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Tag Archive: sea level rise

  1. Greenland’s Coastal Ice Passed Climate Tipping Point 20 Years Ago, Melting 3x Faster, Study Says

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    • Faster-than-expected melting of Greenland’s ice fields is worrisome news for … sea level rise.

    Ice caps and glaciers along the coast of Greenland passed a tipping point in 1997, when a layer of snow that once absorbed summer meltwater became fully saturated. Since then, the coastal ice fields—separate from the main Greenland Ice Sheet—have been melting three times faster than they had been, according to a new study published Friday in the journal Nature Communications.

    “The melting ice caps are an alarm signal for the ice sheet. It means long-term ice mass loss is inevitable. It will increase and accelerate if nothing changes,” said lead author Brice Noël, a scientist at the  University of Utrecht Institute for Marine and Atmospheric Research. “It’s very unlikely the ice caps will recover. It’s a climate tipping point—the time at which a change or an effect cannot be stopped.

    Climate scientists are wary of tipping points, when a series of small changes make a much larger change inevitable. The fear is a total meltdown of the Greenland Ice Sheet, which would raise global sea level by 24 feet, Noël said. Overall, the rate of ice sheet melting is accelerating, according to peer-reviewed studies cited in the most recent Arctic report from NOAA.

    On a warming planet, there will be less snow and more rain. That will limit the formation of healthy snow that could absorb the runoff in summer. Additional melt will just run off toward the ocean, raising sea level,” he said. “What we saw there in normal conditions, before 1997, is that the snow was able to absorb most of the melt and then refreeze. So the melting was not contributing to sea level rise before 1997, even though warming was already ongoing.

    The new study, which included scientists from the Netherlands, Switzerland, Norway, Denmark and the United States, focused on coastal ice caps and glaciers at 12 locations around Greenland, tracking the melt-freeze cycle from 1958 to 2015. The sites represent a total of 38,000 square miles of ice, a little larger than Indiana….

    B. Noël et al A tipping point in refreezing accelerates mass loss of Greenland’s glaciers and ice caps Nature Communications 8, Article number: 14730 (2017) doi:10.1038/ncomms14730

     

  2. Climate breaks multiple records in 2016, with global impacts

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    March 21 2017

    The year 2016 made history, with a record global temperature, exceptionally low sea ice, and unabated sea level rise and ocean heat, according to the World Meteorological Organization (WMO). Extreme weather and climate conditions have continued into 2017.

    WMO issued its annual statement on the State of the Global Climate ahead of World Meteorological Day on 23 March. It is based on multiple international datasets maintained independently by global climate analysis centres and information submitted by dozens of WMO Members National Meteorological and Hydrological Services and Research Institutes and is an authoritative source of reference. Because the social and economic impacts of climate change have become so important, WMO partnered with other United Nations organizations for the first time this year to include information on these impacts. WMO also prepared an interactive story map to highlight some of the main trends and events in 2016.

    This report confirms that the year 2016 was the warmest on record – a remarkable 1.1 °C above the pre-industrial period, which is 0.06 °C above the previous record set in 2015. This increase in global temperature is consistent with other changes occurring in the climate system,” said WMO Secretary-General Petteri Taalas….

  3. Over time, nuisance flooding can cost more than extreme, infrequent events

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    Posted: 21 Feb 2017 12:07 PM PST ScienceDaily see full article here

    Global climate change is being felt in many coastal communities of the United States, not always in the form of big weather disasters but as a steady drip, drip, drip of nuisance flooding. These smaller events can actually be more expensive overall, researchers report

    “Catastrophic storms get a lot of media attention and are studied, but we wanted to know more about the non-extreme events,” said Amir AghaKouchak, UCI associate professor of civil & environmental engineering and co-author of a new study on cumulative hazards in the American Geophysical Union journal Earth’s Future…..

