Climate change, sea-level rise and the case for salt marsh restoration in the Bay of Fundy, Canada.

Abstract

Over the next century society will be facing significant increases in temperature and sea-level, which pose a growing threat to low-lying coastal communities. To protect these communities, adaptation strategies are needed that will be sustainable not only in the immediate future, but throughout the next century and beyond. Recent events like the tsunami in Southeast Asia and Hurricane Katrina in Louisiana have illustrated how vulnerable and vastly under-prepared many coastal regions are for storm and natural disaster events. This paper uses the Bay of Fundy as a case study to explore the feasibility of using coastal salt marsh restoration as a tool to adapt to sea-level rise and mitigate climate change. In particular, the ability of marshes to self-adapt to changes in sea-level, their function as a buffer of coastal processes, their cost-effectiveness relative to traditional, static, man-made defences, and their ability to accumulate carbon are explored. Using these attributes of salt marshes, it may be possible to increase the protective capacity of a coastline by increasing the amount of salt marsh through restoration projects. The viability of salt marsh restoration projects in the Bay of Fundy is briefly considered.

Au cours des prochains siecles, la societe devra faire face a des augmentations significa-tives de la temperature et du niveau de la mer, ce qui constitue une menace grandissante pour les communautes etablies dans les zones cotieres de faible elevation. Afin de proteger ces communautes, les strategies d'adaptation qui seront deployees devront non seulement repondre aux besoins a court et moyen terme, mais offrir une solution durable bien au-dela du prochain siecle. Des evenements recents, tels que le tsunami dans le sud-est de I'Asie et I'ouragan Katrina en Louisiane, illustrent bien a quel point plusieurs regions cotieres sont vulnerables et nettement mal preparees pour faire face a des evenements tels que tempetes et catastrophes naturelles. Dans cet article, les auteurs presentent de la situation a la baie de Fundy comme etude de cas pour examiner la faisabilite de la restauration des marais salins cotiers comme outil d'adaptation a la hausse des niveaux de la mer et d'attenuation des effets des changements climatiques. On se penche plus precisement sur la capacite qu'ont les marais a s'adapter aux changements du niveau de la mer, a leur fonction de zone tampon dans les processus cotiers, a leur rapport cout-efficacite comparativement aux defenses artificielles, traditionnelles et statiques construites, enfin, on evalue leur capacite a accumuler le carbone. Par le biais des proprietes des marais salins, il est envisageable d'accroitre la capacite protectrice du littoral par I'augmentation du nombre de marais salins a I'aide de projets de restauration. La viabilite des projets de restauration des marais salins de la baie de Fundy est examinee brievement.

Keywords:

Climate change, sea-level rise, adaptation, mitigation, salt marsh restoration

Introduction

Climate change poses increasing risks to many low-lying coastal communities that are ill-prepared for the inevitable global rise in sea-level. Nearly two-thirds of the world's largest cities and 20% of global population inhabit coastal areas, and risks will be exacerbated in the future given projections of population growth rates above world averages along coasts (IPCC, 2001a). This situation, coupled with limited progress mitigating greenhouse gas (GHG) emissions, has increased the need for consideration of climate change adaptation strategies.