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Tag Archive: sea level rise

  1. California cliffs identified that are at risk of collapse; erosion rates will increase with sea level rise

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    • A new study analyzes cliff erosion throughout California and provides a new hazard index for determining which areas are at most risk.

    December 21, 2017 UC San Diego read full ScienceDaily article here

    ….Actively eroding cliffs make up the majority of the California coastline, and sudden landslides and collapses have caused injuries and several fatalities in recent years. In addition, eroding cliffs currently threaten highways, houses, businesses, military bases, parks, power plants, and other critical facilities — all in all billions of dollars of development.

    Research suggests that erosion rates will increase as sea level rises, further exacerbating these problems….

    ….The study…. provides accurate erosion rates for 680 miles of the California coast, from the US-Mexico border to Bodega Head in Sonoma County. It identifies areas that have eroded faster than others, and introduces a new experimental hazard scale to identify areas that may be at greater risk of impending collapse. It is the first such large-scale study in California using LiDAR data — laser elevation data recorded in aerial surveys — which were used to create detailed 3D elevation maps….

    Adam P. Young. Decadal-scale coastal cliff retreat in southern and central California. Geomorphology, 2018; 300: 164 DOI: 10.1016/j.geomorph.2017.10.010

  2. Changing climate, changing cities: Jakarta Is Sinking So Fast, It Could End Up Underwater in 10 Years

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  3. Anticipate sea level rise extremes now: we could end up with 8 ft by 2100 but won’t know until after 2050 per new study

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    • The use of a physical model indicates that emissions matter more for 21st century sea-level change than previous projections showed
    • “We could end up with 8 feet of sea level-rise in 2100, but we’re not likely to have clear evidence for that by 2050.”
    • The world can make lower sea-level rise outcomes much more likely by meeting the 2015 Paris Agreement goal of bringing net greenhouse gas emissions to zero in the second half of this century, the study shows.
    • Another study found that a 1.5 degrees Celsius world would reach a peak rate of sea-level rise about 0.7 inches per decade less than in a 2 degrees Celsius world — a potentially life-saving reduction for some vulnerable coastal ecosystems.

    December 13, 2017 Rutgers University Read full ScienceDaily article here

    The Earth faces a broad range of possible outcomes with climate change. At the less severe end, 2 feet of global-average sea-level rise by 2100 would submerge land that’s currently home to about 100 million people. Toward the high end, 6 feet of rise would swamp the current homes of more than 150 million. Either scenario would have drastic impacts in New Jersey and other coastal states.

    But the study, published today in Earth’s Future, finds that scientists won’t be able to determine, based on measurements of large-scale phenomena like global sea level and Antarctic mass changes, which scenario the planet faces until the 2060s. So coastal communities should have flexible contingency plans for a broad range of outcomes by 2100 and beyond, the study concludes….

    …The world can make lower sea-level rise outcomes much more likely by meeting the 2015 Paris Agreement goal of bringing net greenhouse gas emissions to zero in the second half of this century, the study shows. Scientists may also become able to distinguish between different scenarios sooner by studying the physics of local ice-sheet changes and refining reconstructions of changes during warm periods in geological history.

    Sea-level rise poses a potentially existential risk to Earth’s low-lying cities and coastal areas, so any projected increase needs to be taken seriously by planners, environmental officials, property owners and others

    …Kopp is also a co-author of another study, led by Tufts University researcher Klaus Bittermann and published today in Environmental Research Letters, assessing the sea-level rise benefits of achieving the Paris Agreement’s more ambitious 1.5 degrees Celsius (2.7 degrees Fahrenheit) temperature target rather than its headline 2 degrees Celsius (3.6 degrees Fahrenheit) target. That study found that a 1.5 degrees Celsius world would reach a peak rate of sea-level rise about 0.7 inches per decade less than in a 2 degrees Celsius world — a potentially life-saving reduction for some vulnerable coastal ecosystems.

