storm surge

New Orleans is sinking

August 14, 2025 By EarthWise Leave a Comment

As climate change accelerates, rising sea levels are putting coastal communities at greater risk of flooding and storm surge. Driven by melting glaciers and warming oceans, global sea levels are rising at an increasing rate. For low-lying cities like New Orleans, even small increases can have serious consequences. And that risk is compounded by another factor: the land itself is sinking.

Much of New Orleans already sits at or below sea level, and parts of the city and its surrounding wetlands are gradually sinking. While most of the city remains stable, a new study by researchers from Tulane University suggests that sections of the region’s $15 billion post-Katrina flood protection system may require ongoing upgrades to keep pace with long-term subsidence.

The study, recently published in the journal Science Advances, used satellite data to track changes in ground elevation across Greater New Orleans between 2002-2020. The researchers found that some areas – including neighborhoods, wetlands, and even concrete floodwalls – are sinking by more than an inch each year. In some spots, the land is dropping by nearly two inches annually.

Alarmingly, some of the concrete floodwalls and levees built to protect the city after Hurricane Katrina are themselves sinking. In a few cases, they are losing elevation faster than sea levels are rising, reducing their capacity to block storm surges.

The study highlights how satellite monitoring can play a critical role in guiding infrastructure maintenance and urban planning – not just in New Orleans – but in vulnerable coastal cities around the world.

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Vertical land motion in Greater New Orleans: Insights into underlying drivers and impact to flood protection infrastructure

Photo, posted September 22, 2010, courtesy of U.S. Army Corps of Engineers via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The coastal squeeze

June 26, 2025 By EarthWise Leave a Comment

Globally, coastal areas are being squeezed between rising seas on one side and human development on the other. The average distance from the high waterline to the first built-up area with human structures or paved roads is less than 400 yards around the world. The narrower a coast, the sooner rising sea levels cause problems.

Narrow coasts have reduced ability to defend against storm surges and other weather events. Construction close to the sea makes coastal areas extra vulnerable. Narrow coasts are also bad news for biodiversity. A study by the Royal Netherlands Institute for Sea Research investigated plant diversity in both the Netherlands and the United States. They found that the wider the coast was, the greater the plant diversity.

In Florida and Georgia, whenever coastal zones reached a couple of kilometers in width, diversity increased rapidly. In the Netherlands, only coastal areas at least 3.8 kilometers wide reached their maximum plant diversity, but such areas are rare. Dutch sand dune areas are typically no more than a kilometer wide, leaving plant diversity at no more than half the possible level.

Limited biodiversity in narrow coastal strips can be somewhat boosted by nature management but would benefit much more by spatial planning. In the Netherlands, a spot called The Sand Motor is where a gigantic amount of sand was deposited off the coast in 2011. Since then, natural forces have spread it along the coast. Such coastal expansion could increase biodiversity. Biodiversity is not a luxury. It makes for a better future for coastal defense, a healthy drinking water supply, and a better human food supply.

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Coastal squeeze is bad for biodiversity, and for us!

Photo, posted June 21, 2017, courtesy of Mark Bias via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Nature: An important climate ally

June 10, 2025 By EarthWise Leave a Comment

Nature is often seen as a victim of climate change, but it’s also one of the most powerful tools we have to fight it. Natural ecosystems, such as forests, wetlands, grasslands, oceans, and soils, absorb and store massive amounts of carbon dioxide. These ecosystems not only help reduce the concentration of greenhouse gases in the atmosphere, but they also regulate temperatures and provide buffers against extreme weather.

One of the most effective strategies for mitigating climate change is simply protecting and restoring these natural areas. For example, mangrove forests – those coastal wetlands filled with tangled, salt-tolerant trees – sequester carbon at high rates and help protect coastal communities from storm surges and rising seas. Peatlands – another type of wetland – store more carbon than all the world’s forests combined – despite only covering 3% of Earth’s land surface. Global restoration efforts are underway, from replanting mangroves in Southeast Asia to rewetting degraded peatlands in Europe.

Creating urban green spaces like parks and community gardens, restoring forests through native tree plantings, and adopting sustainable agricultural practices like cover cropping and agroforestry are all proven to be low-cost, high-impact climate solutions.

While nature-based solutions are gaining recognition, they remain critically underfunded, according to a recent United Nations report. Closing this gap is essential to unlocking nature’s full climate potential.

Investing in nature isn’t just about preserving Earth’s natural beauty. It’s a practical strategy for building a more resilient and sustainable future.

