USGS photo by R.J. Janda.

The reappearance of long-forgotten habitats and the resurgence of species unseen for years may not be among the expected effects of a natural disaster. Yet that’s exactly what researchers have found on the sandy beaches of south central Chile, after an 8.8-magnitude earthquake and devastating tsunami in 2010. Their study also revealed a preview of the problems wrought by sea level rise – a major symptom of climate change.

In a scientific first, researchers from Universidad Austral de Chile and UC Santa Barbara’s Marine Science Institute (MSI) were able to document the before-and-after ecological impacts of such cataclysmic occurrences.

A new paper appearing in the journal PLoS ONE elucidates the surprising results of their collaborative study, pointing to the potential effects of natural disasters on sandy beaches worldwide.

“So often you think of earthquakes as causing total devastation, and adding a tsunami on top of that is a major catastrophe for coastal ecosystems. As expected, we saw high mortality of intertidal life on beaches and rocky shores, but the ecological recovery at some of our sandy beach sites was remarkable,” said Jenifer Dugan, an associate research biologist at MSI.

“Dune plants are coming back in places there haven’t been plants, as far as we know, for a very long time. The earthquake created sandy beach habitat where it had been lost. This is not the initial ecological response you might expect from a major earthquake and tsunami.”

Their findings owe a debt to serendipity. With joint support from Chile’s Fondo Nacional de Desarrollo Cientifico y Tecnologico and the U.S. National Science Foundation’s Long Term Ecological Research program, the scientists were already knee-deep in a collaborative study of how sandy beaches in Santa Barbara and south central Chile respond, ecologically, to man-made armoring such as seawalls and rocky revetments.

As part of that project, the Chilean team surveyed nine sandy beaches along the coasts of Maule and Biobio in late January, 2010. The earthquake hit in February.

Realizing their unique opportunity, the scientists quickly changed gears and within days were back on the beaches to reassess their study sites in the catastrophe’s aftermath. They have returned many times since, diligently documenting the ecological recovery and long-term effects of the earthquake and tsunami on these coastlines, in both natural and human-altered settings.

The magnitude and direction of land-level change brought the greatest impact, drowning beaches especially where the tsunami exacerbated earthquake-induced subsidence – and widening and flattening beaches where the earthquake brought uplift. The drowned beach areas suffered mortality of intertidal life; the widened beaches quickly saw the return of plants and animals that had vanished due to the effects of coastal armoring.

“With the study in California and our study here, we knew that building coastal defense structures, such as seawalls, decreases beach area, and that a seawall results in the decline of intertidal diversity,” said lead author Eduardo Jaramillo, of Universidad Austral de Chile.

“But after the earthquake, where significant continental uplift occurred, the beach area that had been lost due to coastal armoring has now been restored. And the re-colonization of the mobile beach fauna was under way just weeks after.”

With responses varying so widely depending on land-level changes, mobility of flora and fauna, and shore type, the findings show not only that the interactions of extreme events with armored beaches can produce surprising ecological outcomes – but also suggest that landscape alteration, including armoring, can leave lasting footprints in coastal ecosystems.

“When someone builds a seawall, not only is beach habitat covered up with the wall itself, but, over time, sand is lost in front of the wall until the beach eventually drowns,” Dugan said.

“The semi-dry and damp sand zones of the upper and mid intertidal are lost first, leaving only the wet lower beach zones. This causes the beach to lose diversity, including birds, and to lose ecological function. This is an underappreciated human impact on coastlines around the world, and with climate change squeezing beaches further, it’s a very serious issue to consider.”

Jaramillo elaborated, “This is very important because sandy beaches represent about 80 percent of the open coastlines globally. Also, sandy beaches are very good barriers against the sea level rise we are seeing around the world. It is essential to take care of sandy beaches. They are not only important for recreation, but also for conservation.”

The study is said to be the first-ever quantification of earthquake and tsunami effects on sandy beach ecosystems along a tectonically active coastal zone.