    Climate change is driving the growth of cumulative hazards, they noted. A full moon on a clear night triggering higher tides is now enough to cause flooding, because ocean levels are so high. “The frequency is increasing because of sea level rise,” AghaKouchak said. “We call it clear-sky flooding. There’s no rain, but if you have a higher-than-usual tide, you get flooding in these coastal areas.”

    While not catastrophic at the time, these episodes degrade infrastructure and can damage roads and building foundations. More immediately, nuisance flooding forces municipalities to expend resources to pump water out of streets. Communities suffer school closures, traffic interruptions, and reverberating waves of cost and inconvenience. Degraded sewer infrastructure results in heightened public health risks….

    Hamed R. Moftakhari, Amir AghaKouchak, Brett F. Sanders, Richard A. Matthew. Cumulative hazard: The case of nuisance flooding. Earth’s Future, 2017; DOI: 10.1002/2016EF000494

  4. Invasive, native marsh grasses may provide similar benefits to protected wetlands

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    Posted: 27 Feb 2017 12:03 PM PST Science Daily  full article here

    An invasive species of marsh grass that spreads, kudzu-like, throughout North American wetlands, may provide similar benefits to protected wetlands as native marsh grasses. According to new research, the invasive marsh grass’s effects on carbon storage, erosion prevention and plant diversity in protected wetlands are neutral….

    …Phragmites australis, known as the common reed, is an invasive marsh grass that can spread at rates up to 15 feet per year. It thrives throughout North American wetlands, and studies have demonstrated that its densely packed growth pattern chokes out native marsh plants, thereby reducing plant diversity and habitat used by some threatened and endangered birds.

    However, other studies have shown that Phragmites may help reduce shoreline erosion in marshlands and store carbon at faster rates than native grasses… The findings were encouraging. The team found no significant differences between ecosystem services of the marshes they studied, indicating that Phragmites‘ effect was largely neutral. However, Theuerkauf points out that the neutral effect could be due to the protected status of the wetlands they studied and the specific ecosystem services evaluated.

    “Studies that associate Phragmites with negative impacts on wetlands are often conducted in areas that have seen significant human interventions, such as shoreline development or construction of drainage canals, whereas our study was conducted in undisturbed marsh habitat within a protected reserve system,” Theuerkauf says….

    Seth J. Theuerkauf, Brandon J. Puckett, Kathrynlynn W. Theuerkauf, Ethan J. Theuerkauf, David B. Eggleston. Density-dependent role of an invasive marsh grass, Phragmites australis, on ecosystem service provision. PLOS ONE, 2017; 12 (2): e0173007 DOI: 10.1371/journal.pone.0173007

  5. Antarctic Iceberg Size of Delaware Could Break Off in Weeks

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    CIARA O’ROURKE  Feb 9, 2017 02:50 PM ET see full article here

    Scientists are eyeing a growing crack in one of Antarctica’s ice shelves. A portion of the Larcen C shelf the size of Delaware could break off in months, or even weeks — an event that could signal the impending collapse of another of the southernmost continent’s ice shelves and an ominous sign of the impacts of a warming planet.

    While that wouldn’t contribute to sea level rise around the world, ice shelves act as breaks for the flow of land ice, which lies behind them. Without ice shelves in their paths, glaciers slide more easily into the oceans, which would push up global sea levels.

    The crack in the Larsen C shelf, already more than 100 miles long and slicing through 820 feet of ice, grew another six miles in just three weeks last month. Only 12 miles of ice connects the portion that’s at risk of breaking off from the rest of the shelf….

  6. Who’s Still Fighting Climate Change? The U.S. Military

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    Despite political gridlock over global warming, the Pentagon is pushing ahead with plans to protect its assets from sea-level rise and other impacts. Here’s how.

    Laura Parker Natl Geo Feb 7 2017  See full article here

    …Sea level at Norfolk has risen 14.5 inches in the century since World War I, when the naval station was built. By 2100, Norfolk station will flood 280 times a year, according to one estimate by the Union of Concerned Scientists. This visibly changing geography made Norfolk the natural poster child for the climate challenges confronting the Defense Department—and seems as good a setting as any to consider the fate of climate science and the military in the new political era in Washington that will set the bar for how climate science is pursued by the government.

