PRESS-NEWS.org - Press Release Distribution
FREE PRESS RELEASES DISTRIBUTION

Analysis of Greenland ice cores adds to historical record and provide glimpse into climate's future

The International North Greenland Eemian Ice Drilling (NEEM) project results indicate that melting of Antarctic ice sheet may have contributed more to sea level rise than melting of the Greeland ice sheet some 100,000 years ago

Analysis of Greenland ice cores adds to historical record and provide glimpse into climate's future
2013-01-25
(Press-News.org) A new study that provides surprising details on changes in Earth's climate from more than 100,000 years ago indicates that the last interglacial--the period between "ice ages"--was warmer than previously thought and may be a good analog for future climate, as greenhouse gases increase in the atmosphere and global temperatures rise.

The research findings also indicate that melting of the massive West Antarctic ice sheet may have contributed more to sea-level rise at that time than melting of the Greenland ice sheet.

The new results from the North Greenland Eemian Ice Drilling (NEEM) project were published in the Jan. 24 edition of Nature.

Members of the research team noted that they were working in Greenland during the summer of 2012 during a rare modern melt event similar to those discussed in the paper.

"We were quite shocked by the warm surface temperatures observed at the NEEM ice camp in July 2012," said Dorthe Dahl-Jensen, of the University of Copenhagen, the NEEM project leader.

"It was simply raining, and, just as during the Eemian period, meltwater formed subsurface ice layers. While this was an extreme event, the present warming over Greenland makes surface melt more likely, and the predicted warming over Greenland in the next 50-100 years will potentially have Eemian-like climate conditions."

The Eemian interglacial period began about 130,000 years ago and ended about 115,000 years ago.

The project logistics for NEEM are managed by Denmark's Centre for Ice and Climate. The Arctic Sciences Section in the National Science Foundation's Division of Polar Programs manages the U.S. support for the project.

In addition to Denmark and the United States, researchers from Belgium, Canada, China, France, Germany, Iceland, Japan, the Netherlands, South Korea, Sweden, Switzerland and the United Kingdom are also partners in NEEM.

The research published this week shows that during the Eemian interglacial, the climate in North Greenland was about 8 degrees Celsius warmer than at present. Despite this strong warming signal during the Eemian--a period when the seas were roughly four to eight meters higher than they are today--the surface in the vicinity of NEEM was only a few hundred meters lower than its present level, which indicates that the Greenland ice sheet may have contributed less than half of the total sea rise at the time.

"The new findings reveal higher temperatures in Northern Greenland during the Eemian than paleo-climate models have estimated," said Dahl-Jensen.

The researchers looked at surface elevation and ice thickness in the early and later parts of the Eemian. Following the previous glacial period, 128,000 years before present, the surface elevation in the vicinity of NEEM was 200 meters higher than the present and the ice thickness decreased at a very high rate of 6 centimeters per year. Some 122,000 years before the present, the surface elevation was 130 meters below the present. In the late Eemian, 122,000 to 115,000 before present, the surface elevation remained stable at a level of 130 meters below the present with an ice thickness of 2,400 meters.

The research team estimated the Greenland ice sheet's volume reduced by no more than 25 percent over 6,000 years. The rate of elevation change in the early part of the Eemian was high and the loss of mass from the Greenland ice sheet was likely on the the same order as changes observed during the last ten years.

"The good news from this study is that Greenland is not as sensitive as we thought to temperature increases in terms of disgorging ice into the ocean during interglacial periods," said Dahl-Jensen. "The bad news is that if Greenland did not disappear during the Eemian, Antarctica, including the more dynamically unstable West Antarctica, must be responsible for a significant part of the 4-8 meters of sea-level rise."

Jim White, director of the Institute of Arctic and Alpine Research at the University of Colorado, Boulder, and the lead U.S. investigator on the NEEM project, said that while three previous ice cores drilled in Greenland in the last 20 years recovered ice from the Eemian, the deepest layers were compressed and folded, making the data difficult to interpret.

With this study, although there was some folding of the lowest ice layers in the NEEM core, sophisticated ice-penetrating radar helped scientists sort out and interpret the individual layers to paint an accurate picture of the warming of Earth's Northern Hemisphere as it emerged from the previous ice age.

"When we calculated how much ice melt from Greenland was contributing to global sea rise in the Eemian, we knew a large part of the sea rise back then must have come from Antarctica," said White. "A lot of us had been leaning in that direction for some time, but we now have evidence that confirms that the West Antarctic ice sheet was a dynamic and crucial player in global sea rise during the last interglacial period."

