Category Archives: Sea level rise

Greenland ice melt: Imagine a herd of 2000 elephants charging into the sea every SECOND!

2019 Arctic Report Card warns of California-sized algal blooms and imperiled livelihoods

PBS News Hour Science, December 10, 2019

A view of ice melting during a heatwave in Kangerlussuaq, Greenland is seen in this August 1, 2019 image obtained via social media. Photo by Caspar Haarloev from "Into the Ice" documentary via Reuters
A view of ice melting during a heatwave in Kangerlussuaq, Greenland is seen in this August 1, 2019 image obtained via social media. From 2002 to 2019, Greenland’s ice sheet lost 267 billion metric tons per year, on average, according to the 2019 Arctic Report Card. Photo by Caspar Haarloev from “Into the Ice” documentary via Reuters

“Two hundred sixty-seven billion tons of ice is really hard to put into context, but you could start by imagining a herd of elephants charging into the ocean from Greenland,” Osterberg said. “If you imagine that, we’re talking about 2,000 elephants charging into the ocean every second. That’s how much mass is going from Greenland into the ocean.” — Erich Osterberg, Dartmouth College climatologist

Dead seals, marked with bald patches, washing onto shores or floating in rivers. A 900-mile-long bloom of algae stretching off the coast of Greenland, potentially suffocating wildlife. A giant, underground storehouse of carbon trapped in permafrost is leaking millions of tons of greenhouse gases into the atmosphere, heralding a feedback loop that will accelerate climate change in unpredictable ways.

These are all bleak highlights from the 2019 Arctic Report Card, unveiled on Tuesday at the American Geophysical Union Fall Meeting. Published annually by the National Oceanic and Atmospheric Administration, the 14th iteration of this peer-reviewed report examines the status of the planet’s northern expanse and changes due to global warming, with potential consequences reaching around the globe.

In addition to scientific essays, this year’s report card for the first time delivers firsthand accounts from indigenous communities confronting the Arctic’s dramatic, climate-caused transformation. More than 70 such communities depend on Arctic ecosystems, which are warming twice as fast as any other location on the planet.

“In the northern Bering Sea, sea ice used to be present with us for eight months a year,” write members of the Chevak, Golovin, Nome, Savoonga, St. Paul Island, Teller, Unalakleet and Wales communities. “Today, we may only see three or four months with ice.”

The 2019 report documented sea ice at its second-lowest level ever recorded during a summer period, out of the last 41 years of satellite observations. This disappearing sea ice not only serves as a natural bridge for Native people hunting for food, but is central to creating the food in the first place. Its loss appears to be tied to dramatic shifts in marine life, as the sea ice helps create cold patches of water where Arctic fish thrive.

Sea ice cover in the Bering Sea on March 20, 2012 (left), and February 24, 2019 (right). Extremely low winter ice extents occurred in the Bering Sea in 2018 and 2019. NOAA Climate.gov image based on NASA satellite images from Worldview

Sea ice cover in the Bering Sea on March 20, 2012 (left), and February 24, 2019 (right). Extremely low winter ice extents also occurred in the Bering Sea in 2018 and 2019. NOAA Climate.gov image based on NASA satellite images from Worldview

Without those cooler pools, economically important marine species from the south — walleye pollock and Pacific cod, for example — are migrating northward, complicating business for the billion-dollar U.S. fisheries operating near Alaska in the Bering Sea.

“Major changes are occurring. For example, we closed the cod fishery early — first time in a long time — because of the decline in stocks there,” Retired Navy Rear Adm. Timothy Gallaudet, deputy NOAA administrator, said Tuesday at a press conference in San Francisco. “Our fishery science really is important to ensure we better manage what’s occurring.”

The Bering Sea and the Barents Sea appear to be the major centers of tumult. Fish leaving southern waters are challenging underwater species — like Arctic cod — for the northernmost territory, and may also consume the marine food typically eaten by seabirds, leaving other species hungry.

Over the last year, the Bering Sea has witnessed mass die-offs of short-tailed shearwaters near Bristol Bay, while the same has happened for ivory gulls in Canada, Greenland, Svalbard and Russia. Populations of Canadian ivory gulls have declined 70 percent since the 1980s, according to the report card.

