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Land use and management activities have a substantial impact on carbon stocks and associated greenhouse gas emissions and removals. However, it is challenging to discriminate between anthropogenic and non-anthropogenic sources and sinks from land. To address this problem, the Intergovernmental Panel on Climate Change developed a managed land proxy to determine which lands are contributing anthropogenic greenhouse gas emissions and removals. Governments report all emissions and removals from managed land to the United Nations Framework Convention on Climate Change based on this proxy, and policy interventions to reduce emissions from land use are expected to focus on managed lands. Our objective was to review the use of the managed land proxy, and summarize the criteria that governments have applied to classify land as managed and unmanaged. We found that the large majority of governments are not reporting on their application of the managed land proxy. Among the governments that do provide information, most have assigned all area in specific land uses as managed, while designating all remaining lands as unmanaged. This designation as managed land is intuitive for croplands and settlements, which would not exist without management interventions, but a portion of forest land, grassland, and wetlands may not be managed in a country. Consequently, Brazil, Canada and the United States have taken the concept further and delineated managed and unmanaged forest land, grassland and wetlands, using additional criteria such as functional use of the land and accessibility of the land to anthropogenic activity. The managed land proxy is imperfect because reported emissions from any area can include non-anthropogenic sources, such as natural disturbances. However, the managed land proxy does make reporting of GHG emissions and removals from land use more tractable and comparable by excluding fluxes from areas that are not directly influenced by anthropogenic activity. Moreover, application of the managed land proxy can be improved by incorporating additional criteria that allow for further discrimination between managed and unmanaged land.

The Amazon Basin contains a multitude of ecosystems, biological and ethnic diversity and the largest extent of tropical forest on Earth, over 5 x 106 km2, and accounts for an estimated 1/3 of the planet’s animal and plant species. Currently only a small number of species are used by man. The region is abundant in water resources. Annual rainfall is 2.3 m over the Amazon Basin, and the mean outflow of the Amazon River into the Atlantic is over 200 000 m3 s-1, which corresponds to 18% of the total flow of fresh water into the world’s oceans. The region stores over 100 Gt of carbon in vegetation and soils. However, over the past 30 years, rapid development has led to the deforestation of over 550 000 km2 in Brazil alone. Current rates of annual deforestation are in the range of 15 000 km2 to 20 000 km2 (INPE 2001), and the spatial pattern of deforestation in Brazilian Amazonia up to 1997 is illustrated in Fig. 26.1.