The intense surface melt in the vicinity of NEEM during the warm Eemian period was seen in the ice core as layers of re-frozen meltwater. Meltwater from surface snow had penetrated the underlying snow, where it re-froze. Such melt events during the past 5,000 years are very rare by comparison, confirming that the surface temperatures at the NEEM site during the Eemian were significantly warmer than today, said the researchers.

The Greenland ice core layers--formed over millennia by compressed snow--are being studied in detail using a big suite of measurements, including stable water isotope analysis that reveals information about temperature and moisture changes back in time. Lasers are used to measure the water stable isotopes and atmospheric gas bubbles trapped in the ice cores to better understand past variations in climate on a year-by-year basis--similar in some ways to a tree-ring record.

"It's a great achievement for science to gather and combine so many measured ice core records to reconstruct the climate history of the past Eemian," said Dahl-Jensen. "It shows what a great team of researchers we have assembled and how valuable these findings are."



INFORMATION:



-NSF-


[Attachments] See images for this press release:
Analysis of Greenland ice cores adds to historical record and provide glimpse into climate's future

ELSE PRESS RELEASES FROM THIS DATE:

Emotional stress reduces effectiveness of prostate cancer therapies in animal model

2013-01-25
WINSTON-SALEM, N.C. – Jan. 25, 2013 – Not surprisingly, a cancer diagnosis creates stress. And patients with prostate cancer show higher levels of anxiety compared to other cancer patients. A new study by researchers at Wake Forest Baptist Medical Center indicates that stress is not just an emotional side effect of the diagnosis; it also can reduce the effectiveness of prostate cancer drugs and accelerate the development of prostate cancer. The findings are published in the February issue of the Journal of Clinical Investigation. The Wake Forest Baptist team, headed ...

INRS develops a nanohybrid with remarkable properties using a new laser-plasma process

2013-01-25
Montreal, January 25, 2013 – By achieving the synthesis of a novel nanohybrid structure by means of the pulsed laser ablation (PLA) technique, Professor My Ali El Khakani and his team paved the way for a new generation of optoelectronic materials. The combination of carbon nanotubes and lead sulfide (PbS) nanoparticles was performed using an effective and relatively simple process that offers considerable latitude for creating other nanohybrids for a variety of applications. The INRS Énergie Matériaux Télécommunications Research Centre researcher's work, published in the ...

No more 'empty nest:' middle-aged adults face family pressure on both sides

2013-01-25
CORVALLIS, Ore. – The "empty nest" of past generations, in which the kids are grown up and middle-aged adults have more time to themselves, has been replaced in the United States by a nest that's full – kids who can't leave, can't find a job and aging parents who need more help than ever before. According to a new study by researchers at Oregon State University, what was once a life stage of new freedoms, options and opportunities has largely disappeared. An economic recession and tough job market has made it hard on young adults to start their careers and families. ...

New tool for mining bacterial genome for novel drugs

2013-01-25
Vanderbilt biochemists have discovered that the process bacteria undergo when they become drug resistant can act as a powerful tool for drug discovery. Their findings – reported this week in the Online Early Edition of the Proceedings of the National Academy of Sciences – should give a major boost to natural products drug discovery – the process of finding new drugs from compounds isolated from living organisms – by substantially increasing the number of novel compounds that scientists can extract from individual microorganisms. Bacteria have traditionally been the ...

New suite of chemicals seen causing disease generations later

2013-01-25
PULLMAN, Wash.—Washington State University researchers have lengthened their list of environmental toxicants that can negatively affect as many as three generations of an exposed animal's offspring. Writing in the online journal PLOS ONE, scientists led by molecular biologist Michael Skinner document reproductive disease and obesity in the descendants of rats exposed to the plasticizer bisephenol-A, or BPA, as well DEHP and DBP, plastic compounds known as phthalates. In a separate article in the journal Reproductive Toxicology, they report the first observation of cross-generation ...

Breast feeding okay for mothers taking immunosuppressant drug

2013-01-25
Highlights The breast milk of mothers taking the immunosuppressant tacrolimus contains only very low levels of the drug. Women taking tacrolimus who wish to breast-feed after appropriate counseling should not be discouraged from doing so. Increasing numbers of pregnant women are taking tacrolimus after organ transplantation and for other conditions. Washington, DC (January 24, 2013) — Women taking the immunosuppressant tacrolimus can rest assured that breast feeding will not elevate their babies' exposure to the drug, according to a study appearing in an upcoming ...