“We as indigenous people have always adapted to our environment — whether something was imposed upon us or not,” Mellisa Johnson, executive director of the Bering Sea Elders, said Tuesday at a press conference in San Francisco. “The Mother Earth is doing what she needs to do because we are not taking care of our land and sea as given. We’re going to continue to adapt and move forward with the change.”

A fledgling short-tailed shearwater (Puffinus tenuirostris) on Heron Island, Australia. Shearwaters migrate north of the Bering Strait in the northern summer. Photo by Auscape/Universal Images Group via Getty Images

A fledgling short-tailed shearwater (Puffinus tenuirostris) on Heron Island, Australia. Shearwaters migrate north of the Bering Strait in the northern summer. Photo by Auscape/Universal Images Group via Getty Images

Ivory gull in Svalbard. Photo by Mats Brynolf via Getty Images

Ivory gull in Svalbard. Photo by Mats Brynolf via Getty Images

Those die-offs may also be due to the rise of algal blooms across the Arctic waterways. Red tides and other harmful algal blooms — typically a phenomena of warmer, southerly waters — are becoming more common in the north, as also detailed in last year’s report.

“Not only are we seeing these blooms in this particular region happening earlier, but they’re also substantially larger than what you would expect even later on in the year,” Karen Frey, a geographer and biogeochemist at Clark University in Worcester, Massachusetts, and co-author of the 2019 Arctic Report Card, told the PBS NewsHour.

Frey described the sea ice as a dark cap on the ocean, reflecting sunlight back into the atmosphere, keeping the algae contained and in check. When sea ice declines, large algal blooms are expected to increase.

Marine algae are essentially waterbound plants — they need sunlight and nutrients to multiply. During the winter, they’re mostly inactive because the Arctic is dark, at times for 24 hours a day. This inactivity allows nutrient to build up during the winter months. Then, as sea ice disappears in spring and summer months, sunlight can penetrate into the water, allowing algae to flourish to levels never before seen.

Without that cap, Arctic seas experiencing some of the highest algal production rates in the world, Frey said. She pointed to a 930-mile-long algal bloom — longer than California — recorded off the eastern coast of Greenland in May 2019. Based on observations from NASA’s Aqua satellite, the biomass in this bloom was 18 times higher than any event on record and occurred one month earlier than the typical peak for algal blooms. Earlier blooms suggest larger sea-choking events lasting for longer portions of the year.

Total mass change (in gigatonnes or billions of metric tons) of the Greenland ice sheet between April 2002 and April 2019. Infographic by Megan McGrew

Total mass change (in gigatonnes or billions of metric tons) of the Greenland ice sheet between April 2002 and April 2019. Infographic by Megan McGrew

Another issue highlighted in the report is the age of the sea ice, which is becoming younger and younger as the years pass. In 1985, old ice — chunks that have been frozen continuously for more than four years — accounted for 33 percent of sea ice in the Arctic ocean.

“Now, it’s just 1 percent. There’s just this little sliver of this old ice remaining,” said Erich Osterberg, a climatologist at Dartmouth College. That decline is noteworthy because older sea ice is much thicker and harder to melt. “Right now, the vast majority of the sea ice is first-year ice. It’s new ice, about 70 percent of it.”

As sea ice vanishes, it allows ocean water to warm, which in turn increases air temperatures and imperils other forms of frozen water.

Greenland, where Osterberg conducts much of his research, is home to the second-largest ice sheet on the planet — and it is disappearing. The Arctic Report Card shows that roughly 95 percent of the Greenland ice sheet melted at some point in 2019, and the magnitude of ice loss rivaled 2012 as the worst year on record. From 2002 to 2019, Greenland’s ice sheet lost 267 billion metric tons per year, on average.

“Two hundred sixty-seven billion tons of ice is really hard to put into context, but you could start by imagining a herd of elephants charging into the ocean from Greenland,” Osterberg said. “If you imagine that, we’re talking about 2,000 elephants charging into the ocean every second. That’s how much mass is going from Greenland into the ocean.”

These melts appear to be happening faster along the edges of the ice sheet, which speak to other disparities occurring across the Arctic region. Some parts of the Arctic are simply warming faster and faring worse than others from year to year. For example, snow cover over the North American Arctic was significantly lower than that of Eurasian portions, which remained normal last year.

