Greenhouse Gases and Sea Levels Shattered Global Records in 2020, Says NOAA

Environmental activists from Extinction Rebellion march from Trafalgar Square during the first day of Impossible Rebellion protests on August, 23, 2021 in London, United Kingdom.
Environmental activists from Extinction Rebellion march from Trafalgar Square during the first day of Impossible Rebellion protests on August, 23, 2021 in London, United Kingdom.

BYKenny StancilCommon DreamsPUBLISHEDAugust 26, 2021SHAREShare via FacebookShare via TwitterShare via Email

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Bolstering the case for meaningful climate action, a major report released Wednesday found that Earth’s atmospheric greenhouse gas concentrations and sea levels both hit record highs in 2020.

Based on the contributions of more than 530 scientists from over 60 countries and compiled by the U.S. National Oceanic and Atmospheric Administration (NOAA), State of the Climate in 2020 is the 31st installment of the leading annual evaluation of the global climate system.

“The major indicators of climate change,” officials from NOAA’s National Centers for Environmental Information pointed out in a statement, “continued to reflect trends consistent with a warming planet. Several markers such as sea level, ocean heat content, and permafrost once again broke records set just one year prior.”

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“Annual global surface temperatures were 0.97°–1.12°F (0.54°–0.62°C) above the 1981–2010 average” in 2020, said NOAA, making last year one of the three warmest on record “even with a cooling La Niña influence in the second half of the year.”

Last year was the warmest on record without an El Niño effect, and “new high-temperature records were set across the globe,” NOAA said. The agency added that the past seven years (2014-2020) had been the seven warmest on record.

Although the coronavirus-driven economic slowdown resulted in an estimated 6% to 7% reduction of carbon dioxide (CO2) emissions in 2020, the global average atmospheric concentration of CO2 increased to a record high of 412.5 parts per million. The atmospheric concentrations of other major greenhouse gases (GHG), including methane and nitrous oxide, also continued to climb to record highs last year despite the pandemic.

According to NOAA, last year’s CO2 concentration “was 2.5 parts per million greater than 2019 amounts and was the highest in the modern 62-year measurement record and in ice core records dating back as far as 800,000 years.” Moreover, “the year-over-year increase of methane (14.8 parts per billion) was the highest such increase since systematic measurements began.”

In addition, global sea levels continued to rise, surpassing previous records.

“For the ninth consecutive year,” said NOAA, “global average sea level rose to a new record high and was about 3.6 inches (91.3 millimeters) higher than the 1993 average,” which is when satellite measurements began. As a result of melting glaciers and ice sheets, warming oceans, and other expressions of the climate crisis, the “global sea level is rising at an average rate of 1.2 inches (3.0 centimeter) per decade.”

Other notable findings of the new report include:

  • Upper atmospheric temperatures were record or near-record setting;
  • Oceans absorbed a record amount of CO2, global upper ocean heat content reached a record high, and the global average sea surface temperature was the third highest on record;
  • The Arctic continued to warm at a faster pace than lower latitudes — resulting in a spike in carbon-releasing fires — and minimum sea ice extent was the second smallest in the 42-year satellite record;
  • Antarctica witnessed extreme heat and a record-long ozone hole; and
  • There were 102 named tropical storms during the Northern and Southern Hemisphere storm seasons, well above the 1981–2010 average of 85.

In contrast to the release less than three weeks ago of the latest assessment from the United Nations’ Intergovernmental Panel on Climate Change, which warned that fossil fuel emissions are intensifying extreme weather disasters — provoking a flurry of reactions and even garnering a short-lived uptick in corporate media’s coverage of the climate emergency — NOAA’s new report was met with less fanfare.

In one of the few early statements issued by members of Congress in response to the report, Rep. Eddie Bernice Johnson (D-Texas) said that “scientists sounded the alarm on the climate crisis again.”

“It is clear that without swift action, we can, unfortunately, expect to set new records like these every year,” said Johnson, chair of the House Committee on Science, Space, and Technology. “The consequences of climate change impact every American — especially disadvantaged communities — across the country; from the devastating floods in Tennessee a few days ago to the record-breaking wildfires in the West.”

“Building a better future for all means acting on climate now,” the lawmaker added. “This situation is urgent, but it’s not hopeless. We have an opportunity to lead the global response in the fight against the climate crisis — we cannot afford to waste it.”

Antarctica’s ‘Doomsday Glacier’ is fighting an invisible battle against the inner Earth, new study finds

https://www.livescience.com/antarctica-doomsday-glacier-geothermal-heat-map

By Brandon Specktor about 8 hours ago

Underground heat is cooking the Thwaites Glacier from below, and could push it closer to collapse.

Antarctica's Twaites Glacier, climate change, ice melt

Antarctica’s Twaites Glacier is facing an assault of heat from the sky, the sea and deep underground. (Image credit: NASA)

West Antarctica is one of the fastest-warming regions on Earth. For evidence, you need look no further than Thwaites Glacier — also known as the “Doomsday Glacier.”

Since the 1980s, Thwaites has lost an estimated 595 billion tons (540 billion metric tons) of ice, single-handedly contributing 4% to the annual global sea-level rise during that time, Live Science previously reported. The glacier’s rate of ice loss has accelerated substantially in the past three decades, partially due to hidden rivers of comparatively warm seawater slicing across the glacier’s underbelly, as well as unmitigated climate change warming the air and the ocean.

Now, new research suggests that the warming ocean and atmosphere aren’t the only factors pushing Thwaites to the brink; the heat of the Earth itself may also be giving West Antarctica’s glaciers a disproportionately nasty kick.

In a study published Aug. 18 in the journal Communications Earth & Environment, researchers analyzed geomagnetic field data from West Antarctica to create new maps of geothermal heat flow in the region — essentially, maps showing how much heat from Earth’s interior is rising up to warm the South Pole.

The researchers found that the crust beneath West Antarctica is considerably thinner than in East Antarctica — roughly 10 to 15 miles (17 to 25 kilometers) thick in the West compared with about 25 miles (40 km) thick in the East — exposing Thwaites Glacier to considerably more geothermal heat than glaciers on the other side of the continent.

“Our measurements show that where the Earth’s crust is only 17 to 25 kilometers thick, geothermal heat flow of up to 150 milliwatts per square meter can occur beneath Thwaites Glacier,” lead study author Ricarda Dziadek, a geophysicist at the Alfred Wegener Institute (AWI), Helmholtz Centre for Polar and Marine Research in Germany, said in a statement.

Because West Antarctica sits in an oceanic trench, the crust beneath the seabed is much thinner than the crust below East Antarctica. Scientists have long suspected that this comparatively thin crust must be absorbing more heat from the planet’s upper mantle (which experiences average temperatures of 392 degrees Fahrenheit, or 200 degrees Celsius), impacting the formation and evolution of glaciers there over millions of years.

