Because of their remote locations, the Pacific Islands rely on ocean and air transportation systems for access to other places, which makes transportation and infrastructure highly sensitive to climate variability and change. The ports and harbors, airstrips and runways, and many coastal highways lie in areas that can easily be impacted from climate extremes. The majority of homes, utilities, wastewater treatment, and road networks are also located along the coast [7, 10]. In risk reduction strategies, transportation and infrastructure are critical, community lifelines. 

Climate extremes, such as heavy rains and storms, have historically caused damage to transportation and other infrastructure. Most islands have coastal highways, and there are places, such as the highway in American Samoa, the North Shore of Oahu, or East Maui, that do not have bypasses or alternative routes should flash flooding, mudslides, and landslides occur. Coastal communities may be isolated for days during road repairs. A forty-two day heavy rainfall in Hawaii in 2006 resulted in an overflow of the urban drainage system, resulting in sewage overflow into the Ala Wai Canal and closures of Waikiki Beach, one of the most popular tourist beaches in the world. The rains also caused extensive roadway flooding, numerous landslides and mudslides, and a dam break, resulting in loss of life [11].

Urbanization on the South Shore, Oahu, Hawaii. Source: Cheryl Anderson. The coastal urban infrastructure lies at risk to multiple hazards, including rising sea levels, flooding, coastal inundation, erosion, and storms.

Typhoons and related flooding can negatively impact port facilities and harbors, and cause roads, airports, and bridges to close [2,10]. Long-term infrastructure damage would impact tourism and cause economic hardship, such as been experienced by many islands following disasters. For example, tourism after Hurricane Iniki on Kauai did not recover for a decade [11]. Storms may impact communications infrastructure, which would reduce the ability to coordinate relief assistance externally and response operations locally. Isolation of the islands means that relief assistance from disaster may take days or weeks. Should harbors or runways suffer damage or have blockages resulting from a disaster, relief could take much longer because of the lack of access. In addition to climate-related disasters, seismic or technological disasters can cause severe infrastructure damage making access difficult in the future and making infrastructure more vulnerable to failures during storms, such as the impacts to Kawaihae Harbor in Hawaii County and to bridges in East Maui from the earthquake in October 2006 [11].

Sea level variation from ENSO events and seasonal tides result in periodic roadway flooding on low-lying atolls, but also in coastal areas like the Mapunapuna area near the Honolulu International Airport and coastal roads in Chuuk.  As a result of sea level rise projected from 18-59 cm in global models [5], islands and atolls will suffer from coastal land loss and flooding as a result of sea level rise [6].

Roadway in Majuro, Marshall Islands. Source: Cheryl Anderson. In Majuro, the ocean can be seen on both sides of the island in some places. The coastal roadway may be at risk from rising sea levels and storms.

Actions taken to reduce vulnerability to transportation and infrastructure from hazards and to build sustainability for longer term changes include:

1. Ensure maritime and port security, and airport security and continuity of operations.

2. Ensure maintenance and inspection of critical infrastructure, especially bridges, dams, sewage and drainage systems, airport runways, and port and harbor infrastructure.

3. Use long-term planning strategies for updating community lifeline infrastructure, such as energy utilities, water and wastewater systems, telecommunications, and transportation-related infrastructure.

4. Build redundancy into the communications connectivity program and ensure interoperability among different agencies and levels of government, especially for disaster response operations.

5. Ensure hardening of operations structures and facilities and infrastructure, such as grounding of electric lines where possible or increased wind ratings of utility poles, protection of generators and equipment where these are above ground in case of flood waters, and implement improved building codes for critical facilities.

6. Site baseyards and heavy equipment away from coastlines in protected areas and ensure fuel reserves to enable debris clearance following a disaster.

7. Develop sustainability initiatives to reduce dependency on imported goods, increase use of renewable energy, and support sustainable ground transportation systems.

Many of the protective measures that increase sustainability for islands rely on integrated, coordinated planning and maintenance practices; however, coastal infrastructure may still be at risk because of the inflexibility in moving systems.  Since most islands have limited land areas for buildings, roads were often constructed along shorelines with limited options for moving these roads inland.  Coastal armoring and hardening may increase beach erosion and prevent natural coastal processes that provide protection to islands, although there may be difficulty in moving roadways inland.  Under the rationale that climate change and sea level rise are the result of practices from large industrialized countries, small islands developing states (SIDS) have pursued funding in the UNFCCC conference of parties negotiations on climate change because of the dramatic costs associated with heightening roads, runways, and other critical infrastructure [17, 3].  In the development of adaptation strategies, most islands recognize the need to address protection of their critical infrastructure, transportation systems, and community lifelines for survival, because islands across the Pacific have already witnessed threats from short-term climate events and realize the vulnerability of coastal infrastructure.