    Kopp et al. Evolving Understanding of Antarctic Ice-Sheet Physics and Ambiguity in Probabilistic Sea-Level Projections. Earth’s Future (AGU). DOI: 10.1002/2017EF000663

    Summary: Recent ice-sheet modeling papers have introduced new physical mechanisms—specifically the hydrofracturing of ice shelves and the collapse of ice cliffs—that can rapidly increase ice-sheet mass loss from a marine-based ice-sheet, as exists in much of Antarctica. This paper links new Antarctic model results into a sea-level rise projection framework to examine their influence on global and regional sea-level rise projections and their associated uncertainties, the potential impact of projected sea-level rise on areas currently occupied by human populations, and the implications of these projections for the ability to constrain future changes from present observations. Under a high greenhouse gas emission future, these new physical processes increase median projected 21st century GMSL rise from ∼80 to ∼150 cm. Revised median RSL projections for a high-emissions future would, without protective measures, by 2100 submerge land currently home to more than 153 million people. The use of a physical model indicates that emissions matter more for 21st century sea-level change than previous projections showed. Moreover, there is little correlation between the contribution of Antarctic to sea-level rise by 2050 and its contribution in 2100 and beyond, so current sea-level observations cannot exclude future extreme outcomes.

  4. CA case studies on natural shoreline infrastructure for coastal resilience: NEW from NOAA, TNC, Point Blue and ESA

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    November, 2017 by Jenna Judge, NOAA Sentinal Site Cooperative (reprinted from an email)

    Case Studies of Natural Shoreline Infrastructure in California,” conducted with support from California’s Fourth Climate Change Assessment and led by Jenna Judge of the NOAA Sentinel Site Cooperative, in partnership with The Nature Conservancy, Point Blue, and Environmental Science Associates.

    Sea level rise and associated flooding will threaten nearly $100 billion worth of property along the California coast by 2100, and there is no question that coastal landowners and planners will act to protect their assets from these losses. In the absence of compelling reasons or guidance to do otherwise, they will overwhelmingly default to the industry standard – specifically, the construction of coastal armoring (seawalls, revetments, dikes, and levees).

    An alternative to coastal armoring is natural infrastructure, which has been shown to be a cost-effective approach to mitigating risk of floods, storms and sea level rise in many places. Natural infrastructure enhances the ability of natural systems to respond to sea level rise and migrate landward, ensuring their survival. In turn, these systems provide co-benefits for coastal communities: coastal ecosystems can serve as protective buffers against sea level rise and storm events while continuing to provide access, recreation opportunities, and other social benefits.

    Jenner Headlands, by Ryan DiGaudio, Point BlueJenner Headlands, Sonoma County, CA. Photo by Ryan DiGaudio/Point Blue

    In spite of the well-known advantages of natural infrastructure, property owners continue to default to coastal armoring to protect their assets. There are a number of obstacles in deploying natural infrastructure that result in this preference for coastal armoring, but among them is a documented lack of familiarity with what natural infrastructure is and how it works.

    This detailed case studies report is designed to fill this awareness gap. The case studies, highlighting projects ranging from sediment augmentation in Seal Beach to dune restoration in Humboldt, are designed to give coastal managers a sense of the breadth of approaches to coastal adaptation and what it takes to plan, permit, implement, and monitor them.

    The report can be accessed here (pdf).

    [NOTE: Point Blue scientists are also collaboratively addressing coastal resilience on a national scale with the National Fish and Wildlife Foundation, NOAA, US Army Corps of Engineers, the National Environmental Modeling and Analysis Center, and NatureServe.  We are addressing questions such as: How do we know which coastal species and which habitats will be most threatened by climate change impacts? Where will restoration and other habitat enhancement projects also benefit human communities?

    On December 13th and 14th we’re helping to bring coastal managers and stakeholders together to identify vulnerable species and areas, missing data sets, and priority restoration areas. Learn more here. Help us spread the word by sharing with coastal stakeholders you know.]

     

  5. Ice Apocalypse – Rapid collapse of Antarctic glaciers could flood coastal cities by the end of this century.

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    • High tides would creep higher, slowly burying every shoreline on the planet, flooding coastal cities and creating hundreds of millions of climate refugees. All this could play out in a mere 20 to 50 years — much too quickly for humanity to adapt.
    • Six feet of sea level rise is more likely than three feet. But if carbon emissions continue to track on something resembling a worst-case scenario, the full 11 feet of ice locked in West Antarctica might be freed up, their study showed…
    • Another recent study indicates that Pine Island’s glaciers shattered in a relatively short amount of time at the end of the last ice age.
    • A fast transition away from fossil fuels in the next few decades could be enough to put off rapid sea-level rise for centuries. That’s a decision worth countless trillions of dollars and millions of lives.

    by Eric Hothaus November 21, 2017  Read full Grist article here

    ….Land-based ice, …when it falls into the ocean, it adds to the overall volume of liquid in the seas. Thus, sea-level rise. Antarctica is a giant landmass — about half the size of Africa — and the ice that covers it averages more than a mile thick. Before human burning of fossil fuels triggered global warming, the continent’s ice was in relative balance: The snows in the interior of the continent roughly matched the icebergs that broke away from glaciers at its edges.