In the new study, the researchers quantified that difference in heat flow for the first time. Using a variety of magnetic field datasets, the team calculated the distance between the crust and the mantle at various spots throughout Antarctica, as well as the relative heat flow in those areas.

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It’s hard to tell exactly how warm the glacier is where the ice meets the seabed, as different types of rock conduct heat differently — however, the researchers said, it’s clear that this extra supply of heat in the West can only mean bad news for Thwaites.

“Large amounts of geothermal heat can, for example, lead to the bottom of the glacier bed no longer freezing completely or to a constant film of water forming on its surface,” study co-author Karsten Gohl, also a geologist at AWI, said in the statement. Either of these conditions could cause the glacier’s ice to slide more easily over the ground, causing the glacier’s ice loss to “accelerate considerably,” Gohl added.RELATED CONTENT

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A scenario like that could put the Doomsday Glacier’s name to the test; if Thwaites Glacier were to entirely collapse into the ocean, global sea levels would rise by about 25 inches (65 centimeters), devastating coastline communities around the world, Live Science previously reported. What’s more, without the glacier plugging the edge of the West Antarctic Ice Sheet like a cork in a bottle of wine, ice loss could accelerate dramatically in the entire region, leading to unprecedented levels of sea level rise.

Researchers will soon have a chance to further hone their measurements of the heat flow below Antarctica. A major international research project is currently underway at the South Pole, including missions to drill ice cores that stretch down to the bed of Thwaites Glacier. Heat flow measurements from these core samples could give scientists a better idea of how much time is left on the Doomsday Glacier’s ticking clock.

Online Map Shows How Rising Sea Levels Will Impact Humanity

https://www.forbes.com/sites/davidbressan/2021/08/10/online-map-shows-how-rising-sea-levels-will-impact-humanity/?sh=cb63e9e5a8a2

Aug 10, 2021,08:09am EDT|39,741 views

David BressanContributorScienceI deal with the rocky road to our modern understanding of earthFollow

NASA_JPL_online_visualization_sea_level_change
A new visualization tool will make data on future sea level rise from the Intergovernmental Panel on … [+] NASA/JPL-CALTECH

NASA’s Sea Level Change Team has created a sea level projection tool based on the Intergovernmental Panel on Climate Change (IPCC) report that visualizes the impacts of future sea level rise on coastlines and communities.

More than 600 million people (around 10 percent of the world’s population) live in coastal areas that are less than 10 meters (32 feet) above sea level.

Global mean sea levels rose by about 20 centimeters (almost 1 foot) between 1901 and 2018, faster than any time in the last 3,000 years.https://embedly.forbes.com/widgets/media.html?src=https%3A%2F%2Fwww.youtube.com%2Fembed%2Fm5PPURqEONI&display_name=YouTube&url=https%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3Dm5PPURqEONI&image=http%3A%2F%2Fi.ytimg.com%2Fvi%2Fm5PPURqEONI%2Fhqdefault.jpg&key=3ce26dc7e3454db5820ba084d28b4935&type=text%2Fhtml&schema=youtube

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Models of future sea level rise generally hover around a meter (3 feet) or so within the next 100 years, but how much ice will melt, the temperature of the oceans, oceanic currents, tidal range and coastal geomorphology will affect the local sea level change.

The online map allows users to click anywhere on the global ocean and coastlines, and pick any decade between 2020 and 2150: The tool then will deliver a detailed report for the location based on the projections in the IPCC’s Sixth Assessment Report, released on August 9, which addresses the most updated physical understanding of the climate system and climate change.MORE FOR YOUWhy We Need To Explore The ‘Shakespearean’ Ocean Moons Of Uranus—And There’s No Time To WasteMeteor Shower Tonight? Why You Need To Know Precisely When The Perseids Peak Where You Live To See ‘Shooting Stars’This Is Why Quantum Mechanics Isn’t Enough To Explain The Universe

The IPCC has provided global-scale assessments of Earth’s climate every five to seven years since 1988, focusing on changes in temperature, ice cover, greenhouse gas emissions, and sea level across the planet. Their sea level projections are informed by data gathered by satellites and instruments on the ground, as well as analyses and computer simulations.

“What’s new here is a tool that we are providing to the community, to distribute the latest climate knowledge produced by the IPCC and NASA scientists in an accessible and user-friendly way while maintaining scientific integrity,” said Nadya Vinogradova Shiffer, program scientist and manager at NASA, who directs NASA’s Sea Level Change science team.

“As the first data-delivery partnership between the IPCC and a federal agency, NASA’s new sea level projection tool will help pave the way for future activities that facilitate knowledge sharing, open science, and easy access to the state-of-the-art climate science. This information is critical to increase climate resilience of nations with large coastal populations, infrastructure, and economies that will be impacted by sea level rise,” said Vinogradova Shiffer.

Along with providing snapshots of rising sea levels in the decades to come, the tool enables users to focus on the effects of different processes that drive sea level rise. Those processes include the melting of ice sheets and glaciers and the extent to which ocean waters shift their circulation patterns or expand as they warm, which can affect the height of the ocean.

“As communities across the country prepare for the impacts of sea level rise, access to good, clear data is key to helping save lives and livelihoods,” said NASA Administrator Bill Nelson. “NASA’s new sea level projection tool will arm the American people and decision makers with the information needed to make critical decisions about economic and public policy, to protect our communities from the potentially devastating effects of sea level rise.”

The tool can display possible future sea levels under several greenhouse-gas-emission and socioeconomic scenarios. A low-emissions future limiting global warming to 1.5 degrees, a “business as usual” trajectory with emissions on their current track and a projected global warming of 2 to 4 degrees above preindustrial levels by the end of the century, and an “accelerated emissions” scenario with temperatures rising well beyond 4 degrees. A low-emission future, for example, would occur if humanity reduces its greenhouse gas emissions, lessening the effects of climate-driven sea level change. A high-emission projection would lead to the most rapid and significant rise in sea level. Warming of over 2 degrees could be enough for Greenland’s ice sheet to melt, which would cause sea levels to rise globally by more than 2 meters (6 feet), TheScientist website reportsRising sea levels not only will displace an estimated 267 million people worldwide, but increase the risk for floods, cause beach erosion and habitat loss for animals and plants living on or near the shoreline.

“The goal is to deliver the projection data in the IPCC report in a usable form while also providing easy visualization of the future scenarios,” said Ben Hamlington, a research scientist at NASA’s Jet Propulsion Laboratory in Southern California, who leads the agency’s Sea Level Change science team.

The sea level projection tool should help people at all levels of government in countries around the world to forecast future scenarios and to develop coastal resources accordingly. “Making sea level science accessible is our primary goal,” said Carmen Boening, a NASA oceanographer who also heads the agency’s Sea Level Portal, which hosts the projection tool.

Another interactive atlas released by the IPCC shows temperature and precipitation changes on a global scale according to the climate change scenarios used to model the sea levels.

