English Abstract The feasibility of the various technical options
available for increasing carbon stocks, in mainly agricultural soils, is
discussed by agro-ecological zone. Our exploratory scenarios, which use
necessarily coarse assumptions about the potential for increased carbon
sequestration in the soil, show that from 14 apporximately 7 Pg C may be
sequestered over the next 25 years - with even higher potentials over a 50
year period - if the world's 'degrated' and 'stable' Agricultural Lands are
restored and/or submitted to appropriate management. When the 'degraded'
and 'stable' Agriculural Lands, Extensive Grasslands and Forest Regrowth
categories are considered, this would be 20 apporximately 10 Pg C. On
average, from 0.58 to 0.80 Pg C yr -1 can be sequestered in the soils, of
the regions under consideration, according to these scenarios; this would
correspond with about 9-12% of the anthropogenic CO2-C produced annually.
The scenarios assume that 'best' management and/of manipulation of a large
portion of the globe's soils is possible; yet their implementation need not
necessarily be feasible due to the economic, environmental and
societal/cultural conditions. Migitation of atmospheric CO2 by increased
carbon sequestration in the soil, particularly makes sense in the scope of
other global challanges such as combatting land degradation, improving soil
quality and productivity, and preserving biodiversity. Effective mitigation
policies will likely be based on a combination of many modest and
economically sound reductions, which confer added-benefits to society. In
identifying these 'best practices', due attention must be paid also to any
possible adverse environmental and socio-economic effects some of these
practices may have.