    Now, as carbon dioxide traps more heat in the atmosphere and warms the planet, the scales have tipped.

    A wholesale collapse of Pine Island and Thwaites would set off a catastrophe. Giant icebergs would stream away from Antarctica like a parade of frozen soldiers. All over the world, high tides would creep higher, slowly burying every shoreline on the planet, flooding coastal cities and creating hundreds of millions of climate refugees.

    All this could play out in a mere 20 to 50 years — much too quickly for humanity to adapt.

    …A study they published last year was the first to incorporate the latest understanding of marine ice-cliff instability into a continent-scale model of Antarctica. Their results drove estimates for how high the seas could rise this century sharply higher. “Antarctic model raises prospect of unstoppable ice collapse,” read the headline in the scientific journal Nature, a publication not known for hyperbole.

    Instead of a three-foot increase in ocean levels by the end of the century, six feet was more likely, according to DeConto and Pollard’s findings. But if carbon emissions continue to track on something resembling a worst-case scenario, the full 11 feet of ice locked in West Antarctica might be freed up, their study showed….

    At six feet, though, around 12 million people in the United States would be displaced, and the world’s most vulnerable megacities, like Shanghai, Mumbai, and Ho Chi Minh City, could be wiped off the map.

    At 11 feet, land currently inhabited by hundreds of millions of people worldwide would wind up underwater. South Florida would be largely uninhabitable; floods on the scale of Hurricane Sandy would strike twice a month in New York and New Jersey, as the tug of the moon alone would be enough to send tidewaters into homes and buildings…

    In a new study out last month in the journal Nature, a team of scientists from Cambridge and Sweden point to evidence from thousands of scratches left by ancient icebergs on the ocean floor, indicating that Pine Island’s glaciers shattered in a relatively short amount of time at the end of the last ice age….

    …“Every revision to our understanding has said that ice sheets can change faster than we thought,” he says. “We didn’t predict that Pine Island was going to retreat, we didn’t predict that Larsen B was going to disintegrate. We tend to look at these things after they’ve happened.”

    There’s a recurring theme throughout these scientists’ findings in Antarctica: What we do now will determine how quickly Pine Island and Thwaites collapse. A fast transition away from fossil fuels in the next few decades could be enough to put off rapid sea-level rise for centuries. That’s a decision worth countless trillions of dollars and millions of lives. “The range of outcomes,” Bassis says, “is really going to depend on choices that people make.”

    Robert M. DeConto & David Pollard. Contribution of Antarctica to past and future sea-level rise. Nature 531, 591–597 (31 March 2016). doi:10.1038/nature17145

    Matthew G. Wise et al, Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks, Nature (2017). DOI: 10.1038/nature24458
  6. From Miami to Shanghai: 3C of warming will leave world cities below sea level

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    • An elevated level of climate change would lock in irreversible sea-level rises affecting hundreds of millions of people, Guardian data analysis shows
    • local preparations for a 3C world are as patchy as international efforts to prevent it from happening. At six of the coastal regions most likely to be affected, government planners are only slowly coming to grips with the enormity of the task ahead – and in some cases have done nothing.
    • UN Environment Program said that the international body said government commitments were only a third of what was needed.

    Hundreds of millions of urban dwellers around the world face their cities being inundated by rising seawaters if latest UN warnings that the world is on course for 3C of global warming come true, according to a Guardian data analysis.

    Famous beaches, commercial districts and swaths of farmland will be threatened at this elevated level of climate change, which the UN warned this week is a very real prospect unless nations reduce their carbon emissions.

