The Delta Blues: Why Climate Change Adaptation is Crucial in the World’s Deltas

Deltas are biodiversity hotspots that drive economic development and house thriving cities, yet they are particularly vulnerable to climate change. They require urgent adaptation measures to prevent losses that could stifle entire economies.

W ith fertile soils and some of the planet’s richest biodiversity, deltas generally belong to the world’s most densely populated areas. Trade and agricultural production have long flourished in these hubs of intense human and economic activity.

Deltas are climate hotspots where people, food production, wildlife and economic development meet the impacts of climate change – yet despite their indisputable value, climate adaptation in deltas does not receive the interest and funding it… Click To Tweet

“In the race to adapt to climate change, deltas currently stand at the starting line. A lot of work must be undertaken to address adaptation in deltas, and we have to begin by understanding just how valuable these environments are as biodiversity hotspots and engines of economic growth, and just how gravely threatened they are by climate risks,” said Patrick Verkooijen, CEO of the Global Center on Adaptation (GCA).

In 2021, GCA launched a report that explores best practices in adaptation and resilience through inspiring case studies in selected delta countries. “Living with water: climate adaptation in the world’s deltas” aims to push delta adaptation efforts up the political agenda while presenting scalable and replicable adaptation best practices.

The report highlights that today, 500 million people live in delta and coastal urban regions, a figure expected to rise by 50 percent by 2050. Deltas are drivers of economic growth, and many, have a higher GDP per capita than the economies that host them. The Mekong Delta, for instance, is home to 20 million people and supports approximately a quarter of Vietnam’s GDP.

Vibrant cities and thriving agricultural and industrial centers exist along the world’s deltas. Europe’s largest seaport is located in the cosmopolitan delta city of Rotterdam. The biodiversity-rich Fraser delta has made the bustling city of Vancouver a major Canadian trade center. And the world’s largest delta, the Ganges-Brahmaputra-Meghna delta shared by India and Bangladesh, is home to nearly 200 million people and a major agriculture center with, amongst other, intense paddy cultivation.

What are deltas?

Deltas form at the mouths of rivers, where they deposit sediment and merge with another body of water such as the ocean. Deltas are nutrient-rich wetland habitats, and like most wetlands, they host diverse ecosystems and act as natural buffers for extreme weather events, such as storms, hurricanes and cyclones. They also filter water that flows downstream, reducing the impact of river pollution.

Floating market in the Mekong Delta at Cai Rang, Vietnam.

A ticking time bomb

Because climate change will be primarily expressed through water, delta regions are especially vulnerable to its effects.

A report by the Intergovernmental Panel on Climate Change (IPCC) asserts with “high confidence” that even if the world were to reduce greenhouse gas emissions and lower global temperatures, deltas will be confronted with “high to very high risks” from rising sea levels in the future.

Sea levels are expected to rise by 0.5 meters by 2050 and over a meter by 2100. These projections place large parts of many deltas at risk of submergence. Indeed, experts predict that by 2050, seventeen percent of Bangladesh will be submerged, triggering the displacement of an estimated 20 million people. Saline intrusion is already threatening the soils, water supply and food security of many vulnerable populations in deltas.

Without urgent adaptation measures, the losses in some delta regions could stifle entire economies. Damage to infrastructure, crop production and fishing could reduce the GDP per capita by 19.5 percent in Bangladesh and by 9 percent in the Volta delta in Ghana. Food insecurity and the loss of livelihoods would be severe.

While many delta regions lack integrated climate adaptation plans, the nature of deltas provides opportunities for progress and innovative solutions.

In its flagship report Adapt Now, GCA proposes three ‘revolutions’ to accelerate adaptation that apply to deltas: understanding, planning and finance.

The complex issue of adaptation in deltas must be understood and viewed through a systems lens to address social, hydrological and economic interdependencies. Long-term, locally-led adaptation and investment plans must be developed and supported by political commitment. And finally, an increased level of financial resources must be mobilized, targeting the most vulnerable delta communities and taking advantage of the opportunity provided by Covid-19 economic recovery plans.

This integrated approach is being promoted by WWF’s Resilient Asian Deltas (RAD) Initiative, in collaboration with GCA, in Asia’s six biggest deltas. The initiative aims to improve the understanding of deltas and the processes that maintain them, while catalyzing action at scale. Nature-based solutions case studies and real-world climate financing options are being developed, and a community of practice to bring together delta practitioners from across the region is being established.

“Adapting to climate change is a continuous process that takes time and resources and that needs to be embedded in a long-term vision and strategy,” said Joep Verhagen, Program Lead of GCA’s Water and Urban Team. He noted that implementation of several flood defence and climate adaptation plans in the Netherlands, such as the Delta Plan, is a continuous process spanning decades and is supported by long-term budget allocations.

Minimizing the threat of climate change and accelerating adaptation in delta regions is challenging but certainly possible. The Dutch approach of living with water, which evolved from fighting against the sea to living with it, and from controlling floods to making room for rivers, provides a valuable example.

In 2022, GCA will be scaling up its efforts to accelerate adaptation in deltas. In Bangladesh, GCA is currently preparing to work on urban and water resilience in the Bangladesh Delta.

GCA’s Water Adaptation Community recently launched a Community of Practice (CoP) on deltas. The World’s Deltas CoP is a platform for knowledge sharing and learning across different delta networks and initiatives around the world, such as RAD and the Delta Alliance.

“With so many different delta initiatives, and the need to facilitate each of them, we need to be innovative and scale up our engagement with more partners. WAC will come in to, for example, be a platform to share experiences on how deltas around the world have dealt with or can deal with various issues, for example subsidence,” said Ase Johannessen, GCA’s WAC Facilitator.

WAC is organizing a webinar on Adaptation in Deltas at 9:30 CET on 24th February. For more information about WAC and its activities, click here or contact Johannessen, at

Christopher Howe, Lead of WWF’s RAD Initiative, and GCA’s Joep Verhagen and Ase Johannessen contributed to this blog.

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