling by the TRIFFID model of Cramer et al. (2001), and the lower limit is from Gruber et al. (2004). The upper (maximum theoretical potential) and lower (actually achievable) limits of managed carbon sequestration are from Cannell (2003).

Was this article helpful?

0 0

Post a comment