    The Defense Department has been planning for climate change for more than a decade, often in the face of roadblocks set up by climate science skeptics in Congress. In 2014 and again last year, Republicans in the House of Representatives added language to Defense Department spending bills prohibiting funds from being spent to plan or prepare for climate change. …

    The Defense Department assiduously avoids the politics of climate science debate, while pressing ahead. “We don’t talk about climate change,” Capt. Dean VanderLey told visiting journalists in a tour of the base before the election. “We talk about sea-level rise. You can measure it.”…

    …The Defense Department operates more than 555,000 facilities on 28 million acres of land with a replacement value of $850 billion, according to the Government Accountability Office. Some 1,200 military installations are in the United States. GAO auditors surveyed the military’s holdings in 2014 to assess the climate impacts. Their report, which drew little notice at the time, focused on 15 unidentified sites where sea-level rise and severe weather are damaging runways, roads, seawalls, and buildings.

  7. Giant iceberg, 5,000 square kilometers, set to calve from Larsen C Ice Shelf, Antarctica

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    British Antarctic Survey ScienceDaily 06 Jan 2017   see full article here

    A huge iceberg looks set to break away from the Larsen C ice shelf on the Antarctic Peninsula. Satellite observations from December 2016 show a growing crack in the ice shelf which suggests that an iceberg with an area of up to 5,000 square kilometers [size of Delaware] is likely to calve soon……..An ice shelf is a floating extension of land-based glaciers which flow into the ocean. Because they already float in the ocean, their melting does not directly contribute to sea-level rise. However, ice shelves act as buttresses holding back glaciers flowing down to the coast. Larsen A and B ice shelves, which were situated further north on the Antarctic Peninsula, collapsed in 1995 and 2002, respectively. This resulted in the dramatic acceleration of glaciers behind them, with larger volumes of ice entering the ocean and contributing to sea-level rise….

    The crack through Larsen C ice shelf is visible as a dark line from bottom right to top left of this satellite image. Image captured on 26 October 2016.
    Credit: Image courtesy of British Antarctic Survey…
    More from Washington Post:
    The crack in this Antarctic ice shelf just grew by 11 miles. A dramatic break could be imminent.
    An enormous rift in one of Antarctica’s largest ice shelves grew dramatically over the past month, and a chunk nearly the size of Delaware could break away as soon as later this winter, British scientists reported this week. Washington Post.  Jan 08
  8. Climate change could trigger strong sea level rise

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    International research team presents findings from frozen ‘climate archive’ of Antarctica

    Jan 5 2017  Univ of Bonn  ScienceDaily see full article here

    About 15,000 years ago, the ocean around Antarctica has seen an abrupt sea level rise of several meters. It could happen again. An international team of scientists with the participation of the University of Bonn is now reporting its findings in the magazine Scientific Reports.

    Michael E. Weber …”The changes that are currently taking place in a disturbing manner resemble those 14,700 years ago.” At that time, changes in atmospheric-oceanic circulation led to a stratification in the ocean with a cold layer at the surface and a warm layer below. Under such conditions, ice sheets melt more strongly than when the surrounding ocean is thoroughly mixed. This is exactly what is presently happening around the Antarctic….

    Iceberg in the southeastern Weddell Sea region. Credit: Photo: Dr. Michael Weber
  9. Paris climate agreement enters into force: international experts respond

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    https://theconversation.com/paris-climate-agreement-enters-into-force-international-experts-respond-68124

    Experts agree that a new era for climate policy here. But the hard work starts now.

    The Paris climate agreement, first struck in December 2015, enters into force today. The treaty commits countries worldwide to keep carbon emissions “well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5°C”.

