Sea Level Rise Models

Increasing rates of sea level rise caused by global warming are expected to lead to permanent inundation, episodic flooding, beach erosion and saline intrusion in low-lying coastal areas. Sea level rise is a significant and growing threat to the coastal region of New Jersey, USA and this study presents a comprehensive assessment of the expected impacts. We project future sea level rise based on historical measurements and global scenarios, and apply them to digital elevation models to illustrate the extent to which the New Jersey coast is vulnerable. We estimate that 1 to 3 % of New Jersey’s land area will be affected by inundation and 6.5 to over 9 % by episodic coastal flooding over the next century. We also characterize potential impacts on the socioeconomic and natural systems of the New Jersey coast focusing on Cape May Point for illustrative purposes. We then suggest a range of potential adaptation and mitigation opportunities for managing coastal areas in response to sea level rise. Our findings suggest that where possible a gradual withdrawal of development from some areas of the New Jersey coast may be the optimum management strategy for protecting natural ecosystems.

During June of 2014, the town of Bowdoinham, Maine approved a new Comprehensive Plan for the coming years. As part of this plan, they included a section on adapting to sea-level rise and more severe rainstorms caused by climate change. By looking at past sea-level rise in the region and IPCC reports, the town developed projections for how much sea-level would rise nearby. Bowdoinham estimates sea-level in the area will rise at least one foot by 2050 and two feet by 2100, although they mention these estimates may be conservative. The report details the quantities of roads, railroads, buildings, and land that would be inundated by such sea-level rise. They also predict how much inundation would occur during a 100-year storm if various rises in sea-level were to occur. Additionally, they note that extreme precipitation events in the future may be 20% more severe than current local storm drains have been built to effectively deal with. Finally, they propose a number of recommendations including community education, participation in the FEMA National Flood Insurance CRS Program, and increasing resiliency of crucial transportation infrastructure.

Section 1. (Effective from passage) Not later than February 15, 2014, the Department of Energy and Environmental Protection and The University of Connecticut shall, in accordance with section 11-4a of the general statutes, report to the joint standing committee of the General Assembly having cognizance of matters relating to the environment on the joint efforts of said department and university to establish a Connecticut Center for Coasts. Such report shall include, but not be limited to, the following:

1. A detailed description of the mission for such a center that shall include, at a minimum, conducting research, outreach and education projects to guide the development of technologies and regulatory provisions that increase the protection of ecosystems, coastal properties and other lands and attributes of the state that are subject to the effects of rising sea levels,
2. the proposed governance of such center, including appointment of a center director, establishment of an advisory board and the requisite staffing level for such center,
3. a plan for the center's performance of:

• (A) Mapping exercises to assess and visualize key characteristics of shoreline resiliency, such as shoreline changes,
• (B) pilot-scale engineering and impact assessment studies,
• (C) consensus building efforts to determine state-wide uniform guidelines for planning and development purposes, including the expected rate of sea level rise for the next one hundred years,
• (D) ways to develop state-wide, science-based planning and management alternatives,
• (E) development in science and information-based outreach and technology transfer programs for state and local agencies and officials involved in planning and development,
• (F) an assessment of soft shore protection strategies in Long Island Sound and the development of instructional guides for the use of such soft shore protection strategies,
• (G) a comprehensive coastal infrastructure inventory and risk assessment,
• (H) an analysis of the impact of seawalls in urban and rural communities,
• (I) the development of uniform, state-wide models that predict inundation flood scenarios under slow, constant sea level rise and under storm surges,
• (J) projects that lead to the development of rapid storm damage assessment technology,
• (K) developing design guidelines for the construction and repair of seawalls, and
• (L) developing tools for determining appropriate shore protection strategies and providing coastal protection information to a diverse range of end users,

  4. a listing of the existing university and department resources that will be utilized in the performance of the center's responsibilities and a description of the specific ways in which each resource will be used to perform such responsibilities, and (5) the sources and amounts of funding that the department and university, either jointly or individually, intend to secure or secured for the purpose of establishing such center.

