How Can We Prepare for Future Sea Level Rise?

Rising sea levels and the potential for stronger storms pose an increasing threat to coastal cities, residential communities, businesses, infrastructure, beaches, wetlands, and ecosystems.

How well can we identify the areas – and the roads, bridges, and other infrastructure – susceptible to sea level rise and storm surge?

Abt Global has led or partnered in efforts to advise municipalities, states, federal agencies, and others on which areas are most likely to be affected by sea level rise. The models also capture and explain the uncertainty of such estimates due to limited data or other factors.

“Increasingly, states and local governments are preparing for climate change – not just to protect their infrastructure and investments, but to meet their most important obligation: Protecting public health and safety,” said Joel Smith, Abt principal associate and expert on climate change.

For example, Abt has worked on coastal inundation estimates for the New Jersey Transport Planning Authority, and the U.S. Environmental Protection Agency (EPA). Abt is providing guidance on how to assess sea level rise impacts for Caltrans, California’s department of transportation. And outside the U.S., Abt is the lead on a project to project the impact of climate change – including sea level rise – on transportation in 26 countries in Latin America and select cities in Asia.

Change is Coming

The steady rise in global sea levels, recorded by tide gauges around the world as well as satellite data, is due primarily to:

• The expansion of the oceans as they warm;
• Water from melting glaciers and land-based ice sheets; and
• Regional land sinking, such as in Nova Scotia, which has experienced roughly 7 inches of sinking in the last century.

Abt is using a number of techniques in unison to illustrate the potential threat of coastal inundation in the next century.

For example, Abt – with project lead Cambridge Systematics – in 2010 provided the North Jersey Transportation Planning Authority with sea level rise and storm surge estimates along the New Jersey coast for 2050 and 2100. The project modeled areas vulnerable to inundation using output from global climate models of sea level rise under several future climates. The project also used storm surge estimates from the highest-observed local tides or category one hurricane projections from the National Oceanic and Atmospheric Administration (NOAA).

The analysis found that, under a medium-level impact scenario in 2100, coastal New Jersey could see more than 48 miles of roadways impacted and 2.9 miles of New Jersey Transit tracks inundated, among other effects.
 

Abt Global is part of a team working on flood modeling for Caltrans, the state’s department of transportation. The work provides flood estimates for a number of scenarios, including sea level rise and storms.

Also, Abt is creating FloodCounts, a mapping web tool. The tool is a map viewer with national inundation for several sea level rise scenarios, intersected with other data to show possible damages to residential and commercial buildings. It is especially useful for describing regional impact, such as counties, and for comparing effects across different regions.

Abt – as a subcontractor for Parsons Brinkerhoff – is conducting a similar analysis of sea level rise for Caltrans. When finished, the agency will be able to utilize existing projections from a detailed sea level rise and wave models to project coastal water levels under a number sea level rise and storm conditions and when those may occur. 
 

The Potential Impact on Wetlands and Beaches

Abt has been a leader in wetland analysis and restoration. Now we’re also examining how these systems may be affected by climate change and sea level rise.

In Ocean County, New Jersey we modeled annual changes to tidal wetlands based on feedback between plants, inundation, and elevation for changes to sea level rise as well as alternative shoreline protection scenarios, such as building sea walls and beach renourishment. The model also explores the response of beaches that are not replenished by human deposition of sand.

In the mid-Atlantic, Abt created summaries of the amount of land by elevation, land use/shore protection, and state/county to estimate the areas potentially vulnerable to future sea level rise. Abt also generated mini-reports for:

• The coastal counties Accomack and Northampton counties in Virginia;
• Maryland and Delaware coastal bays;
• New Jersey’s Atlantic Coast back-barrier bays;
• The south and north shores of Long Island, New York;
• Raritan Bay and the Hackensack Meadowlands in New Jersey; and
• The Hudson River and New York City.

Outside of the U.S., Abt is modeling the impact of climate change in 26 Latin American countries for the Inter-American Development Bank. The project is projecting:

• Change in sea level rise;
• The average annual change in temperature and precipitation;
• Changes in extreme temperatures; and
• The frequency of today’s 20, 30, 50, 100, and 300-year extreme daily precipitation events in the future.

“Abt is committed to serving as a trusted research partner to key decision-makers on climate change,” Smith said. “Much is at stake as we begin to see how the sea level rise and change in coastal storms will affect America’s aging infrastructure.”