A frozen beach on the Bering Sea coast is seen near the last stretch mushers must pass before the finish line of the Iditarod dog sled race in Nome, Alaska, March 11, 2014. The Bering Sea is experiencing the most dramatic changes in the Arctic. Photo by REUTERS/Nathaniel Wilder

A frozen beach on the Bering Sea coast is seen near the last stretch mushers must pass before the finish line of the Iditarod dog sled race in Nome, Alaska, March 11, 2014. The Bering Sea is experiencing some of the most dramatic changes in the Arctic. Photo by REUTERS/Nathaniel Wilder

The way that permafrost — perennially frozen ground — appears to be thawing may spell ill tidings for atmospheric levels of greenhouse gases. Permafrost holds the corpses of plants, animals and microbes that died in Arctic and boreal habitats over hundreds of thousands of years.

That’s a huge cache of carbon, namely along the southern borders of the Arctic and ranging from 1,460 to 1,600 billion metric tons, currently locked in the ground. If fully released, this permafrost carbon may accelerate climate change faster than currently predicted. And this year’s Arctic Report card spotlights how those gases are already leaking — to the tune of about half a billion metric tons (or 1.1 trillion pounds)–into the atmosphere.

“We’re not really accounting for this extra carbon coming out of the Arctic,” said Ted Schuur, an ecosystem scientist at Northern Arizona University who wrote the report card’s essay on permafrost. For comparison, humans burn enough fossil fuels each year to release about 10 billion metric tons of carbon.

While Arctic communities may be suffering the most now, elsewhere is starting to feel the effects, too — as the warming air disrupts weather patterns, throws off the polar jet stream and causes summer heat waves and winter cold snaps across much of North America and Europe.

“Things that we see happen in the Arctic are kind of foreshadowing what we expect elsewhere,” Schuur said.


Nsikan Akpan, digital science producer for PBS NewsHour and co-creator of the award-winning, NewsHour digital series ScienceScope.
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    Amid flooding and rising sea levels, residents of one barrier island wonder if it’s time to retreat

    The Washington Post, by  Frances Stead Sellers,  Nov. 9, 2019 PST

    OCRACOKE, N.C. — On any normal late-fall day, the ferries that ply the 30 miles between Swan Quarter and this barrier island might carry vacationing retirees, sports fishermen and residents enjoying mainland getaways after the busy summer tourist season.

    But two months ago, Hurricane Dorian washed away all signs of normalcy here. After buzz-cutting the Bahamas, the giant storm rolled overhead, raising a seven-foot wall of water in its wake that sloshed back through the harbor, invading century-old homes that have never before taken in water and sending islanders such as post office head Celeste Brooks and her two grandchildren scrambling into their attics.

    Ocracoke has been closed to visitors ever since. Island-bound ferries carry yawning container trucks to haul back the sodden detritus of destroyed homes. And O’cockers — proud descendants of the pilots and pirates who navigated these treacherous shores — are faced with a reckoning: whether this sliver of sand, crouched three feet above sea level between the Atlantic Ocean and Pamlico Sound, can survive the threats of extreme weather and rising sea levels. And if it can’t, why rebuild?

    “That’s the unspoken question. That’s what nobody wants to say,” said Erin Baker, the only doctor to serve this community of 1,000. “It’s a question of how do we continue to have life here.”

    Scientists have long warned that Ocracoke’s days are numbered, that this treasured island is a bellwether for vast stretches of the U.S. coast.

    “Virtually everyone from Virginia Beach south to the U.S./Mexico border is going to be in the same situation in the next 50 years,” said Michael Orbach, professor emeritus of marine affairs at Duke University. “And it’s only going to get worse after that.”

    If Ocracoke’s ultimate prognosis is grim, Tom Pahl, the township’s county commissioner, remains committed to its recovery.

    “Is this really sustainable? The answer is pretty clearly no,” he said. “But what’s the timeline? No one has been able to say, ‘You’ve got 15 years, 40 years, 100 years.’ The clear-eyed vision is resiliency then retreat.”

    [As North Carolina focuses on getting ahead of hurricanes, some residents are hesitant to move]

    The disaster has in some ways shortened people’s outlook.

    “I don’t think we’re thinking that far ahead right now,” said Monroe Gaskill, 64, echoing in the distinctive island brogue the immediate concerns of many “ol’ toimers”: whether the island will be open in time for duck-hunting season later this month; where students will study next semester when they have to relinquish their temporary classrooms in the old Coast Guard Station; and what will become of all the displaced residents, who are holed up in rental units, once the tourists return next Easter.

