While that report projected vessel activity, it did not explore the environmental impacts of increased shipping in terms of air emissions or the potential climate impacts from increases in short-lived climate pollutants such as black carbon. The new paper provides emissions estimate for the projected traffic growth outlined in that earlier report. The emissions report focuses on the low- and mid-range diversion scenarios—i.e., ships diverting from prior routes to Arctic routes.

• The low-diversion scenario assumes 2% diversion from the Panama and Suez canals between July and November of 2025. This equates to approximately 1% of the total annual traffic through those canals.

• The mid-range estimate assumes that approximately 2% of annual vessel traffic through those canals is diverted through the Bering Strait in 2025, largely through the Northern Sea Route nearest to Russia.

The ICCT team combined these diversion scenarios with regional traffic growth projections to estimate potential criteria-pollutant emissions assuming the use of current fuels compared to the implementation of requirements for the use of low-sulfur fuel of either 0.5% or 0.1%.

Regulatory background. The International Maritime Organization’s (IMO) regulations on pollution from ships are found within the International Convention on the Prevention of Pollution from Ships (MARPOL 73/78).

Most recently MARPOL was amended through the “1997 Protocol,” which added Annex VI, Regulations for the Prevention of Air Pollution from Ships. MARPOL Annex VI sets limits on NO_x and SO_x emissions from ship exhaust, and prohibits deliberate emissions of ozone-depleting substances.

Annex VI defines two sets of emission and fuel quality requirements:

• global requirements; and

• more stringent requirements applicable to ships in Emission Control Areas (ECA). (Earlier post.)

Global requirements include Tier II engine standards (NO_x) and a global limit on marine bunker fuel sulfur content, currently set at 3.5% (35,000 ppm) compared to a global average of 2.7% (27,000 ppm). This limit is scheduled to reduce to 0.5% (5,000 ppm) in 2020, although members of the shipping industry are currently calling for IMO to delay the requirement until at least 2025.

ECAs can be designated for SOX and PM, and/or NOX, subject to a proposal from a Party to Annex VI. Currently, North America and the US Caribbean have established emission control areas for NO_x requiring new-build ships to meet progressively tougher NO_x standards in addition to limits for SOX emissions requiring the use of either 0.1% (1,000 ppm) sulfur fuel or exhaust gas scrubbers. Neither ECA extends west of Kodiak, Alaska, and neither includes the Aleutian Islands or areas north into the Arctic.

Findings and recommendations. The ICCT team found that the low-growth vessel diversion scenario, not including container ships, would cause at least a 150-230% increase above 2011 levels if the current fuel regulations continue in force through 2025. If container vessel diversion is included, low-growth scenario emissions would increase by 200 to 300 percent above 2011 levels, assuming continued use of heavy fuel oil (HFO) and marine diesel oil (MDO). Mid-range emissions were concomitantly higher.

However, they also found that the use of 0.5% sulfur (5,000 ppm) fuel in 2025 for the low-growth scenario would reduce SO_x emissions by 35% and BC by 5% relative to 2011, while keeping PM roughly constant.

They found additional reductions for 0.1% (1,000 ppm) fuel in 2025, which decreased SO_x, PM, and BC emissions by 87%, 35%, and at least 5%, respectively. These decreases would occur despite an additional 120 ocean going vessels traveling through the US Arctic compared with the 2011 baseline.

A number of policies can mitigate shipping emissions growth in the U.S. Arctic between now and 2025. Upholding the implementation date of 0.5% fuel sulfur, rather than delaying to 2025 or later, would provide benefits beginning in 2020 extending through the period of time when increases in vessel traffic are actively occurring. Extending the North American ECAs into Arctic waters would provide additional air-quality and human health benefits associated with 0.1% sulfur fuel and the use of Tier III engines for reduced NOX. Regional benefits would be increased by cooperative bilateral action with Canada, or additionally multilateral action with other Arctic nations to extend the Arctic ECA to larger areas of the Arctic.

Other potential avenues for reducing Arctic emissions from vessels include designations of Marine Protected Areas (MPA) under domestic conservation frameworks, or possibly the designation of particularly sensitive sea areas (PSSA) under the IMO. Both options would provide guidelines for limiting vessel operations within the areas and specifying either speed limits or fuel requirements for operation, both of which could reduce emissions.

—Azzara and Rutherford, ICCT Working Paper 2015-1

Resources

• Alyson Azzara and Dan Rutherford (2015) “Air pollution from marine vessels in the US High Arctic in 2025” ICCT Working Paper 2015-1