Climate change, rising seas may lead to extinction of small island nations

https://www.nbcnews.com/news/world/climate-change-rising-seas-may-lead-extinction-small-island-nations-n1276394

“Climate emergency is intensifying, we are on the front lines,” Mohamed Nasheed, the president of the Maldives, said.YOUR VIDEO BEGINS IN: 00:15TAP TO UNMUTE

Aug. 10, 2021, 5:28 AM PDTBy Patrick Smith

Island nations across the world are warning that they face catastrophic consequences of rising sea levels and possible extinction, after a landmark U.N. report warned of the effects of a warming world.

An alliance of 39 coastal and low-lying nations said the Intergovernmental Panel on Climate Change report was a “major alert for the world” and called on more powerful countries to do all they can to keep global warming to no more than 1.5 degrees Celsius to “save lives and livelihoods.”

“We have to turn this around,” Diann Black-Layne, the lead negotiator for the Alliance of Small Island States, said in a statement Monday after the IPCC report was released.

“The IPCC confirms the experience of small island states: that cyclones are getting more intense, and that sea levels are rising, but it also confirms we can still curb the worst of it.”

Image: Large parts of the village Eita has drowned in flooding from the sea, Kiribati.
Large parts of the village Eita has drowned in flooding from the sea, Kiribati.Jonas Gratzer / LightRocket via Getty Images file

Keeping temperature rises to 1.5 degrees Celsius (2.7 Fahrenheit) instead of 2 degrees Celsius, a target of the 2015 Paris climate agreement, would avoid a long-term rise of three meters (9.6 feet), she said.

“That is our very future, right there,” she said.

The IPCC report, released Monday, warned that while warming could be stopped by halting carbon emissions, sea levels would continue to rise even in a best-case scenario, putting coastal communities at risk of flooding and destruction.

Download the NBC News app for breaking news and politics

The Alliance of Small Island States represents countries across the world, including Singapore, Seychelles, Fiji, Papua New Guinea, Dominican Republic, Cuba, the Bahamas and Belize.

So concerned is the remote nation of Kiribati in the Pacific, made up of three low-lying archipelagos that at their tallest stand no more than 6 feet above sea level, that plans have been made to physically raise its islands above the sea, in partnership with China.

A rise of just 3 feet could submerge as much as two thirds of Kiribati by the end of this century, the IPCC has said.

Mohamed Nasheed, president of the Maldives, one of the world’s lowest-lying countries, which has for years campaigned for climate action, said the situation could not be more serious.

“This report is devastating news for the most climate-vulnerable countries like the Maldives. It confirms we are on the edge of extinction. Climate emergency is intensifying, we are on the front lines. Our nations are already battered by extreme climate,” he said on Twitter.

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Kimberly Nicholas, a professor and climate and sustainability expert at Lund University in Sweden who has acted as an observer at two global climate summits, said the Maldivian president was right in his assessment.

“I think it’s probably fair. That’s how I would feel if I lived in one of those low-lying island nations,” she told NBC News.

Image: An area of reclaimed land is pictured on the island of Thulusdhoo on Dec.10, 2019 near Male, Maldives.
An area of reclaimed land is pictured on the island of Thulusdhoo in 2019, near Male, Maldives.Carl Court / Getty Images file

“Humans do have the power to stop warming pretty quickly and that’s good news. When we stop adding carbon pollution we expect warming to stop.

“But there are things such as sea level rise that are not reversible. The report says the sea level is committed to rise, due to continuing warming of the deep ocean and ice sheet melts,” Nicholas said.

Joseph Moeno-Kolio, head of the Pacific region for the environmental activist group Greenpeace, blamed Australia — a major carbon emitter and exporter of fossil fuels — for exacerbating the crisis for neighboring islands.

“Australian Prime Minister Scott Morrison met last week with Pacific leaders and committed to supporting the Pacific family,” he said in a statement. “This report has found that if Morrison’s obsession with fossil fuels isn’t immediately ended, these words might one day be nothing more than an empty lament on the family tomb.”

Climate change is largely caused by big, prosperous nations while smaller coastal countries tend to be much poorer. Nicholas warned this disparity would see those that pollute the least suffer the most.

“It’s really clear how unfair climate change is,” she said. “It’s primarily caused by burning fossil fuels, and it’s a few countries and individuals within countries who burned the majority of it and enjoyed the benefits they provided.

“The majority of the world has not burned much carbon at all and is suffering the worst impact. That equity dynamic is so important to keep in mind.”

Speaking at a news conference Tuesday, Morrison accepted that his country had a part to play in reducing climate change, but defended Australia’s record and said carbon emissions had dipped 20 percent since 2005.

He argued that the developing world accounted for two thirds of carbon emissions and that China’s output was “more than the OECD combined.”

“The emissions keep going up because of the choices that [developing nations] will necessarily make. And, so, what’s important is that we ensure that the technology breakthroughs that are necessary to transform the world over the next 10, 20 and 30 years are realized,” he said.

Meltwater Pulse 1A: Melting Ice Sheets Caused Sea Levels to Rise Up to 18 Meters

TOPICS:Climate ChangeDurham UniversityOceanographySea Level

By DURHAM UNIVERSITY APRIL 16, 2021

Melting Ice Arctic Antarctic Concept

It is well known that climate-induced sea level rise is a major threat. New research has found that previous ice loss events could have caused sea-level rise at rates of around 3.6 meters per century, offering vital clues as to what lies ahead should climate change continue unabated.

A team of scientists, led by researchers from Durham University, used geological records of past sea levels to shed light on the ice sheets responsible for a rapid pulse of sea-level rise in Earth’s recent past.

Geological records tell us that, at the end of the last ice age around 14,600 years ago, sea levels rose at ten times the current rate due to Meltwater Pulse 1A (MWP-1A); a 500 year, ~18 meter sea-level rise event.

Until now, the scientific community has not been able to agree about which ice sheet was responsible for this rapid rise, with the massive Antarctic Ice Sheet being a likely suspect, but some evidence pointing towards ice sheets in the Northern Hemisphere.

The new study uses detailed geological sea-level data and state-of-the-art modeling techniques to reveal the sources of MWP-1A. Interestingly, most of the meltwater appears to have originated from the former North American and Eurasian ice sheets, with minimal contribution from Antarctica, reconciling formerly disparate views.

In addition to flooding vast areas of low-lying land, this unparalleled discharge of freshwater into the ocean — comparable to melting an ice sheet twice the size of Greenland in only 500 years — will have disrupted ocean circulation, with knock-on effects for global climate. Knowing the source of the meltwater will improve the accuracy of climate models that are used to replicate the past and predict changes in the future.

The results are important for our understanding of ice-ocean-climate interactions which play a significant role in shaping terrestrial weather patterns. The findings are particularly timely with the Greenland ice sheet rapidly melting, contributing to a rise in sea levels and changes to global ocean circulation.

