What are nature-based solutions?
Where land and water meet, there is unparalleled potential. Drawn by access to marine resources and trade routes, people have settled along the world’s coastlines throughout history. In today's globalized world, 37% of humans live along the coast (United Nations Ocean Conference fact sheet 2017). The combined values from shipping, tourism, and commercial and subsistence fishing mean that living by the sea offers a great opportunity.
Coastlines are also frontlines: it is here where many hazards cause the greatest havoc. In 2004, the Indian Ocean tsunami killed at least 228,000 people and caused estimated losses of USD 15 billion. On a much more regular basis, cyclones and hurricanes kill and destroy as they reach land with maximum speed.
As an analysis of disaster data related to cyclones, hurricanes, and typhoons shows (based on the EMDAT database), the number of average annual fatalities has decreased from 20,600 (1990-99) to 2,800 (2010-19), while economic losses have starkly increased over the same period (from USD 16.4 to 69.6 billion). Although two storms (Bangladesh 1991, Myanmar 2008) caused more than 130,000 deaths each, advances in early warning and preparedness have lowered the fatalities: less than 5% of global annual disaster deaths of 60,000 (2010-19) were related to storms. In many places, the combination of land subsidence, poor water management, degradation of ecosystems, and sea-level rise combine to increase vulnerability to extreme weather events and greater exposure to stressors.
Healthy coastal ecosystems such as mangroves, reefs, dunes, and swamps help protect people and assets from damaging forces. Yet for numerous reasons, these valuable ecosystems remain unprotected and continue to be destroyed.
The good news is that much can be done to regain nature’s protective benefits. Nature-based solutions (NbS) are actions that address societal challenges (such as climate change and disaster risk) by protecting, sustainably managing, and restoring natural or modified ecosystems (IUCN 2016).
They can be categorized into four groups:
- Fully natural solutions that utilize naturally occurring systems, such as coral reefs, marshes, and mangroves;
- Managed natural solutions that utilize interventions, such as artificial coral or shellfish reefs, renourished beaches and dunes, planted marshes and mangroves;
- Hybrid solutions that combine structural engineering (“gray infrastructure”) and natural features (“green infrastructure"), such as marsh-levee systems or dune-dyke systems; and
- Environment-friendly structural engineering that is beneficial to natural systems, such as vegetated engineering or bamboo sediment fences (Pontee et al 2016:30.).
Aside from reducing climate-related disaster risk, NbS typically enhance food security, water security, social and economic development, and human health. In short, NbS increase resilience through nature.
The case for nature is strong, and NbS can be integrated into wider disaster risk reduction (DRR). This guide shows you how to do that, taking you through the eight stages towards increased coastal resilience.
Let’s get started. We recommend learners to read through the rest of this introduction, and then the Blue Guide in its entirety, from Stage 1 through Stage 8. Use the menu to the left, and click Stage 1: Ideate and Scope.