Undervalued impacts of sea-level rise: vanishing deltas

Abstract

Current SLR might be considered a significant extinction force because of its high potential to degrade, reduce, or eliminate deltaic and coastal habitats, thereby promoting huge diversity losses. Nonetheless, the effects of SLR are still too frequently ignored in terms of designing biodiversity conservation strategies or developing urban/rural areas. SLR represents a serious threat to millions of people living in densely populated deltas. Almost 40% of major deltas, most of them already overpopulated, may increase their population density by >100 hab./km2 (2000-2050). Most adaptive measures to confront SLR in deltaic habitats will become more expensive and more difficult to execute with continued human growth. Growing populations also increasingly exploit biodiversity goods and services, adding stress to the deltaic ecosystems that strive to acclimatize to SLR. Beyond a certain point, additional pressure would favor their collapse. To achieve some degree of success, adaptive measures might be reinforced by specific policies and regulations, such as migration control and development restrictions. Biodiverse and sparsely populated deltas housing ethnic minorities may remain unattended and rely on their own resilience to SLR, whereas wealthy and densely populated deltas will be given priority. The selection of strategies to adequately address SLR in delta environments should be performed in the context of long-term planning. Because the long term is full of uncertainties, space- and time-specific research efforts should be devoted to address knowledge gaps before information demands become progressively too pressing.