What we’re learning about hurricanes. And how societies handle them.
I’ve lived through impressive tropical storms, twice on sailboats safe in harbor, but I can’t really imagine a hurricane with 150 mph winds like Ida. That’s the business of coastal scientists, engineers and other experts. Here’s what they’re telling me:
It might not always seem this way, but in the past few years the National Hurricane Center has notably upped its game for predicting storm tracks.
The lamentable history of New Orleans before and after Hurricane Katrina is beautifully described in Andy Horowitz’s Katrina. Once again Hurricane Ida is highlighting society’s lack of interest in guarding the vulnerable, while maintaining systemic foulups like police focused on protecting property rather than people.
The rebuilt New Orleans levee system “is less ambitious than the one Louisianans lobbied for after Katrina, and the protection it offers grows weaker every day, as the wetlands that buffer the city from the Gulf of Mexico get wetter,” as Horowitz wrote in the New York Times. “But it kept the Gulf of Mexico out of the city, which was its job.”
That was a straightforward goal for the Army Corps of Engineer’s $15-billion New Orleans levee project. Achievable goals may be far less clear for megaprojects under consideration for other U.S. cities. Case in point, Miami just turned thumbs down on a Corps plan built on a massive seawall.
Miami is among the urban areas hoping to adopt “nature-based systems” (oyster reefs, salt marshes, sea grass meadows, mangroves… ) as part of their resiliency efforts. NBS is a big theme in the Texas coastal spine proposal, centered not just on enormous sea gates but on miles of sand dunes. As with traditional gray engineering, NBS measures have strengths and weaknesses; salt marshes retain no magic if they’re buried under a surge of seawater.
Traditional benefit/cost analyses for such projects that consider only financial factors “might lead a government to protect only the parts of a city that contain high-value properties while dismissing parts of a community where less advantaged people live,” notes a National Academies report on localized climate action.
There’s much talk about “managed retreat” from endangered coastal sites but so far this radical step is taken only when there is no choice at all. “There are reasons people live where they live,” as one prominent engineer pointed out to me.
Hurricanes can rip away the accoutrements of civilization over surprisingly huge areas–for instance, Ida killed more people in the Big Apple than the Big Easy. But with the huge exception of rainfall, the worst structural damage is usually highly localized. Properly designed and constructed buildings often survive hurricanes surprisingly well, and the big problem for their occupants becomes waiting for restored power, water, roads and other lifelines.
As Boston plans for resilient waterfronts, there’s still a case for a barrier in the outer harbor.
Along Boston Harbor, the big worries from climate change are sea-level rise and storms—but not in that order, William Golden remarked in a Environmental Business Council (EBC) of New England session on December 10.
Currently in Boston, sea-level rise is “a nuisance issue that can be addressed for another 30 or 40 years with a couple of feet of seawall,” said Golden, an attorney and environmental activist best known for filing the lawsuit that led to the cleanup of Boston Harbor. “The real issue is storm surge.”
That is, when the sea climbs to scary heights—say, the 14-foot-above-high-tide wall of water that swamped lower Manhattan in Superstorm Sandy in 2012.
Much of the Boston waterfront was originally tidal flats and its edges remain highly vulnerable to ocean storms, which are growing more numerous and often more terrifying. In this record-breaking year, 12 named Atlantic storms hit the U.S., one clobbering Louisiana with winds over 150 mph and a storm surge of 17 feet.
Now leading the Boston Harbor Regional Storm Surge Working Group, Golden renewed his call for a harbor barrier stretching from Hull to Deer Island in outer Boston Harbor, guarding against storms for 15 cities and towns with 175 miles of coastline. (Such a barrier wouldn’t do anything about sea-level rise, which instead would be addressed by relatively modest structures onshore.)
Boston turned down this concept in 2018 after a preliminary feasibility study argued that the sea-gate system would be less cost-effective than onshore measures, take decades to build and pose uncertain technical risks. Golden and his allies, however, remained unconvinced.
Sanjay Seth, Boston’s climate resilience program manager, didn’t comment on the harbor barrier proposal at the EDC meeting but did outline the city’s active program to defend itself onshore.
“There are several areas of Boston that can serve as entry points for significantly damaging floods,” Seth noted. “We do have a real but very narrow window to achieve a unified network of protection in the city. .. Climate change really isn’t waiting.”
The downtown Boston waterfront, with its almost completely private ownership and messy underpinnings, may be the hardest neighborhood to handle. “There’s no silver bullet here,” Seth said. Instead, the plan calls for a mix of four options: raising the main roads closest to the waterfront, reconfiguring parks and other open spaces, beefing up the Harborwalk, and placing structures directly in the sea.
