The climate regulation service provided by miombo landscapes
Date
2018
Authors
Wilson, Sally
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Abstract
The African miombo woodlands are perhaps the world’s largest relatively unexploited but
potentially arable land resource, located on a subcontinent where population growth remains high
and demands for food security and development are pressing. This study aims to quantify the
tradeoff between landscape transformation of various types and the climate regulation service
provided by the miombo landscape. Net radiative forcing, expressed in terms of its carbon dioxide
emission equivalent (CO2e) over a one century horizon was calculated for an intact (‘historical’)
miombo landscape and for three hypothetical but observation-constrained derivatives: one
developed through extensive subsistence farming; another by intensive, large-scale commercial
farming; and one developed using ‘eco-agriculture’ improved smallholder techniques. The time
course of net radiative forcing resulting from net carbon dioxide (CO2), methane (CH4) and nitrous
oxide (N2O) emissions, from all significant sources (including production and decomposition
processes, fires, cultivation, enteric emissions, termites, etc.) was assessed, as well as the net
change in surface reflectance (albedo) for the four representative landscapes. It was found that the
loss of climate regulation service was greatest when the entire landscape was converted to
commercial agriculture, with conversion via subsistence extensification, offering the most
protection for the climate regulation service. Conversion to eco-agriculture falls somewhere in
between. If the loss of climate regulation service is expressed per unit agricultural production, the
pattern is reversed, favoring commercial intensification as the choice mode of production. It was
found that contrary to the conventional approach of evaluating the climate regulation service
entirely on the basis of net carbon storage, the changes in other greenhouse gases (notably CH4,
but also to a smaller extent N2O), and surface albedo made substantial contributions to the changes
in the climate regulation service provided by miombo landscapes.
Description
A dissertation submitted to the Faculty of Science, University of the Witwatersrand,
Johannesburg, in fulfillment of the requirements for the degree of Master of Science.
Johannesburg, 2018
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Citation
Wilson, Sally Ann, (2018) The climate regulation service provided by miombo landscapes, University of the Witwatersrand, Johannesburg, https://hdl.handle.net/10539/25867.