    Even as some houses are being bulldozed, neighbors are working together to raise others.

    “Now I know there is no such thing as high enough,” said Janet Spencer behind the counter of the hardware store, which reopened without power right after the storm. She and her husband jacked up their home 18 years ago — just one cinder block too few to keep out Dorian. Still, she said, long-term residents won’t leave.

    “It’s the only thing we know,” she said.

    The home of Edward and Stella O’Neal is torn down due to damage caused by flooding during Hurricane Dorian in Ocracoke. (Daniel Pullen/for The Washington Post)
    The home of Edward and Stella O’Neal is torn down due to damage caused by flooding during Hurricane Dorian in Ocracoke. (Daniel Pullen/for The Washington Post)
    Monroe Gaskill, a commercial fisherman and licensed hunter guide, said he thinks people on the island are more focused on their immediate concerns right now. (Daniel Pullen/for The Washington Post)
    Monroe Gaskill, a commercial fisherman and licensed hunter guide, said he thinks people on the island are more focused on their immediate concerns right now. (Daniel Pullen/for The Washington Post)

    There are hazards everywhere, said Amy Howard, 47, a local historian and craft store manager, and hurricanes have shaped the culture of this storied village. She showed off the floorboards her great-grandfather cut out in 1933 to relieve pressure from mounting water and prevent the house from floating off its foundations. The building was raised in 1944 after a storm, and her father plans to elevate it further.

    Alton Ballance, a descendant, like Gaskill and Howard, of the island’s earliest white settlers, has heard the call to retreat. “Time to get off that island!” one friend, an ocean scientist, has told him. “There may come a day when it’s not feasible to continue,” Ballance concedes, but for now he is methodically stripping out the old family home and installing new electrical outlets waist-high.

    “It’s easy for people in government and sometimes in the media to target a small place like this,” Ballance said, rocking back and forth on a porch swing outside the room where his mother was born.

    The Federal Emergency Management Agency provided support for rebuilding roads and other infrastructure. But a recent decision to deny residents individual assistance, which would have helped with temporary housing, has provoked ire when so many coastal communities received funds after hurricanes such as Sandy in 2012.

    FEMA said it provides the funding only when state and local resources are overwhelmed.

    North Carolina Gov. Roy Cooper has signaled his commitment to rebuilding. But the islanders’ sense of injustice reflects a broad dilemma, according to Rob Young, director of the Program for the Study of Developed Shorelines at Western Carolina University — a lack of clarity about which parts of the nation’s threatened shoreline can and should be protected.

    “There is no clear national plan,” said Young, so FEMA’s decision “comes across as arbitrary.”

    While Young does not advocate mass migration, wetter storms are raising questions about using taxpayer money to rebuild coastal communities.

    “At some point, there is going to be a breaking point,” he said, “when the public sector is either not going to want or to be able to afford to accept the risk.”

    Meanwhile, the future of the Outer Banks is made more precarious by development, said Stanley Riggs, who devoted his career at East Carolina University to studying the state’s 10,000-mile coastline.

    “We’re loving these islands to death,” Riggs said, constructing roads and bridges to bring in tourists and blocking the natural flow of tides and storms that over millennia have shaped the 175-mile string of shifting sand banks.

    What remains of Highway 12 is piled up to be hauled away after flooding caused by Hurricane Dorian. (Daniel Pullen/for The Washington Post)
    What remains of Highway 12 is piled up to be hauled away after flooding caused by Hurricane Dorian. (Daniel Pullen/for The Washington Post)

    Riggs served on a state advisory panel that in 2010 predicted more than three feet of sea-level rise by 2100, prompting a backlash from lawmakers skeptical of climate change and developers.  A compromise bill, based on a shorter timeline, passed in 2012, even as the jeopardy has become clearer here: The coastline of Cape Hatteras, north of Ocracoke, is eroding rapidly, retreating by more than a mile since Hurricane Isabel in 2003; to the south, once-vibrant Portsmouth is a ghost town.

    Sitting outside the makeshift classrooms, middle school science teacher Patricia Piland described how climate science has become real for her eighth-graders. Their curriculum this semester focuses on the hydrosphere, but she has moderated her message for students shell shocked by their narrow escape.

