Cook Islands Transport Air Pollution Profile 2026

Outline

COOK ISLANDS

TRANSPORT AIR POLLUTION PROFILE

Supported by:

Background

The Cook Islands, a small upper-middle-income Pacific island nation with a population of approximately 14,000 in 2024, maintains relatively favorable air quality conditions compared to regional benchmarks. The annual population-weighted concentration of PM2.5 declined from 4.7 micrograms per cubic meter in 2000 to 4.0 micrograms per cubic meter in 2023, exceeding the World Health Organization's air quality guideline of 5 micrograms per cubic meter. This performance positions the Cook Islands below the Pacific Islands regional average of 5.8 micrograms per cubic meter recorded in 2022. However, the country's transport sector plays an increasingly dominant role in ambient air pollution, contributing a complex emissions profile that reflects its unique geography and development trajectory.

Transport sector emissions exhibit distinct modal patterns shaped by the archipelagic nature of the Cook Islands. By 2022, the transport sector accounted for 67 percent of total PM2.5 emissions nationally, underscoring its disproportionate environmental footprint. The modal distribution reveals domestic navigation as the primary contributor, responsible for 73 percent of transport-related PM 2.5 emissions, followed by road transport at 27 percent and domestic aviation at 1 percent. Rail transport remains absent from the national transport system. This distribution represents a notable shift from 2010, when road transport contributed 45 percent and domestic navigation 53 percent, indicating a growing reliance on maritime connections between the nation's dispersed islands. The evolving composition of road sector emissions further complicates the pollution profile, with non-exhaust sources—including resuspended dust, brake wear, and tire wear—contributing 33 percent of road sector PM 2.5 emissions by 2022, nearly doubling from 17 percent in 2010.

Nitrogen oxide (NOx) emissions from transport have declined more recently, although the sector's contribution remains substantial. NOx emissions grew modestly by 0.7 percent annually between 2000 and 2010 before declining by 1.6 percent per year between 2010 and 2022. By 2022, transport accounted for 36 percent of total national NOx emissions, with road transport responsible for 62 percent of transport NOx, domestic navigation for 34 percent, and domestic aviation for 4 percent. The share of road transport decreased from 70 percent in 2010, while the contribution of domestic navigation increased from 21 percent over the same period. This shift parallels broader changes in transport patterns and fleet composition across the archipelago. Meanwhile, NOx emissions from non-transport sectors grew by 2.5 percent annually since 2010, suggesting that emission reductions in transport have been partially offset by growth in other economic activities.

Sulfur oxide (SOx) emissions from transport present a contrasting trajectory characterized by maritime dominance. After declining by 3.6 percent annually between 2000 and 2010, transport SOx emissions grew by 1.9 percent per year between 2010 and 2022, with the sector contributing 10 percent of total national SOx emissions by 2022. Domestic navigation overwhelmingly dominates transport SOx emissions, accounting for 98 percent, while domestic aviation contributes 2 percent and road transport has essentially eliminated SOx emissions, declining from 1 percent in 2010 to negligible levels by 2022. The concentration of SOx emissions in domestic shipping reflects the continued use of higher-sulfur marine fuels, a challenge common to many Pacific island nations with limited port infrastructure and fuel quality standards. The maritime sector's rising SOx contribution from 94 percent in 2010 to 98 percent in 2022 signals an urgent need for policy interventions targeting fuel quality and vessel standards.

Black carbon (BC) emissions from transport, which have significant climate and health implications, declined by 2.2 percent annually between 2010 and 2022 after growing 0.9 percent annually in the previous decade. By 2022, domestic navigation contributed 59 percent of transport BC emissions, road transport 41 percent, and domestic aviation 1 percent. The modal distribution shifted substantially from 2010, when road transport accounted for 65 percent and domestic navigation 33 percent. This transition reflects both improvements in road vehicle technologies and the growing prominence of inter-island shipping in the national transport system. Methane (CH4) emissions from transport grew by 1.2 percent between 2000 and 2010 before declining by 0.8 percent between 2010 and 2022, with the road sector contributing 91 percent of transport CH4 emissions by 2022. Non-methane volatile organic compound (NMVOC) emissions grew by 1.2 percent between 2000 and 2010 and remained stable thereafter, with road transport responsible for 48 percent of transport NMVOC emissions by 2022.

Energy consumption patterns in the Cook Islands transport sector remain overwhelmingly dependent on petroleum products, with oil accounting for 100 percent of transport energy consumption in 2023, unchanged from 2010 and 2015. This complete reliance on fossil fuels reflects the limited deployment of alternative fuels and technologies, with biofuels and electricity each contributing zero percent to transport energy consumption by 2023. The modal distribution of energy consumption mirrors pollution patterns: the road sector accounted for 61 percent of total transport energy in 2023, domestic navigation 22 percent, and domestic aviation 18 percent. Rail remains absent from the energy profile. The persistence of fossil fuel dependence presents both climate challenges and economic vulnerabilities, particularly given the Cook Islands' exposure to volatile international oil prices and its geographic remoteness from global energy markets.

The nascent electric vehicle transition in the Cook Islands shows modest progress but remains at an early stage. Between 2017 and 2024, the value of electric vehicle imports reached 1 million US dollars, representing 2 percent of total road vehicle imports by 2024. The composition of EV imports favors light-duty vehicles, which constitute 88 percent, followed by two-wheelers at 12 percent, while goods vehicles and buses remain negligible. The United Nations Environment Programme's E-Mobility Readiness Index assigns the Cook Islands a score of 37 out of 100, reflecting significant barriers to electrification. The country scores 8 in technology and market readiness, zero in policy frameworks, 21 in energy infrastructure, and 8 in financial instruments, highlighting the need for comprehensive policy development, grid modernization, and financing mechanisms to accelerate the electric mobility transition. These constraints reflect broader challenges facing small island developing states in deploying new technologies with high upfront costs and limited economies of scale.

Motorization rates in the Cook Islands have increased substantially, reaching 1,036 vehicles per thousand population in 2024 compared to 634 in 2000, far exceeding the Asia-Pacific regional average of 317 vehicles per thousand population in 2024. This high motorization rate, driven by tourism, dispersed settlements, and limited public transport alternatives, amplifies the environmental pressures from road transport despite the country's small population. The growth in vehicle ownership has contributed to rising non-exhaust emissions from tire wear, brake wear, and road dust resuspension, which now constitute a significant portion of road sector particulate emissions. Managing motorization growth while transitioning toward cleaner technologies represents a central challenge for transport sector environmental management in the Cook Islands, requiring integrated policies addressing vehicle standards, fuel quality, land use planning, and alternative mobility options suited to the archipelago's unique geography and development context.