Future Expansion Of Agriculture and Pasture Acts to Amplify Atmospheric CO2 Levels in Response to Fossil-Fuel and Land-Use Change Emissions
- 332 Downloads
The expansion of crop and pastures to the detriment of forests results in an increase in atmospheric CO2. The first obvious cause is the loss of forest biomass and soil carbon during and after conversion. The second, generally ignored cause, is the reduction of the residence time of carbon when, for example, forests or grasslands are converted to cultivated land. This decreases the sink capacity of the global terrestrial biosphere, and thereby may amplify the atmospheric CO2 rise due to fossil and land-use carbon release. For the IPCC A2 future scenario, characterized by high fossil and high land-use emissions, we show that the land-use amplifier effect adds 61 ppm extra CO2 in the atmosphere by 2100 as compared to former treatment of land-use processes in carbon models. Investigating the individual contribution of each of the six land-use transitions (forest ↔ crop, forest ↔ pasture, grassland ↔ crop) to the amplifier effect indicates that the clearing of forest and grasslands to arable lands explains most of the CO2 amplification. The amplification effect is 50% higher than in a previous analysis by the same authors which considered neither the deforestation of pastures nor the ploughing of grasslands. Such an amplification effect is further examined in sensitivity tests where the net primary productivity is considered independent of the atmospheric CO2. We also show that the land-use changes, which have already occurred in the recent past, have a strong inertia at releasing CO2, and will contribute to about 1/3 of the amplification effect by 2100. These results suggest that there is an additional atmospheric benefit of preserving pristine ecosystems with high turnover times.
KeywordsAmplification Effect Terrestrial Biosphere Pristine Ecosystem Strong Inertia Amplifier Effect
Unable to display preview. Download preview PDF.
- Berthelot, M., Friedlingstein, P., Monfray, P., Dufresne, J., LeTreut, H., and Fairhead, L.: 2002, ‘Global response of the terrestrial biosphere to CO2 and climate change using a coupled-carbon cycle model’, Global Biogeochem. Cycles 16(4).Google Scholar
- Bollen, J., Eickhout, B., Vuuren, D., Leemans, R., Kreileman, E., den Elzen, M., Oostenrijk, R., Schaeffer, M., de Vries, B., Hilderink, H., Strengers, B., and Bouwman, L.: 2001, ‘The Image 2.2 implementation of the SRES scenarios: A comprehensive analysis of emissions, climate change and impacts in the 21st century’, CD ROM Publication 481508018, RIVM, Bilthoven, The Netherlands.Google Scholar
- Bopp, L., Legendre, L., and Monfray, P.: 2002, ‘La pompe carbone va-t-elle se gripper?’ La Recherche (July–August), 48–51.Google Scholar
- Bopp, L., Monfray, P., Aumont, O., Dufresne, J.-L., LeTreut, H., Madec, G., Terray, L., and Orr, J.: 2001, ‘Potential impact of climate change on marine export production’, Global Biogeochem. Cycles 15(1), 81–99.Google Scholar
- Cannell, M.: 1999, ‘Relative importance of increasing atmospheric CO2, N deposition and temperature in promoting European forest growth’, in Karjalainen, T., Spiecker, H., and Laroussinie, O. (eds.), Causes and Consequences of Accelerating Tree Growth in Europe.Google Scholar
- Cramer, W., Bondeau, A., Woodward, F., Prentice, I., Betts, R., Brovkin, V., Cox, P., Fischer, V., Foley, J., Friend, A., Kucharik, C., Thomas, M., Ramankutty, N., Stich, S., Smith, B., White, A., and Young-Molling, C.: 2001, ‘Global response of terrestrial ecosystem structure and function to CO2 and climate change: Results from six dynamic global vegetation models’, Global Change Biol. 7, 357–373.Google Scholar
- Friedlingstein, P.: 1995, ‘Modelisation du cycle du carbone biospherique et etude du couplage biosphere-atmosphere’, Ph.D. Thesis, Institut d’aeronomie spatiale de Belgique, Brussel; Aeronomica Acta A 392–1995.Google Scholar
- Friedlingstein, P., Fung, I., Holland, E., John, J., Brasseur, G., Erickson, D., and Schimel, D.: 1995, ‘On the contribution of CO2 fertilization to the missing biospheric sink’, Global Biogeochem. Cycles 9(4), 541–556.Google Scholar
- Gitz, V. and Ciais, P.: 2003, ‘Amplifying effects of land-use change on atmospheric CO2 levels’, Global Biogeochem. Cycles 17(1), 1024.Google Scholar
- Goudriaan, J., Goot, J. R., and Uithol, P. W.: 2001, Terrestrial Global Productivity, Chapt. Productivity of Agro-Ecosystems, Academic Press.Google Scholar
- Guo, L. and Gifford, R.: 2002, ‘Soil carbon stocks and land use change: A meta analysis’, Global Change Biol. 8, 345–360.Google Scholar
- Houghton, R. and Hackler, J.: 2001, ‘Carbon flux to the atmosphere from land-use change’, Technical Report, ORNL/CDIAC, Electronic datas at available at http://cdiac.esd.ornl.gov/ndps/ndp050.html.
- Joos, F., Bruno, M., Fink, R., Siegenthaler, U., Stocker, T. F., Quere, C. L., and Sarmiento, J. L.: 1996, ‘An efficient and accurate representation of complex oceanic and biospheric models of anthropogenic carbon uptake’, Tellus 397–417.Google Scholar
- Prentice, I.: 2001, IPCC Third Scientific Assessment Report of Climate Change, Chapt. The Carbon Cycle and Atmospheric Carbon Dioxide, pp. 183–237; Cambridge University Press, New York.Google Scholar
- Schulze, E.-D., Valentini, R., and Sanz, M.-J.: 2002, ‘The long way from Kyoto to Marrakesh: Implications of the kyoto protocol negotiations for global ecology’, Global Change Biol. 8, 505–518.Google Scholar
- Schulze, E.-D., Mollicone, D., Achard, F., Matteucci, G., Federici, S., Eva, H. D., and Valentini, R.: 2003, ‘Making deforestation pay under the Kyoto Protocol?’, Science 299, 1669.Google Scholar