3.2. Additional Activities³

28. When the inclusion of additional activities under Article 3.4 is considered, it is possible to interpret "activity" broadly (e.g., cropland management) or narrowly (e.g., change in tillage method, fertilization, or cover crops). Under either interpretation, it is, in principle, possible to choose either a land-based or an activity-based method of carbon accounting or a combination of both (see Section 4). These combined choices will affect the accuracy, feasibility, cost, transparency, and verifiability of monitoring and reporting of emissions and removals, including non-CO2 greenhouse gases, and attributing them to specific activities. [2.3.2.2, 4.3.1, 4.3.2]

29. The term "broad activity" means an activity definition that is land- or area-based, where the net effect of all practices applied within the same area are included. A broad activity definition is likely to require land-based accounting (see paragraph 34). This definitional approach would capture the net emission or removal effects of practices that deplete carbon stocks as well as those that increase removals by sinks. Broad activity definitions, particularly in cases where land-use change is involved, may make it difficult to separate human-induced changes from naturally induced changes. [2.3.2, 4.3.2]

30. The narrow definition of "activity" is based on individual practices, such as reduced tillage or irrigation water management. The narrow definition may lend itself to activity-based accounting, but land-based accounting is also possible. Under activity-based accounting, discrete definitions and associated rates of emissions or removals are needed for each individual practice. Narrow definitions raise the potential for multiple activities to occur on a single land area, raising accounting issues (see paragraph 33). Narrow activity definitions may facilitate the separation of human-induced changes from natural influences (see paragraph 45). [4.2.1, 4.3.2, 4.3.4]

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