Carbon dioxide sources and sinks simulation
The Kyoto Protocol, the commitment made by more than 170 countries to reduce their carbon dioxide (CO2) emissions, is due to expire in 2012. At present, international talks are underway to formulate a new treaty. For Europe and other developed continents, a key feature of the agreement is that they are allowed to offset, in part, CO2 emissions against carbon accumulated by changes in land use management. For example, planting woodland that would act as a carbon sink. Of course, every model is correct in its own right but the processes involved are so many and complex that each produces its own estimate on large-scale carbon uptake. For example, discussions and arguments continue on the extent of usefulness of carbon sinks. They may be limited due to the counter-effect of increased drought during summertime that may well reduce any benefit conferred by increased periods of photosynthesis in Spring. The European project CAMELS aimed to utilise all data sources including CO2 fluxes and measurements, satellite retrievals of vegetation chlorophyll and forest parameters. These would then be combined with present terrestrial ecosystem models (TEMS) to produce estimates of the European land carbon sink. Project partners at the Meteorological Office in the UK studied the carbon cycle throughout the 20th century. The MOSES (Met Office Surface Exchange Scheme) model was used to simulate sinks and sources of CO2. MOSES predicts land-atmosphere exchanges of CO2 by simulating photosynthetic activity and plant and soil respiration responses to imposed climate changes. Another UK Met office study using historical information input data from two independent source data sets for an even longer period of 300 years. These were utilised to model the effects of land-use induced by human interference over this period. In this model, the history of the grazing land was taken into account. Whether it was derived from forest or natural grassland affects the nature of the soil carbon pool. The models from integrated data sets that form the basis of these results from the Met Office are available as coordinated input for international programmes. In view of the dynamic nature of climate prediction that is itself a work in progress, models giving an accurate reliable picture are of paramount importance.