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Mangrove forests and rising seas

Financing Nature-based Solutions for a better future

Finding peatlands

The Importance Of Urban Green Spaces

Photo, posted October 23, 2011, courtesy of the Everglades National Park / NPS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rising seas are destroying buildings

April 8, 2025 By EarthWise Leave a Comment

Alexandria is the second largest city in Egypt and is the largest city on the Mediterranean coast. Its history goes back over 2,300 years and it was once home to a lighthouse that was among the Seven Wonders of the Ancient World and a Great Library that was the largest in the ancient world. The modern city has more than 6 million residents but still has many historic buildings and ancient monuments. But perhaps not for long.

Rising seas and intensifying storms are taking a toll on the ancient port city. For centuries, Alexandria’s historic structures have endured earthquakes, storm surges, tsunamis, and more. They are truly marvels of resilient engineering. But now, climate change is undoing in decades what took millennia for humans to create.

Over the past two decades, the number of buildings collapsing in Alexandria has risen tenfold. Buildings are collapsing from the bottom up as a rising water table weakens soil and erodes foundations. Since 2001, Alexandria has seen 290 buildings collapse. Comparing present-day satellite imagery with decades-old maps, the authors of a study by the Technical University of Munich have tracked the retreat of Alexandria’s shorelines to determine where seas have intruded into groundwater. The authors say that more than 7,000 buildings in Alexandria are at risk. They call for building sand dunes and planting trees along the coast to block encroaching seawater.

The true cost of this gradual destruction goes far beyond bricks and mortar. This is the gradual disappearance of historic coastal cities. Alexandria is a warning for such cities around the world.

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In This Storied Egyptian City, Rising Seas are Causing Buildings to Crumble

Photo, posted September 11, 2012, courtesy of Sowr via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Natural solutions for coastal defense

May 30, 2024 By EarthWise Leave a Comment

Protecting coastal cities and towns from the dangers of tsunamis, storm surges, and sea-level rise has become an ever-increasing challenge. There are so-called hard coastal defenses as well as nature-based solutions. A new study by the University of Tokyo has found that combining the two types of defenses may be the most effective way to protect, support, and enrich coastal communities.

Sea walls, dikes, dams, and breakwaters are the traditional hard measures. They are popular and have proven track records but are facing challenges to keep pace with increasing climate risks. They are expensive to build and require continuous upgrades and repairs. While they do provide protection from many disaster risks, they also can cause significant disruption to coastal ecosystems as well as to coastal communities.

Nature-based coastal defenses include such things as mangroves and coral reefs. So-called soft measures involve restoring, rehabilitating, reforesting, and nourishing natural ecosystems that protect coastal areas.

The Tokyo researchers analyzed the defense strategies in terms of risk reduction, climate change mitigation, and cost-effectiveness over a 20-year period. The results of the study were that among all coastal defense options in lower-risk areas, hybrid measures provide the highest risk reduction and can harness the advantages of both hard and soft measures.

The findings provide strong evidence for integrating nature-based components into coastal defenses, but these approaches have not yet been adequately tested in circumstances of extreme events and high-risk urgency. Research in this area has important implications for policy makers, coastal planners, and communities looking to make evidence-based decisions.

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A natural touch for coastal defense

Photo, posted October 22, 2021, courtesy of Kevin Dooley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

New York is raising its shoreline

January 18, 2024 By EarthWise Leave a Comment

Superstorm Sandy in 2012 flooded 17% of New York City and caused $19 billion in damage. In its aftermath, plans emerged to create floodwalls, raised elevations, high-capacity drainage, and other infrastructure to protect the city from future Sandy-like events.

Like all large infrastructure projects in densely populated places, the remaking of New York’s shoreline has only moved along in fits and starts. But there has been significant progress.

The East Side Coastal Resiliency (ESCR) project is the largest urban resiliency project currently underway in the United States. The first piece of it – the Asser Levy renovation – was completed in 2022. Over the next three years, the $1.8 billion ESCR will reshape two-and-a-half miles of Lower Manhattan’s shoreline. The ESCR is just one part of a much larger $2.7 billion initiative called the BIG U, which is a series of contiguous flood resilience projects that will create 5.5 miles of new park space specifically designed to protect over 60,000 residents and billions of dollars in real estate against sea level rise and storm surges.