Summary

Overview map. (Source: JRC)

Interactive map

This Volcanic eruption of Pago in New Britain-SW Pac is expected to have a medium humanitarian impact based on the magnitude and the affected population and their vulnerability.

Current volcano eruption

• Source: VAAC Darwin
• Location (latitude/longitude): -5.583, 150.517
• Date: 03/05/2012 to 03/05/2012

Volcano Ash Advisories for air traffic

Although Volcano Ash Advisories (VAAC) are not intended for assessing humanitarian impact, the observations of the plume are relevant for understanding local impact. The actual impact (like ash fall) depends on the type of eruption and is not known.

Not calculated

Timeline of eruptions

For accessing reports of previous advisories, please click on the advisory number in the table below.

ID	Alert color	Date	Source	eventid	episodeid	episodedate	version	eventtype	alertlevel	alerttype	alertscore	link	country	eventname	severity	severitytype	severityunit	severitytext	population	populationtype	populationtext	vulnerability	vulnerabilitytext	sourceid	iso3	hazardcomponents	dateadded	Centroid
1		5/3/2012 5:30:00 AM	DARWIN	82	1	5/3/2012 5:30:00 AM	1	VO	Red	automatic	3		New Britain-SW Pac	Pago	0				0	Population affected		0		DARWIN			1/1/0001 12:00:00 AM	POINT (150.517 -5.583)
2		5/3/2012 6:00:00 AM	DARWIN	82	2	5/3/2012 6:00:00 AM	1	VO	Red	automatic	3		New Britain-SW Pac	Pago	0				0	Population affected		0		DARWIN			1/1/0001 12:00:00 AM	POINT (150.517 -5.583)
3		5/3/2012 7:15:00 AM	DARWIN	82	3	5/3/2012 7:15:00 AM	1	VO	Orange	automatic	2		New Britain-SW Pac	Pago	0				0	Population affected		0		DARWIN			1/1/0001 12:00:00 AM	POINT (150.517 -5.583)

More information

Data resources

For a full list of available products related to this event, please refer to the GDACS Data Resources page.

About the data

Information related to the volcano eruption has been collected from official reports published by the Global Volcanism Program and/or Volcano Ash Advisories published by one of the Volcano Ash Advisory Centres.

Disclaimer

While we try everything to ensure accuracy, this information is purely indicative and should not be used for any decision making without alternate sources of information. The JRC is not responsible for any damage or loss resulting from the use of the information presented on this website.

Mt. Baekdu eruption’s impact on NE Asia (25)

Citing the rise of the surface temperature of Mt. Baekdu, geologists predict its eruption in a couple of years. / Korea Times file

Mt. Baekdu has been carefully observed since 1999 when a volcanic observatory was built in China, and since 2002, there have been some symptoms of an eruption.

By Park Chang-seok

Yes, one! There’s only one thing about which they think in a same way – a concern about possible eruption of Mt. Baekdu. The two Koreas remain at odds in everything. But they are one in voicing how to counter the possible volcanic explosion of the highest mountain in the Korean Peninsula

Inter-Korean anxiety is mounting, with growing apocalyptic predictions on the dormant volcano. A South Korean geological expert has warned that the volcano could erupt sometime around 2014 and 2015.

Former North Korean leader Kim Jong-il reportedly said people in some regions of Yanggang and North Hamgyeong Provinces were feeling anxiety over a volcanic eruption of Mt. Baekdu. Kim called for quick countermeasures by the North Korean authorities.

If a volcano, located on the border between North Korea and China erupts, damage could be 10 to 100 times greater than that caused by the April 2010 eruptions in Iceland. Experts predict that the ashes would not only hit the neighboring area but damage agriculture and cause serious disruptions in industrial activities and air flights. The Korean Peninsula, China, Japan and Russia would be severely damaged.

