Abstract
Humans utilise about 40% of the earth’s net primary production (NPP) but the
products of this NPP are often managed by different sectors, with timber and forest
products managed by the forestry sector and food and fibre products from croplands and
grasslands managed by the agricultural sector. Other significant anthropogenic impacts on the global carbon cycle include human utilization of fossil fuels and impacts on less
intensively managed systems such as peatlands, wetlands and permafrost. A great deal of
knowledge, expertise and data is available within each sector. We describe the contribution
of sectoral carbon budgets to our understanding of the global carbon cycle. Whilst many
sectors exhibit similarities for carbon budgeting, some key differences arise due to
differences in goods and services provided, ecology, management practices used, landmanagement
personnel responsible, policies affecting land management, data types and
availability, and the drivers of change. We review the methods and data sources available
for assessing sectoral carbon budgets, and describe some of key data limitations and
uncertainties for each sector in different regions of the world. We identify the main gaps in
our knowledge/data, show that coverage is better for the developed world for most sectors,
and suggest how sectoral carbon budgets could be improved in the future. Research
priorities include the development of shared protocols through site networks, a move to full
carbon accounting within sectors, and the assessment of full greenhouse gas budgets.