The preferred strategy for the downtown is a line of defense along the outside edge of the waterfront. “It’s not going to be easy, but it’s going to be doable,” said Seth. He acknowledged that success will require “entirely new levels of public/private coordination, as well as new, more robust coordination among private property owners themselves.”
Golden applauded Boston’s resilience planning but pointed out the limitations of any land-based measures. “Flood walls, particularly when they’re meant to address storm surge and sea level rise, can separate the public from the water,” he noted. The walls also can leave marine uses such as cargo shipping and ferry traffic unprotected. Moreover, the structures can act as bathtubs that need pumps to clear themselves after heavy rainstorms.
Harbor barriers can minimize those problems. Truly massive barriers are quietly guarding London, Rotterdam, Saint Petersburg and other cities. Smaller ones have worked well in New Bedford and other New England cities, Golden pointed out.
The leading U.S. contender for a giant gate system is the one proposed for Galveston Bay and Houston, part of a grand scheme for the Texas coast that seems headed to Congress this spring.
William Merrell of Texas A&M in Galveston came up with the concept back in 2008 while he was trapped in an apartment building by high water of Hurricane Ike. Once known as the Ike Dike, now as the Texas coastal spine, the idea is “extremely simple,” Merrell said during the EDC meeting. “Stop the water at the coast.”
The central barrier would cross Bolivar Roads, the main entrance to Galveston Bay and the Houston Ship Channel. It would combine a set of 300-foot-wide vertical-lift gates with massive horizontal swinging gates on the navigation channel, like those in Rotterdam. Left open in normal conditions, these entry points would allow almost-normal tidal flow. In addition to the gates, the project would bundle in defensive local measures for the city of Galveston and other sites inside the Bay, along with 43 miles of beach and dune restoration on barrier islands plus a wealth of ecosystem restoration efforts.
A far more colossal harbor barrier has been proposed for metropolitan New York, where Sandy killed more than 100 people. This humongo structure could close the Ambrose shipping channel with a five-mile barrier stretching from the Rockaways to Sandy Hook. Additionally, a one-mile barrier could close the East River.
This regional system would work together with lower onshore barriers designed to deal with sea level rise and most storms, said Robert Yaro, professor of practice at the University of Pennsylvania School of Design, at the EBC session.
However, New York City chose instead to pursue a number of very large onshore projects, with very little to show to date. “Nothing’s operational after eight years, and none of them are fully funded,” Yaro said.
“Every one of these onshore barriers is a lot more complicated, a lot more expensive and a lot more time-consuming than anybody anticipated at the outset,” he added. Many protective measures depend on deployable flood barriers, an operational nightmare. And it’s still not at all clear that there’s even a working concept to protect Wall Street, whose waterfront is particularly constrained.
“When you add up the cost of the various onshore barrier systems that have been proposed for the New York metropolitan area, they exceed the cost of an offshore barrier system,” Yaro said. He also declared that even projects on this enormous scale can be constructed in a few years if the will is there—for instance, the Army Corps of Engineers rebuilt the New Orleans barrier system in less than five years after Hurricane Katrina.
“We believe that the surge barriers that we’re proposing will give us a hundred years or more to adapt our region to climate change,” Yaro said. “We need to have some time to plan to reinvent our cities and our civilization around the even more destructive changes that may be coming.”
“We’ve got to be more resilient, but we’ve got to be smarter about how we do it,” he summed up.
For Golden, that means a deeper study of the potential for a Boston harbor barrier, leading toward a shovel-ready coastal defense plan that could tap into the federal funding that he sees on the horizon. When and if such big bucks arrive, “we need to know what we’re going to do with that money,” he said.
Living Breakwaters will bring many coastal benefits, but direct flood protection is not among them.
When Superstorm Sandy hit Staten Island at the mouth of New York Harbor, the storm surge rose to 16 feet and 24 people died. Eight years later, the island is inching ahead on raising new seawalls and rebuilding dunes and buying out properties in the zones that can’t be protected.
And launching Living Breakwaters, a pioneering “nature-based” project off the town of Tottenville in the southwestern corner of Staten Island, which is finally out for construction bids.
Living Breakwaters will install a set of eight meticulously designed, partly submerged structures aimed to reduce shoreline erosion and storm waves, help to restock local finfish and shellfish populations, and offer opportunities for community learning about marine ecosystems and social resilience.
The $60 million project originated in the Rebuild by Design competition held by the U.S. Department of Housing and Urban Development after Sandy, said project leader Kate Orff, speaking at a University of Maryland Center for Environmental Science webinar on November 5.
“What’s truly innovative about this project is it aims to be combinatory,” said Orff, founding principal of SCAPE, a landscape architecture and urban design studio in New York. “It combines risk reduction of a physical breakwater with fostering an active shoreline culture, rebuilding the shoreline, and rebuilding the three-dimensional ecological substrate through active oyster restoration.”