A volcanic eruption begins when pressure on a magma chamber forces magma up through the conduit and out the volcano’s vents. When the magma chamber is completely filled, the type of eruption partly depends on the amount of gas and silica in the magma. The amount of silica determines how sticky (level of viscosity) the magma is and water provides the explosive potential of steam.

The 2010 Iceland eruption caused enormous disruption to air travel across Western and Northern Europe, although relatively small in size for volcanic eruptions. About 20 countries closed their airspace and it affected hundreds of thousands of travelers. A very high proportion of flights within, to, and from Europe were cancelled, creating the highest level of air travel disruption since the World War II.

Geological studies

Fears of a Mt. Baekdu eruption loom large with ensuing warnings based on a series of geological studies from experts. A growing number of scholars have not ruled out the possibility of another eruption, linking the collapse of Korea’s ancient kingdom, Balhae, with the previous one.

One theory comes from professor Hiroshi Machida of Tokyo Metropolitan University. Machida first presented a view in 1992 that the eruption of Mt. Baekdu (Mt. Changbai in Chinese) led to the fall of Balhae, which had expanded its sovereignty to the vast Manchuria territory. His theory was based on volcanic ash found in Tomakomai, a port city in southern Hokkaido, in 1981. The ash was named “Baekdu-Tomakomai volcanic ash” (B-Tm) after Mt. Baekdu and Tomakakomi city where it was found, according to So Won-ju who wrote the book “Secret of Mt. Baekdu’s Great Eruption.”

Machida’s theory has gained momentum as an increasing number of geologists and climate change researchers have presented views that the ash was produced in the eruption of the highest mountain in the Korean Peninsula in the 10th century. The eruption of the 2,744 meter-high mountain was billed as the largest in the history of mankind and was about 50 times stronger than that of Mt. Vesuvius of Italy in 79 A.D. which led to the burying and destruction of the Roman city Pompeii.

Balhae (Bohai in Chinese) was established by Dae Jo-yeong, a former Goguryeo general, in 698 after the fall of Goguryeo. Dae Jo-yeong took the helm of Jin (Zhen in Chinese), founded by his father Dae Jung-sang in 696, and renamed the country Balhae, declaring it as the successor state of Goguryeo (37 B.C. – 668 A.D.).

Balhae’s ruin

Balhae occupied the southern parts of Manchuria and Primorsky Krai (now Russia’s Far East), and the northern part of the Korean Peninsula. It was defeated by the Khitans in 926, and most of its northern territories were absorbed into the Liao Dynasty, also known as the Khitan Empire, founded in 907 while the southern parts were absorbed into Goryeo Kingdom (918-1392).

A dominant view related to Balhae’s decline had been Khitans’ 926 invasion. Some conventional historians believed that the rampancy of ethnic conflicts between the ruling Koreans and underclass Mohe (Malgal) caused its fall. But some refute these allegations, giving more weight on the catastrophic explosion of Mt. Baekdu as a primary cause for Balhae’s ruin rather than Khitans’ attack.

Balhae had been engaged in a war with the Khitans for about two weeks and then collapsed immediately. How could Balhae with a long 200-year history fall so easily in such a short period of battle? Some historians raised doubts about the early collapse, pointing to Mt. Baekdu erupting as a cause for Balhae’s ruin.

The massive explosion was believed to have created a tremendous amount of volcanic ash, damaging agriculture and even societal integrity. The Khitans were believed to have taken advantage of this natural disaster in putting the volcano-stricken Balhae under their complete control. The eruption might have prevented Balhae survivors from rebuilding their nation in consideration of the catastrophe.

A variety of indicators, suggested by geologists and Balhae dynasty researchers who have monitored the change of Baekdu’s geographical features, are backing a scenario of the recurrence of the Mt. Baekdu eruption. Some experts say that an eruption is imminent. Geologist Yoon Sung-hyo at Pusan National University strongly believes Mt. Baekdu could erupt anytime soon.”

According to historical records, major activity on the mountain in the 940s created a caldera on its peak, whose circumference is nearly 14 kilometers with an average depth of 213 meters and a maximum of 384 meters. Atop the mountain is Cheonji, literally meaning “heavenly lake,” the largest caldera in the world.

Volcanic ash

Volcanic ash from Mt. Baekdu eruption has been found as far away as the southern part of Hokkaido, Japan. Geologists predict the occurrence of great Mt. Baekdu eruptions every 1,000 years and that of minor ones every 200 to 300 years. Minor eruptions were recorded in 1413, 1597, 1668 and 1702 with the last activity being recorded in 1903.

Among other indicators backing the scenario of a future eruption is the height of Mt. Baekdu, which has grown nearly 10 centimeters since 2002. Experts say an expanding magma pool, a precondition for an eruption, is gradually pushing up the height of the mountain as well as the temperature on the surface. On Oct. 1, 2006, a Russian satellite found the surface temperature of the mountain notably higher than before. The finding came just days after North Korea conducted an underground nuclear test in its northern territory, which could have been a catalyst reactivating magma flows, according to analysts.

Mt. Baekdu has been carefully observed since 1999 when a volcanic observatory was built in China, and since 2002, there have been some symptoms of an eruption. Seismic activity near the mountain has increased dramatically, and the concentration of hydrogen and helium emissions, both of which are volcanic gases have risen 10-fold. And there’s ample possibility that Mt. Baekdu may erupt in the near future.

If Mt. Baekdu erupts, it would no doubt bring about grave consequences for the two Koreas as well as the surrounding states, including China, Japan and Russia. The biggest immediate threat is the 2 billion tons of water in the lake on top of the crater. An eruption would likely cause severe flood damage, engulfing roads and homes within a 30-kilometer radius in just 3 hours and 20 minutes, a geological report found recently.

Mt. Baekdu’s caldera

The greatest victim of a Mt. Baekdu explosion may be North Korea, especially Yanggang and Hamgyeong Provinces. The two regions, located on the tip of the Korean Peninsula, may be covered with ash in just two hours.

In about eight hours, ash may reach Ulleungdo and Dokdo, two far eastern islands of South Korea, and in 12 hours, land on Tottori Prefecture, Japan. After 18 hours, volcanic ash would likely spread beyond Japan.

The National Institute for Disaster Prevention conducted a simulation in 2010 to test how far volcanic ash can spread if Mt. Baekdu erupts. According to the results, the effects can be different depending on the timing. If it happens in winter, Japan is expected to be more affected due to the northwest monsoon. On the other hand, a summer eruption would affect South Korea more.

Mt. Baekdu’s caldera has nearly two billion tons of water. If volcanic heat evaporates the water and is mixed suddenly with volcanic ashes, it would be strong enough to engulf even Vladivostok in Russia and Hokkaido in northern Japan, according to experts. The construction of nuclear power plants by North Korea and China in the neighborhood may certainly pose a grave threat to all Northeast Asians, with the view that Mt. Baekdu’s explosion would for sure cause subsequent nuclear catastrophes, as seen in Japan’s 2011 tsunami disaster. A volcanic explosion is the most terrible natural disaster which cannot be easily avoided by human wisdom and knowledge.

With unrelenting outbreaks of record-breaking natural disasters around the world and especially in the wake of Japan’s massive earthquake that is now estimated to have killed nearly 10,000, the world’s eyes are drawn to Mt. Baekdu. Multinational and regional cooperative monitoring systems are needed beyond ideological barriers to take preemptive measures against a possible eruption.

By all indications, Mt. Baekdu is a real danger and it’s not clear how long it will stay inactive. A Mt. Baekdu eruption, if it takes place, will not be a matter for a certain country but a global concern to determine the future of Northeast Asian civilization.

Environment Info

Volcanic eruptions

An important measure of eruptive strength is the Volcanic Explosivity Index (VEI), a magnitudic scale ranging from 0 to 8 that often correlates to eruptive types.

During a volcanic eruption, lava, tephra (ash, lapilli tuff, volcanic bombs and blocks), and various gases are expelled from a volcanic vent or fissure.

Several types of volcanic eruptions have been distinguished by volcanologists. These are often named after famous volcanoes where that type of behavior has been observed.

Some volcanoes may exhibit only one characteristic type of eruption during a period of activity, while others may display an entire sequence of types all in one eruptive series.

Park Chang-seok is currently a resident research fellow of the Korea Institute of Public Administration (KIPA). Park, a former Korea Times managing editor and a Kyung Hee University media professor, is the author of “The History of Korean English Newspaper” and “News English.” He is the editor of KIPA’s two English books “Korea: From Rags to Riches” and “Discover Korea in Public Administration.”

Underwater eruption suspected near Iwoto

The Yomiuri Shimbun

An underwater volcanic eruption may have occurred near Iwoto island, the Japan Meteorological Agency has said.

The Maritime Self-Defense Force confirmed a change in the color of the water northeast of Iwoto–about 1,250 kilometers south of Tokyo–at about 3:40 p.m. on Sunday after volcanic tremors–lasting about half an hour–were observed in the early morning on the island, according to the agency.

Moderate Quake Jolts Western Iran, Injures 8

A moderate earthquake jolted a small town in western Iran near the Iraqi border on Thursday, injuring eight people and damaging buildings, Iranian media reported.

The magnitude 5.5 quake hit the sparsely populated area near the town of Mourmouri, about 300 miles (480 kilometers) southwest of the capital Tehran, at 2:39 p.m., said the semiofficial Mehr news agency.

The report said the quake sent people rushing out of their homes in Mourmouri and that scores of buildings were damaged in nearby towns of Abdanan and Dehloran.

The area has experienced dozens of moderate earthquakes over the past few weeks.

Iran is located on seismic fault lines and is prone to earthquakes, experiencing at least one slight quake a day on average.

In 2003, some 26,000 people were killed by a magnitude 6.6 quake that flattened the historic southeastern city of Bam.

After a mini heatwave and the wettest April on record, now parts of Britain are braced for a taste of some wintry weather.Forecasters say it will be turning much colder as we head towards the weekend, with some areas seeing unseasonable frost and sub-zero temperatures.Sky weather presenter Nazaneen Ghaffar said: “It’s all thanks to a cold front slowly moving southwards across the UK on Friday. This will bring with it colder air into northern areas.

It’ll be chilly for Scotland and Northern Ireland and northern Scotland could see a few wintry showers.

“On Saturday again some wintry showers are likely over the hills of Scotland.”

Flood warnings and alerts remain in place after the recent heavy rainfall, with some rivers set to reach their peaks.

The Environment Agency is urging people to keep away from swollen rivers and not attempt to walk or drive through flood waters.

On Monday, a mental health tribunal judge died when his car was swept away by 5ft of fast-flowing water at a ford in Headley, Hampshire.

Although the wettest April on record has started to restore water levels below ground, experts say it will take a lot more time and rain to undo the effects of two dry winters and bring swathes of England out of drought.

Environment Secretary Caroline Spelman has even raised the possibility of standpipes returning to UK streets if the country is hit by a third dry winter in a row.

“Whereas it’s most unlikely we would have standpipes this year, if we have another dry winter that becomes more likely.

“We really do need a wet winter to get back to normal conditions,” Mrs Spelman said.

See all the Environment Agency alerts here

One in four Britons have been using their hosepipes in spite of the ban, a survey claims.

A poll of more than 1,000 people living in drought-affected areas for Gardeners’ World magazine found that 25% had been totally or partially ignoring the ban imposed by seven water companies on April 5.

Red Flag Warning

FIRE WEATHER MESSAGE

GRAND JUNCTION CO

SALT LAKE CITY UT

Experiments may dramatically underestimate how plants will respond to climate change in the future. That’s the conclusion of an analysis of 50 plant studies on four continents, published this week in an advance online issue of the journal Nature, which found that shifts in the timing of flowering and leafing in plants due to global warming appear to be much greater than estimated by warming experiments.

“This suggests that predicted ecosystem changes-including continuing advances in the start of spring across much of the globe-may be far greater than current estimates based on data from experiments,” said Elizabeth Wolkovich, an ecologist at the University of British Columbia who led an interdisciplinary team of scientists that conducted the study while she was a postdoctoral fellow at the University of California, San Diego.

“These findings have extensive consequences for predictions of species diversity, ecosystem services and global models of future change,” said Elsa Cleland, an assistant professor of biology at UC San Diego and senior author of the study, which involved 22 institutions in Canada, Sweden, Switzerland, the U.K. and the U.S.

“Long-term records appear to be converging on a consistent average response to climate change, but future plant and ecosystem responses to warming may be much higher than previously estimated from experimental data.”

Predicting plant responses to climate change has important consequences for human water supply, pollination of crops and the overall health of ecosystems. Shifts in the timing of annual plant events-which biologists call “phenology”-are some of the most consistent and visible responses to climate change.

Long-term historical records show that many plant species have shifted their leafing and flowering earlier, in step with warming temperatures over recent decades.

Because historical records are not available in most locations and climate change may produce temperatures higher than previously recorded, however, ecologists often rely on experiments that warm small field plots to estimate plant responses to temperature and project future conditions.

With support from the National Center for Ecological Analysis and Synthesis, a research center funded by the National Science Foundation, the State of California and the University of California, Santa Barbara, the scientists created new global databases of plant phenology to compare the sensitivity of plants to temperature- that is, how much plants shift their timing of leafing and flowering with warming. These were calculated from experiments and then compared to long-term monitoring records.

Wolkovich and her colleagues found that experiments underpredicted plant phenological responses to temperature by at least fourfold compared to long-term records. Long-term historical records consistently showed that leafing and flowering will advance, on average, 5 to 6 days per degree Celsius-a finding that was strikingly consistent across species and datasets.

“These results are important because we rely heavily on these experiments to predict what will happen to communities and ecosystems in the future,” said Ben Cook, a climatologist at the NASA Goddard Institute for Space Studies and Columbia University, who helped bring together the research team.

Wolkovich said a number of factors could explain this discrepancy-including additional effects of climate change not mirrored by warming experiments, or specific aspects of the experimental design such as the degree of warming.

But her team’s analyses found that within the range of temperature increases considered, responses were not noticeably affected by the degree of warming or the number of years the study spanned. Instead, the discrepancy may be driven by exactly how researchers manipulate temperatures and how accurately they measure them.

“Researchers use a variety of methods to increase temperatures in the field-including heating cables in the soil, small greenhouse-like structures and heating above plants,” explains Wolkovich. “We found that plant sensitivities to temperature vary with the design of the experiment, with above plant warming producing consistent advances in flowering.”

Additionally, because the comparison was based on a metric that considered plant responses per degree Celsius of temperature change, experiments that overestimate their temperature increases could underestimate the change in leafing and flowering per degree of warming.

The difference in estimated responses from experiments versus long-term records has important consequences for predictions of species diversity, ecosystem services and global models of future change.

“Continuing efforts to improve the design of warming experiments while maintaining and extending long-term historical monitoring will be critical to pinpointing the cause of the mismatch,” said Wolkovich.

