National Climate Assessment: Flooding and Sea Level Rise

Actions on climate resilience and adaptation are essential but lagging far behind what’s needed given the accelerating pace of climate impacts. That’s a central message of the Fifth National Climate Assessment, which is the most comprehensive federal government analysis of how climate change is and will affect the nation. 

The report paints a clear-eyed picture of how climate change is already affecting the United States and will continue to – even under the most optimistic emissions reduction scenarios.

This is particularly true with regards to flooding and sea level rise. Over just the last few years, the nation has been pummeled by a series of climate-fueled flooding disasters, hurricanes, and extreme storms. The impacts of climate change are accelerating.

Inland flooding is on the rise as extreme storms cause rivers to jump their banks and city streets flood when runoff has nowhere to go. Our challenges are just beginning with sea level rise is now beginning to accelerate, which will make flooding a fact of life along the nation’s coastlines. 

According to this new assessment and the most recent sea level rise assessment from NOAA, U.S. coastlines will see as much sea level rise between now and 2050 as in the prior century. In less time than it takes to pay off a 30-year mortgage, U.S. coastlines will see 12-20 inches of sea level rise on average, with areas like the Western Gulf of Mexico facing up to 27 inches by 2050. 

To adapt to this new reality, local governments, states, and the federal government need to embrace two main courses of action:

• Drastically curtail development in coastal areas and floodplains.
• Make relocation assistance more timely, equitable, and easier to secure for people who need to move to higher ground.

There are a number of things we can do to accomplish both and do so in a way that’s equitable and puts the most vulnerable members of our society first. 

Discourage development in coastal areas and floodplains.

The collision of climate change with increasing development in flood-prone areas is becoming very expensive and very dangerous.  What are some of the ways that people could be discouraged from living in these vulnerable low-lying areas, many of which may become permanently inundated in coming decades?

First, let’s tell people the truth about flooding and sea level rise risks

In the United States, we make it exceedingly difficult for people to learn about the potential for flooding to occur. 

Most states do not require that past flood damages be disclosed to a home buyer. And even fewer require landlords to give renters the same information. The result is that people unknowingly move into areas that are already susceptible to flood disasters. 

You can find out if your state has good flood disclosure requirements by checking out NRDC’s Flood Disclosure Scorecard. FEMA and the Biden administration are calling on Congress to make flood disclosure a national requirement, which development interests are already opposing.  

Another problem is that the official flood risk maps produced by the Federal Emergency Management Agency (FEMA) do not give people the information they need – what flood risks look like in the future.  FEMA’s flood maps are based exclusively on historical data. They essentially tell you what the floor risk was, not what it’s going to beThat’s just not useful.  It means we are siting and building development based on conditions that no longer exist. 

FEMA is in the process of making changes. The agency is considering changes to its flood mapping procedures and future flood risks are changing with regards to sea level rise, extreme storms, and other climate factors. An official advisory committee just recommended big changes in FEMA’s mapping methodology to better reflect future flood risks. This is a welcome, if long overdue, step forward. 

Second, account for future climate impacts in development decisions 

Today, states and local governments do not adopt building or zoning codes that take into account how sea-level rise or flooding will affect development in the future. Only about one-third of states and local governments have even adopted building codes that incorporate basic flood resilience features, according to FEMA.

FEMA could help change that, by updating its own minimum floodplain development standards. Through the National Flood Insurance Program, FEMA is required to adopt and update these standards. But these standards were adopted in the mid-1970s and have never been updated.  In 2021, NRDC and the Association of State Floodplain Managers successfully petitioned FEMA and the agency is now in the process of overhauling these regulations. Adoption of new rules will likely require every state and over 22,000 local governments to ensure that their building and zoning codes to meet these new, climate-informed minimum requirements. 

