The impacts of sea level rise are being felt in varying degrees of severity across the Pacific. On Pacific islands, increased and prolonged inundation is forcing governments to relocate some citizens while on the west coast of the United States, governments are considering how to protect airports, sewage treatment plants and other critical infrastructure. It is crucial to understand how climate change will impact the coast and what can be done to mitigate damage.
There are two major driving forces behind sea level rise: thermal expansion and global ice melt. Thermal expansion is a result of warming ocean waters; as the ocean heats up, it expands. The Greenland and Antarctic ice sheets, which make up most of the ice covering Earth’s surface, are melting, contributing to rising seas. Both driving forces are impacted by temperature - the warmer the earth becomes, the more sea level will rise.
Sea level rise is not the only climate change impact threatening coastal communities. Combined with expected increases in storm intensity and changing precipitation patterns, we expect sea level rise to lead to increases in coastal erosion, coastal inundation, saltwater intrusion, flooding and sedimentation. To learn more about expected changes to the ocean and coast as a result of climate change, visit the COS climate microsite.
Rising Above the Tide: Sea Level Rise Across the Pacific
The exact timing and magnitude of sea level rise for a given location are difficult to determine. We already see differences across the Pacific Basin.
Over the past 100 years, sea level in California has risen at the same rate as the global mean, approximately 2 mm per year. During the past few decades, however, anomalous large-scale wind and ocean circulation patterns have suppressed sea level off California, with no measurable change since 1980. During this same period, the strengthening of trade winds in the Western Pacific has resulted in rates of sea level rise as high as approximately 10 mm per year, contributing to significant variability in the rates of sea level rise across the Pacific Basin. It is not clear if the North Pacific will maintain these uneven rates of sea level rise, or if wind and circulation patterns will change, allowing the excess water in the Western Pacific to “slosh back” to the Eastern Pacific, resulting in a rapid increase in sea level along the California coastline.
What can we do about it?
Planning for climate change is difficult due to the lack of regionally specific data and uncertainty associated with climate projections. While uncertainty will always exist, we know sea level is rising, and we know it will continue to rise as long as the earth’s atmosphere and ocean continue to warm. Scientific bodies and publications such as the International Panel on Climate Change, the Pacific Islands Regional Climate Assessment and the recent National Research Council’s report entitled, Sea-Level Rise for the Coasts of California, Oregon, and Washington: Past, Present, and Future, provide ranges for coastal communities to consider when preparing for a future impacted by climate change.
Today, researchers are developing innovative analyses and models of our ocean that may improve sea level rise predictions. For example, Rob Dunbar, the Director of the Earth Systems Program at Stanford University, is using isotopic and biogeochemical methods for measuring ocean temperatures at the poles, tropics and within the deep ocean interior, providing sound scientific information on how our oceans are warming.
In addition, to help raise awareness and illuminate strategies for planning and adaptation for the U.S. West Coast, the Center for Ocean Solutions will host Progress Towards Preparing for the Future: Climate Change and the Monterey Bay Shoreline. This workshop, slated for October 25, 2012, will discuss impacts of sea level rise in the Monterey Bay region as a result of climate change and address potential ways to coordinate and prepare responses to these shoreline changes. We hope you can join us!
Beyond the West Coast, COS is leading efforts to address coral reef ecosystems which stand to be heavily impacted not only by rising sea levels but also by increased ocean acidification and increased sea surface temperature. A COS-convened working group on coral reefs and climate change produced the Scientific Consensus Statement on Climate Change and Coral Reefs. Tapping into international concern for these rainforests of the sea and broad consensus that these ecosystems are at risk, the consensus statement garnered thousands of signatures from scientists across the globe. Leaders within the Pacific - the Micronesian Chief Executives, the Association of Pacific Island Legislatures and the Pacific Forum - are meeting this challenge by formally resolving to take local action now to increase the resilience of coral reef ecosystems in the face of climate change.