Of the findings, lead author Yucheng Lin, in the Department of Geography at Durham University notes: “Despite being identified over 30 years ago, it has been surprisingly challenging to determine which ice sheet was the major contributor to this dramatic rise in sea levels.

“Previously, scientists tried to work out the source of the sea-level rise based on sea-level data from the tropics, but the majority of those studies disagreed with geological records of ice sheet change.

Our study includes novel information from lakes around the coast of Scotland that were isolated from the ocean due to land uplift following the retreat of the British Ice Sheet, allowing us to confidently identify the meltwater sources.”

Co-author Dr. Pippa Whitehouse, in the Department of Geography at Durham University said “The technique we have used allows us to really dig into the error bars on the data and explore which ice-melt scenarios were most likely.

“We found that most of the rapid sea-level rise was due to ice sheet melt across North America and Scandinavia, with a surprisingly small contribution from Antarctica.

“The next big question is to work out what triggered the ice melt, and what impact the massive influx of meltwater had on ocean currents in the North Atlantic. This is very much on our minds today — any disruption to the Gulf Stream, for example due to melting of the Greenland Ice Sheet, will have significant consequences for the UK climate.”

Rising sea levels due to warming climate pose a great risk to society, improving our understand of why and how fast change could happen will help us plan for the impacts.

Reference: “A reconciled solution of Meltwater Pulse 1A sources using sea-level fingerprinting” by Yucheng Lin, Fiona D. Hibbert, Pippa L. Whitehouse, Sarah A. Woodroffe, Anthony Purcell, Ian Shennan and Sarah L. Bradley, 1 April 2021, Nature Communications.
DOI: 10.1038/s41467-021-21990-y

Yucheng Lin is funded by a Durham University – China Scholarship Council joint scholarship.

The Scotland data was collected and analysed by Durham University researchers, funded by the Natural Environment Research Council.

Current climate model simulations overestimate future sea-level rise

https://phys.org/news/2021-04-current-climate-simulations-overestimate-future.html

APRIL 9, 2021

by Utrecht University, Utrecht University Faculty of Science

sea
Credit: CC0 Public Domain

The melting rate of the Antarctic ice sheet is mainly controlled by the increase of ocean temperatures surrounding Antarctica. Using a new, higher-resolution climate model simulation, scientists from Utrecht University found a much slower ocean temperature increase compared to current simulations with a coarser resolution. Consequently, the projected sea-level rise in 100 years is about 25% lower than expected from the current simulations. These results are published today in the journal Science Advances.https://65cf01d7103f8788f2c2aecbe76ab80c.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html

Estimates for future sea-level rise are based on a large ensemble of climate model simulations. The output from these simulations helps to understand future climate change and its effects on the sea level. Climate researchers continually aim to improve these models, for example by using a much higher spatial resolution that takes more details into account. “High-resolution simulations can determine the ocean circulation much more accurately,” says Prof. Henk Dijkstra. Together with his Ph.D. candidate René van Westen, he has been studying ocean currents in high-resolution climate model simulations over the past few years.

Ocean eddies

The new high-resolution model takes into account ocean eddy processes. An eddy is a large (10-200 km) swirling and turbulent feature in the ocean circulation, which contributes to the transport of heat and salt. Adding ocean eddies into the simulation leads to a more realistic representation of the ocean temperatures surrounding Antarctica, which is key for determining the mass loss of the Antarctic ice sheet. “The Antarctic ice sheet is surrounded by ice shelves which reduce the flow of land ice into the ocean,” Van Westen explains. “Higher ocean temperatures around Antarctica increase the melting of these ice shelves, resulting in an acceleration of land ice into the ocean and consequently leading to more sea-level rise.”https://www.youtube.com/embed/a9m61TsJDa0?color=whiteComparison of the new high-resolution model (left) with the previously used low-resolution one (right). Credit: Utrecht University

The current climate model simulations, which do not take ocean eddies into account, project that the ocean temperatures around Antarctica are increasing under climate change. The new high-resolution simulation shows quite different behavior and some regions near Antarctica even cool under climate change. “These regions appear to be more resilient under climate change,” says Van Westen. Dijkstra adds: “One obtains a very different temperature response due to ocean-eddy effects.”

Supercomputer

The new high-resolution model projects a smaller mass loss as a result of ice-shelf melt: only one third compared to current climate models. This reduces the projected global sea-level rise by 25% in the upcoming 100 years, Van Westen mentions. “Although sea levels will continue to rise, this is good news for low-lying regions. In our simulation, ocean eddies play a crucial role in sea-level projections, showing that these small-scale ocean features can have a global effect.”

It took the team about one year to complete the high-resolution model simulation on the national supercomputer at SURFsara in Amsterdam. Dijkstra: “These high-resolution models require an immense amount of computation, but are valuable as they reveal smaller-scale physical processes which should be taken into account when studying climate change.”


Explore furtherAntarctic ice loss expected to affect future climate change

Melting ice sheets caused sea levels to rise up to 18 meters

https://phys.org/news/2021-04-ice-sheets-sea-metres.html

APRIL 1, 2021

by Durham University

Melting ice sheets caused sea levels to rise up to 18 metres
An isolation lake in north-west Scotland. Sediment analysed from the bottom of this low-lying lake tells us that it was once connected to the ocean. Credit: Professor Ian Shennan, Department of Geography, Durham University.

It is well known that climate-induced sea level rise is a major threat. New research has found that previous ice loss events could have caused sea-level rise at rates of around 3.6 meters per century, offering vital clues as to what lies ahead should climate change continue unabated.https://157f41d0b4c5fff7dd16ec13b546e18a.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html

A team of scientists, led by researchers from Durham University, used geological records of past sea levels to shed light on the ice sheets responsible for a rapid pulse of sea-level rise in Earth’s recent past.

Geological records tell us that, at the end of the last ice age around 14,600 years ago, sea levels rose at ten times the current rate due to Meltwater Pulse 1A (MWP-1A); a 500 year, ~18 meter sea-level rise event.

Until now, the scientific community has not been able to agree about which ice sheet was responsible for this rapid rise, with the massive Antarctic Ice Sheet being a likely suspect, but some evidence pointing towards ice sheets in the Northern Hemisphere.

The new study uses detailed geological sea-level data and state-of-the-art modelling techniques to reveal the sources of MWP-1A. Interestingly, most of the meltwater appears to have originated from the former North American and Eurasian ice sheets, with minimal contribution from Antarctica, reconciling formerly disparate views.

In addition to flooding vast areas of low-lying land, this unparalleled discharge of freshwater into the ocean—comparable to melting an ice sheet twice the size of Greenland in only 500 years—will have disrupted ocean circulation, with knock-on effects for global climate. Knowing the source of the meltwater will improve the accuracy of climate models that are used to replicate the past and predict changes in the future.

The results are important for our understanding of ice-ocean-climate interactions which play a significant role in shaping terrestrial weather patterns. The findings are particularly timely with the Greenland ice sheet rapidly melting, contributing to a rise in sea levels and changes to global ocean circulation.