What Living Breakwaters won’t do is keep out floodwater.
Instead, they will work in tandem with a dune restoration project, one of whose goals is flood reduction.
“Just stopping flooding is only one of maybe 10 different concepts that we have to think about when we think about purpose,” Orff said. “If one were to build a four-foot linear seawall in this area, with any intense rain event the entire town of Tottenville would get flooded out.”
The breakwaters are configured to bring down the crests of waves coming from the east and southeast, the most common direction in storms. The structures also will minimize shoreline erosion, which is primarily driven by day-to-day waves, and help marine ecosystems recover more quickly after storms.
The design goal is to handle storms with up to 30-inch sea-level rise. “One of the nice things about breakwaters is they don’t stop functioning with sea-level rise,” commented Joseph Marrone, associate vice president and area lead for urban and coastal resiliency at the international engineering firm Arcadis. “They’ll still provide wave reduction and erosion reduction… along with the ecological benefits.”
Built with a mix of hard stone and “bio-enhancing” concrete, the breakwaters will incorporate precast tide pools and other components tailored to provide niche habitats for many marine species. Additionally, “we worked with the Billion Oyster Project and educators on shore to advance the idea of oyster gardening and rebuilding the historic reefs that were once part of this ecosystem,” Orff said.
She sees bringing back such ecosystems as an obligation in resilience projects.
Moreover, it’s critical to test these natural and nature-based measures at scale. “A 20-by-20-foot bed of wetlands won’t have a lot of impact relative to risk reduction, but larger contiguous systems absolutely will,” she said.
“As we are looking more towards natural nature-based features, because we are looking now simultaneously at the climate crisis, sea-level rise, more rainfall, et cetera, we’re also looking at a crisis of biodiversity,” Orff emphasized. “We need to begin to think about all of these things at the same time.”
And to plan more proactively, “because otherwise we’ll get constantly caught in this disaster response framework,” she said.
Resilience roadmaps should stop focusing solely on protecting today’s built shorelines, Orff suggested. Instead, they can reflect how those dynamic coastal environments might benefit from layered solutions “that can keep people safer and can also keep our shorelines living and alive and suitable for marine life,” she said. Among the options, nature-based measures often may be much better suited for the wild complexity of future environments and events.
Orff also calls for a common blue-sky vision in which the almost endless groups of coastal stakeholders all march in the same direction. “When we’re just working at this tiny scale and fighting the small battles, it feels like we’ll never add up to enough to really meet the climate crisis and ecological crisis that we’re facing,” she said.
Built on four centuries of filled land, Boston is wildly vulnerable to the next major hurricanes or winter northeasters. These risks only accelerate as storms get worse and sea levels rise. To their credit, the city and state understood this exposure years ago and have been steadily working away on climate resilience initiatives. One project was to consider a grand Boston Harbor barrier that would close off much or all of the harbor against big ocean storms. A study led by the University of Massachusetts found, however, that such a barrier would be thoroughly impractical.
But maybe not. William Golden, famous here for kicking off the legal struggles that triggered the harbor cleanup a few decades ago, today launched an open meeting of a Boston Harbor storm surge working group. The group’s premise is straightforward: the best defense against the sea is a layered defense that combines a re-thought harbor barrier (to fend off the storms) and relatively modest local measures such as berms (to handle sea level rise).
Among points by Golden and his allies:
There are many alternative barrier routes and designs, some sketched out above by Duncan Mellor of Tighe & Bond. These might mostly follow shallow water, use dual gates for the shipping channels rather than the never-built-anywhere single gate structure examined by UMass researchers, and be considerably less massive. That might make them dramatically less expensive than the $7-12 billion pricetag UMass experts suggested.
Depending on your assumptions about how long construction takes and what you pay for money (discount rates), costs again might drop significantly. And unlike smaller projects, federal funding just might be available.
A barrier that guards the entire harbor, not just Boston, could provide benefits that no one has counted yet. Most dramatically, the savings in regional flood insurance payments might be many times the investment.
The default alternative of building high local berms/seawalls everywhere brings up seriously worrying questions. For one, what about the places that can’t afford them? For another, how will all these patchwork walls connect? And do we really know how to efficiently build a watertight 20-foot seawall all along, say, the North End waterfront, with its crazy web of buried infrastructure and weak geological underpinnings?
Our safeguards against the sea will have domino effects far beyond Boston. “This is going to affect the economy of the whole region,” Golden said. “It’s an existential threat.”
Pre-filled Boston, courtesy Leventhal Map & Education Center, Boston Public Library
As climate change deepens, we’ll need to understand entirely new marine ecosystems.
Here’s the good news: Since 1990, the catch of Maine lobsters has quintupled.
Okay, the rest of the news, as in other stories about climate change, is not so good.