In a time of rising seas and increasingly powerful storms, flood-prone coastal U.S. cities – including Boston, Norfolk, Charleston, Miami, and San Francisco – are moving toward embracing the long-held Dutch concept of “living with water”, which emphasizes infrastructure that can both repel and absorb water while also providing recreational and open space.

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After a Decade of Planning, New York City Is Raising Its Shoreline

Photo, posted November 1, 2012, courtesy of Rachel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Salt Marshes And Climate Change | Earth Wise

May 5, 2023 By EarthWise Leave a Comment

Salt marshes are coastal wetlands that are flooded and drained by salt water brought in and out by the tides. These low-lying wetlands are also sometimes called tidal marshes because they occur in the zone between low and high tides. These wetlands are some of the most biologically productive ecosystems on Earth.

Cape Cod’s beautiful salt marshes are as important as they are iconic. They act as carbon sinks, protect coastal development from storm surge, play an outsized role in nitrogen cycling, and provide critical habitats for many fish, shellfish, and coastal birds.

According to scientists from the Marine Biological Laboratory in Woods Hole, Massachusetts, more than 90% of salt marshes around the world are likely to be underwater by the end of the century.

Since 1971, scientists from the Marine Biological Laboratory have mapped vegetative cover in Great Sippewissett Marsh in Falmouth, Massachusetts, to examine whether increased nitrogen in the environment would impact species of marsh grass. Because of the length of the study, the researchers were also able to investigate the impacts of climate change on the ecosystem, especially those driven by accelerating sea level rise.

The research team found that increased nitrogen favored higher levels of vegetation and accretion of the marsh surface. However, the researchers found that salt marshes will not be able to outpace the submergence from global sea level rise – no matter how much nitrogen is applied.

Sea level rise is the biggest threat to salt marshes around the world. Mitigating some of these projected losses is critical in order for salt marshes to continue to provide their important ecosystem services for people and the planet.

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Most of the World’s Salt Marshes Could Succumb to Sea Level Rise by Turn of Century

Photo, posted September 27, 2011, courtesy of Chris M Morris via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

2022 Temperature Report | Earth Wise

February 8, 2023 By EarthWise Leave a Comment

The average surface temperature for the Earth in 2022 tied with 2015 as the fifth warmest on record. The warming trend for the planet continued with global temperatures 1.6 degrees Fahrenheit above the average baseline for 1951-1980 that NASA uses for its studies. Compared with the late 19th century average used in setting climate goals, global temperatures are up about 1.1 degrees Celsius, or 2 degrees Fahrenheit.

Overall, the past nine years have been the warmest since modern recordkeeping began in 1880. The rising temperatures have moved in concert with rising levels of greenhouse gases entering the atmosphere from human activity. Many factors can affect the average temperature in any given year including El Nino and La Nina conditions in the Pacific. But the longer-term trend is quite clear. Global temperatures continue to rise.

Greenhouse gas emissions have reached all-time high levels despite increasing efforts to reduce them. There was a real drop in levels in 2020 due to reduced activity during COVID-19 lockdowns, but they rebounded soon thereafter.

The Arctic region continues to experience the strongest warming trends, as much as four times the global average. Arctic warming has a major impact on weather at lower latitudes as it changes the behavior of the jet stream as well as affecting ocean currents and water temperatures.

As global temperatures continue to rise, rainfall and tropical storms have become more intense, droughts have become more severe, and ocean storm surges have had increasing impact. From torrential monsoons in Asia to megadroughts in the U.S. Southwest, extreme weather has become the new normal.

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NASA Says 2022 Fifth Warmest Year on Record, Warming Trend Continues

Photo, posted June 20, 2020, courtesy of Daxis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Reef Insurance | Earth Wise

January 4, 2023 By EarthWise Leave a Comment

Coral reefs around the world face multiple dangers from warming waters, acidification, human activity, and more. Powerful storms often cause tremendous damage to reefs. When possible, snorkelers and divers are deployed to try to repair damage to reefs. But philanthropy and government grants are basically the only resources available to fund such actions.

Three years ago, tourist businesses and the government in the Mexican state of Quintana Roo purchased an insurance policy to offset costs of protecting the local parts of the Mesoamerican Reef. The environmental group the MAR Fund later took out an insurance policy on the rest of the reef in Mexico, Belize, Guatemala, and Honduras.

With this precedent, the Nature Conservancy recently purchased an insurance policy on behalf of the state of Hawaii to help offset repair work on its coral reefs. It is the first U.S. coral insurance contract.

Coral reefs are more than just hosts for marine life. They provide barriers against ocean storm surges, which is a major financial incentive for protecting them and hence an incentive to invest in insurance.