    “One girl said, ‘So, we’re screwed.’ ” Piland recalled. “I told them I believe we can plan for sea-level rise.” Doing so, she said, will require working with nature rather than responding to the demands of developers.

    Enrollment at the school has dropped from 174 to 157 since the storm, and Brooks, the post office head, is seeing the community fray slightly as families file change-of-address forms. “There will be more,” she predicted, weeping as she recalled the trauma of being trapped by rising water.

    Some people who lost their jobs took off quickly. Others are still deciding. Tom Parker, 66, who moved here 20 years ago, wiped away tears as he sat under the live oak tree where he has made a steady income charging tourists $1 to have their photo taken among its gnarled branches.

    “I’m tired of having this constant risk of having it all destroyed,” he said.

    But for many people who come here to wait tables or clean motel rooms, Ocracoke remains a place of opportunity, not retreat. The storm was a setback for Idalid Maldonado, a seasonal worker already facing problems this year with her visa, but she hopes it’s only a temporary one.

    She set down the wheelbarrow she has been using to lug the salt-stained contents out of guest rooms to ponder whether she will be back next summer.

    “I don’t know,” Maldonado said. “I don’t know.”

    About one-third of Ocracoke’s population is Latino, many of whom came like Maldonado to serve summer visitors and then were seduced by the gentle year-round rhythm of island life where children can roam free.

    “We talked about moving, but here, it’s a special place,” said Gloria Benitez-Perez, whose husband is in the construction business and built their house on stilts. “We are going to be fine.”

    A pile of debris grows in Ocracoke. (Daniel Pullen/for The Washington Post)
    A pile of debris grows in Ocracoke. (Daniel Pullen/for The Washington Post)
    Local artists painted and displayed signs to boost morale in Ocracoke after Hurricane Dorian. (Daniel Pullen/for The Washington Post)
    Local artists painted and displayed signs to boost morale in Ocracoke after Hurricane Dorian. (Daniel Pullen/for The Washington Post)

    But, like the shipwrecks that surface after storms, existing problems gained prominence following Dorian’s blow. Stanley “Chip” Stevens, owner of Blackbeard’s Lodge, named after the fearsome buccaneer who was beheaded here, said there has been no full accounting of Dorian’s damage and of the impact on people living in sheds and trailers who are “the backbone of our service workforce.”

    He advocates more building, not less, to support the “shadow economy” on which Ocracoke — and impoverished Hyde County — depend.

    “What the island needs is affordable housing,” Stevens said.

    Aid workers, meanwhile, comment on the extraordinary challenges of offshore construction. Every box of nails, each bottle of bleach and all the two-by-fours have to be driven out through low-lying country before being loaded for the almost three-hour ride across the Sound. Contractors face a round-trip commute of six hours or more, or they have to find a place to stay.

    There is another, shorter, route out of Ocracoke.

    North of the village, past the discarded cars and the corroded appliances, Highway 12 leads through the National Park’s windswept dunes to an isolated ferry terminal.

    Dorian chewed up the tarmac. Only four-wheel drives are allowed to make the trip, tucking in behind a tow truck that leads over rutted, chassis-scraping sand to the waiting Hatteras ferry.

    Once the road is passable — perhaps by late November — it will provide a lifeline. But it won’t restore normalcy or eliminate the sense that this little paradise is in limbo.

    “The hard part hasn’t started yet,” said Baker, the island doctor, who is monitoring patients’ stress at the metal mobile clinic shipped in to replace her flooded facility. The hurricane that pummeled the Bahamas had reduced to a Category 1 by the time it swamped Ocracoke, she said.

    “There’s a whole new level of fear for those who stay.”

    Erin Baker, the only doctor in the community of 1,000, in front of her temporary clinic. Her facility was damaged by flooding from Hurricane Dorian. (Daniel Pullen/for The Washington Post)
    Erin Baker, the only doctor in the community of 1,000, in front of her temporary clinic. Her facility was damaged by flooding from Hurricane Dorian. (Daniel Pullen/for The Washington Post)
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      Something strange is happening to Greenland’s ice sheet

      What should be like a snowcone is becoming more like a popsicle, speeding up the runoff from the melting ice sheet.

