An update on the Alaska pipeline

The 48 inch-diameter trans-Alaska pipeline was completed in June 1977, 27 months after the first length of pipe was laid. This line was built by private contractors working for Alyeska Pipeline Service Company, the agent for the eight major oil companies that own the oil being transported. The total construction cost was over $9.5 billion. The trans-Alaska pipeline transports crude oil from the oil fields on Alaska’s North Slope to the Port of Valdez. It flows with an average 20 million gallons a day.

How does it look 44 years later, after climate changes and global warming? I looked up various sources for information. David Hasemyer, writing for Inside Climate News, describes how the thawing permafrost has damaged the strategic pipeline and how that has become an ongoing threat. He says that the thawing permafrost threatens to undermine the supports that hold up an elevated section of the pipeline and affect its structural integrity. A resulting oil spill would be very difficult to clean up in a delicate and remote landscape.

This section of the pipeline is 80 ft long and is shifting as the permafrost thaws, causing some of the support braces to tilt and bend. This is called slope creep and appears to be the first instance of this damage. The proposed solution is to replace the damaged braces and to construct a cooling system to maintain the permafrost. The Alaska Department of Natural Resources has approved the use of ‘thermosyphons’, tubes that suck the heat out of permafrost to keep the frozen slope in place and prevent further damage.

Carl Weimer, Special Projects Advisor for the Pipeline Safety Trust, a watchdog non-profit agency based in Bellingham, Washington, USA, says that this is a wake-up call and should trigger discussions between regulators and the petroleum industry about the effects climate change is having on pipeline safety in general.

There are about 124,000 existing thermosyphons along the path of the pipeline. They are bored into the permafrost from 15-70 ft, in areas where warming would cause it to thaw.

In June 2020, thawing permafrost was blamed for the collapse of a fuel tank in northern Siberia, which dumped 21,000 tons of diesel fuel that seeped into the Ambarnaya river, when a historic Siberian heatwave caused one of the tank’s support pillars to buckle.

As CNN pointed out, the accident may have partly been caused by the climate crisis. That is because melting permafrost may have caused the storage tank to sink. Northern Asia and Siberia had recorded temperatures, on average, more than 4°C above normal during the first four months of 2020. That is the most above-normal temperature of any region in the world, so far this year. The Arctic is warming twice as fast as the rest of the world.

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