Among the changes we would like to see:

• Require properties in the floodplain to be elevated higher, like 2-4 feet higher or more, depending on local risks. Better yet, don’t build in the floodplain at all.
• FEMA should ban the practice of “fill and build”, whereby developers elevate homes by hauling in piles of dirt to build houses on. While that practice might make the new homes safer, it comes at the expense of the surrounding homes, who now receive the excess runoff. Now imagine entire subdivisions being elevated in this manner and you can see why flooding gets worse for everyone else. Banning fill and build has long been called for by members of the Anthropocene Alliance. 
• FEMA must adopt more rigorous design and siting standards for critical infrastructure. Currently FEMA requires that hospitals be built to the same standard of flood protection as hot dog stands, but one is probably more important to be open and operating in the midst of flood disaster. 

Similarly, we need to move government investments out of low-lying areas.  President Biden put in place the Federal Flood Risk Management Standard to ensure that federal investments can withstand future climate conditions (i.e. don't build where it is/will be flooding or inundated). That standard is slooooowly being implemented, with HUD and FEMA leading the way and most other federal agencies lagging behind. 

The standard requires all federally funded projects to be built with an additional margin of safety for flooding or that future climate projections guide the siting and design, to help ensure that the project is safe from flooding for it’s entire design life.

The above are all examples of ways that the nation can begin to steer development out of harm’s way. Every new development that goes into a vulnerable low-lying area is something that we’ll eventually have to get out of that location as the waters rise.  We need to embrace the old adage, “If you want to get out of a hole, you first have to stop digging.”

Getting people out of harm’s way and to higher ground

As flooding gets worse and as sea levels rise, millions of people are going to need to relocate to higher ground. And many, if not most, people are going to need assistance to do so. As it now stands, it’s extremely difficult for a person to get that assistance.

Over roughly 30 years FEMA has provided funding for about 45,000 voluntary buyouts of flood prone homes. At that pace, FEMA programs will provide relocation assistance to 135,000 more buyouts over the next 90 years. But that’s a drop in the bucket compared to the projected 4.2 million Americans who could see their homes inundated by three feet of sea level rise in coastal areas by the end of the century. Millions more will need to be relocated due to recurring storm surge and flooding along the nation’s inland cities, rivers, and waterways. 

Currently, it can take years for people to secure this type of assistance from FEMA, or another federal agency.  That’s not going to cut it, particularly for lower income people who can’t simply afford to abandon their home and move.

We can make this assistance more readily available, with planning and foresight.  Through a series of workshops with both buyout project managers and people who have had their homes purchased through such efforts, NRDC and our partners developed the following recommendations. Among those recommendations:

• Plan for providing buyouts and incorporate them as an option into current planning processes (i.e. land use plans, capital plans, hazard mitigation plans, etc).  Communities need to look ahead and realize what parts of their community are most vulnerable and where they may need to consider “un-building” rather than continue developing. 
• Prepare for offering buyouts before a flood disaster happens.  It’s critically important to talk to community members about the future and what the options are.  If community members think relocation is the best option, then start laying the groundwork to make those happen.  Normally communities don’t seriously think about this option until after a flood disaster strikes.
• Design for equitable outcomes from the start.  Providing assistance to relocate should not stop at buying a flooded home at market prices. A home that’s flooded multiple times will naturally be worth less than the identical home on higher ground, especially in neighborhoods that may have faced decades of disinvestment. Buyout programs need to be designed to help people get to a safer location. That means not only compensating them for their old home, but also providing assistance finding a new home and additional assistance to find a comparable home that is in a safe location. New Jersey’s Blue Acres program is a good example of how buyouts can provide relocation assistance, not just buy a flooded home. 

The latest National Climate Assessment paints a very clear picture of the challenges ahead, both in efforts to curb the emissions that are the root cause of climate change, but also in the work that is required to protect communities from the unavoidable impacts. 

Flooding and sea level rise are among the most visible and pressing impacts of climate change. The latest assessment not only highlights the challenges ahead, but also lays out some of the strategies and actions that we need to be putting in place in order to address all aspects of the climate crisis.  NRDC and many other local, state, and national organizations are similarly pressing for solutions to some of these daunting challenges.