4.3.2. How Broadly or Narrowly are "Activities" Defined?

In this context, the term "broad" is used to denote an activity definition that is essentially land- or area-based, where the net effect of all practices that might be applied to the same area over the same time period are included within the activity. For example, the broad activity of "cropland management" might embrace practices such as conservation tillage, improved fertilization, and irrigation water management. If broad definitions are applied, periodic stock change measurements that statistically sample the area to be monitored could be used to estimate the net effect of altered carbon emission or sink processes. Where statistical sampling methods are used, monitoring larger areas becomes more cost-effective because the number of samples required for a given degree of statistical accuracy does not scale up proportionately with increased area.
The term "narrow" denotes an activity definition that is based on individual practices, such as reduced tillage or irrigation water management. Where individual practices are used as the basis for reporting, associated rates of reduced emissions or increased sinks need to be developed through model estimates or research plots-which in many instances are not yet available for all environmental circumstances. Estimates of annual rates of carbon stock change could then be estimated as a product of the area affected by the practice and the associated rate of emission or sink (perhaps by general soil type, if needed for accuracy). Such estimates could be verified by using other data sources or by a sampling technique that measured soil carbon stock change on the area where the practice had been reported. Non-CO2 GHG emission estimates could be included where appropriate (on agricultural soils, these emissions may already be reported under the IPCC Guidelines, so care may need to be taken to avoid double-counting).

Some implications regarding definition of activities follow:

A)  Broad
• Activity definitions can be fairly loose.
• Lends itself to land-based stock change CO2 flux measurements; helps minimize double-counting or undercounting.
• Non-CO2 GHG fluxes must be estimated with practice-based models or other methods.
• Verifiable by a third party, using different methods and at a later date, using techniques such as statistical sampling or remote sensing.

B)  Narrow
• Activity definitions critical; must be unambiguous, implementable, and verifiable.
• Lends itself to activity-based model estimates of fluxes. Where multiple activities occur on the same land area, there is a potential for double-counting.
• CO2 and non-CO2 emissions can be estimated with activity-based models. Where more than one activity occurs on a land area, some of which are not included in Article 3.4 accounting, stock change measures would be more difficult.
• Verifiable by auditing activity statistics and independently checking them using other data sources. Verifying where activities have occurred in prior years may be difficult or impossible if no visible evidence remains.

Both options would require further decisions about the modalities, rules, and guidelines necessary for implementation. Some options are discussed in Section 4.6 and in Chapter 2.

The process of selecting activities would be facilitated and made more transparent and consistent by the development of criteria for activity selection (Section 4.7).

One approach to structuring activities broadly is suggested by Figure 4-6, which indicates how broadly defined activities might be fitted into a land-cover classification system. If such a scheme were used, every activity, no matter how it were defined, would fit in one of the boxes in the matrix. A national inventory based on a sampling scheme that produced statistically reliable estimates for each land cover/land use box in the matrix could produce national estimates of carbon stock change across all land uses and land cover areas. Therefore, if Parties differed somewhat over the definition of an activity, the practices carried out within the activity, or a definition of land cover such as forest, the impact on total accounting would be minimal because the impact would simply shift from one box in the matrix to another. If such an approach were adopted, a full-carbon accounting system (Chapter 2) would be required, wherein each major land area and land use were sampled on a periodic basis. Such a system is in place in some countries (national forest inventories are one example) but may currently be infeasible for some.

Figure 4-6: Suggested land-cover, land-cover/use change, and forestry matrix that illustrates how activities might be identified with different land cover areas. Numbers in parentheses indicate relevant Article in Kyoto Protocol, where apparent.

The activities reviewed in Section 4.4 are categorized in a way that is consistent with this broadly defined approach-not to prejudge the decisions to be taken by the Conference of Parties (COP) but to keep the presentation to a reasonable length. For more specific information on a few of the practices that might be considered as additional activities under the narrow-definition approach, see the Fact Sheets at the end of the chapter.

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