Introduction
Photosynthetic carbon fixation comprises a major component of the global carbon cycle. Data on net primary productivity (NPP) may be sparse, but a consistent NPP data set may be used to calibrate, parameterize and evaluate models of terrestrial carbon cycling, as well as for validation of remote sensing data and other applications (identifying trends, investigating biogeochemical processes, etc.). It is also useful to place such data within the context of carbon cycling and carbon storage worldwide. For example:- How much carbon exists in the biosphere, and where exactly is it stored?
- How much is in fossil fuels (coal, oil, gas), and how large are current fossil-fuel emissions?
- How much is in living biomass (plants/ animals/ humans)?
- How much carbon dioxide is there altogether in the atmosphere, or dissolved in the oceans, and how much is locked up in geological reserves such as carbonates?
- Viewable ASCII file versions of Amthor's 1998 data
(worldnpp1.txt) and Lieth's 1975 data
(worldnpp2.txt)
- viewable ASCII file showing world carbon flows, stocks and balances, circa 1990 (Hall and Scurlock, 1993)
(worldnpp3.txt)
Some differences between Lieth's 1975 estimates and the recent review by Amthor et al. are summarised in the following graphs (browsable .JPG images):
Although extreme dry deserts and ice are included here as ecosystems (or land cover types), differences in accounting make it hard to compare forest types between the two sources. Amthor et al. (1998) drop altogether two of Lieth's (1975) forest categories, account for northern peatlands separately from the remainder of the boreal forest zone, and consider urban and other human-modified land area as a new category. However, their larger area for savannas and desert/semidesert makes up most of this difference.
Principal References
Amthor, J.S. and members of the Ecosystems Working Group (1998) Terrestrial Ecosystem Responses to Global Change: a research strategy. ORNL Technical Memorandum 1998/27, Oak Ridge National Laboratory, Oak Ridge, Tennessee. 37 pp.
Hall, D.O. and J.M.O. Scurlock (1993) Biomass production and data. In: Photosynthesis and Production in a Changing Environment: a Field and Laboratory Manual (D.O. Hall et al., eds). Chapman and Hall, London. pp. 425-444.
Lieth, H.F.H. (1975) Primary production of the major vegetation units of the world. In: Primary Productivity of the Biosphere (H. Lieth, and R.H. Whittaker, eds.). Ecological Studies 14. Springer-Verlag, New York and Berlin. pp. 203-215.
Further Reading and Useful Links (see also references cited at the foot of each of the above tables)
Hall, D.O. (1989) Carbon flows in the biosphere: present and future. Journal of the Geological Society of London 146, 175-181.
Scurlock, J.M.O. and D.O. Hall (1991) The carbon cycle. New Scientist 132, No. 1793 (Inside Science supplement No. 51, 2-Nov-1991) pp. S1-S4.
BP Amoco Statistical Review of World Energy, an annual publication of BP Amoco p.l.c., 1 Finsbury Circus, London EC2M 7BA, UK. Also available on-line:
http://www.bp.com/worldenergy/
World Bank World Development Report, an annual publication. Also available on-line:
http://www.worldbank.org/poverty/wdrpoverty/report/index.htm
(Table 10: Energy Use and Emissions, by country, is particularly useful):
http://www.worldbank.org/poverty/wdrpoverty/report/tab10.pdf
World Resources Institute Pilot analysis of global ecosystems (PAGE): Forest ecosystems:
http://pubs.wri.org/pubs_description.cfm?PubID=3055
Forestworld - a private/public sector resource for international information on timber production, wood characteristics, sustainability, etc., including easy-to-read tables of national forestry production statistics derived from U.N. FAO (Food and Agriculture Organisation) data.