Research shows how the climate of New Hampshire and the Seacoast region has changed over the past century, and predicts that the future climate of the region will be affected by human activities that are warming the planet. The most current climate report for New Hampshire (Wake et al, 2011) describes historic trends over the past century and likely changes in New Hampshire’s climate over the next century and is designed to help residents and communities plan and prepare for changing climate conditions.1

Overall, New England has been getting warmer and wetter over the last century, and the rate of change has increased over the last four decades according to detailed analysis of data collected at four meteorological stations (Durham and Concord NH; Lawrence, MA; and Portland, ME).

• Since 1970, mean annual temperatures have warmed, with the greatest warming occurring in winter.
• Average minimum and maximum temperatures have also increased over the same time period, with minimum temperatures warming faster than mean temperatures.
• Both the coldest winter nights and the warmest summer nights are getting measurably warmer.

The Coastal Resilience Initiative (CRI) is the City of Portsmouth’s first look at the potential impact from a changing climate. Coastal communities like Portsmouth are most vulnerable to impacts of sea level rise and coastal storm surge.

The objectives of the Coastal Resilience Initiative were to:

• Describe the range of climate change and sea level rise scenarios that researchers have identified for the New Hampshire Seacoast region;
• Map four sea level elevations to show how these scenarios would impact the City of Portsmouth in the next 40 to 90 years;
• Using these maps, identify physical assets (buildings and infrastructure) and natural resources that are vulnerable to sea level rise and coastal storm surge;
• Develop preliminary strategies for adapting to future conditions, and estimates of the costs of these adaptation actions;
• Provide recommendations to guide adaptation planning, including policies and regulations.

The study products include a set of flood elevation maps, a vulnerability assessment, a preliminary outline of potential adaptation strategies, and recommendations for future planning, regulation and policies. This report represents a starting point for the City to identify avenues to implement adaptation measures that impart resiliency in the built environmental and protect natural systems.

Study Purpose and Limitations

The purpose of this report is to provide a broad overview of spatial and temporal risk and vulnerability of public and private assets as a result of projected changes in climate. This report should be used for preliminary and general planning purposes only, not for parcel-level or site- specific analyses.

The best available predictive information about future climatic conditions specific to sea level rise were utilized in the preparation of this report which with LiDAR (Light Detection and Ranging) data collected by aircraft in 2011 serves as the primary source information for this project. That said, the vulnerability assessment performed for the project was limited by several factors including the vertical accuracy of elevation data (derived from LiDAR) and the static analysis applied to map coastal areas subject to future flooding which does not consider wave action and other coastal dynamics. Also, the estimated damages to buildings and infrastructure listed in Table 4 of the report are based upon the elevations of the land surrounding them, not the structure itself.

The modeled information in this report is based on the best understanding of the current and predicted future climate for this region. As model results and climate based projections are improved this report and reports of this type will need to be updated to reflect that new information, which could change the predicted amount of sea level rise and future climate impacts.

Most scientists now agree that climate change, i.e., global warming, is occurring at a rate much faster than the normal climatic cycles, due to anthropogenic causes of greenhouse gases. Because global warming is changing the ocean currents and wind patterns, climate is changing world-wide. Some of these changes are beneficial, such as a longer growing season for farmers; however, most are harmful. The negative impacts include more frequent and severe weather extremes, such as more intense storms and droughts, more variability in weather, and sea level is rising, putting coastal communities at greater risk. Such climate changes are expected to increase in the foreseeable future; and Land Use Planners need to be prepared for the impacts on their communities. While there are many ways to help mitigate climate change, mainly through reduction in greenhouse gas production, our study is concerned with adaptation to the adverse impacts of climate change.

This project is intended to provide an understanding of climate change impacts on land uses, and the tools that can be used to assess these impacts and adapt to them. While Land Use Planners deal with municipal land use issues, they receive engineering input from municipal engineers and outside consultants. Thus, the more technical tools in this project are intended for use by engineers and scientists assisting Land Use Planners.

This document is a simplified summary of the main report, which contains an explanation of the tools methodology, as well as additional details on the topics in each chapter.

The Technical Paper addresses the issue of freshwater. Sealevel rise is dealt with only insofar as it can lead to impacts on freshwater in coastal areas and beyond. Climate, freshwater, biophysical and socio-economic systems are interconnected in complex ways. Hence, a change in any one of these can induce a change in any other. Freshwater-related issues are critical in determining key regional and sectoral vulnerabilities. Therefore, the relationship between climate change and freshwater resources is of primary concern to human society and also has implications for all living species.