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A high proportion of natural ecosystems has already been converted to human-domi-
nated use, such as cropland. There is a range of estimates of the amount of land un-
der agricultural use. The Millennium Ecosystem Assessment found that 24% of the
Earth’s land surface was under ‘cultivated systems’ (Millennium Ecosystem Assess-
ment 2005), but Foley
et al.
(2005) report that 40% of the land surface was under
cropland and pasture, an area similar to that covered by forest. The following section
considers the potential for managing carbon in temperate and tropical agriculture and
in plantation forestry.
CARBON MANAGEMENT
IN HUMAN-DOMINATED
ECOSYSTEMS