Understanding Sea-Level Rise and Variability - Sea-level rise and variability: synthesis and outlook for the future

Coastal zones have changed profoundly during the 20th century with growing populations and economies (Figure 1 .2 ). Increasing urbanization was a major driver of this change. Today, many of the world ' s megacities are situated at the coast. At the same time, sea level has been rising and is projected to continue to rise further. However, coastal developments have generally occurred with little regard to the consequences of rising sea levels, even in developed regions such as Europe (Tol et al. 2008 ). An improved understanding of sea -level rise and variability is required to reduce the uncertainties associated with projections for sea -level rise, and hence contribute to more effective coastal planning and management. The preceding chapters have provided an overview of our understanding of sea -level change. These chapters benefi tted from the discussion of position papers at a workshop on sea -level rise and variability held under the auspices of the World Climate Research Programme (WCRP) at the Intergovernmental Oceanographic Commission of the United Nations Educational, Scientifi c and Cultural Organization (UNESCO) in Paris in 2006. The workshop was attended by 163 scientists from 29 countries representing a wide range of expertise and supported by 34 organizations. The workshop prompted and underpinned new research initiatives. This chapter provides a synthesis of the fi ndings and recommendations from this community discussion, including a summary