Methane

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Fugitive emissions from BC’s natural gas industry

The environmental consequences of the expanded development of unconventional gas in North Eastern British Columbia, as laid out by Tyler Bryant and Matt Horne in The Tyee, include: risks of groundwater contamination from fracking; water use; the provision of electricity; the triggering of earthquakes; and the industrialisation of the landscape over large swaths of the NE of the Province. Apart from the emissions released by end use of the gas,  the largest single environmental impact—certainly the largest global impact—is likely to stem from leaks and deliberate venting of greenhouse gases during the production and transportation of the natural gas. Unfortunately, this is also one of the most poorly quantified risks.

According to British Columbia’s Ministry of Environment, about 108,000 metric tons of methane are being released into the atmosphere every year by the oil and gas industry. These emissions come from deliberate venting and through unintentional leaks—also known as fugitive emissions—from pipelines, wells and processing plants. While this sounds like a lot, according to the Ministry it only amounts to 0.3% of the total amount of natural gas produced in BC in 2011. However, compared to estimated leakage rates in the gas industry of the United States, which range widely from about 1 to 8%, these estimates are very low outliers. Even the lowest of the US estimates is three times as large as the BC figures.

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Fugitive methane emissions in BC: correspondence with Ministry of Environment

An email discussion with environmental journalist Stephen Leahy prompted me to look into the amount of fugitive methane emissions from the natural gas industry in NE British Columbia.  The data on various BC Government websites are not easy to reconcile, so, on March 18th  2013,  I wrote an enquiry on the query form provided at the website of the BC Ministry of Environment.

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Subcap Methane Feedbacks, Part 1: Fossil methane seepage in Alaska

Originally published at Skeptical Science.

As permafrost thaws, methane is released as the vegetable matter in the soils decomposes. This methane bubbles to the surface in lakes and ponds and accumulates under the ice in the wintertime. New research has shown that the most vigorous methane seeps in Alaska are fed also by methane emitted by thermal decomposition of organic matter in deeper and much older sediments. Continuous permafrost acts as a top seal to this fossil methane, preventing it from reaching the surface and, as global warming melts and perforates this cap, we can expect the pent-up gas to be released more quickly. This source of methane, released from traps under the permafrost, is a potential third source of methane feedback in the Arctic, in addition to permafrost soils and methane hydrates. 

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Subcap Methane Feedbacks. Part 2: Quantifying fossil methane seepage in Alaska and the Arctic

Originally posted at Skeptical Science

The previous article in this series looked at the recent discovery of significant releases of fossil methane through the thawing permafrost in Alaska. In this second instalment we will look at the potential of the rest of the Arctic to produce subcap methane, and will compare the size of these seeps to other global methane-producing mechanisms.

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Subcap Methane Feedbacks. Part 3: Methane from beneath the ice

Originally posted at Skeptical Science

The previous two parts (one here and two here) of this series examined the evidence for seeps of geological methane through the cap provided by permafrost and looked at estimates of the magnitude of such seeps in relation to other sources of atmospheric methane. In this section, we will look at the emerging evidence for actual and potential methane releases related to glaciers and ice sheets. The sources of this methane are varied: fossil methane released through reactivated fractures; organic matter once buried and now exhumed; and possible methane hydrates lurking under the big ice sheets.

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Subcap Methane Feedbacks. Part 4: Speculations

Originally posted at Skeptical Science

Previous articles in this series have reviewed recent research on methane sources from beneath permafrost and ice sheets. Part 1 looked at subcap fossil methane seeps in Alaska;Part 2 provided a perspective for the size of these seeps in relation to other natural and human sources; and Part 3 looked at potential methane sources resulting from the withdrawal of glaciers and ice sheet. In this final section, I will try to make estimates of what subcap methane emissions may mean for future climate change; more as a speculative basis for discussion rather than an authoritative prediction. Firstly, though, I will argue for a role for subcap methane emissions on the East Siberian Arctic Shelf (ESAS). 

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