Of the findings, lead author Yucheng Lin, in the Department of Geography at Durham University notes: “Despite being identified over 30 years ago, it has been surprisingly challenging to determine which ice sheet was the major contributor to this dramatic rise in sea levels.

“Previously, scientists tried to work out the source of the sea-level rise based on sea-level data from the tropics, but the majority of those studies disagreed with geological records of ice sheet change.

Our study includes novel information from lakes around the coast of Scotland that were isolated from the ocean due to land uplift following the retreat of the British Ice Sheet, allowing us to confidently identify the meltwater sources.”

Co-author Dr. Pippa Whitehouse, in the Department of Geography at Durham University said “The technique we have used allows us to really dig into the error bars on the data and explore which ice-melt scenarios were most likely.

“We found that most of the rapid sea-level rise was due to ice sheet melt across North America and Scandinavia, with a surprisingly small contribution from Antarctica.

“The next big question is to work out what triggered the ice melt, and what impact the massive influx of meltwater had on ocean currents in the North Atlantic. This is very much on our minds today—any disruption to the Gulf Stream, for example due to melting of the Greenland Ice Sheet, will have significant consequences for the UK climate.”

Rising sea levels due to warming climate pose a great risk to society, improving our understand of why and how fast change could happen will help us plan for the impacts.

The study is published in Nature Communications.

Sea-level rise is accelerating to its highest levels in at least 2,000 years across the Northeast, including New York City, study says

https://www.cnn.com/2021/03/26/weather/sea-level-rise-accelerating-east-coast/index.html

By Jackson Dill and Brandon Miller, CNN

Updated 9:41 AM ET, Fri March 26, 2021Rising water caused by Hurricane Sandy rushes into the Carey Tunnel (formerly the Brooklyn-Battery Tunnel), on October 29, 2012 in New York City. Rising water caused by Hurricane Sandy rushes into the Carey Tunnel (formerly the Brooklyn-Battery Tunnel), on October 29, 2012 in New York City.

(CNN)Along a stretch of the East Coast that includes New York City, sea-level rise has increased at its fastest rate in the prior 100 years compared to the past 2,000 years, according to a new study led by Rutgers University.”The global rise in sea-level from melting ice and warming oceans from 1900 to 2000 led to a rate that’s more than twice the average for the years 0 to 1800 — the most significant change,” Rutgers said of the study’s findings.The study uses new techniques and focuses on six specific locations in the northeastern US, including three in New Jersey and one each in Connecticut, New York and North Carolina.Human-induced climate change is fueling this more dramatic rise. The research shows that emissions of carbon dioxide and other greenhouse gases by humans burning fossil fuels have warmed up our planet, causing the oceans to warm and glaciers to melt.

Sea-level ‘budgets’ break down contributors to rising water

This research is the first of its kind to utilize what the researchers call “sea-level budgets” while determining the rate at which the ocean is rising over an extensive period.close dialog

Do you want the news summarized each morning?We’ve got you.Sign Me UpBy subscribing you agree to ourprivacy policy.A sea-level budget examines the change in sea level over time at global, regional and local scales. It breaks down how sea level is affected by different phenomena, which are divided into scales. At each of these scales, there are various factors that contribute to the rising water levels, or in some cases falling levels.At the global scale, for example, factors such as water temperatures play a role while at a local scale, the budget may consider land subsidence, which can vary by town.”If you want to know what’s driving the sea level change, this budget approach is a way to break down those individual components,” said Jennifer Walker, the lead author of this study and a post-doctoral researcher at Rutgers University.What this research has found is that the rising levels at these locations does succeed any falls over the time period examined.”Regional land sinking was the dominant component of sea level change on those long timescales,” explained Walker.

Sea level rise is increasing fastest in populous coastal areas, study says

Sea level rise is increasing fastest in populous coastal areas, study saysThe study found that southern New Jersey has had the largest sea-level rise in the past 2,000 years because of sinking land.This land subsidence “is from the effect of the Laurentide ice sheet from our last Ice Age,” Walker told CNN. “The ice sheet retreated thousands of years ago, and the land is still readjusting from the effect of that past sheet.”There are also other factors, which include groundwater extraction and changing ocean currents.”US East Coast sea level rise rates are elevated because of the slowing Gulf Stream,” said Brian McNoldy, a senior research associate at the University of Miami Rosenstiel School of Marine and Atmospheric Science, who was not part of the study.Walker added that over the past 200 years roughly, “We have rates that are double the average, compared to the last 2,000 years … Where it used to be this regional land sinking being the dominant force, now it’s this global component, which is driven by the ice melt and warming of the oceans.”These graphics show the sea level rise rates over time by each sea-level budget. The light gray resembles the most dominant budget, linear. This category factors in land subsidence caused by the natural compaction of land and the Laurentide ice sheet melting. The pie charts also highlights how the linear sea-level budget is the largest component of sea-level rise in New Jersey. The other shadings on the graphs signify the three other sea-level budgets: global (red), regional non-linear (light blue) and local (purple). The dashed black line on the graphs shows the total sea level rise when combining these four budgets.These graphics show the sea level rise rates over time by each sea-level budget. The light gray resembles the most dominant budget, linear. This category factors in land subsidence caused by the natural compaction of land and the Laurentide ice sheet melting. The pie charts also highlights how the linear sea-level budget is the largest component of sea-level rise in New Jersey. The other shadings on the graphs signify the three other sea-level budgets: global (red), regional non-linear (light blue) and local (purple). The dashed black line on the graphs shows the total sea level rise when combining these four budgets.At this global scale, sea level rise was found to have been primarily caused by “increased ocean mass and volume from glacier and ice sheet melt and thermal expansion on a global scale in response to greenhouse forcing of warming sea surface and surface air temperatures,” the research states.While the sea-level budgets have risen in at least the past century, over time some have fallen, too. Prior to around 1600 of the Common Era, the regional non-linear budget had a decreasing sea level rate. These lowering sea levels are likely caused by “broad climate transitions in the North Atlantic,” according to the research. This includes pressure patterns over the North Atlantic, which basically is where the low and high pressure systems are located.

Climate change is causing rates to accelerate

These global factors were not a dominant contributor to sea-level rise prior to the year 1800, but that has changed in recent times. “The increasing influence of the global component is the most significant change in the sea-level budgets at all six sites,” according to the study.This means that humans are causing the seas to rise and that they are dominating Earth’s systems, scientists say.The data collected for a location in northern New Jersey shows that from 1400 to 1500 CE, global budget sea levels likely rose at a rate of 0.13 millimeters per year. A few hundred years later in the period from 1900 to 2000, or the 20th century, the rate increased drastically to 1.30 millimeters per year.Meanwhile, the regional and local sea-level budgets were either constant or had significantly lower changes.At the global scale, for example, there have been rises in sea level over the course of several centuries but then falls. This is a natural cycle. But what has been happening recently in the 20th century has not been completely natural due to a more significant, upward acceleration of water levels.Walker said trends in rising sea levels can be linked to the greenhouse gases already emitted, and that rates will continue to accelerate.

