Climate Change
The agriculture, forestry and the land use sector acts both as a source of greenhouse gas emissions as well as a carbon store, contributing about 20% of total greenhouse gas emissions, but removing about 16%.
The main gases emitted by the agriculture sector are nitrous oxide and methane, with only a small amount of CO2 from energy use, with most of the methane emissions due to enteric fermentation from livestock.
Forestry makes a net contribution to reducing atmospheric CO2 by carbon uptake in growing biomass, and through forest vegetation and soils. Various options for reducing the emissions of greenhouse gases from these sectors have been proposed, including alternative ‘carbon-neutral’ energy crops, increased C sequestration through different ground covers and land management, reducing methane emissions from livestock, more efficient use of organic and inorganic fertilisers, and increased afforestation.
Most previous studies have tended to focus on aspects of greenhouse gas mitigation in isolation, and have not considered to any great extent how they interacted with other aspects.
For example, options have been identified as having potential to reduce methane emissions to the atmosphere, but it is not clear if this in turn would increase nitrous oxide emissions due to a higher soil redox potential and, therefore, have little impact on overall Global Warming Potential.
Moreover, several of these options involve a cost to the land manager, thus creating a ‘social dilemma’, in which individual interests of making a livelihood conflict with societal goals of reducing greenhouse gas emissions. Farmers, for example, may have to accept lower crop yields by reducing the amount of fertiliser they apply, or reducing the number of livestock they carry, so that emissions of nitrous oxide are minimised.
If the societal goals are to be achieved, ways of reconciling these social dilemmas need to be found.
Understanding social dilemmas has been the focus of much research using agent-based models. These models generally treat the biophysical environment as a relatively static entity, and do not often simulate processes within it, such as soil water and nutrient dynamics.
Similarly, models of these latter processes do not include any social processes. Thus, there is now an urgent need to bring this all together and work towards combining social, economic and biophysical processes at the landscape level into an integrated ‘socio-ecosystem’ model. Such a model can then be used to evaluate strategies that land managers might adopt to help reduce greenhouse gas emissions without compromising their own livelihoods, as well as investigating other adaptation strategies in the wider sense.
More on changing landscapes and climate change
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Updated: 10 Jan 2012, Content by: RM
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