The new Hawaiian insurance policy has a premium of $110,000 a year and will provide $2 million in protection. Payouts occur when wind speeds go above 50 knots. No further proof of damage is required.

The Nature Conservancy has created teams called ‘Reef Brigades’ composed of snorkelers and divers who recover reef fragments, store them in ocean or shore-based nurseries, and then re-attach them when conditions are safe. It can be very expensive to do this sort of work, particularly when new corals grown in a nursery are required.

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Analysis: First U.S. coral insurance marks the rise of the reef brigades

Photo, posted September 14, 2011, courtesy of Greg McFall/NOAA Office of National Marine Sanctuaries via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The State Of The Birds | Earth Wise

November 28, 2022 By EarthWise Leave a Comment

The U.S. Committee of the North American Bird Conservation Initiative has published the State of the Birds 2022, an assessment of bird populations in North America. The news is not good. The report identifies 70 Tipping Point species, which are those that have lost half or more of their breeding population since 1970 and are on track to lose another half or more in the next 50 years. According to research published in Science in 2019, the United States and Canada have lost 3 billion breeding birds since 1970, which is about a quarter of the total population.

More than half of the bird species in the United States are in decline. According to the Conservation Initiative, the tipping point species in particular require proactive conservation protections to avoid becoming endangered. Species that inhabit grasslands are declining more rapidly, while waterfowl like ducks and geese are actually increasing. That increase is most likely a result of the investments in conservation funded by the hunting industry.

Those waterfowl gains demonstrate that when there are concerted efforts to protect and promote bird populations, positve changes can happen. Some say that protecting birds is not a high priority given all the other crises in the world, but what is good for birds is also good for people. For example, planting trees and other vegetation to enhance bird habitat also helps to sequester carbon, protect coastlines from storm surges, increase groundwater recharge, and reduce urban heating effects.

The loss of 3 billion birds is a major biodiversity crisis and requires action. Bird conservation benefits wildlife, people, entire ecosystems, and our planet.

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What’s Good for Birds Is Good for People and the Planet. But More Than Half of Bird Species in the U.S. Are in Decline

Photo, posted November 4, 2020, courtesy of Tom Koerner/U.S. Fish and Wildlife Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Rising Threat Of Rising Seas | Earth Wise

February 3, 2020 By EarthWise Leave a Comment

Global sea level rose by about 6 inches during the 20th century. It is currently rising more than twice as fast and accelerating. The rate of rise was 2.5 times faster from 2006 to 2016 than it was for nearly all of the 20th century.

Sea level rise occurs when glaciers and ice sheets lose mass. Much of that meltwater comes from Greenland and Antarctica. But levels also rise because, as water warms, it expands. Added to that are the effects of human activities such as groundwater depletion and a geological phenomenon called isostatic adjustment that is going on in parts of the East Coast where the land is actually sinking.

In Atlantic Canada, sea level rise is outpacing the global average and has already led to boardwalks swamped by swelling tides, drowned forests, submerged wharfs, and threatened historic shoreline buildings.

Recent research suggests that globally, land now occupied by 300 million people could be affected by floods at least once a year by 2050 unless carbon emissions are significantly reduced, and coastal defenses strengthened. (This new figure is more than three times higher than earlier estimates).

Researchers at Dalhousie University in Nova Scotia are studying nature-based strategies for mitigating the effects of the rising seas. These include conserving or restoring coastal ecosystems like dunes, wetlands, and reefs which could provide protection at a lower cost than building seawalls and other man-made obstacles. Wetlands, for example, can reduce the force of waves and act as obstacles to storm surges, while also trapping sediment and stemming erosion. Wetlands also serve as important carbon stores, but it is estimated that roughly half of the world’s coastal wetlands have been lost over the past 100 years to human activity and extreme weather events.

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The Looming Threat of Rising Sea Levels – And What We Can Do About it

Photo, posted February 14, 2015, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Should New York Build A Storm Surge Barrier?

December 6, 2019 By EarthWise Leave a Comment

In 2012, Superstorm Sandy’s storm surge combined with a high tide and buried lower Manhattan under 13 feet of water. Across all five boroughs, subways, highways, and parking garages flooded and homes and businesses were destroyed. Sandy caused nearly $20 billion in damages in New York City alone and more than 50 people died.

Ever since that disaster took place, there have been discussions about building storm surge barriers to protect the city from future storms. Columbia University’s Sabin Center recently hosted an event to discuss the feasibility of building such barriers.