The bumper crops of lobsters apparently have been driven by warming in the Gulf of Maine. Sea surface temperatures have climbed about four times as much in recent decades in the Gulf as in the global ocean average, according to Andrew Pershing, chief scientific officer at the Gulf of Maine Research Institute.
Warmer water in the Gulf also has knocked down populations of other marine life, including some we eat (or once ate) such as northern shrimp and cod.
For hundreds of years, cod in the northwest Atlantic was one of the world’s richest fisheries. Back in the 1970s, my older brother took a trip to Georges Bank as a whale watcher on a giant Russian factory ship. At night, the sea looked like a city, dotted with the lights of dozens of fishing vessels busily sucking up cod and everything else on the seafloor.
Cod never recovered. The U.S. soon took control of our waters out 200 miles and managed the seafood take as well as it could. But most of the cod we eat now comes from China or Iceland.
Today climate change is delivering not just disruptions in ocean temperature and circulation patterns but acidification, extreme storms, loss of mangroves and marshes… As fisheries are disrupted around the world, the familiar difficulties of managing them get worse.
We don’t really know how to model newly emerging marine ecosystems, Tatiana Rynearson of the University of Rhode Island remarked at the Metcalf session. We lack the years of data needed to understand the fluctuations in conditions and populations, as Jorge García Molinos and colleagues pointed out in a 2015 paper.
Our need for long-term ocean monitoring and related research couldn’t be clearer, but climate change research is under heavy attack in the U.S.
Fortunately, compared to most of the waters of the world, we do have good historical information on Gulf of Maine waters and seafood. And while lobsters are a luxury food, they offer a positive example for management.
Unlike the case in some other states, Maine fishers must toss back lobsters that are too big as well as too small. Simulations have shown that saving the big ones has helped the shellfish survive the fishing onslaught in the Gulf, where 90% of legal-size lobsters are caught each year, Pershing said.
The saga of Maine lobsters, of course, rolls on. The catch dropped significantly in the last two years, and the highest landings keep moving north.
The Thames Barrier is still prepped for decades defending London against high water.
On Tuesday, the warmest winter day ever recorded in Britain, there was not a cloud in the sky over the Thames Barrier. A tug calmly pulled its barge through one of the channels in the Barrier, which shuts off the Thames when the incoming tide will rise over sixteen feet. This offbeat superdam doesn’t look like anything else: a necklace of giant steampunk silver mussel shells stretched a third of a mile across the river. London began seriously contemplating means of protection after a major dousing in the great North Sea storm of 1953. The Barrier went into operation three decades later. It has decades of usefulness ahead; although climate change was not considered in its design, sea levels along the southern English coast aren’t inching up from geologic causes as fast as originally expected. The Barrier has been shut about 200 times, 50 of them in the 2013/2014 season, when the culprit was not super surges from the ocean but super rain surges that incoming tides would have pumped up further. “It is designed to be bomb-proof and failure-proof,” the Londonist once noted. “When a 3,000-tonne dredger hit the Barrier in 1997, the ship sank. The Barrier lost a ladder.” One of these decades, the enormous wall may be supplemented by a much more enormous dike downstream. In the meantime, “the structure is fundamental to the lives of millions of Londoners,” the London Review of Bookscommented, “which may be the reason very few of them want to look at it.”
Environmental writers tell great stories about life across our fast-changing globe.
We’re seeing a remarkable series of stories about climate change and other manmade or partly manmade threats—some even complete with hints of solutions. Here’s a fairly random baker’s dozen from this striking crop (hmm, only two of these pieces come from for-profit publications).
On a clear hot August day you can take a ferry to Spectacle Island and walk a winding path up to its northern summit, admiring wildflowers and eating blackberries. The summit is the highest point of land on Boston Harbor, with low wooded islands scattered around.
Off to the east you can spot a windmill near the huge sludge-digesting eggs of Deer Island, and a second windmill a few miles south at the tip of the Hull peninsula. These two points of land bracket the entrance from Massachusetts Bay to the harbor’s inner archipelago.
One distant day, Deer Island and Hull also may anchor a massive sea barrier, holding off an ocean that’s now projected to climb as much as eight feet by 2100.
Today it’s hard to imagine how we might start to build such a Big Dike, given our current politics.
But you can also see hopeful signs on this Spectacle for our ability to clean up our own messes.
The first time I sailed past the island it was a garbage dump, with the remnants of a horse-rendering plant buried under many feet of still-smoldering refuse.
Now that’s all taken away and replaced by fill from the Big Dig. The island was reengineered and replanted. Rich ecosystems began to reappear. On summer days like this, children swim a stone’s throw away from the site of the old factories.
In wildness is the preservation of the world, as Thoreau said. But not just in wildness.