Essential Climate Variables GTOS 64

LAND
Land cover

T9 Assessment of the status
of the development of the standards for the
Terrestrial Essential Climate Variables

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FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS (FAO)
Rome, 2009

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ABSTRACT

Land cover change is a pressing environmental issue, acting as both a cause and a consequence of climate change. Reliable observations are crucial to monitor and understand the ongoing processes of deforestation, desertification, urbanization, land degradation, loss of biodiversity, ecosystem functions, water and energy management, and the influence of land cover changes on the physical climate system itself. A number of disciplines (geography, ecology, geology, forestry, land policy and planning, etc.) use and refer to land cover and land cover change as one of the most obvious and detectable indicators of land surface characteristics and associated human induced and natural processes. Current and future IPCC Assessment Reports are based upon an uncertain understanding of the land surface dynamics and related processes. Applications of land cover and land dynamics in climate change-related Earth System Models and Impact Assessment Models need to be better linked and coordinated. The importance of these issues requires continuous monitoring systems and data.

Land cover is defined as the observed (bio)- physical cover on the Earth’s surface. It includes vegetation and man-made features as well as exposed rock, bare soil and inland water surfaces. The primary units for characterizing land cover are categories (such as forest or open water) or continuous variables classifiers (e.g. fraction of tree canopy cover). Secondary outputs of land cover characterization include surface area of land cover types (hectares), land cover change (area and change trajectories), and observation by-products such as field survey data or processed satellite imagery.

With evolving technology, it has become increasingly feasible to derive land cover information from a combination of in situ surveys and earth observation satellite data at global, regional, and national scales. Inconsistencies exist between the different land cover map products or change monitoring systems, thus complicating our ability to successfully synthesize land cover assessments on regional and global scales.