Flood risk is growing for US homeowners due to climate change. Current insurance rates greatly underestimate the threat, a new report finds

Flood risk is growing for US homeowners due to climate change. Current insurance rates greatly underestimate the threat, a new report findsThis acceleration will increase the number of days per year of flooding events, sometimes known as sunny-day floods. Tidal cycles can play a role in this, including the King Tides in the fall that produce the highest tidal levels of the year. Combine that with rising seas and that will lead to more coastal flooding days, regardless of the weather.There is another component to how sea level rise can have a big impact: large storms. Walker noted, “With these big storm events, you can really see the impacts more greatly.”A storm like Hurricane Sandy in 2012 crippled much of the Northeast, including New York City, with record storm surge. “The impacts from a big storm like that are just going to be exacerbated on top of (the rising seas).”Walker said the effects of sea level rise during significant weather events pose a longer-term challenge once the levels do get even higher.

Sea level rise is increasing fastest in populous coastal areas, study says

By Jackson Dill and Brandon Miller, CNN

Updated 8:12 PM ET, Tue March 9, 2021This aerial picture shows people rowing a raft over a flooded road in Jakarta on February 20, 2021, following heavy overnight rains. The combination of so many people and the multitude of rivers has made this city especially prone to relative sea level rise.This aerial picture shows people rowing a raft over a flooded road in Jakarta on February 20, 2021, following heavy overnight rains. The combination of so many people and the multitude of rivers has made this city especially prone to relative sea level rise.

(CNN)Coastal communities are experiencing sea level rise four times worse than global water rise, according to a new study released Monday.Groundwater pumping, extraction of materials from the ground and sediment production are all happening near the coasts and that is causing the land to actually sink — compounding the effects of a rising sea level.It is no coincidence that these are the same locations where people live, worsening the impacts and increasing the vulnerability.Many of the largest, most populated cities in the world are built along the deltas of major rivers, where there is the added exposure of rivers connecting to the ocean.Content by BabbelMake 2021 the year you learn a new languageThis language learning service is designed to get you conversational in a new language in just 3 weeks, no matter your skill level or prior experience.Much of the coast is uninhabited by people, but where there is civilization, there tends to be a greater rise in water levels.According to the study, it quantifies “global-mean relative sea-level rise to be 2.5 mm per year over the past two decades. However, as coastal inhabitants are preferentially located in subsiding locations, they experience an average relative sea-level rise up to four times faster at 7.8 to 9.9 mm per year.”

Coastal lands are sinking

This is the first ever study that factors in land subsidence into current sea level rise observations globally.close dialog

Receive Fareed Zakaria’s Global Analysisincluding insights and must-reads of world newsActivate Fareed’s BriefingBy subscribing you agree to ourprivacy policy.“We’ve actually quantified (sea level rise) and are able to get the relative magnitude. And it’s surprising — it’s surprisingly large. We’re making the point that climate change is bad and climate induced sea level rise is bad,” Robert Nicholls, lead author of this research and director of the UK’s Tyndall Centre for Climate Change Research, told CNN.

The slowing down of ocean currents could have a devastating effect on our climate

The slowing down of ocean currents could have a devastating effect on our climate“But we have this additional process that is making things even worse. And of course, these things add up. It doesn’t really matter whether the sea rises or the land sinks, the people living on the coast still have the same impacts.”Sea level rise is happening in many parts of the world. Where the land is rising, sea level rise is not as significant. Not as many people live where the land is rising, however.But where the land sinks, the relative rise of the sea is higher — and unfortunately that is where people tend to live. In fact, more than one in five people live along the coastline where the sea level is increasing at 10 mm (or 0.4 inches) or more per year, despite the fact that it encompasses less than 1% of the world’s coastline.In other parts of the world, like parts of the southeastern US, geological changes are not big contributors.”There’s places where the land isn’t really moving much at all,” said Brian McNoldy, a senior research associate at the University of Miami who was not a part of the study. “And you really are just seeing the effects of ocean levels increasing.”One of the biggest contributors to this subsidence is river deltas.”Deltas are where rivers bring sediment to the sea,” Nicholls said. “And the weight of the sediment plus the compression with the sediment causes consolidation … So you don’t get (rising land) with the deltas, you just get sinking and that can be exacerbated by groundwater withdrawal and drainage.”This global map shows the average relative sea level rise rate in millimeters per year, and is weighted for population (second map). The map is divided into 23 different coastal regions, and the shadings are based on how sea levels are currently rising every year. When weighting the data to population opposed to coastal length (first map), the sea level rise is greater because of human activity that promotes subsidence and loss of elevation. Portions of Asia are experiencing the highest rate of water rise when factoring in both the length average and population average. Source: Nature Climate Change, March 2021This global map shows the average relative sea level rise rate in millimeters per year, and is weighted for population (second map). The map is divided into 23 different coastal regions, and the shadings are based on how sea levels are currently rising every year. When weighting the data to population opposed to coastal length (first map), the sea level rise is greater because of human activity that promotes subsidence and loss of elevation. Portions of Asia are experiencing the highest rate of water rise when factoring in both the length average and population average. Source: Nature Climate Change, March 2021″Rapid rates of subsidence in deltas and especially cities on deltas are also human-caused, mostly due to groundwater pumping, also oil and gas extraction, and sediment resupply prevented by upstream dams, flood defenses, sand extraction or mining.”Scientists have already been aware of the implications of human-linked climate change to sea level rise, but now there is research that investigates rising and lowering land also caused by humans.”The process that we’re really talking about here is fundamentally down to where people choose to live. And then the fact that they actually made the subsidence worse.”There is a natural cause of the rising and sinking lands, however. According to the study, the melting ice sheets during the ice age thousands of years ago lead to and is still causing rising land near Hudson Bay in Canada.

Asia experiencing highest rate of sea level rise

Coastal sections of Asia have been the most impacted by sea level rise in relation to land subsidence. That’s because there is a prevalence of deltas and very populous cities.”South, Southeast and East Asia is noteworthy, as these regions collectively contain 71% of the global coastal population below 10 m in elevation,” according to the research.

India's groundwater crisis threatens food security for hundreds of millions, study says

India’s groundwater crisis threatens food security for hundreds of millions, study says“In Jakarta, subsidences of over 10 centimeters per year — It may be even locally faster than that. You can get very, very large changes, but in very small areas,” Nicholls said. “But they’re important because lots of people live there.”The map below highlights just a few of the many rivers and canals within Jakarta. The combination of so many people and the multitude of rivers has made this city especially prone to relative sea level rise.