A study by the U.S. Army Corps of Engineers called the NY and NJ Harbor and Tributaries Focus Area Feasibility Study (HATS, for short) evaluates five options for coastal protection, which range in scope and price.

The most extensive option would involve constructing six miles of storm surge gates along with 26 miles of floodwalls, levees, and buried seawalls. This option would cost $62 billion but could theoretically save $131 billion in damages and protect 95% of the study area.

The study also considers the side effects of building storm surge barriers. These include environmental impacts such as effects on fish and wildlife, water quality, noise and vibrations, and changes in water flow. While these effects can be quite serious and there is opposition from many quarters related to environmental impacts, others point out that there is really no other credible defense against storm surge. The debate over whether or not to build storm surge barriers could easily last for many more years.

In the bigger picture, storm surge barriers do nothing to protect against rain-driven flooding, sea level rise, and tidal floods which continue to increase.

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Should New York Build a Storm Surge Barrier?

Photo, posted October 30, 2012, courtesy of Pamela Andrade via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Which Cities To Save From The Changing Climate

October 28, 2019 By EarthWise Leave a Comment

After several years of brutal flooding and hurricanes in the U.S., a distressing debate is emerging: if there is not enough money available to protect every coastal community from the effects of global warming, how do we decide which ones to save first.

Recent research looked at the costs involved in providing basic storm-surge protection in the form of sea walls for all coastal cities with more than 25,000 residents. That number was $42 billion. Expanding the list to include communities smaller than 25,000 people would increase that cost to more than $400 billion. Realistically, that is just not going to happen.

This particular study only looked at sea walls and no other methods for minimizing flood risk, such as moving homes and businesses away from the most flood-prone areas. It also didn’t look at additional and costlier actions that will be required even with sea walls, such as revamping sewers, storm water, and drinking water infrastructure.

The facts are that many cities, especially small ones, will not be able to meet the costs facing them. Those that can’t will depend on federal funding. But even optimistically large proposals for federal infrastructure spending are likely to fall far short of the vast need. Ultimately, the money will end up being spent where it can do the most good – even if it means that some places are left out.

But what criteria will be used to direct the money? Economic value? Historic significance? Population? Political influence?

This is a looming and massive issue whose chief obstacle may be that many officials refuse to acknowledge that it is happening. This is the next wave of climate denial – denying the costs that we are all facing.

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With More Storms and Rising Seas, Which U.S. Cities Should Be Saved First?

Photo, posted October 31, 2018, courtesy of Patrick Kinney via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Cost Of Rising Seas

October 1, 2019 By EarthWise Leave a Comment

Coastal cities in the United States are grappling with the need for extensive infrastructure projects to protect against rising seas and worsening storms. The cost of these projects will be enormous, and it is unclear how to pay to them.

Boston has many neighborhoods in low-lying areas, and it is estimated that $2.4 billion will be needed to protect the city from flooding. The city abandoned plans to build a harbor barrier that would have cost $6 to $12 billion because it was economically unfeasible.

Charleston, South Caroline needs $2 billion to reduce flooding that occurs regularly during high tides. The Houston, Texas area needs $30 billion to provide protection against a 100-year flood. Hurricane Harvey caused $125 billion in damages in Texas in 2017. New York City is considering a $10 billion storm surge barrier and floodgates to shield parts of the city from rising waters.

Florida faces the greatest exposure to flooding with an estimated $76 billion in costs to address some of its problems.

At the federal level, multiple agencies represent potential funding sources, but none offer the kind of money required to address the need. This places a heavy burden on state and local governments. Various states have passed legislation related to shoreline resiliency and flood abatement, but relatively little funding has been approved. Some bond measures have passed, but the totals are small compared with what is needed.

Educating people about the costs of not doing anything or not doing enough soon enough is essential. As Hurricane Katrina demonstrated, not spending a large amount of money on resilience can result in having to spend a colossal amount of money on recovery.

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Who Will Pay for the Huge Costs of Holding Back Rising Seas?

Photo, posted December 26, 2013, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Saving Venice From The Sea

January 26, 2018 By EarthWise Leave a Comment

The risks of rising sea waters are growing more apparent every year. While the world struggles with taking action to reduce the carbon emissions that are driving the sea level rise, cities around the world are building sea walls designed to protect them from storm surges and flooding. Most of these are massive, complex infrastructure projects that cost billions of dollars and take decades to complete.