Reference in Article 3.4 to "changes in greenhouse gas emissions.and removals" imply that credit will be based on a comparison between two points in time or two paths through time. There are several ways this comparison might be done, and the Protocol itself prescribes three alternatives in different places. Any one of the alternatives might be adapted (or slightly modified) for activities under Article 3.4. The choice will have significant implications for the amount of credits available and the data required for accounting. The choice could also affect accounting of the interaction of activities undertaken under Article 3.3 and Article 3.4 and the consistency of national and project accounting (see Chapter 5). These three possibilities-all of which may pose problems in implementation-are discussed in the following sections and illustrated in Figure 4-12.
|Figure 4-12: Three possibilities for evaluating change in carbon stocks attributable to Article 3.4 activities. Figure shows total carbon stock (above) and annual change (below) for an activity that causes an increase in carbon stocks and the path that would have been followed without the activity. The activity is arbitrarily assumed to have begun in 1990. The example chosen shows an increase in carbon stocks with respect to business-as-usual, but the principles are equally relevant if the activity resulted in a decrease in carbon stocks with respect to business-as-usual. If the stock in 2008 is taken as the reference (Section 220.127.116.11), the credit for the first commitment period will be as shown by arrow 1. If the change in carbon stocks in 1990 is taken as the reference (Section 18.104.22.168), the credit will be as shown by arrow 2. If the business-as-usual scenario is taken as a baseline (Section 22.214.171.124), the credit will be as shown by arrow 1 minus arrow 3.|
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