There
is an increasingly noisy debate about the mining of the Alberta tar sands. The
discussion about the Keystone pipeline to transport the oil to the Gulf for
processing prior to export should pale beside the real issue – that of the
environmental damage in Alberta.
This
potential mining covers an area larger than the state of Rhode Island, but it
is remote from most of us so why should we care? Well, the claim is that the
landscape will be returned to a better state than it is now. So do we know what
a better state means?
A
new analysis by Rooney et al in the recent Proceedings of the National Academy
of Science throws new light on the issues. The area is covered by extensive
wetlands which have extensive peat coverage built up over a very long time.
Peatland restoration is a difficult problem as the plants are sensitive to the
salts in the water and the land has to be level.
The
land will have extensive spoil hills and good drainage – not what’s required
for peat development. The endpit lakes that are required to help clean up the
water won’t help either.
The
authors of the new study point out a critical feature though. The mining
procedure is already one that is carbon usage intensive, but the carbon problem
that has not been evaluated is the liberation of the sequestered carbon in the
peat. Now the plan is to strip the existing peat and mix it back in the soil as
part of the landscape restoration, but this process has recently been shown to
accelerate the decomposition of the peat. Roughly this is about
10M t/C stored that will be liberated.
The
annual loss of carbon sequestration potential is about 7kt/C per year. After
the mining is finished, there will be about a third of the potential peatlands
trying to recover.
With
more concessions, the figures will increase. As the study points out, it is
time for a rigorous cost/benefit analysis taking into account all the factors
so that we can all see and understand the complete set of issues.