    Data from the Climate Central group of scientists analysed by Guardian journalists shows that 3C of global warming would ultimately lock in irreversible sea-level rises of perhaps two metres. Cities from Shanghai to Alexandria, and Rio to Osaka are among the worst affected. Miami would be inundated – as would the entire bottom third of the US state of Florida.

    The Guardian has found, however, that local preparations for a 3C world are as patchy as international efforts to prevent it from happening. At six of the coastal regions most likely to be affected, government planners are only slowly coming to grips with the enormity of the task ahead – and in some cases have done nothing.

    This comes ahead of the latest round of climate talks in Bonn next week, when negotiators will work on ways to monitor, fund and ratchet up national commitments to cut CO2 so that temperatures can rise on a safer path of between 1.5 and 2C, which is the goal of the Paris agreement reached in 2015.

    The momentum for change is currently too slow, according to the UN Environment Programme. In its annual emissions gap report, released on Tuesday, the international body said government commitments were only a third of what was needed. Non-state actors such as cities, companies and citizens can only partly fill this void, which leaves warming on course to rise to 3C or beyond by the end of this century, the report said….

  7. Scientific reticence on climate change- Jim Hansen

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    26 October 2017  by James Hansen read this draft discussion and find links to other papers here

    I am writing Scientific Reticence and the Fate of Humanity in response to a query from the editor of Atmospheric Chemistry and Physics who handled Ice Melt, Sea Level Rise and Superstorms. That paper, together with Young People’s Burden makes the case for a low global warming target and the urgency of phasing out fossil fuel emissions. We argue that global warming of 2°C , or even 1.5°C, is dangerous, because these levels are far above Holocene temperatures and even warmer than best estimates for the Eemian, when sea level reached 6-9 meters (20-30 feet) higher than today. Earth’s history shows that sea level adjusts to changes in global temperature. We conclude that eventual sea level rise of several meters could be locked in, if rapid emission
    reductions do not begin soon, and could occur within 50-150 years with the extraordinary climate forcing of continued “business-as-usual” fossil fuel emissions….
  8. Expect the Unexpected: SF Baylands and Climate Change – Point Blue post for Resilient by Design

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    Expecting the unexpected (originally posted for the Bay Area: Resilient By Design)

    2015-03-04 RMApano.jpgPoint Blue photos

    Trying to predict the future of our baylands could seem foolhardy given uncertainty in climate change, ecological “tipping points,” and how people prepare for these changes. Despite this, the region’s shoreline will be transformed in response to climate change and a growing human population. As we plan for the future, we must consider how to manage this transformation for people and wildlife, minimizing negative impacts and maximizing benefits.

    Securing nature’s benefits for people and wildlife

    Bay Area residents deeply value the baylands for providing healthy bird and fish habitat, improved water quality, reduced flooding, and world-class recreational opportunities. Our community’s commitment has been demonstrated by the more than  $500 million invested in wetland conservation and restoration since 1985 (as tracked by the SF Bay Joint Venture). This dedication was on full display when a supermajority of voters recently opted to tax themselves for more Baylands restoration in the face of accelerating climate change.

    PIX-CR-BN 175.jpg

    Looking forward, we need to ensure that:

    • our investments in bayland conservation are resilient to rising seas and increasingly intense storm events;
    • human assets such as roads, buildings and bridges, are protected, or appropriately relocated or redesigned;
    • underserved communities are actively engaged; and,
    • these vital adaptation endeavors entail the least cost.

    Prepare for extremes for greatest resilience

    We must also recognize that ecological change will be continuous, with sudden spurts of significant transformation.  Studies of past geologic eras, for example, show that ecosystems shifted dramatically in relatively short periods of time.  Today, we are already experiencing ecosystem transformations on a human time scale in Alaska and other parts of Earth’s polar regions where temperatures have warmed twice as fast as in the Bay Area.

    In addition, rising seas, storm events (e.g., “Superstorm” Harvey), drought and other climate change impacts continue to exceed what the science projected just a few years ago.

    Thus, the most resilient adaptation solutions will be those that are flexible and sensitive to a range of future scenarios, including extreme events at the highest end of what we know to be plausible today.

