Rivers can be climate change solutions, too (commentary)

by Michele Thieme on 30 March 2021

  • The usual avenues for addressing and adapting to climate change–like protecting forests and ramping up clean energy sources–typically overlook one powerful solution: rivers.
  • Rivers and their floodplains have the potential to act as shock absorbers to climate change, and are powerful agents for keeping wildlife and communities healthy and resilient.
  • The most effective climate action plans will account for this and incorporate rivers into their plans for a climate-resilient future, argues Michele Thieme, a freshwater scientist at World Wildlife Fund.
  • This post is a commentary. The views expressed are those of the author, not necessarily Mongabay.

This past December marked the 5th anniversary of the landmark Paris Agreement. Soon after, the Biden Administration rejoined the Paris Agreement as one of their first actions in office. And in January, the Climate Adaptation Summit once again convened global leaders and local stakeholders to accelerate adaptation action.

As these milestones reinvigorate a call to action for our politicians and business leaders to act on climate and “ramp up climate ambition,” all eyes inevitably turn to the usual avenues for addressing and adapting to climate change: forests, clean energy and waving goodbye to our toxic relationship with fossil fuels. And while mitigation efforts continue to dominate the conversation, adaptation is ever-increasing in importance in global discussions as extreme weather and its impacts worsen around the world and countries work to build stronger national commitments.

Funding, policies and actions supporting adaptation, especially nature-based solutions, however, remain weak. They overlook a powerful resource in the fight to adapt to a changing climate: rivers.

We are seeing the climate crisis manifest through water. Droughts and floods are increasing in frequency and severity from the Mekong River to the arid Rio Grande, from the plains of Africa to the world’s largest tropical wetland, South America’s Pantanal.

Rivers and their floodplains have the potential to act as shock absorbers to climate change. But maximizing their ability to do so requires strategic interventions that keep their natural features intact or incorporate green and grey infrastructure that allow natural processes to occur. Governments and business leaders must prioritize climate adaptation actions that include rivers as part of the toolbox of nature-based solutions for solving the climate crisis.

Zacambu River in Peru. Image by Rhett A. Butler for Mongabay.

Rivers: Unsung heroes of climate adaptation

Rivers are powerful agents for keeping wildlife and communities healthy and resilient. Their natural functions provide life-giving resources and, critically for sinking deltas around the world, protect coastal areas against rising sea levels. Let’s dive deeper on a few of these functions:

  • Sediment flow: Rivers carry sediment all the way to the ocean where, over time, the deposited sediment accumulates to build a delta. Deltas that are starved of natural sediment flows are at risk of being inundated by rising seas. The natural flows also provide sediments to reinforce riverbanks and deliver nutrients to fertile agricultural lands and mangrove forests along the floodplains and a river’s edge. Infrastructure, such as dams, blocks the flow of sediment, one of the causes of sinking and shrinking deltas.For example, over 100 billion tons of sediment is now stored behind upstream dams, greatly reducing sediment flows to coasts around the world. According to a recent study, at least 25 million people live in sediment-starved deltas and thus are vulnerable to increased coastal flooding and inundation.
  • Flood risk reduction: Floodplains and wetlands along rivers are like sponges, providing a buffer for the rising and swelling of rivers, especially during flooding events. As climate change exacerbates floods, it is more important than ever that we protect and restore floodplains and wetlands. Without action, the costs to society are potentially enormous. For example, coastal flooding alone could cost up to $1 trillion per year in damages by 2050 in coastal cities if no adaptation action is taken. Restoring floodplains and coastal wetlands, along with other interventions, is a critical preventative measure against such losses.
  • Food and water security: River systems are among the most biologically diverse and productive ecosystems on the planet. Early civilizations flocked to rivers for their ability to support fertile agricultural lands, clean drinking water, and protein such as fish. This holds true today. River fisheries and those from other inland wetlands provide a source of protein for hundreds of millions of people As communities become increasingly stressed by climate change, it is more important than ever to protect the basic needs that rivers provide.

See related: Review all of Mongabay’s features on solutions to challenges like climate change here.