Case Studies: Sea Level Rise in the Pacific
- Community Displacement in Torres Island, Vanuatu: Rising sea level is highly threatening to low-lying island nations and to the delta populations of South and Southeastern Asia and the Nile Delta in Africa. Flooding in these regions will inundate low-lying areas, impacting coastal infrastructure and agriculture while forcing people from their homes. Coastal habitats such as wetlands, deltas, salt marshes, mangroves and beaches will also be impacted and may disappear if their movement inland is blocked by development. As sea levels rise, subsoil seepage of sea water will degrade freshwater resources and cause salt damage to agricultural crops. Further complicating these impacts is the fact that these areas often have limited capacity to address them. In the Torres Islands, Vanuatu, rising sea levels forced villages to relocate several hundred meters inland, creating the world’s first climate change “refugees.”
- Coastal Wetland Destruction in Ecuador: Rising ocean surface temperatures are leading to increased intensity of storms which result in greater damage to coastal habitats. In Ecuador, the risk of inundation is apparent; about 55 percent of coastal wetlands have already been affected by flooding due to increased storm surge as a result of rising sea levels over the past 35 years. Coastal communities are becoming more vulnerable to storm impacts as habitats are lost or damaged since they provide key protective functions such as erosion control and storm surge buffers.
- Preparing for Sea Level Rise in San Francisco Bay, Calif.: Adapting to Rising Tides (ART) Project is a collaborative planning effort to help San Francisco Bay Area communities adapt to rising sea levels. The ART Project has engaged local, regional, state and federal agencies and organizations as well as non-profit and private associations. Together, they are working towards the project goal of increasing the Bay Area’s preparedness and resilience to sea level rise and storm events while protecting critical ecosystem and community services. The project study area is a portion of the Alameda County shoreline from Emeryville to Union City and inland areas potentially exposed to mid- and end-of-century sea-level rise and storm event impacts. Check out ART’s recently released report, Vulnerability and Risk Assessment Report, to learn more about their work.
Research on Sea Level Rise in the Pacific
This month we highlight sea level rise in the Pacific in three articles that discuss the current status of sea level rise, explore threats such as coastal erosion and investigate possible solutions in adaptive management strategies. Click on the title links below to view the abstracts in the library, and while you are there, have a look around!
National Research Council (2012).
The National Research Council released a report that details sea level rise predictions on the west coast of the United States in 2030, 2050 and 2100. The report takes into account regional factors such as climatic patterns like the El Niño Southern Oscillation, effects from the melting ice sheets and geologic processes such as plate tectonics. Click here to watch Gary Griggs, Director of the Institute of Marine Sciences at the University of California Santa Cruz and committee member for the report, discuss key findings.
This article presents a method to assess the contributions of 21st century sea level rise and groundwater extraction to sea water intrusion in coastal aquifers. The developed method is illustrated with simulations of sea water intrusion in the Seaside Area sub-basin near the City of Monterey, Calif. (USA), where predictions of mean sea level rise through the early 21st century range from about 4-35 inches (10-90 cm) due to increasing global mean surface temperature.
This article investigates how sea level rise threatens islands and coastal communities due to vulnerable infrastructure and populations concentrated in low-lying areas. Technology such as LiDAR (Light Detection and Ranging) data was used to produce high-resolution DEMs (Digital Elevation Model) in order to assess the potential impacts of future rise. It concludes that vulnerability mapping and use of technology raises awareness of the potential impacts of sea level rise to the community, economy and habitats of islands and provides a valuable tool for coastal communities and policy makers considering adaptation strategies.
Explore the Library!
Did you know that the Pacific Ocean Library now contains more than 6,700 articles, government publications and reports from the Pacific region that focus on the greatest threats, environmental and socioeconomic impacts, and potential solutions for the region? The library is a great resource for anyone involved in coastal and ocean conservation and management. Each month, we select focal topics of importance to practitioners, managers, academics, decision makers and stakeholders within Pacific Ocean communities and add interesting reports, resources and tools to help provide you with a robust one-stop information source. This month, we added 43 new articles related to sea level rise in the Pacific. To view these articles and browse for other helpful resources on topics of interest, click here. If you have an idea for a focal topic, send it to us at firstname.lastname@example.org.
Text Box Sources:
- http://www.centerforoceansolutions.org/montereybay/about-sea-level-rise-california as of 10/8/12
- http://dels.nas.edu/Report/Level-Rise-Coasts/13389 as of 10/8/12
- http://www.centerforoceansolutions.org/content/support-consensus-statement-climate-change-and-coral-reefs as of 10/8/12
 https://pangea.stanford.edu/people/faculty/robert-dunbar as of 10/8/12