Flood CanalSunter RiverCiliwung RiverJakarta, Indonesia

Imagery ©2021 TerraMetricsTerms of UseReport a map error

In the US, cities like New Orleans, which is near the Mississippi River delta, are also sinking. This correlates with one of the highest rises in relative sea level in the country.According to NOAA, the greatest relative sea level rise has been measured near coastal Louisiana and southeastern Texas.”A place where the combined effects of sinking land and sea level rise is in the northern Gulf Coast areas, like coastal Louisiana,” said McNoldy, of the University of Miami.In Galveston, Texas, sea levels have risen 6.62 mm per year or about one-quarter of an inch per year during the time period of 1957 to 2011. NOAA said this is “equivalent to a change of 2.17 feet in 100 years.”When asked what can be done about this issue, Nicholls said mitigating the threats of climate change is most crucial.”I think the important thing is we have a great effort, and rightly so, to actually mitigating climate change and the Paris Agreement,” Nicholls said.The report also says reducing groundwater withdrawal and managing deltas can reduce land subsidence.

https://www.cnn.com/2021/03/09/world/sea-level-rise-increasing-with-sinking-land/index.html

Collapse of Greenland Ice Sheet to Raise Sea Level Faster Than Expected

Estimates of ‘just’ 90 centimeters sea level rise by 2100 ignore Antarctica’s slower but hefty contribution, warns oceanographer John EnglanderShare in FacebookShare in TwitterSend in e-mailSend in e-mailZen ReadPrint article

https://www.haaretz.com/science-and-health/.premium-collapse-of-greenland-ice-sheet-to-raise-sea-level-faster-than-expected-1.9500959

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Glacier on west Greenland in August 2007, as it bends in its normal descent to the sea. Due to warming the melting glacier has retreated far inland

Glacier on west Greenland in August 2007, as it bends in its normal descent to the sea. Due to warming the melting glacier has retreated far inlandCredit: John Englanderhttps://googleads.g.doubleclick.net/pagead/ads?guci=2.2.0.0.2.2.0.0&client=ca-pub-3622156405313063&output=html&h=90&slotname=3ba61e6.55512a6&adk=1550347297&adf=1813269496&pi=t.ma~as.3ba61e6.55512a6&w=728&lmt=1612298169&psa=0&format=728×90&url=https%3A%2F%2Fwww.haaretz.com%2Fscience-and-health%2F.premium-collapse-of-greenland-ice-sheet-to-raise-sea-level-faster-than-expected-1.9500959&flash=0&wgl=1&dt=1612297834232&bpp=309&bdt=70786&idt=2662&shv=r20210201&cbv=r20190131&ptt=9&saldr=aa&abxe=1&cookie=ID%3D087b7090bd20714b-2296ab2277c6005b%3AT%3D1612297836%3ART%3D1612297836%3AS%3DALNI_Mb3SHl_z5guq4gFmHIkXemhpXcaHw&prev_fmts=0x0&nras=1&correlator=8331324905522&frm=20&pv=1&ga_vid=861100363.1612297791&ga_sid=1612297794&ga_hid=933169505&ga_fc=0&u_tz=-480&u_his=1&u_java=0&u_h=640&u_w=1139&u_ah=607&u_aw=1139&u_cd=24&u_nplug=3&u_nmime=4&adx=49&ady=1356&biw=1123&bih=538&scr_x=0&scr_y=0&eid=21068769%2C21068893%2C21068946%2C21067496&oid=3&pvsid=752869766386047&pem=630&ref=https%3A%2F%2Fnews.google.com%2F&rx=0&eae=0&fc=896&brdim=0%2C0%2C0%2C0%2C1139%2C0%2C1139%2C607%2C1139%2C537&vis=1&rsz=o%7Co%7CoEebr%7C&abl=NS&pfx=0&fu=8192&bc=31&ifi=8&uci=a!8&btvi=1&fsb=1&xpc=IghYckrBLt&p=https%3A//www.haaretz.com&dtd=MRuth SchusterGet email notification for articles from Ruth SchusterFollowPublished at 23:48

The vast ice sheet on Greenland has become unstable and technology isn’t storming to the rescue. The world is not on a trajectory to “curb” global warming at 1.5 degrees Celsius – we’re almost there already. “Everybody is asleep. It’s like the Titanic,” wails sea level rise guru John Englander, an oceanographer and author who has made it his life’s mission to shake the world awake before it’s too late.

Too late for what? To secure coastlines all over the world ahead of the rising sea, which is pushing coastlines farther inland. To protect property values, to strategize and reorganize economic priorities, to move seaside nuclear reactors, you name it. Life as we know it.

Part of the reason for the global somnolescence is that scientific reports by nature err on the side of caution. Thus, the current sea level rise estimates for 2050 or 2100 (which distract from the fact that sea level rise will continue afterward) are typically conservative, which in this case means they understate the real rise. It’s also considered rude to conclude that the world is careening toward hell in a handbasket.- Advertisment –

But the world is not on a minimalist trajectory. It is not heading for a “mere” 40-centimeter (16-inch) increase by 2100 based on the optimistic scenario, which is losing credence. The official (UN-IPCC) high end of forecasts is around 90 centimeters by 2100 – but even that is too optimistic in Englander’s view, as he warned in a joint paper with other academics in December: “Twenty-first century sea level rise could exceed IPCC projections for strong-warming futures.”

Sea level rise by 2100 could be 2 meters. It could be 3, or 4 meters, he says. The only thing we know is that we don’t know: the situation is fluid, you should excuse the expression. And we know that a lot of the water will come from Greenland.

To warn the general population, however, Englander feels science’s kid gloves are inappropriate at this point. Mounting evidence indicates climate change is accelerating and creating vicious circles that quicken it even more. The destabilization of Greenland’s ice sheet is a case in point.

John Englander during his 2006 expedition of Antarctica.

It is hard to reconcile reports of its accelerated melting and destabilization with estimates that it will, nonetheless, take maybe five to six centuries for all Greenland’s ice to melt. Englander explains this seeming incongruity.

“I’ve been there several times, leading expeditions,” he tells Haaretz. “It’s hard to comprehend how vast Greenland is. It’s 2,500 kilometers north to south and about 1,000 kilometers east to west, literally from east of the Mississippi in the U.S., and from Maine to Florida” – i.e., nearly 2.2 million square kilometers.- Advertisment –

In Middle Eastern terms, Greenland is about the size of Saudi Arabia. (Israel is about 22,000 square kilometers in area – about twice the size of B-15, the biggest-ever iceberg caught on camera, which calved off the Ross Ice Shelf. )https://www.youtube.com/embed/lBfzFt_kgNU?start=0&controls=1&loop=0&modestbranding=1&rel=1&autoplay=false&enablejsapi=1&mute=undefined

Greenland is covered by a layer of ice 1 to 3 kilometers thick; if it all melts, it will raise global sea levels by over 7 meters. No one thinks that can happen quickly. It will take centuries, at least. “The question is what will happen by 2050 and 2100,” Englander drives home the point.

