OPINION: IPCC REPORT.

"Land Use, Land-use Change, and Forestry," the recently released special report from the Intergovernmental Panel on Climate Change, will inform the debates over the Kyoto Protocol but will not resolve the political questions raised by the agreement.

The special report is an important milestone in the implementation of the United Nations Framework Convention on Climate Change signed at the 1992 Rio Conference. U.N. negotiators requested the report shortly after the adoption of the Kyoto Protocol in late 1997.

In Kyoto 39 nations agreed to achieve greenhouse gas emission reduction targets by 2012. The calculations for those reductions will include carbon stock changes in forests because of afforestation, reforestation, and deforestation and, the negotiators agreed, also could include other carbon changes in agricultural soils and forest management if suitable methods of calculation, monitoring, and verification could be established. Given this challenge, U.N. negotiators asked the IPCC to prepare a report outlining the scientific and technical challenges if Kyoto were implemented.

What emerges in this 370-page document is that the "devil is in the details." The scientific community has fairly well agreed on how the global carbon cycle works and how the way people use land affects it. Scientists have documented how millions of tons of carbon dioxide have been added to the atmosphere by deforestation, for example, and by the conversion of grassland soils to cultivated agriculture. It is equally true that land-use changes, such as reforesting marginal cropland or restoring grasslands, can produce a net shift of carbon from the atmosphere to the land. Scientific methods exist to estimate the extent of changes and to monitor them in a manner that can be tested and certified by external auditors.

The challenge to U.N. negotiators is establishing a consistent set of definitions and accounting procedures so reports from various governments reasonably reflect exchanges of carbon between the atmosphere and the land as a result of changes in land use and forestry. That sounds easy, but it isn't.

The IPCC study found many different definitions of "forest." Some were based on tree canopy cover or density; others were administrative. None were well suited to administration of the Kyoto Protocol. For example, it would be possible--when forest is defined as land with 10 percent tree canopy cover--to degrade a forest from 100 percent to 10 percent tree canopy cover without triggering any emissions calculation based on deforestation. In the reverse situation a good manager could take a degraded forest and restore it without getting credit for those actions.

The time required is one of the major complications in any calculation of carbon exchanges. The Kyoto Protocol sets a five-year period for the first measurements, from 2008 to 2012. That is a brief period for many systems, and measuring change across those years may result in accounting that does not accurately reflect the changes' impact on the atmosphere. How periods beyond 2012 will be established has yet to be shown. As the report notes, if the periods are contiguous, accurate accounting will be much easier.

The report is designed to help negotiators understand the implications of different definitions and accounting systems rather than point toward the "correct" method. Therefore, the report will not reduce the political controversies over Kyoto's implementation. People will continue to disagree about "what is best" or "what is fair" for different countries and situations. Science can inform those questions, but it cannot answer them.

Editor's note: Consultant Neil Sampson is a former executive vice president of AMERICAN FORESTS and a coordinating lead author on the IPCC special report.