      When the remnants of Europe’s second summertime heat wave migrated over Greenland in late July, more than half of the ice sheet’s surface started melting for the first time since 2012. A study published Wednesday in Nature shows that mega-melts like that one, which are being amplified by climate change, aren’t just causing Greenland to shed billions of tons of ice. They’re causing the remaining ice to become denser.

      “Ice slabs”—solid planks of ice that can span hundreds of square miles and grow to be 50 feet thick—are spreading across the porous, air pocket-filled surface of the Greenland ice sheet as it melts and refreezes more often. From 2001 to 2014, the slabs expanded in area by about 25,000 square miles, forming an impermeable barrier the size of West Virginia that prevents meltwater from trickling down through the ice. Instead, the meltwater becomes runoff that flows overland, eventually making its way out to sea.

      As the ice slabs continue to spread, the study’s authors predict more and more of Greenland’s surface will become a “runoff zone,” boosting the ice sheet’s contribution to global sea level rise and, perhaps, causing unexpected changes.

      It’s easy to think of Greenland as a solid, impenetrable hunk of ice. But in reality about 80 percent of the ice sheet’s surface is like a snowcone: A dusting of fresh snowfall covers a thick layer of old snow, called firn, that’s slowly being compressed into glacier ice but still contains plenty of air pockets. When the top of this snow cone melts in the summer, liquid water percolates down into the firn, which soaks it up like a 100-foot-thick sponge.

      MacFerrin and his colleagues got their first hint that the firn may be losing its absorbency in the spring of 2012, when they were drilling boreholes through the firn in southwest Greenland. They started finding dense, compacted layers of ice in core after core, just below the seasonal snow layer. It was, MacFerrin says, as if a “turtle shell” had formed over the firn.

      MacFerrin and his colleagues immediately wondered whether that shell might be preventing meltwater from percolating into the firn.

      “That was May of 2012,” MacFerrin says. “And July was this record-breaking melt year, and we got our answer very quickly.”

      That summer, for the first time on record, meltwater from this part of Greenland visibly started to flow away as runoff.

      Realizing they had witnessed something significant, the researchers set about drilling more cores over a larger region to see how extensive the ice shell was. They discovered that it spanned a transect 25 miles long and was having widespread effects on local hydrology.

      Those findings, published in 2016 in Nature Climate Change, were the springboard for the new study. Using radar data from NASA’s IceBridge airborne campaign, as well as ground-based surveys, MacFerrin and his colleagues have now created a first-of-its-kind map of ice slabs across the entire surface of Greenland.

      Based on modelling results, the researchers think the shell began to form and spread widely in the early 2000s. As of 2014, it covered some 4 percent of Greenland’s surface, according to the new analysis. Every summer that extensive melting occurs, it gets thicker and spreads inland to colder, higher ground.

      “Every handful of years, these big melt summers are doing a number on the firn,” MacFerrin says. “That’s causing this whole process to grow inland pretty quickly.”

      This photo is a segment of a firn core, essentially a baby ice slab that eventually will grow into a meters-thick slab of ice.

      PHOTOGRAPH BY DR. KAREN ALLEY

      Sea level rise and unexpected consequences 

      Ice slabs have already caused Greenland’s runoff zone to expand by about 26 percent, according to the new study. So far the additional runoff has only added about a millimeter to global sea levels. Greenland now contributes a little under a millimeter per year to rising sea levels, through a combination of icebergs breaking off glaciers and melt occurring at the surface and base of the ice sheet.

      But if Greenland’s surface hardens more, runoff could rise dramatically. Under a worst-case scenario where carbon emissions continue to climb until the end of the century, the researchers calculated that ice slab proliferation could add up to 3 inches of sea level rise by 2100, boosting the ice sheet’s overall sea level rise contribution by nearly a third. In both a middle-of-the-road scenario where emissions peak by mid-century and the high emissions one, the amount of runoff from Greenland’s interior roughly doubles by century’s end.

      But more runoff is only one potential consequence of the transformation taking place in Greenland’s ice. Kristin Poinar, a glaciologist at the University of Buffalo who wasn’t involved in the study, pointed out that slabs of solid ice aren’t nearly as reflective as bright white snowfall.

      “And so, if we start getting these ice slabs forming near the ice sheet’s surface, it could potentially…cause the ice sheet to absorb more solar radiation and warm up,” she says. “And that would create more ice slabs.”

