Monitoring Length/Time Scales and Techniques
The IPCC has published the following figure illustrating the range of temporal and spatial scales at which ecological processes occur and monitoring techniques appropriate for the length/time scales. Forest inventories involve many of these methods and cover spatial scales from 1 to 109 ha and temporal scales from 1 to 100 years.
- Methods exist for measuring the amount of carbon in all components of terrestrial ecosystems, as well as for measuring changes in this amount. The methods vary in complexity, precision, accuracy, and cost.
- Methods used to measure carbon, or a change in carbon, are different from those used to attribute cause to an observed change in carbon (e.g., direct human activity versus natural causes).
- This distinction is important because the Protocol is concerned with human-induced, rather than total, changes in carbon. Even the most direct measurements on small plots do not distinguish mechanisms or yield attribution.
- Attribution must be inferred from controlled experiments or from ecosystem process models that are based on the mechanism thought to be held responsible for the change (e.g., land-use change versus CO2 fertilization).
The IPCC Guidelines
The IPCC Guidelines consist of three volumes: the Reference Manual, the Workbook, and the Reporting Instructions to be used for reporting under the Kyoto Protocol. The desired principles of these inventory guidelines include completeness, comparability, transparency, and accuracy.
- considers changes in only two carbon pools, such as aboveground biomass and carbon in the top 0.3 m of the soil
- does not provide explicit methods for other pools, including below-ground biomass, harvested wood products, and deep soil carbon
- The soil carbon method accounts for cultivation of soils and land-use change involving soils.
- assumes that stocks of forest products are not increasing significantly
- does not account for the effects of forest fires and other disturbances
The Reference Manual:
- uses similar principles to the Workbook, but adds comparability and transparency through a common, simplified approach
- provides a comprehensive approach to carbon accounting by covering all of the main land-use change and forestry activities
- strives for comprehensive & balanced accounting of carbon pools, sources, and removals of GHGs from anthropogenic activities in relation to LUCF
- helps estimate national changes in aboveground and below-ground biomass, soil, soil surface litter, and harvested wood products for all forests, shrublands, grasslands, and agricultural lands
- does not differentiate between direct human-induced activities and indirect human activities
The Reporting Instructions provide:
- a range of definitions for anthropogenic activities
- a glossary of terms
- tables to report anthropogenic emissions and removals of GHGs
The following image summarizes the carbon accounting approach: