Tag Archives: sea level change

Ice Island Calves off Petermann Glacier

Ice Island Calves off Petermann Glacier : Natural Hazards.

Ice Island Calves off Petermann Glacier

acquired July 20, 2011download large image (716 KB, JPEG, 2000×2600)
acquired July 20, 2011download GeoTIFF file (7 MB, TIFF, 2000×2600)
acquired July 20, 2011download Google Earth file (KMZ)

In August 2010, the Petermann Glacier along the northwestern coast of Greenland calved an ice island roughly four times the size of Manhattan. Nearly a year later, on July 20, 2011, a piece of that ice island—named Petermann Ice Island-A (PII-A) and about the same size as Manhattan—was still visible to the Moderate Resolution Imaging Spectroradiometer(MODIS) on NASA’s Terra satellite.

The Canadian Ice Service (CIS) tracked the ice island as it drifted through the Labrador Sea. On July 8, 2011, the CIS reported that the PII-A was approximately 55 square kilometers (21 square miles), and was continuing to lose surface area through calving and melting. On July 20, MODIS observed PII-A slightly south of where it had been a month earlier.

On July 21, 2011, MSNBC reported that PII-A was slowly drifting toward Newfoundland. The glacier was not likely to reach land; its base would probably become grounded on the sea floor off the coast. The ice chunk did, however, pose a potential hazard for shipping lanes and offshore oil rigs.

  1. References

  2. Canadian Ice Service (2011, July 8). Petermann Ice Island Updates. Accessed July 22, 2011.
  3. MSNBC. (2011, July 21). Massive ice island drifts toward Canada. Accessed July 22, 2011.

NASA image courtesy Jeff Schmaltz, MODIS Rapid Response, NASA Goddard Space Flight Center. Caption by Michon Scott.

Instrument: 
Terra – MODIS

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New Scientist special about what we do/don't know about Climate change

Climate change: What we do – and don’t – know – New Scientist.

(Image: Maria Stenzel)

There is much we do not understand about Earth’s climate. That is hardly surprising, given the complex interplay of physical, chemical and biological processes that determines what happens on our planet’s surface and in its atmosphere.

Despite this, we can be certain about some things. For a start, the planet is warming, and human activity is largely responsible. But how much is Earth on course to warm by? What will the global and local effects be? How will it affect our lives?Watch movie online A Cure for Wellness (2017)

In these articles, Michael Le Page sifts through the evidence to provide a brief guide to what we currently do – and don’t – know about the planet’s most burning issue.

KNOW

Greenhouse gases are warming the planet

From melting glaciers and earlier springs to advancing treelines and changing animal ranges, many lines of evidence back up what thermometers tell us
Read more

DON’T KNOW

How high greenhouse gas levels will rise

We can’t say how much Earth will warm over the coming years unless we know how much more greenhouse gas will end up in the atmosphere
Read more

KNOW

Other pollutants are cooling the planet

We pump all kinds of substances into the atmosphere. Some of them reflect the sun’s heat back into space and so cool things down
Read more

DON’T KNOW

How great our cooling effects are

Pollutants that form minute droplets in the atmosphere have horrendously complex effects – so it’s far from certain what they mean for global warming
Read more

KNOW

The planet is going to get a lot hotter

Extra carbon dioxide means a warmer world – and then positive feedback effects from things like water vapour and ice loss will make it warmer still
Read more

DON’T KNOW

Just how much hotter things will get

On current trends the temperature rise could exceed 4 °C as early as the 2060s. But even that could be an underestimate
Read more

DON’T KNOW

How things will change in each region

Which regions are going to turn into tropical paradises? Which into unbearably humid hellholes? It would be useful to know. Unfortunately, we don’t
Read more

KNOW

Sea level is going to rise many metres

Studies of past climate indicate each 1 °C rise in the global mean temperature eventually leads to a 20-metre rise in sea level
Read more

DON’T KNOW

How quickly sea level will rise

Do we have time to get temperatures back down before seas rise by more than a few metres? We have little clue how much room we have for manoeuvre
Read more

DON’T KNOW

How serious the threat to life is

The problem for the plants, animals and people living today is that they and we have adapted to the unusually stable climate of the past few thousand years
Read more

KNOW

There will be more floods and droughts

Warm air holds more moisture. This means more rain or snow overall, and more intense rain or snowfall on average
Read more

DON’T KNOW

Will there be more hurricanes and the like?

A wetter atmosphere will provide more of the fuel that powers extreme events like hurricanes, but it is not clear how often this fuel will be ignited
Read more

DON’T KNOW

If and when tipping points will come

The Amazon could become grassland. Massive amounts of methane could be released from undersea hydrates. And we may not realise in time to do anything about it
Read more

Long-lost Lake Agassiz offers clues to climate change

Long-lost Lake Agassiz offers clues to climate change.

ScienceDaily (Oct. 5, 2011) — What caused water levels to drop in an immense yet long-vanished lake? Research by a University of Cincinnati geologist suggests that conditions 12,000 years ago encouraged evaporation.

Not long ago, geologically speaking, a now-vanished lake covered a huge expanse of today’s Canadian prairie. As big as Hudson Bay, the lake was fed by melting glaciers as they receded at the end of the last ice age. At its largest, Glacial Lake Agassiz, as it is known, covered most of the Canadian province of Manitoba, plus a good part of western Ontario. A southern arm straddled the Minnesota-North Dakota border.

Not far from the ancient shore of Lake Agassiz, University of Cincinnati Professor of Geology Thomas Lowell will present a paper about the lake to the Geological Society of America annual meeting in Minneapolis. Lowell’s paper is one of 14 to be presented Oct. 10 in a session titled: “Glacial Lake Agassiz — Its History and Influence on North America and on Global Systems: In Honor of James T. Teller.”

Although Lake Agassiz is gone, questions about its origin and disappearance remain. Answers to those questions may provide clues to our future climate. One question involves Lake Agassiz’ role in a thousand-year cold snap known as the Younger Dryas.

As the last ice age ended, thousands of years of warming temperatures were interrupted by an abrupt shift to cold. Tundra conditions expanded southward, to cover the land exposed as the forests retreated. This colder climate is marked in the fossil record by a flowering plant known as Dryas, which gives the period its name.

“My work focuses on abrupt or rapid climate change,” Lowell said. “The Younger Dryas offers an opportunity to study such change. The climate then went from warming to cooling very rapidly, in less than 30 years or so.”

Scientists noted that the Younger Dryas cold spell seemed to coincide with lower water levels in Lake Agassiz. Had the lake drained? And, if so, had the fresh water of the lake caused this climate change by disrupting ocean currents? This is the view of many scientists, Lowell said.

Lowell investigated a long-standing mystery involving Lake Agassiz — a significant drop in water level known as the Moorhead Low. It has long been believed that the Moorehead Low when water drained from Lake Agassiz through a new drainage pathway. Could this drainage have flowed through the St. Lawrence Seaway into the North Atlantic Ocean?

“The most common hypothesis for catastrophic lowering is a change in drainage pathways,” Lowell said.

The problem is, better dating of lake levels and associated organic materials do not support a rapid outflow at the right time.

“An alternative explanation is needed,” he said.

Lowell’s research shows that, although water levels did drop, the surface area of the lake increased more than seven-fold at the same time. His research suggests that the lower water levels were caused by increased evaporation, not outflow. While the melting glacier produced a lot of water, Lowell notes that the Moorhead Low was roughly contemporaneous with the Younger Dryas cold interval, when the atmosphere was drier and there was increased solar radiation.

“The dry air would reduce rainfall and enhance evaporation,” Lowell said. “The cold would reduce meltwater production, and shortwave radiation would enhance evaporation when the lake was not frozen and sublimation when the lake was ice-covered.”

Further research will attempt a clearer picture of this ancient episode, but researchers will have to incorporate various factors including humidity, yearly duration of lake ice, annual temperature, and a better understanding of how and where meltwater flowed from the receding glaciers.

Lowell’s efforts to understand changes in ancient climates have taken him from Alaska to Peru, throughout northern Canada and Greenland.

In Greenland, Lowell and a team of graduate students pulled cores of sediment from lakes that are still ice-covered for most of the year. Buried in those sediments are clues to long-ago climate.

“We look at the mineralogy of the sediments,” Lowell said, “and also the chironomids. They’re a type of midge and they’re very temperature sensitive. The exact species and the abundance of midges in our cores can help pinpoint temperature when these sediments were deposited.”

Lowell’s research was initially funded by the Comer Foundation. In recent years, the National Science Foundation has provided funding for this work.

When the Geological Society of America meets this year the University of Cincinnati will be well represented, with more than two dozen papers and presentations. Topics range from ice-age climate to the health effects of corrosion in drinking water pipes.

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Europe's oceans changing at unprecedented rate

Europe’s oceans changing at unprecedented rate: report | Reuters.

LONDON | Tue Sep 13, 2011 3:26pm EDT

(Reuters) – Europe’s seas are changing at an unprecedented rate as ice sheets melt, temperatures rise and marine life migrates due to climate change, a report by the Climate Change and European Marine Ecosystem Research (CLAMER) project warned.

Scientists examined a mass of EU-funded research on the impacts of climate change on Europe’s marine environment and identified the gaps and priorities for future work.

“Change has been clearly visible and is much more rapid than we thought was possible,” Carlo Heip, chair of the CLAMER project and lead author of the report, told Reuters on Tuesday.

Over the past 25 years, sea water temperatures have increased as Arctic sea ice has melted. The combination of rising sea-levels and increased winds has contributed to the erosion of 15 percent of European coasts, the report said.

Warming has speeded up in the past 25 years at around 10 times faster than the average rate of increase in the 20th century, it added.

From 1986 to 2006, sea surface temperature rises for European waters were three to six times higher than the global average.

“Scenario simulations suggest that by the end of the 21st century, the temperature of the Baltic Sea may have increased by 2 to 4 degrees centigrade, the North Sea by 1.7 degrees, and the Bay of Biscay by 1.5 to 5 degrees,” the report said.

Melting ice sheets and glaciers add more uncertainty. Current estimates for 2100 suggest European sea levels could rise 60 cms and up to 1.9 meters at some British coasts.

Sea level rise threatens populations in all low-lying areas of Europe, but countries such as Britain, France and the Netherlands could be less vulnerable because they are rich enough to adopt coastal protection measures.

Changes in the marine food chain have also occurred as organisms have migrated to the Atlantic from the Pacific via seasonal ice-free passages through the Arctic.

While some species can thrive in other oceans, any major upheaval to the marine ecosystem could have devastating effects, the report said.

CLAMER also found that some bacteria strains were becoming more prevalent and could be a potential threat to human health. For example, cholera strains have increased in the North Sea over the past 50 years, perhaps due to temperature change.

Among its many recommendations, CLAMER urged more study of seal-level changes due to ice sheets breaking up or melting, coastal erosion, temperature changes, ocean acidification, marine ecosystems and circulation changes.

“The main message is we need to keep our fingers on the pulse,” said Heip.

The full report is available at: www.clamer.eu/

(Editing by Janet Lawrence)

Sea level rise more from Antarctica than from Greenland during last interglacial

Sea level rise less from Greenland, more from Antarctica, than expected during last interglacial.

Where did all that extra water come from? Mainly from melting ice sheets on Greenland and Antarctica, and many scientists, including University of Wisconsin-Madison geoscience assistant professor Anders Carlson, have expected that Greenland was the main culprit.

But Carlson’s new results, published July 29 in Science, are challenging that assertion, revealing surprising patterns of melting during the last interglacial period that suggest that Greenland’s ice may be more stable — and Antarctica’s less stable — than many thought.

“The Greenland Ice Sheet is melting faster and faster,” says Carlson, who is also a member of the Center for Climatic Research in the Nelson Institute for Environmental Studies. But despite clear observations of that fact, estimates of just how much the ice will melt and contribute to sea level rise by the end of this century are highly varied, ranging from a few centimeters to meters. “There’s a clear need to understand how it has behaved in the past, and how it has responded to warmer-than-present summers in the past.”

The ice-estimation business is rife with unknown variables and has few known physical constraints, Carlson explains, making ice sheet behavior — where they melt, how much, how quickly — the largest source of uncertainty in predicting sea level rises due to climate change.

His research team sought a way to constrain where ice remained on Greenland during the last interglacial period, around 125,000 years ago, to better define past ice sheet behavior and improve future projections.

The researchers analyzed silt from an ocean-floor core taken from a region off the southern tip of Greenland that receives sediments carried by meltwater streams off the ice sheet. They used different patterns of radiogenic isotopes to identify sources of the sediment, tracing the silt back to one of three “terranes” or regions, each with a distinct geochemical signature. The patterns of sedimentation show which terranes were still glaciated at that time.

“If the land deglaciates, you lose that sediment,” Carlson explains. But to their surprise, they found that all the terranes were still supplying sediment throughout the last interglacial period and thus still had some ice cover.

“The ice definitely retreated to smaller than present extent and definitely raised sea level to higher than present” and continued to melt throughout the warm period, he adds, but the sediment analysis indicates that “the ice sheet seems to be more stable than some of the greater retreat values that people have presented.”

The team used their results to evaluate several existing models of Greenland ice sheet melting during the last interglacial period. The models consistent with the new findings indicate that melting Greenland ice was responsible for a sea level rise of 1.6 to 2.2 meters — at most, roughly half of the minimum four-meter total increase.

Even after accounting for other Arctic ice and the thermal expansion of warmer water, most of the difference must have come from a melting Antarctic ice sheet, Carlson says.

“The implication of our results is that West Antarctica likely was much smaller than it is today,” and responsible for much more of the sea level rise than many scientists have thought, he says. “If West Antarctica collapsed, that means it’s more unstable than we expected, which is quite scary.”

Ultimately, Carlson says he hopes this line of research will improve the representation of ice sheet responses to a warming planet in future Intergovernmental Panel on Climate Change (IPCC) reports. Temperatures during the last interglacial period were similar to those expected by the end of this century, and present-day temps have already reached a point that Greenland’s glaciers are melting.

The Science paper was co-authored by UW-Madison colleagues Elizabeth Colville, Brian Beard, Alberto Reyes, and David Ullman and Oregon State University researchers Robert Hatfield and Joseph Stoner, and supported by UW-Madison and the National Science Foundation.

Too late to turn back Rising oceans?

Rising oceans: Too late to turn the tide?.

If sea levels rose to where they were during the Last Interglacial Period, large parts of the Gulf of Mexico region would be under water (red areas), including half of Florida and several Caribbean islands. (Credit: Illustration by Jeremy Weiss)

ScienceDaily (July 18, 2011) — Thermal expansion of seawater contributed only slightly to rising sea levels compared to melting ice sheets during the Last Interglacial Period, a University of Arizona-led team of researchers has found.

The study combined paleoclimate records with computer simulations of atmosphere-ocean interactions and the team’s co-authored paper is accepted for publication in Geophysical Research Letters.

As the world’s climate becomes warmer due to increased greenhouse gases in the atmosphere, sea levels are expected to rise by up to three feet by the end of this century.

But the question remains: How much of that will be due to ice sheets melting as opposed to the oceans’ 332 billion cubic miles of water increasing in volume as they warm up?

For the study, UA team members analyzed paleoceanic records of global distribution of sea surface temperatures of the warmest 5,000-year period during the Last Interglacial, a warm period that lasted from 130,000 to 120,000 years ago.

The researchers then compared the data to results of computer-based climate models simulating ocean temperatures during a 200-year snapshot as if taken 125,000 years ago and calculating the contributions from thermal expansion of sea water.

The team found that thermal expansion could have contributed no more than 40 centimeters — less than 1.5 feet — to the rising sea levels during that time, which exceeded today’s level up to eight meters or 26 feet.

At the same time, the paleoclimate data revealed average ocean temperatures that were only about 0.7 degrees Celsius, or 1.3 degrees Fahrenheit, above those of today.

“This means that even small amounts of warming may have committed us to more ice sheet melting than we previously thought. The temperature during that time of high sea levels wasn’t that much warmer than it is today,” said Nicholas McKay, a doctoral student at the UA’s department of geosciences and the paper’s lead author.

McKay pointed out that even if ocean levels rose to similar heights as during the Last Interglacial, they would do so at a rate of up to three feet per century.

“Even though the oceans are absorbing a good deal of the total global warming, the atmosphere is warming faster than the oceans,” McKay added. “Moreover, ocean warming is lagging behind the warming of the atmosphere. The melting of large polar ice sheets lags even farther behind.”

“As a result, even if we stopped greenhouse gas emissions right now, the Earth would keep warming, the oceans would keep warming, the ice sheets would keep shrinking, and sea levels would keep rising for a long time,” he explained.

They are absorbing most of that heat, but they lag behind. Especially the large ice sheets are not in equilibrium with global climate,” McKay added. ”

Jonathan Overpeck, co-director of the UA’s Institute of the Environment and a professor with joint appointments in the department of geosciences and atmospheric sciences, said: “This study marks the strongest case yet made that humans — by warming the atmosphere and oceans — are pushing the Earth’s climate toward the threshold where we will likely be committed to four to six or even more meters of sea level rise in coming centuries.”

Overpeck, who is McKay’s doctoral advisor and a co-author of the study, added: “Unless we dramatically curb global warming, we are in for centuries of sea level rise at a rate of up to three feet per century, with the bulk of the water coming from the melting of the great polar ice sheets — both the Greenland and Antarctic Ice Sheets.”

According to the authors, the new results imply that 4.1 to 5.8 meters, or 13.5 to 19 feet, of sea level rise during the Last Interglacial period was derived from the Antarctic Ice Sheet, “reemphasizing the concern that both the Antarctic and Greenland Ice Sheets may be more sensitive to warming temperatures than widely thought.”

“The central question we asked was, ‘What are the warmest 5,000 years we can find for all these records, and what was the corresponding sea level rise during that time?'” McKay said.

Evidence for elevated sea levels is scattered all around the globe, he added. On Barbados and the Bahamas, for example, notches cut by waves into the rock six or more meters above the present shoreline have been dated to being 125,000 years old.

“Based on previous studies, we know that the sea level during the Last Interglacial was up to 8.5 meters higher than today,” McKay explained.

“We already knew that the vast majority came from the melting of the large ice sheets in Greenland and Antarctica, but how much could the expansion of seawater have added to that?”

Given that sea surface temperatures were about 0.7 degrees warmer than today, the team calculated that even if the warmer temperatures reached all the way down to 2,000 meters depth — more than 6,500 feet, which is highly unlikely — expansion would have accounted for no more than 40 centimeters, less than a foot and a half.

“That means almost all of the substantial sea level rise in the Last Interglacial must have come from the large ice sheets, with only a small contribution from melted mountain glaciers and small ice caps,” McKay said.

According to co-author Bette Otto-Bliesner, senior scientist at the National Center for Atmospheric Research (NCAR) in Boulder, Colo., getting the same estimate of the role ocean expansion played on sea level rise increases confidence in the data and the climate models.

“The models allow us to attribute changes we observe in the paleoclimate record to the physical mechanisms that caused those changes,” Otto-Bliesner said. “This helps tremendously in being able to distinguish mere correlations from cause-and-effect relationships.”

The authors cautioned that past evidence is not a prediction of the future, mostly because global temperatures during the Last Interglacial were driven by changes in Earth’s orbit around the sun. However, current global warming is driven by increasing greenhouse gas concentrations.

The seasonal differences between the northern and the southern hemispheres were more pronounced during the Last Interglacial than they will be in the future.

“We expect something quite different for the future because we’re not changing things seasonally, we’re warming the globe in all seasons,” McKay said.

“The question is, when we think about warming on a global scale and contemplate letting the climate system change to a new warmer state, what would we expect for the ice sheets and sea levels based on the paleoclimate record? The Last Interglacial is the most recent time when sea levels were much higher and it’s a time for which we have lots of data,” McKay added.

“The message is that the last time glaciers and ice sheets melted, sea levels rose by more than eight meters. Much of the world’s population lives relatively close to sea level. This is going to have huge impacts, especially on poor countries,” he added.

“If you live a meter above sea level, it’s irrelevant what causes the rise. Whether sea levels are rising for natural reasons or for anthropogenic reasons, you’re still going to be under water sooner or later.”

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Sea levels rising at fastest rate in 2,000 years and other sea level news

Sea levels rising at fastest rate in 2,000 years – Telegraph.

Sea levels rising at fastest rate in 2,000 years

Sea levels are rising faster than at any point in the past 2,000 years because of the impact of global warming, scientists have found.

Sea levels rising at fastest rate in 2,000 years

Since then the average rise in sea levels in North Carolina, where the study was based, it has been higher than 2mm per year Photo: ALAMY

What will climate change and sea level rise mean for barrier islands?

What will climate change and sea level rise mean for barrier islands?.

ScienceDaily (June 15, 2011) — A new survey of barrier islands published earlier this spring offers the most thorough assessment to date of the thousands of small islands that hug the coasts of the world’s landmasses. The study, led by Matthew Stutz of Meredith College, Raleigh, N.C., and Orrin Pilkey of Duke University, Durham, N.C., offers new insight into how the islands form and evolve over time — and how they may fare as the climate changes and sea level rises.

Barrier islands like the Chandeleur Islands are constantly building, eroding, and shifting under the normal actions of wind and waves. A powerful storm like Katrina can produce changes that otherwise may have taken many years, and most of the changes seen here are probably the result of Katrina. (Credit: NASA’s Earth Observatory)

The survey is based on a global collection of satellite images from Landsat 7 as well as information from topographic and navigational charts. The satellite images were captured in 2000, and processed by a private company as part of an effort funded by NASA and the U.S. Geological Survey.

During the 20th century, sea level has risen by an average of 1.7 millimeters (about 1/16 of an inch) per year. Since 1993, NASA satellites have observed an average sea level rise of 3.27 millimeters (about 1/8 of an inch) per year. A better understanding of how climate change and sea level rise are shaping barrier islands will also lead to a more complete grasp of how these dynamic forces are affecting more populated coastal areas.

Stutz, the study’s lead author, highlighted a series of key findings from the new survey during an interview with a NASA science writer.

Every barrier island is unique

Every island chain has a complex set of forces acting on it that underpin how islands form and how they’re likely to change over time. Barrier islands often develop in the mouths of flooded river valleys as sea level rises, but they can also form at the end of rivers as sediment builds up and creates a delta. Other important factors in barrier island formation include regional tectonics, sea level changes, climate, vegetation and wave activity. “Understanding how such forces impact barrier islands is the key to understanding how climate change will affect our coastlines,” noted Stutz.

Sea level rise can eliminate — or create — barrier islands

Scientists estimate that the rate of sea level rise will likely double or triple in the next hundred years due to climate change. Paradoxically, gradual sea level rise can generate new barrier islands. Rising seas create shallow bays that develop barrier islands in the mouths of the bays along certain types of coastline.

Stutz’s analysis found rising sea level in the last 5,000 years is associated with the greatest barrier island abundance, especially in the North Atlantic and Arctic. Stable or falling sea level, meanwhile, a pattern more typical of the Southern Hemisphere in the last 5,000 years, has produced fewer islands and a higher percentage of islands along river deltas.

However, extremely rapid sea level rise — especially when coupled with decreases in sediment supply — can simply inundate islands causing them to break up and disappear. Islands are eroding rapidly along the Mississippi Delta, Eastern Canada and the Arctic for these reasons.

“However, rising sea level is not just like pouring more water into a bathtub,” Stutz emphasized. Islands react differently based on the geology in a region and how the waves and tides in an area are affected. People tend to assume sea level rise means fewer islands no matter what, but the rate of rise is critical.”

There are far more barrier islands than previously thought

A survey conducted by the same researchers tallied 1,492 barrier islands in 2001, but Stutz and Pilkey counted more than 2,149 this time. The difference: the researchers had access to higher-quality satellite imagery that covered a larger portion of the globe than they did last time. “It’s not that 657 islands appeared overnight. We simply did a more thorough job of counting what was already out there,” said Stutz. The researchers counted extensive island chains in Brazil, Madagascar and Australia that the previous survey had left out.

Barrier islands cluster along tectonically calm coasts

Stable coasts, such as the eastern coast of the United States, tend to have wide, low relief areas with shallow estuaries that are conducive to barrier island formation. In contrast, continental margins near actively colliding plates, which generate earthquakes and volcanoes, produce fewer barrier islands. At active margins, such as the rocky cliffs along the Pacific, steep grades typically dominate coastal areas and prevent the formation of islands.

Northern and Southern hemisphere islands differ

The Northern Hemisphere is home to the majority — 74 percent — of barrier islands. That’s not surprising because the Northern Hemisphere contains about the same proportion of land. A less intuitive insight: the majority of Northern Hemisphere islands are in high-latitude Arctic or temperate climate zones, while most Southern Hemisphere islands are tropical. Why the discrepancy? Relative sea levels have fallen slowly in much of the Southern Hemisphere for the last 5,000 years, but the opposite has happened in the Arctic.

Storms are key molders of barrier island shape

Storms tend to cause islands to retreat, carve new inlets that make them shorter and more numerous, and sometimes destroy them completely. The frequency of storms varies by latitude and climate. The Arctic and most temperate coasts experience regular storms, while more tropical areas experience few storms and more gentle swells most of the year, conditions that encourage the formation of sandy beaches. Major storms can cause drastic changes to barrier islands. After Hurricane Katrina, for example, many islands in the Mississippi River Delta were destroyed or radically changed.

Arctic barrier islands are retreating the fastest

Barriers islands in the Arctic make up nearly a quarter of the world’s barrier islands, and they’re more vulnerable to climate change than islands anywhere else in the world. The reason: melting of sea ice and the permafrost that buffers Arctic islands from waves have left them susceptible to constant pounding from storms. Recently measured erosion rates in the Beaufort Sea show Arctic barrier islands eroding three to four times faster than islands in the continental United States. Any further acceleration in erosion rates could result in the rapid breakup of many Arctic islands, Stutz’s analysis noted.

More research is needed, especially on a local scale

Coastal areas will likely experience major changes in sea levels this century due to climate change. The shifts, however, will be anything but uniform. NASA research shows that some coasts are experiencing sea level rise significantly faster than the global average of 3.27 millimeters (about 1/8 of an inch) per year, while other areas are experiencing slower rates of rise and even falling sea levels. “It would be nice if we could say we can predict exactly how a given island or island chain will react to rising sea levels or some other environmental change, but we’re simply not there yet for most islands, especially for many tropical islands where research dollars are scarce. We’re still a long way from being able to accurately model how an individual island will change as a result of climate change or even simple development pressure,” said Stutz.

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Google Earth 'Flood'

Google Earth ‘Flood’.

Google Earth layer for showing effects of rising sea levels

Try Globe Glider!

The Globe Glider extension for Google Earth is now available for beta testing…

 

Try it here!

 

Google Earth ‘Flood’

This network link for Google Earth will ‘flood’ an area of the globe to a certain height above sea level.

Click here to open the network link in Google Earth.

Go to the area that you want to see flooded and refresh the network link (right-click on the network link in Google Earth and choose ‘refresh’).

 

The elevation is set with the ‘elev’ parameter in the link. You can edit the network link and change the number after ‘?elev=’ to set a new elevation (in meters, 1000 feet = 305 m).

 

The ‘water’ level is inaccurate for larger areas because it doesn’t follow exactly the curvature of the earth.