Agriculture Reference
In-Depth Information
CARBON SEQUESTRATION
One of the most frustrating aspects of the global climate change debate is the
seeming paucity of ways to deal with the problem, and the discussions seem to be
very polarized. Can anything be done to ameliorate the increase in carbon being
released to the atmosphere? Actually, one promising area involves sequestration.
We can approach sequestration from two perspectives. First, it is an ongoing
process on Earth. The arrows in Figure 7.1 show that carbon compounds, espe-
cially CO
2
and CH
4
, find their way to the ocean, forests, and other carbon sinks.
Like many geobiochemical processes, sequestration can be influenced by human
activity. Thus, there is a conservation aspect to protecting these mechanisms that
are working to our benefit.
The second approach is one that is most familiar to the engineer; that is,
we can apply scientific principles to enhance sequestration. The sequestration
technologies include new ways either to sequester carbon or to enhance or
expedite processes that already exist.
Conservation is an example of a more “passive” approach. There are currently
enormous releases of carbon that, if eliminated, would greatly reduce loading to
the troposphere. For example, anything we can do to protect the loss of forest,
woodlands, wetlands, and other ecosystems is a way of preventing future problems.
In fact, a high percentage of the terrestrial fluxes and sinks of carbon involves the
soil. Keeping the soil in place must be part of the overall global strategy to reduce
greenhouse gases (see the discussion box “Soil: Beyond Sustainable Sites”).
Soil: Beyond Sustainable Sites
Good design requires an understanding of soil. Design professionals are often
principally concerned with soil mechanics, particularly such aspects as gel
strength and stability, so that it serves as a sufficient underpinning for structural
foundations and footing. They are also concerned about drainage, compaction,
shrink-swell characteristics, and other features that may affect building site
selection. More recently, green building programs have included soils as part
of the overall strategy. This is a valuable first step, but the value of soils goes
beyond the sustainability of an individual building site.
SOIL's VALUE
Soil is classified into various types. For many decades, soil scientists have
struggled with uniformity in the classification and taxonomy of soil. Much
of the rich history and foundation of soil scientists has been associated with
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