Sustainable development goals offer new opportunities for tropical delta regions

Marine and lacustrine delta regions constitute only 1% of the Earth's surface but are home to over 500 million people.1 They are key contributors to agricultural production at the national and regional levels and thus enable alleviation of global food insecurity risks. In addition, tropical megadeltas sustain rich ecosystems that provide a variety of services and are noted for high biodiversity and natural resources.2 At the same time, however, their geographical location, coupled with often poor land use and river basin management, implies that deltas, more than other coastal areas, are prone to natural hazards and disasters such as subsidence, flooding, coastal erosion, and cyclones/typhoons. These environmental shocks have been proven to lead to high out migration and threaten human security in already relatively economically poor regions.3 Climate change, in particular sea-level rise, exacerbates the existing vulnerabilities by increasing the risks of rapid-onset disasters, as well as creeping processes such as salinity intrusion.4,5 Many deltas around the world are therefore threatened.6 This exposure to environmental change has important consequences on people's livelihoods and human development of the delta regions and beyond. In the case of the Amazon delta, the state-level human development index of the Brazilian State of Pará, where most of the deltaic area is located, is the third lowest among the 27 Brazilian states, with the education subindex ranking second poorest.7 In this commentary we discuss new opportunities for the way that the proposed Sustainable Development Goals (SDGs) agenda interacts with delta regions and highlight key policy measures needed to address the existing gaps.