The Role of Sustainable Land Management for Climate ... - CAADP

!
A first major impact in Africa would be on the rate of land conversion to cultivation, which as
noted above, is still high. In fact, according to Figure 3.3, land use change and deforestation
accounts for the overwhelming amount of greenhouse gas emissions in Africa, about 64%, which
is a much greater share of GHG emissions than elsewhere in the world. As will be discussed
below, many of the SLM practices which are useful for climate change adaptation and mitigation
are also productivity enhancing, and as such would depress the push factors which have long
induced rapid land conversion in Africa, as has been the experience in Asia.
In addition to their effects on land use change, SLM practices can also have important
mitigation effects in situ, on the agricultural lands themselves. The UNFCCC (2008) estimates
that for Africa, 924 mega tons of additional CO 2 could be stored with the adoption of improved
agricultural practices. Much of this (89%) is predicted to come from soil carbon, because
although the amount of additional carbon that can be sequestered in soils is less than the potential
above ground (e.g. through trees),for a given size of land, the total volume of soil is high. The
types of practices that can build soil carbon almost always represent win-win outcomes because
improved soil carbon has been proven to contribute positively to plant growth and agricultural
productivity (Swift and Shepherd 2007).
Table 3.3 provided a list of many types of land and water management practices that can
contribute to soil carbon build up (last column). Table 3.4 enriches that by providing estimates
of the amount of soil carbon sequestration that could be achieved through effective application of
alternative land management practices (Smith and Martino 2007). First, it should be noted that
the potential for increased carbon sequestration is higher in humid areas than in dry areas, for
most SLM practices. For example, many SLM practices that are being practiced by some
farmers in Africa, such as improved agronomy, minimum tillage, nutrient management, and
agroforestry can each store between 0.26 and 0.33 tons per hectare of additional CO 2 equivalent
per year, per hectare in the drier areas and between 0.55 and 0.80 in more humid areas. Second,
more significant restoration activities are likely to be much more effective in soil carbon
sequestration than practices that support intensive agriculture. Hence, table 3.4 shows much
higher per hectare carbon storage from set asides (i.e. exclosures), and restoration of organic
soils (e.g. peats) and degraded lands. The same can hold true for rehabilitation of degraded
rangeland where set aside practices and revegetation efforts could significantly increase carbon
storage. The table also indicates that farmers are likely to be able to enhance soil carbon
!
%'!