AGU (American Geographical Union) has issued a report to demonstrate how warming temperatures and melting sea ice increase fog in the Arctic, creating a costly obstacle for Trans-Arctic shipping.
As the Arctic warms and loses sea ice, trans-Arctic shipping has increased, reducing travel time and costs for international trade. However, the new study finds that the Arctic Ocean is getting foggier as ice disappears, reducing visibility and causing costly delays as ships slow to avoid hitting dangerous sea ice.
How it works
As the ice recedes, cold air is exposed to more warm water, and warm vapor condenses into fog in those new passages. Hidden chunks of ice already pose risks to vessels making their way through foggy, low-visibility routes.
Arctic sea ice has been shrinking for decades. That loss has opened shipping channels in the Northwest Passage and the Northern Sea Route, allowing even non-icebreaker vessels to skip the time-consuming Panama and Suez Canals farther south.
Key Points
- About 20%–30% of Arctic shipping routes experience frequent sea fog frequency more than 20%
- Sea fog increases the shipping time by 23%–27% along the Northwest Passage and 4%–11% along the Northern Sea Route than previous estimations
- Shipping routes by minimizing the impacts of sea fog can save 0.3–1 days sailing time by detouring dense-sea-fog region
Arctic sea fog change
To examine how climate change has impacted fog conditions along Arctic shipping routes, and to see how conditions will change during the 21st century, researchers used data on Arctic fog collected from 1979 to 2018 and climate projections from the Fifth Phase of the Coupled Model Intercomparison Project. The researchers also modeled alternate routes that could minimize foggy days during transit.
Findings
- Ships crossing the Northwest Passage are more likely to encounter fog than ships in the Northern Sea Route.
- Fog in the Northwest Passage, which avoids the Panama Canal, is more frequent and persistent and so likely to increase sailing time by up to three days.
- Sailing time for the less-foggy Northern Sea Route, avoiding the Suez Canal, is projected to be no more than one day longer.
- Both proposed passages would encounter less fog if the routes shifted farther away from the sea ice edge.
Impact
Fog is already cutting into time gained by taking the much shorter Arctic routes; shipping speeds on foggy days are slower than on clear days, Chen found. As the Arctic gets foggier, shipping could continue to slow unless routes are adjusted. With daily operating costs for large container ships typically reaching $50,000 to $150,000, a multi-day delay due to fog quickly increases the costs of a trans-Arctic crossing.
The future
The result of the study highlights the importance of Arctic sea fog when designing the trans-Arctic shipping routes in the future when Arctic sea ice continues its decline but still covers the Northern Sea Route (NSR) and the Northwest Passage (NWP) to some extent.
The future of shipping in the Arctic is unclear, but fog could pose a significant challenge. When designing shipping routes across the Arctic, we need to consider the impact of fog.
…said Xianyao Chen, a physical oceanographer at the Ocean University of China and author of the study.
Avoiding ice is critical. This study did a good job at identifying the risks of fog — an important environmental constraint in the Arctic, and one that has largely been ignored.
… said Scott Stephenson, a physical scientist at the RAND Corporation.
