Anthropogenic CO emissions /GtC yr
2
+1
CO concentration /ppmv
2
Figure 10 CO
emissions
profiles and concentrations
under the three scenarios
considered: unmitigated
(IS92a: top line), S750
(middle line) and S550
(bottom line). The
emissions are as calculated
using the Bern carbon
cycle model, and are taken
from IPCC
stabilizes CO
concentrations by 2250, whilst the S550 scenario assumes
stabilization occurs by 2150. Achieving stabilization at 750 ppmv and 550 ppmv,
under the pathways assumed here, requires cuts in annual CO
emissions of
around 13% and 30% respectively by 2025, relative to the 2025 emissions
assumed under IS92a. We interpret these stabilization scenarios as representing
actual CO
concentrations for the purposes of crop and vegetation modelling
(e.g. actual CO
concentration reaches 750 ppmv by 2250), because there are no
accepted stabilization scenarios for the other radiatively significant trace gases.
IPCC, Stabilisation of Atmospheric Greenhouse Gases: Physical, Biological and Socio-economic
Implications, Intergovernmental Panel on Climate Change Technical Paper III, Intergovernmental
Panel on Climate Change, 1997.
M. Parry and M. Livermore
132
2
+1
CO concentration /ppmv
2
Figure 10 CO
emissions
profiles and concentrations
under the three scenarios
considered: unmitigated
(IS92a: top line), S750
(middle line) and S550
(bottom line). The
emissions are as calculated
using the Bern carbon
cycle model, and are taken
from IPCC
stabilizes CO
concentrations by 2250, whilst the S550 scenario assumes
stabilization occurs by 2150. Achieving stabilization at 750 ppmv and 550 ppmv,
under the pathways assumed here, requires cuts in annual CO
emissions of
around 13% and 30% respectively by 2025, relative to the 2025 emissions
assumed under IS92a. We interpret these stabilization scenarios as representing
actual CO
concentrations for the purposes of crop and vegetation modelling
(e.g. actual CO
concentration reaches 750 ppmv by 2250), because there are no
accepted stabilization scenarios for the other radiatively significant trace gases.
IPCC, Stabilisation of Atmospheric Greenhouse Gases: Physical, Biological and Socio-economic
Implications, Intergovernmental Panel on Climate Change Technical Paper III, Intergovernmental
Panel on Climate Change, 1997.
M. Parry and M. Livermore
132