    The US Navy, for example, is now investing in strategies to address the more extreme scenarios.  According to a Harvard Business Review assessment, the Navy is raising coastal infrastructure and “improving its ability to recover rapidly when damage occurs.”  They are requiring “planners to provide additional justification when a new building is to be situated within two meters [6.6 feet] of sea-level-rise forecasts.” And, “buildings that pass this new hurdle must incorporate flood barriers and backup systems to withstand rising sea levels and storm surges.” While this “bets” approach may cost more initially, it will be essential to avoiding catastrophic outcomes from extreme and difficult to predict events.

    Highway 37: a multi-benefit, long-term approach

    “the most resilient adaptation solutions will be those that are flexible and sensitive to a range of future scenarios”

    Future planning for the Bay Area would benefit from applying the Navy’s approach.  For example, a recent UC Davis analysis of adaptation alternatives for the Highway 37 corridor, stretching from Novato to Vallejo, found that a levee embankment (making the road higher and wider to prevent flooding) would cost less than one third of a raised causeway. Given the challenges with funding transportation infrastructure improvements, it is understandable that planners may desire this alternative.

    However, the embankment would have the greatest negative ecological impacts of any of the alternatives considered.  It might constrain other future restoration alternatives in San Pablo Baylands, and will not be resilient to the high end scenarios of sea level rise and storm surge events forecasted by scientists today.  Caltrans directed UC Davis to only evaluate the costs of construction needed to prevent overtopping from three feet of sea level rise (plus a 100-year storm surge and three feet of wave run-up). This is now considered low based on the most recent science report from the state and other new studies.

    Based on these higher sea level rise projections, it is likely that the costs for the levee embankment alternative could increase substantially while the cost of the raised causeway alternatives could remain close to the same. The raised causeway options – or a bridge that would avoid the baylands entirely- would also re-establish hydrological connectivity between the baylands north of Highway 37 and the bay, reintroducing physical processes that facilitate natural adaptation to sea level rise and provide other benefits to people and wildlife.

    We urge planners, policy makers and designers, as they help the Bay Area become more resilient and responsive to continuous climate change, increasingly extreme events and unexpected transformations, to embrace Oscar Wilde’s insightful words, “To expect the unexpected shows a thoroughly modern intellect!”

  9. Students, Cities and States Take the Climate Fight to Court

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    • Several groups and individuals around the United States have gone to court to try to do what the Trump administration has so far declined to do: confront the causes and effects of global warming.
    • Efforts in the United States are part of a wave of litigation around the world, including a 2015 decision in which a court in the Netherlands ordered the Dutch government to toughen its climate policies; that case is under appeal. A 2017 report from the United Nations Environment Program found nearly 900 climate litigation suits in more than 20 countries.

    read full NY Times article here

    In California, two counties and a city recently sued 37 fossil fuel companies, seeking funds to cover the costs of dealing with a warming world. In Oregon, a federal lawsuit brought on behalf of young people is moving toward a February trial date, though the so-called children’s suit could be tossed out before that. And more than a dozen state attorneys general have sued to block Trump administration moves to roll back environmental regulations.

    ….In the new suits, Marin and San Mateo Counties and the City of Imperial Beach are accusing the oil companies of knowing that their industry would cause catastrophic climate change and covering up the evidence.

    Serge Dedina, the mayor of Imperial Beach, said his community was already dealing with coastal flooding and increasingly heavy rains, and sees more to come as the sea level rises. “How do we make sure those responsible pay the costs so that residents of communities like mine don’t have to pay the costs?” he asked.

    The supervisor for District 3 of Marin County, Kathrin Sears, said, “It’s time to hold these oil, gas and coal companies accountable for the damage they knew their products would cause.

    ….Perhaps the most effective litigators in the fight against climate change could turn out to be state attorneys general. During the Obama administration, conservative attorneys general like Oklahoma’s Scott Pruitt, who had a particularly close relationship with fossil fuel interests, fought environmental initiatives and often had private-sector players as fellow plaintiffs.

    Now Mr. Pruitt heads the Environmental Protection Agency, and progressive attorneys general, especially New York’s Eric T. Schneidermanare suing just as enthusiastically, along with environmental groups, to counter the administration’s efforts to roll back climate change regulations.

    Their pushback could already be having an effect. Last week, the Environmental Protection Agency reversed itself on a one-year delay it had announced on enforcing a rule regarding ozone — one day after attorneys general filed a lawsuit challenging the delay