“These efforts will yield a more accurate picture of future plant communities and ecosystems with continuing climate change.”

http://www.weather.com/news/thousands-st-louis-area-impacted-hail-damage201205


http://phys.org/news/2012-05-underestimate-responses-climate.html


http://news.nationalgeographic.com/news/2012/05/120501-yellowstone-supervolca…


http://spaceweather.com/


http://rsd.gsfc.nasa.gov/goes/


http://www.haarp.alaska.edu/haarp/data.html


http://sdo.gsfc.nasa.gov/data/


http://umtof.umd.edu/pm/


http://sohodata.nascom.nasa.gov/cgi-bin/soho_movie_theater


http://www.ips.gov.au/HF_Systems/6/5


http://solarimg.org/artis/


http://www.swpc.noaa.gov/wsa-enlil/cme-based/


http://hisz.rsoe.hu/alertmap/index2.php


http://ccmc.gsfc.nasa.gov/cgi-bin/SWMF_RealTime_browse.cgi


http://grb.sonoma.edu/

Rare April Freezing Rain in Brazil

Residents of Morro Grande, São José dos Missing, reported that at 10am on Monday there was rain for about a minute of white ice grains (granular snow).This was verified by the MetSul Meteorology, whose survey indicated freezing rain in Bento Goncalves, Caxias do Sul, San Marcos High Happy, Cinnamon, Capon Beautiful South, Ipe and Vacaria, San Joaquin in Santa Catarina, and possibly in Aparados and Serra Gaucho.In the case of freezing rain, which looks like a kid sleet, precipitation leaves the cloud like snowflakes on a cold portion of the atmosphere. Then it goes through an intermediate layer of warmer air, but because it is not thick enough, it just melts part of the flakes. Before reaching the surface, however, the flakes are melted by a new layer of cooler air and they freeze yet again, precipitating in the form of ice.The conditions were thus very conducive to the occurrence of winter precipitation (snow or freezing rain) with cold air temperatures and negative between 1500 and 2000 meters altitude, and the presence of a trough (an area of lower pressure) on the River Grande do Sul and Santa Catarina. It is one of the classic models for snow in southern Brazil: a continental high-pressure trough or cyclone ensuring moisture flow.

Source: Metsul Blog (In Portuguese)

As the Earth’s climate warms, a melting ice sheet produces a distinct and highly non-uniform pattern of sea-level change, with sea level falling close to the melting ice sheet and rising progressively farther away. The pattern for each ice sheet is unique and is known as its sea level fingerprint.

Now, a group of geophysicists from the University of Toronto, Harvard and Rutgers Universities have found a way to identify the sea level fingerprint left by a particular ice sheet, and possibly enable a more precise estimate of its impact on global sea levels.

“Our findings provide a new method to distinguish sea-level fingerprints in historical records of sea levels, from other processes such as ocean waves, tides, changes in ocean circulation, and thermal expansion of the ocean,” says Carling Hay, a Ph D candidate in the Department of Physics at the University of Toronto and lead author of a study published in Proceedings of the National Academy of Sciences (PNAS).

“It may indeed allow us to estimate the contributions of individual ice sheets to rising global sea levels.”

Scientists around the world are trying to estimate both the current rate of sea level rise and the rates of ice sheet melting, and yet little work has been done to combine the two problems and answer these questions simultaneously.

Hay and colleagues Jerry Mitrovica and Eric Morow of Harvard University, and Robert E. Kopp of Rutgers University sought out statistical techniques that had not previously been applied to this problem, and began developing the new method using data analysis techniques common in other fields such as engineering science, economics, and meteorology.

The researchers then tested and refined the method by applying it to synthetic data sets – i.e., data sets with the same amount of noise as real data, but with known melting signals. The tests provide important guidance for the application of the method to actual sea-level records.

“We are now applying our methodology to historical sea level records to provide a new estimate of total sea level rise and the melt rates of the Greenland and West Antarctic ice sheets, over the 20th century,” says Hay.

“Preliminary results show intriguing evidence for acceleration of globally averaged sea-level rise in the second half of the period, along with a simultaneous rise in temperature. Once our study of historical records is complete, the next step will be to incorporate satellite-based measurements of sea-level changes.”

The findings are reported in the paper “Estimating the sources of global sea level rise with data assimilation techniques.” The research is supported by funding from the Canadian Institute for Advanced Research, Harvard University, and the US Department of Energy American Association for the Advancement of Science Fellowship Program.