Parties have identified several issues in applying the Guidelines. Some of these issues have been the subject of continuing debate; several remain unresolved and relevant for the Protocol:
Carbon pools. Because the Guidelines allow flexible reporting of carbon pools, Parties do not always report the same set of carbon pools. Some Parties report changes in aboveground biomass and soil carbon only; others include below-ground biomass, soil carbon, and wood products (FCCC, 1997a).
Managed land and forests. All managed land and forests should be included in national inventories. Natural, unmanaged (for wood products) forests are not considered to be subject to anthropogenic activities (IPCC, 1997, Vol. 3, p 5.11) and are therefore excluded from national inventories. Some Parties, however, have reported that the distinction between "managed" and "unmanaged" is problematic (Lim et al., 1997). Ambiguity often arises in the treatment of conservation reserves or where land is managed to enhance the growth of natural forests. As a result, the definition of "managed" land and forest is not consistently applied among Parties-which has implications for the land area that is included in a national inventory. Several options could be applied to ease reporting: Parties could report the definition of "managed" used for the inventory; the existing definitions of "managed" in the Guidelines could be clarified; or a range of categories for "managed" could be developed for the Guidelines.
Forest fires. Only GHGs from anthropogenic fires should be included in the inventory. Separation of natural from anthropogenic forest fires is technically very difficult, however (Chapter 2). Furthermore, the Guidelines do not treat biomass burning in a consistent way. They do not provide accounting methods to estimate CO2 emissions from anthropogenic forest fires and other disturbances, nor for the uptake of CO2 through regrowth following disturbance; the Guidelines assume that emissions and regrowth balance on a national scale when averaged over several years (Lim et al., 1997). Only emissions of trace gases from prescribed burning and forest clearing are included. The foregoing issues have implications for the comparability of national inventories. Chapter 2 notes that even with clear definitions, however, distinguishing between changes of carbon stock resulting from human activity and those caused by natural events may be difficult.
Uncertainty. The uncertainty of estimates in changes in carbon stock is often cited as variable (IPCC, 1997). Much of this imprecision is caused by uncertainty in emission factors and activity data or the use of inappropriate default data and assumptions. Uncertainty also arises from the differing interpretation of the IPCC categories of sinks and sources provided in the Guidelines. These reported uncertainties-especially in the category of changes in forest and other woody biomass stocks-may not be larger than those for CH4 and N2O emissions from other sectors (FCCC, 1997a). Parties can report levels of confidence in their estimates of GHGs with the Guidelines. Although the GPG do not specifically address the LUCF sector, they provide information on the generic treatment of uncertainties for all sectors.
Transparency and verifiability. In the Guidelines, Parties are requested to provide reporting tables, worksheets, and supporting documentation for transparency. The worksheets provide a higher degree of transparency than the summary tables, although they are not sufficient for transparency. The UNFCCC Guidelines on Reporting and Review (FCCC, 1999, 2000) provide more rigorous reporting tables for Annex I Parties and refer to the use of the GPG for verification of national GHG inventories.
Frequency of measurements. Changes in growing stock tend to be very slow in the boreal region and in part of the temperate region (Chapter 2). Because few countries have measurements of annual growth increments, detecting changes in carbon stock over this time interval may be difficult. Chapter 2 presents a range of methods for detecting changes in stock and flux and indicates the strengths and weaknesses of each method. Although remote sensing is promising, one constraint is that there are no systems in place to collect adequate data on forest clearing or regrowth during the first commitment period. Furthermore, in some regions the data from satellite imagery are often taken several years apart and may not coincide with the desired (annual or 5-year) time frame.
Other reports in this collection