Why Cleaning Up an Arctic Oil Spill Would Be Impossible

by Tim Donaghy

January 15, 2015

Oil spills are a terrible, horrible, no good, very big mess, even in in the best of times. But as a new report shows, cleaning up an oil spill in the pristine Arctic Ocean would be next to impossible. Even as Gulf Coast residents and ecosystems are still reeling from the Deepwater Horizon disaster of 2010, Shell Oil has announced plans to begin exploration drilling this coming summer in the Chukchi Sea north of Alaska.

Polar bear jumping on iceflow, Herald Island, Chukchi Sea.

© Greenpeace / Daniel Beltrá

Oil spills are a terrible, horrible, no good, very big mess, even in in the best of times. But as a new report shows, cleaning up an oil spill in the pristine Arctic Ocean would be next to impossible. Even as Gulf Coast residents and ecosystems are still reeling from the Deepwater Horizon disaster of 2010, Shell Oil has announced plans to begin exploration drilling this coming summer in the Chukchi Sea north of Alaska.

A new report entitled Estimating an Oil Spill Response Gap for the U.S. Arctic Ocean shows that current oil spill control technologies will only be effective a certain percentage of the time during the summer months — and will be mostly useless during the winter when pack ice covers the drill site. The report, which was funded by the U.S. government, conducts a sophisticated analysis of wind, ice and ocean conditions and concludes that various oil spill control measures will be ineffective anywhere from 18% to 56% of the time during the summer drilling season.

The only sure way to avoid a spill is not to drill. Although Shell is doing their best to downplay therisk of an accident, the U.S. governments draft Environmental Impact Statement estimates that there is a 75 percent chance of a large oil spill during the lifetime of Shells project. And once spilled, the harsh conditions in the Arctic seas will make traditional oil spill clean up a nightmare worthy of Dante.

Deepwater Horizon Oil Rig Disaster

Fire boat response crews battle the blazing remnants of the off shore oil rig Deepwater Horizon.

Three Ways to Mop Up A Spill

When an accident occurs and hydrocarbons are spilled into an ocean environment there are several strategies for cleanup, although none of them are 100 percent effective and some are arguably worse than the spill itself. The three main strategies considered in the Response Gap report are (1) mechanical recovery, (2) burning, and (3) dispersants.

Mechanical recovery, sometimes known as booming and skimming, involves the use of floating booms to contain the spilled oil, which can then be skimmed off the surface of the water and stored in tankers. This is probably the least environmentally damaging clean-up technique, although in most situations it can only re-capture a fraction of the spilled oil. In the Deepwater Horizon spill, only 3 percent of the oil was successfully skimmed.

Burning the spilled oil is not much more effective because it leaves behind a residue that must also be skimmed and collected. The uncontrolled burning of hydrocarbons also release particulate matter (or soot) and and other hazardous substances into the atmosphere (to say nothing of the greenhouse gases). Whats more, black carbon (a component of soot) is particularly destructive in the arctic environment because it has been shown to amplify the warming process by reducing the reflection of sunlight from snow and ice.

Deepwater Horizon Oil Spill Response

Gathered concentrated oil burns during a controlled oil fire in the Gulf of Mexico two weeks after the BP Deepwater Horizon mobile oil drilling platform exploded, caught fire and sank killing 11 workers.

Even more destructive are the use of chemical dispersants such as Corexit 9500, which was used in the Gulf. Dispersants can break up oil slicks into smaller, water soluble fragments. This can prevent oil slicks from reaching fragile shoreline ecosystems but it comes at a high cost. The use of dispersants actually increases the harm to plant and animal life in the water column. One study found a 52-fold increase in thetoxicity of oil to marine life when mixed with Corexit 9500.

Working in a Harsh Environment

Most past experience with oil spills has been in warm waters. For example the Gulf of Mexico was the site of two of the worst oil spills in history, the 2010 Deepwater Horizon disaster and the 1979 Ixtoc I spill in Mexican waters. However, the environment of the Chukchi Sea is considerably more harsh, and the unique arctic conditions make the traditional clean-up methods described above difficult or impossible to carry out. The Response Gap report looks at historical records on wind speeds, wave heights, temperature, wind chill, visibility and ice coverage and makes estimates for how often spill control technologies could conceivably be used in the Arctic.

For example, Arctic seas often see high winds and large waves, but the report finds that oil controlling booms start to lose their effectiveness in 3 foot waves and stop working entirely when the waves reach six feet high. Cold weather can make it difficult to apply dispersants to oil slicks and the presence of ice reduces their effectiveness, as dispersants rely on ocean waves to mix the oil and chemicals together.

Whats more, all three techniques require the presence of human workers, support ships and aircraft, and if conditions are too extreme then control operations cannot be carried out. Low temperatures and severe wind chill can make it unsafe for response crews to be working outside, high winds can create icing problems leading to equipment malfunction, and aircraft cannot fly when visibility is low. Finally, the presence of hazardous sea ice can put a halt to all response activities, as it did during Shells 2012 drilling season when a Manhattan-sized ice floe forced the rig off the drill site for several days.


Figure 1 from the Response Gap report. Tactics most likely to be feasible (least likely to be precluded) by season, for the Chukchi Sea.

As the report shows, the single most effective control technique is the application of dispersants from a ship, and even then, it will only be effective around 82% of the time. All the other techniques score lower. We can expect that burning the spilled oil will be ineffective around 34% to 56% of the time (depending on whether the oil is ignited from a ship or from aircraft) while open-water mechanical recovery will be ineffective around 43% of the time. The above figure, reproduced from the report, summarizes the most effective techniques.

All of this adds up to a serious response gap — we simply do not have the technology to contain and clean up an oil spill in the Arctic. In a 2014 report, the National Academies also recognized these gaps and made recommendations for further scientific research and expanded environmental monitoring to mitigate the risks of an oil spill in the Arctic.

Iceberg in Greenland Groenland

Floating ice and icebergs off the coast of West-Greenland.

It Gets Even Worse

As bad as that is, when you read the Response Gap report, you realize that the authors have been quite conservative in their estimates. The real response gap is probably even larger. The analysis doesnt capture the need for several consecutive calm days to mount a response, and it doesnt measure the effectiveness of the response, only whether or not it could be initiated.

Finally, the report obviously cant capture any unforeseen events that might occur, and Shells clumsy, error-strewn2012 drilling attempt doesnt inspire confidence in their ability to rise to these challenges. The New York Times recently published a fascinating report on the events leading up to Shells oil rig, the Kulluk, running aground in a winter storm in late 2012. Thankfully no workers were hurt in that accident and the environmental impact was minimal, but the event shows very clearly the risks of operating in this region of the world.

Alaska native communities depend on the ocean for their livelihood, not to mention the whales, walruses, seals, birds and fish who make up one of the few remaining pristine ecosystems on the planet. Crude oil is something that simply cant be put back in the bottle once it has been spilled; the only way to win is not to drill.

Tim Donaghy

By Tim Donaghy

Tim Donaghy is a Senior Research Specialist with Greenpeace USA. He writes frequently about climate change, offshore oil drilling, energy production, and the Arctic.

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