18.104.22.168. What Are the Consequences of Simplified Reporting?
A low-tier approach to determining a rough order of magnitude of ARD credits
and debits could be based on default values and could be implemented without
reference to specific land areas. Such a low-tier approach has been applied
in country studies cited in Section 3.5.3. One option
for implementation follows:
- Determine the total increase of forest area (Anew)
from afforestation and reforestation between 1990 and 2012 per country, biome,
- Determine the total loss of forest area (Aloss)
from deforestation between 2008 and 2012 per country, biome, or region.
- Determine the carbon stock at maturity (natural forests) or the average
carbon stock over a rotation (managed forests), Cequ.
- Determine the time to reach the carbon stock at maturity (natural forests)
or the carbon stock averaged over a rotation (managed forests) for that country,
biome, or region (Tequ).
- Calculate the equilibrium change in carbon stocks from the area change,
as area change times equilibrium stock change (Anew/loss
- Approximate credits from afforestation and reforestation, as Anew
x Cequ x (5/Tequ).
Only a share of the total equilibrium stock change would be attributed to
the 5-year commitment period because afforestation and reforestation are gradual
processes with an assumed duration of Tequ.
- Approximate debits from deforestation, calculated as Aloss
x Cequ. All or most of the equilibrium stock
change would be attributed to the 5-year commitment period because deforestation,
unlike afforestation and reforestation, is a process that results in stock
changes over only a few years. One would miss the delayed emissions from pre-2008
deforestation, but this effect would cancel out post-2012 delayed emissions
from deforestation in the commitment period.
This approach would reduce data needs and costs but would introduce lower accuracy.
Use of conservative default values would be possible. Exact carbon accounting
of ARD activities for future commitment periods is difficult, however, because
ARD lands are not spatially tracked. This approach could be regarded as an activity-based
approach with ARD lands not geographically referenced. Although the method of
deriving ARD stock changes might be verifiable, the stock changes themselves