Peatlands and Tar Sands

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.


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