      And runoff from ice slabs doesn’t have to flow into the ocean, said Indrani Das, a glaciologist at Columbia University who wasn’t involved in the study. She worries about how it could seep into the large crevasses that exist at lower elevations on the ice sheet. From there, the runoff could, potentially, flow all the way down to bedrock, lubricating the zone where the ice makes contact with it.

      “That could make the ice sheet flow faster,” Das says, which could cause glaciers to spill their contents into the ocean more quickly, like ice cream sliding off a piece of cake.

      To Poinar, the most significant contribution of the new study is that it will allow scientists to improve their projections of future sea level rise, giving coastal communities the information they need to prepare. At the same time, the study highlights the fact that the more carbon we spew into the atmosphere, the more we’re likely to transform Earth’s northern ice sheet in insidious and unexpected ways. And that could have consequences that are difficult to anticipate.

      “We have never observed an ice sheet behaving this way before,” Poinar says. “It’s unprecedented in human scientific history.”

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        Report: How SF Bay communities should combat sea-level rise

        [Editor: Download the Adaptation Atlas  here.  There is also a 2-pg. “Highlight Bullets” and an Adaptation Atlas Interactive website. For more details about this project, visit sfei.org/adaptationatlas. To participate in a report launch webinar being held on May 2 at 2:00 PM PDT, please visit http://bit.ly/adaptationatlaswebinar.  – R.S.]

        Blueprint to battle Bay Area sea-level rise focuses on natural solutions

        By Peter Fimrite, May 2, 2019 
        The Oro Loma marshland along the Heron Bay Trail in Hayward is part of San Francisco bay’s 400 miles of shoreline. Photo: Jessica Christian / The Chronicle

        A blueprint outlining how San Francisco Bay communities should combat sea-level rise was released early Thursday by ecosystem scientists and urban planners who envision a ring of man-made reefs, rocky beaches and graded marshlands around the largest estuary on the Pacific coast.

        The carefully designed features, outlined in the 255-page San Francisco Bay Shoreline Adaptation Atlas, would in many cases replace or bury seawalls, rip rap, culverts and other crude fortifications that experts say won’t hold up as the climate warms and water rises.

        The idea, developed over the past two years by the San Francisco Estuary Institute and SPUR, a San Francisco urban planning research center, is to build eco-friendly features that support wildlife and absorb, rather than repel, the rising tides.

        The report comes at a critical time: The U.S. Geological Survey recently calculated that property damage from sea level rise in the Bay Area could exceed $100 billion by the end of the century if nothing is done to stop carbon dioxide emissions. The Union of Concerned Scientists said 4,100 homes in San Mateo County and nearly 4,400 in Marin County could be underwater by 2045.

        A duck and ducklings swim along a waterway inside the Oro Loma marshland along the Heron Bay Trail in Hayward, Calif., Wednesday, May 1, 2019. Photo: Jessica Christian / The Chronicle

        The causes of climate change need to be addressed, but at the same time, scientists and planners need to brace for the fallout, experts say. Climate scientists say the sea level at the mouth of San Francisco Bay has risen almost 8 inches over the past century.

        “The Bay Area is ground zero for sea-level rise,” said Warner Chabot, executive director of the Estuary Institute, who predicted the atlas would become a national model. “We have a trifecta threat of sea level rise, groundwater rising and lowland flooding from extreme weather patterns, and that guarantees a soupy shoreline future for the Bay Area.”

        The plan, funded by the San Francisco Bay Regional Water Quality Control Board, is the first attempt in the Bay Area to develop a collaborative regional plan to both enhance the ecosystem and protect cities around the bay from the potential ravages of climate change.

        The report was put together over the past two years in collaboration with scientists, planners and policymakers across the region. It provides graphics, explanations of ecological science and a framework for all nine Bay Area counties to build nature-like shorelines that would protect their communities.

        San Francisco Bay has 400 miles of shoreline, including airports, landfills, marinas, wetlands, beaches, ports and residential neighborhoods.

        The researchers divided the shoreline into 30 separate “operational landscape units” based on shoreline geology, terrain and infrastructure. They developed strategies for each section, including projects to re-route creeks into wetland areas, place shell structures offshore, use sediment to bolster shoreline elevations and create beaches to replace rip rap, the concrete or stone rubble placed along banks to prevent erosion.