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Asked if the Greenlandic ice sheet’s recently reported destabilization could change his vague expectation that the melt should take centuries, Englander offers the only answer he can: maybe. Which is all the more reason to wake up.- Advertisment –

Sea level rise cannot be stopped

Even if carbon dioxide emissions were to screen to a halt today, even if cows were to start farting flowers instead of methane, even if every car were to suddenly morph into a tree, further sea level rise is inevitable. Like the Titanic, its direction cannot be diverted anymore, though its momentum might be influenced.

It is time to glance again at John Englander’s famous graph of historic correlations between atmospheric carbon dioxide levels, global mean temperatures, and sea level over the last 400,000 years. The graph shows exactly what the problem is:

John Englander's graph

Atmospheric carbon dioxide has risen to levels last seen millions of years ago, approximately speaking (neither Donald Trump nor the coronavirus changed the trajectory in any meaningful sense). Atmospheric carbon dioxide concentrations and temperature are correlated: if the one rises, so does the other. The higher the CO2, the higher the global mean temperature – at a lag. Again: at a lag. Temperature has yet to proportionately react to the increase in carbon dioxide levels.

Yes, after CO2 rises, temperature will too – but how long the reaction will take depends on a practically infinite array of parameters, so it cannot be predicted with any meaningful accuracy. All we can say is it will happen, and the fact that the globe has experienced year after year of “record heat” is just the start. Oceans, being vast and dense and saline, take longer to react than the air or shallow lakes, but as the air warms, so does their surface and then their depths. The Arctic has been among the worst affected – there are days parts of it are hotter than in Tel Aviv.

Apropos of which, forecasting the future of Israel’s coast is tricky.

“The coastline has moved kilometers inland over the last 50 years,” says Dr. (emeritus) John K. Hall of the Geological Survey of Israel, adding that this conundrum tends to be met with massive denial. “The beaches are eroding, the cliffs are coming down,” he adds. At sea rise levels of 20 to 30 centimeters, it is difficult to draw lines with any accuracy, to say which neighborhoods will be affected and which spared – but the key issue is the likelihood of increasingly violent storms smashing into the beaches and cliffs. “If sea levels come up, storms will beat the hell out of the coast,” Hall predicts.

Anyway, there is a growing unease in global scientific circles about simultaneously warning and reassuring the public. More and more scientists are warning that sea level will rise faster “than previously thought.” Which means what?

Calving face of Eqi Glacier, West Greenland. Note the boat to show scale. Face is roughly one hundred meters high

Forecast: Weasels?

The Greenland ice sheet alone locks up 7 meters of sea level rise, which is bad enough, but Antarctica locks up 65 meters more, Englander explains. All the other glaciers in the world add just 1 more meter. “Looking at glaciers from Mount Kilimanjaro [in Kenya] to the Alps, it’s pocket change” he says.

Ergo: the Arctic island of Greenland and southern continent of Antarctica contain about 98 percent of the ice on land, by volume. Yet modelers have been ignoring Antarctica’s contribution.

This is why? For one thing, because the dynamics and precise timing of Antarctica’s melting ice remain profoundly unclear. As we said, scientists tend to err on the side of caution, lest they be perceived as a pack of yowling Cassandras scorned by policymakers. If you stand on a soapbox shrieking “The end is nigh,” precious few will listen even as avenging angels begin to arrive.

But the result is that projections of half a meter to just-under-a-meter of sea level rise by the century’s end don’t factor in Antarctica, nor do they factor in Greenland’s destabilization, Englander explains.

That is bound to end about as well as the Euripides play performed in 408 B.C.E., where the actor Hegelochus meant to say, “After the storm I see again a calm sea,” but wound up saying, “After the storm I see again a weasel.” Well, 2,500 years belatedly, the unfortunate thespian may have had a point. Those are not calm seas on our horizon.

A weasal. Not to be mistaken for a calm sea.

The Greenlandic irony

What does “Greenland has destabilized” even mean? That parts of the ice sheet and major glaciers are already exhibiting sudden break up and collapse. In 2012, the documentary “Chasing Ice” captured one huge collapse using time-lapse cameras. Meanwhile, Greenland is already the chief contributor to sea level rise today, and it has started to dawn on coastal residents and insurance companies and the like that “something” will have to be done.

Part of Englander’s book due out on April 6, “Moving to Higher Ground” (The Science Bookshelf), discusses exactly these conundrums.

Why is it only an issue now? The science of climate change has been around for decades. Why is anybody still buying a beachside home?

Disappearing glacier southwest Greenland shown in 2016. Note the dark gray color on top of much of the white ice. This is pulverized rock dust known as cryoconite, produced by the grinding glacier from the bedrock. As the glacier recedes the fierce Arctic winds blow this onto the glacier. The dark color increases the heat absorption and hastens the melting; one of the “feedback loops” in the global warming process

Englander blames a failure of imagination. At the height of the Ice Age, the average sea level was 120 meters lower than it is now. As the latest Ice Age waned and the ice sheets melted, sea levels gradually rose – sometimes more abruptly than at other times. But none of that happened during recorded history.

Civilization as we could recognize it – a gradual transition from hunting-gathering to a settled lifestyle – seems to have begun around 12,000 years ago, some places earlier, some places later, well after the Last Glacial Maximum 22,000 years ago. People adore living by the coast and always have. Even Neanderthals are thought to have frolicked in the water and dived for shellfish. And the first villages on low-lying shoreland were indeed inundated. Israeli archaeologists, for example, have found the remains of Neolithic villages off today’s coast, under the waves of the Mediterranean.

But for the last 7,000 or 8,000 years, sea levels have been stable, near present-day heights, and we are not capable of imagining the situation otherwise, Englander postulates.

Sea levels have been creeping up since the industrial revolution began and some cities have noticed – think of Miami and its sunny-day floods. But that is why we simply cannot fathom what a meter or two even mean. It’s beyond our scope of experience.

The last time sea level was above present-day levels was 122,000 years ago, when it was some 7 meters above present, he explains.

Water flowing on in channels on the Greenland ice

“Even at the accelerated warming rate, most people don’t think we’ll get more than a meter out of sea level rise from Greenland this century. But a meter of global sea level rise would be devastating, flooding literally thousands of coastal communities,” he points out the obvious.

Three of the biggest cities in the world are in acute danger: Shanghai, Mumbai and Jakarta, and so are hundreds more from Alexandria to Boston to London.

Ironically, Greenland’s own coastlines are probably safe. This is because as its ice cover melts, the land is rising, as land does when an enormous weight is lifted. It is the obverse of the situation in Jakarta, where the land is sinking because of groundwater depletion, the heavy buildings and sea level rise. Never mind 2100: the city is expected to be 95 percent underwater by 2050.

“The human instinct is to be optimistic, [to hope] technology will come to the rescue. But it doesn’t make sense in this context,” Englander sums up. “The oceans have been warmed almost a degree already and we’re going to warm them 2 degrees more. The ice is going to melt.”