Land Use and Geo-Engineering - Introduction to Carbon Capture and Sequestration - page 527

Tropical forests are the most important carbon reservoirs and are
active carbon sinks owing to the rapid growth of biomass in the warm
and humid climates. These tropical forests have suffered from deforesta-
tion, causing signifi cant carbon emissions. A loss of 6.5-14.8 million ha per
year (the current rate of deforestation) gives an emission of 0.8-2.2 Gt C
per year. Halting or even reversing the deforestation will continue to be an
important topic of discussion.
Peatlands
Peatland soils contain a large amount of carbon (estimated to be 550 Gt,
scattered over the planet). Peatlands occur in water-rich regions where
standing water prevents the decomposition of organic material. If con-
verted to croplands, the peatlands are drained and the decomposition
process begins, with large amounts of carbon emissions as a result.
Peatlands are not a biome, but because of their specifi c properties, it is
important to discuss them separately. Consider, for example, the use of
palm-oil for biofuels in Malaysia and Indonesia. The total carbon emis-
sions from deforestation and drainage of the peatland to make it suitable
for palm oil plantations is much more than what can be gained by using
the biofuel. In this case, conventional fossil fuels are actually a better
alternative!
Summary
In Table 11.2.1 , a summary is given of the properties of the various
biomes. The message of this section is that if we can stop deforestation,
we reduce global emissions. For example, halting deforestation in the
tropical forests will reduce emissions by at least 10%. Whether we are
able to halt or reverse the deforestation will depend on whether we are
able to grow enough food. In Europe and North America, research on
crop effi ciencies and agricultural techniques has resulted in increased
yields by an order of magnitude. It is encouraging to see that the reversal
of deforestation has already taken place in the temperate forests of these
countries. If similar effi ciency gains can be obtained in the tropical
regions, then reverse geo-engineering could signifi cantly impact carbon
emissions.