A farmhouse sits on stilts above a flooded rice paddy in the Mekong Delta. Photo by Daniel Hoherd/Flickr

Current state of affairs

When rivers are able to flow naturally and are not impeded by infrastructure, like dams, we call these “free-flowing” rivers. They are vital to supplying climate adaptation services, but increasingly, human activities are severing rivers. This decline in river health is sounding alarms to freshwater scientists everywhere:

  • Connectivity: Infrastructure development and other man-made changes have fragmented or disrupted two-thirds of Earth’s longest rivers.
  • Species decline: Populations of freshwater species have experienced a staggering 84% decline since 1970
  • Dams and infrastructure: There are roughly 60,000 large dams  around the world, with over 3,700 more hydropower dams currently planned or under construction.

Rivers and their floodplains lose the ability to buffer against floods and to deliver needed sediments to downstream deltas as they are fragmented. The Mekong River illustrates a harsh reality communities face when infrastructure is poorly planned.

The Mekong Delta is currently shrinking and sinking, having lost about 500 hectares of land in the decade leading up to 2012. While sea-level rise and groundwater extraction play a role, the immediate major causes of higher tides and salt intrusion in the delta are sand mining and trapping of sediments behind upstream dams.

Additional planned dams within the Mekong Basin will further exacerbate this problem, putting the tens of millions of people living in the delta at even greater risk for increased land loss, flooding and inundation.

In one hopeful measure, the Cambodian government has put a 10-year moratorium on any new dams on the main stem of the Mekong in Cambodia.

See related: How Vietnam came to embrace a new vision of the Mekong Delta’s future

The Mekong River, a mega-biodiverse river that supports the lives and livelihoods of over 60 million people, is the site of over 100 planned dams. The river is already suffering major negative environmental and social impacts due to dams. Photo credit: VisualHunt.com

Wins to build on

Countries from around the world and other members of the International Union for Conservation of Nature (IUCN) recently signed up to support the motion, ‘Protecting rivers and their associated ecosystems as corridors in a changing climate.’ This sets an important precedent for incorporating river protection into climate action policy.

There are a few other bright spots where governments and civil society are taking action to ensure that rivers and their floodplain and riparian zones can continue to act as corridors and buffers in a changing climate. One example is the recent action of the Colombian government to designate the entire free-flowing Bita River Basin as a Ramsar site, i.e. an internationally protected wetland. Another example is Mexico’s decrees for water reserves across nearly 300 basins that have effectively protected against over-extraction of water or blocking of river flows in some of the most intact basins of the country.

In Mongolia, the government has recently revised and approved 8.2 million hectares of water protection zones including riparian areas from mining and industrial development across seven provinces and is replicating this process in six additional provinces. In the U.S., the Wild & Scenic River designation has so far protected 13,413 miles of 226 rivers in 41 states. And this past autumn, U.S. environmental groups and the hydropower industry signed a joint statement to collaborate on river restoration and decarbonizing US electricity.

The burgeoning efforts to restore rivers began in the United States and have now spread to Europe, where the recent commitment of the European Union to dismantle dams and open up 25,000 km of rivers provides another compelling example. The “Room for the River” initiative of the Dutch government has taken measures at more than 30 locations along the Rhine, the Meuse, the Waal, and the Ijssel to give these rivers space to flood safely.

This progress is evidence that actions that allow rivers to act as corridors and buffers to build resilience in a changing climate are possible and that there is opportunity to replicate these wins.

The Javari River where it forms the border between Peru and Brazil. Photo by Rhett A. Butler for Mongabay.
The Javari River where it forms the border between Peru and Brazil. Photo by Rhett A. Butler for Mongabay.

A path forward

Humanity has always depended on the life-giving resources that rivers provide. As our global temperatures rise, people will be more dependent on rivers than ever before – both in terms of the benefits that they provide and the havoc they can bring if not well managed.

We cannot afford to continue to destroy one of our tools in the fight to adapt to climate change. Rivers need a seat at the table. The best-laid climate action plans will be those that account for the nature-based solutions rivers and floodplains provide in adapting to a changing climate. Business and policy leaders can incorporate rivers into their plans to support the flow towards a climate-resilient future.

When we think of climate solutions, let’s also think of rivers.

Michele Thieme is lead freshwater scientist at World Wildlife Fund (WWF).

Related listening from Mongabay’s podcast: Goldman Prize winner Ana Colovic Lesoska discusses the campaign to stop a dam-building spree in southern Europe, listen here: https://html5-player.libsyn.com/embed/episode/id/17901296/height/90/theme/custom/thumbnail/yes/direction/backward/render-playlist/no/custom-color/3e5014/time-start/00:28:52 Article published by Erik Hoffner

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