Use vaccine logic to reduce climate’s flooding harm

Early in the pandemic, a cartoon circulated depicting COVID-19 as a tsunami about to crash upon some country. Scary enough — but stacked up behind the COVID-19 wave loomed an even larger one, labeled “climate change.”

The message was clear: You think this is bad? Just wait.

Waiting was not required. The past two years have seen a string of record-breaking floods, including the recent inundation of one-third of Pakistan and other disasters bearing climate’s fingerprints.

With COVID-19 there remains one solid reason for hope: vaccines — their rapid arrival and thus far durable performance in saving lives, even with variants.

What about that other wave? As Inger Andersen, executive director of the UN Environment Programme, noted: “There is no vaccine for climate change.”

But vaccines do offer a powerful lesson as we try to minimize impacts triggered by an already changing climate.

With vaccines, we take something harmful (a virus) and use science to deploy a beneficial version of it to reduce risk and harm. We can do the same with floods.

Flooding is already the world’s most costly disaster type — causing $82 billion in damages globally in 2021 — with losses projected to increase dramatically due to climate change. The latest reports from the UN Intergovernmental Panel on Climate Change emphasize that a warming atmosphere will generate more intense floods. Even holding warming to 1.5 degrees Celsius (the most ambitious target to avoid the worst climate change impacts) is projected to result in a doubling of losses and people affected by river floods.

While we can’t actually take a vaccine to stop floods, we can use vaccine logic to reduce the harm from damaging forms of flooding by strategically deploying beneficial forms of flooding — wetlands and floodplains managed as “nature-based solutions.”

Floodplains — the low areas alongside rivers — and wetlands can reduce flood risk because they give floodwaters somewhere to go instead of places we don’t want them, such as cities and farms.

But “vaccine thinking” remains uncommon in flood management. Major floods still generally trigger calls for more dams and levees on rivers. Those calls ignore the bright spots of preventing harmful flooding by directing floodwaters to a floodplain — some of which are almost a century old.

For instance, by the early 20th century, the Sacramento River was mostly flanked by levees set close to the channel, disconnecting the river from its floodplains. This “levees only” approach proved incapable of preventing harmful floods and the city of Sacramento was inundated several times following widespread levee failures.

In response, flood managers reconnected vast areas of floodplain to the river, giving floodwaters a place to spread out, and today those floodplains (called the Yolo and Sutter bypasses) are crucial for reducing flood risk for Sacramento and other towns and farmlands — while providing enormous benefits for fish, wildlife and recreation. Flood managers have also repositioned levees to give floodwaters more room on several rivers in California (the Napa, Feather and Bear) as well as in Missouri, Germany and the Netherlands.

In addition to reconnecting floodplains, vaccine thinking about floodplains can also mean maintaining existing connections. For example, although Hurricane Irene in 2011 caused severe flood damages across Vermont, the town of Middlebury, straddling Otter Creek, largely avoided losses because, upstream, the creek’s floodwaters spread out across 10,000 acres of floodplains and wetlands, cutting the flood peak in half.

There are some caveats to applying vaccine logic to floods: first, while vaccines offer strong protections against severe disease, they need to be part of a broader set of public health interventions. Similarly, floodplains and wetlands have limited utility against some flood types and should be deployed within integrated systems that include zoning, early warning and infrastructure.

Second, as with future pandemic risk, prevention will be more effective and affordable than managing impacts, emphasizing the primacy of stabilizing the climate. But impacts are already occurring, so we must minimize harm through adaptation.

While delivery has fallen far short of stated goals, wealthy countries are still committing to direct $100 billion a year toward climate adaptation in vulnerable countries.

Nature-based solutions, such as floodplains, should be central to global adaptation efforts because, beyond increasing resilience of flood-management systems, they provide multiple other benefits such as improving water quality, replenishing groundwater and highly productive fisheries.

Nature-based solutions’ multiple benefits should also drive their greater uptake in the United States. The 2021 Infrastructure Investment and Jobs Act includes $47 billion for increasing resilience to floods and other disasters projected to increase with climate change. The federal agency responsible for flood management, the U.S. Army Corps of Engineers, has an “Engineering with Nature Program” and implementation of nature-based solutions should be facilitated by a 2021 “comprehensive benefits” policy directive promoting broader planning criteria that would recognize their multiple benefits. However, uncertainty over methods and procedures, along with bureaucratic inertia, largely perpetuate the status quo.

In the short term, further guidance on how to quantify the diverse benefits of nature-based solutions could promote more innovative projects by the Corps. In the long term, Congress could direct the Corps to integrate multiple purposes (e.g., flood management and restoration) into each project as standard procedure. As an example, the California Department of Water Resources, which has responsibility for flood management in the state, has established a Division of Multi-benefit Initiatives to promote the use of floodplains and wetlands in their projects.

As the United States, and countries around the world, prepare to spend billions of dollars in response to rising flood risk, managing flooding — in the right places — is an effective treatment for keeping people safe in a changing world.

Jeff Opperman is World Wildlife Fund’s (WWF) global lead freshwater scientist.