    Countries will pursue self-determined emissions targets, agreed upon before the last round of climate talks, from 2020 onwards. The national targets will be reviewed and strengthened every five years.

    The agreement also commits richer countries to provide funding to poorer countries, which have done the least to contribute to climate change but will suffer its worst effects.

    As the world embarks on its most dedicated effort yet to prevent catastrophic climate change, The Conversation asked a panel of international experts to give their view on the significance of the agreement coming into force.

    Here’s one:

    Stefan Rahmstorf: Governments should be in emergency mode

    The Paris Agreement is the best we could have expected at this point in history. It is a beacon of hope. Almost all nations on Earth have decided to move towards net zero emissions.

    It was high time, and in some respects too late. Paris came almost exactly 50 years after the famous Revelle report from the US president’s scientific advisory panel issued a stark warning of global warming, melting ice caps and rising seas due to our carbon dioxide emissions.

    The long delay in confronting this threat is not least a result of a major, still ongoing obfuscation campaign by fossil fuel interests.

    The goal of the Paris Agreement to limit global warming to 2°C, or better 1.5°C, is necessary. Two degrees of global warming is very likely to spell the end of most coral reefs on Earth. Two degrees would mean a largely ice-free Arctic ocean in summer, right up to the North Pole.

    Two degrees would be very likely to destabilise the West Antarctic ice sheet (evidence is mounting that this has already happened). Such an increase might even destabilise the Greenland ice sheet and parts of the East Antarctic ice sheet, locking in more than ten metres of sea-level rise and sealing the fate of coastal cities and island nations.

    Some major impacts of our fossil fuel burning cannot be prevented now, thanks to the fateful delays already mentioned. But every 0.1°C of warming we avoid helps contain further massive risks to humanity, including major threats to food security.

    Because of all the time that was lost, the remaining emissions budget is very tight: at current rate, we are eating up the budget to stay below 1.5°C (with a 50:50 chance) in about ten years. The budget for 2°C would allow us to keep emitting for about 30 years. If we ramp down emissions rapidly we can stretch these budgets out to last longer, but the key here is to turn the tide of emissions now or we can give up on staying well below 2°C.

    If we take the Paris Agreement seriously (and we should), governments around the world should be in emergency mode, taking rapid and decisive measures to get their emissions down.

  10. Coastal cities at risk from rapid sea-level rise with warming above two degree

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    Coastal cities at risk from rapid sea-level rise with warming above two degree

    Posted: 08 Nov 2016 04:31 AM PST

    The first predications of coastal sea level with warming of two degrees by 2040 show an average rate of increase three times higher than the 20th century rate of sea level rise, report scientists…According to this research, by 2040 with 2 degrees centigrade warming, more than 90% of coastal areas will experience sea level rise exceeding the global estimate of 20cm, with up to 40cm expected along the Atlantic coast of North America and Norway due to ocean dynamics. Furthermore, the impact of this sea level rise will be more pronounced in locations, such as Jakarta, where there is subsidence of the land.

    Dr Svetlana Jevrejeva from the NOC, who is the lead author on this paper, said “Coastal cities and vulnerable tropical coastal ecosystems will have very little time to adapt to the fast sea level rise these predictions show, in scenarios with global warming above two degree.

    A worst case scenario considered involving 5 degrees warming shows that up to 80% of global coastlines could experience changes in sea level of over 1.8 meters by the end of 21st century. This might never happen, but could not be ruled out due to large uncertainties in the contribution of Greenland and Antarctic ice sheets in these sea level rise predications. As a result, millions of people living by the coast could be displaced and the beaches that attract tourists could be destroyed, particularly in low lying coastal cities in South East Asia and in the USA, such as Miami.”…

    -=—

    Svetlana Jevrejeva, Luke P. Jackson, Riccardo E. M. Riva, Aslak Grinsted, John C. Moore. Coastal sea level rise with warming above 2 °C. Proceedings of the National Academy of Sciences, 2016; 201605312 DOI: 10.1073/pnas.1605312113