        The study incorporates in its recommendations restoration projects that are under way, like one at Giant Marsh in North Richmond. The California State Coastal Conservancy is installing 350 reef structures there, planting eel grass and connecting the wetlands to upland habitat. The goal is to create a sloping tidal system that starts in the water with oyster shell mounds that reduce wave action, then shifts into eel grass in the sub-tidal area and eventually marshland that slows down storm surges.

        Marilyn Latta of the State Coastal Conservancy holds a miniature version of a reef structure, a living shoreline element that acts as a home for oysters and to combat sea level rise, placed off the Point Pinole shoreline in Richmond. Photo: Jessica Christian / The Chronicle
        Oyster blocks placed by the State Coastal Conservancy as a living shoreline element designed to act as a home for native oysters and combat sea level rise are seen in the water off the Point Pinole shoreline in Richmond, Calif. Wednesday, May 1, 2019. Photo: Jessica Christian / The Chronicle

        Wetlands restoration has been going on for years in the former salt ponds in the South Bay and along Highway 37 in the North Bay, buffer zones that the atlas recommends expanding. The report recommends building a Highway 37 bridge or causeway so that tidewater can better migrate into the restored wetlands.

        At least 18,000 acres of potential wetlands in the Bay Area have been acquired and are slated for restoration. The goal is to eventually restore 100,000 acres of bay marsh, much of it in the Napa and Suisun areas, along the Petaluma River and in the South Bay.

        Another idea in the report is to reroute Santa Clara County’s Calabazas Creek, which was diverted long ago, so that it flows into restored wetlands that need the sediment from the creek to grow. The wetlands near Calabazas are among 16,000 acres of former salt ponds in the South Bay that were cut off from the bay by earthen berms and dikes.

        Alameda Creek, Novato Creek and many other waterways in the Bay Area should also be realigned to help build up the marshes, said Julie Beagle, deputy director of the institute’s resilient landscape program and lead author of the study.

        “We can use the sediment that comes out of our hills,” Beagle said. “We have to think of our sediment as a resource.”

        Scientist Amy Richey, with the San Francisco Estuary Institute, views a defensive shoreline on the Heron Bay Trail in Hayward. Photo: Jessica Christian / The Chronicle

        The authors collaborated with the California Department of Transportation, the Sonoma Land Trust and several cities in Marin and Sonoma counties to identify places along Highway 37 and near Petaluma, Napa and Sonoma creeks where new wetlands could be created.

        The East Bay also is a critical area, according to the report’s authors. One example of a successful strategy, they said, is the horizontal levee built near a wastewater facility by the Oro Loma Sanitary District in Hayward. The levee uses vegetation planted on a slope that covers a vertical wall previously used to break waves. This setup allows the district to protect the facility and filter-treated wastewater through the ground instead of dumping it in the bay.

        Beagle said she would like to see the beaches that once existed from Point Richmond to the Bay Bridge restored. Instead, the Highway 80 corridor is now protected mostly by rip rap, which she said speeds up erosion by essentially increasing the power of the waves that smack into the rock.

        “There’s no reason in my mind that it can’t be a beach,” she said. “There is a huge amount of mudflats and shallow water, pocket beaches and small marshes. This is a place where different types of beaches would fit. You could even cover the rip rap with sand or a coarser, more porous material that would soften the wave action.”

        Other strategies would have to be used for areas with less room for restoration, like Foster City, which is protected by seawalls. One solution would be to engineer shell beaches or jetties that would knock down the waves and create green infrastructure to work in coordination with the wall.

        And, Beagle said, there is no way around the decrepit seawall in San Francisco, which is all that keeps the bay from reclaiming inland blocks built on landfill, including portions of the Financial District. Still, she said, it can be rebuilt as a green seawall, with pockets and textures that promote the growth of submerged aquatic vegetation, invertebrates, small mammals and fish.

        The report does not address how much money would be needed — or where it would come from — to complete the projects outlined in the report. Up to $100 billion will be needed over the next 20 years just to rebuild the Bay Area’s aging shoreline infrastructure, according to recent estimates.

        “We only have a few years to get a lot of these projects going because natural solutions take time to evolve,” Beagle said. “We need to get moving.”

        Peter Fimrite is a San Francisco Chronicle staff writer.
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