Kidney disease accounts for most of the increased risk of dying early among diabetics

2013-01-25
Highlights Among people without diabetes or kidney disease, 10-year mortality was 7.7%. Among individuals with diabetes but without kidney disease, mortality was 11.5%. Among those with both diabetes and kidney disease, mortality was 31.1%. 26 million people in the US and 340 million people in the world have type 2 diabetes. Washington, DC (January 24, 2013) — One in every 10 Americans has diabetes, and a third or more of those with the condition will develop kidney disease. It may be possible to live a long and healthy life with diabetes, but once kidney disease ...

Love triumphs over hate to make exotic new compound

2013-01-25
Northwestern University graduate student Jonathan Barnes had a hunch for creating an exotic new chemical compound, and his idea that the force of love is stronger than hate proved correct. He and his colleagues are the first to permanently interlock two identical tetracationic rings that normally are repelled by each other. Many experts had said it couldn't be done. On the surface, the rings hate each other because each carries four positive charges (making them tetracationic). But Barnes discovered by introducing radicals (unpaired electrons) onto the scene, the researchers ...

Science needs a second opinion: Researchers find flaws in study of patients in 'vegetative state'

2013-01-25
NEW YORK (Jan. 24, 2013) -- A team of researchers led by Weill Cornell Medical College is calling into question the published statistics, methods and findings of a highly publicized research study that claimed bedside electroencephalography (EEG) identified evidence of awareness in three patients diagnosed to be in a vegetative state. The new reanalysis study led by Weill Cornell neurologists Drs. Andrew Goldfine, Jonathan Victor, and Nicholas Schiff, published in the Jan. 26 issue of the journal Lancet, reports the statistical results and methodology used by a research ...

Chameleon pulsar baffles astronomers

2013-01-25
Using a satellite X-ray telescope combined with terrestrial radio telescopes the pulsar was found to flip on a roughly half-hour timescale between two extreme states; one dominated by X-ray pulses, the other by a highly-organised pattern of radio pulses. The research was led by Professor Wim Hermsen from The Netherlands Institute for Space Research and the University of Amsterdam and will appear in the journal Science on the 25th January 2013. Researchers from Jodrell Bank Observatory, as well as institutions around the world, used simultaneous observations with the ...

LAST 30 PRESS RELEASES:

Scientists model 'true prevalence' of COVID-19 throughout pandemic

New breakthrough to help immune systems in the fight against cancer

Through the thin-film glass, researchers spot a new liquid phase

Administering opioids to pregnant mice alters behavior and gene expression in offspring

Brain's 'memory center' needed to recognize image sequences but not single sights

Safety of second dose of mRNA COVID-19 vaccines after first-dose allergic reactions

Changes in disparities in access to care, health after Medicare eligibility

Use of high-risk medications among lonely older adults

65+ and lonely? Don't talk to your doctor about another prescription

Exosome formulation developed to deliver antibodies for choroidal neovascularization therapy

Second COVID-19 mRNA vaccine dose found safe following allergic reactions to first dose

Plant root-associated bacteria preferentially colonize their native host-plant roots

Rare inherited variants in previously unsuspected genes may confer significant risk for autism

International experts call for a unified public health response to NAFLD and NASH epidemic

International collaboration of scientists rewrite the rulebook of flowering plant genetics

Improving air quality reduces dementia risk, multiple studies suggest

Misplaced trust: When trust in science fosters pseudoscience

Two types of blood pressure meds prevent heart events equally, but side effects differ

New statement provides path to include ethnicity, ancestry, race in genomic research

Among effective antihypertensive drugs, less popular choice is slightly safer

Juicy past of favorite Okinawan fruit revealed

Anticipate a resurgence of respiratory viruses in young children

Anxiety, depression, burnout rising as college students prepare to return to campus

Goal-setting and positive parent-child relationships reduce risk of youth vaping

New research identifies cancer types with little survival improvements in adolescents and young adul

Oncotarget: Replication-stress sensitivity in breast cancer cells

Oncotarget: TERT and its binding protein: overexpression of GABPA/B in gliomas

Development of a novel technology to check body temperature with smartphone camera

The mechanics of puncture finally explained

Extreme heat, dry summers main cause of tree death in Colorado's subalpine forests

[Press-News.org] Analysis of Greenland ice cores adds to historical record and provide glimpse into climate's future
The International North Greenland Eemian Ice Drilling (NEEM) project results indicate that melting of Antarctic ice sheet may have contributed more to sea level rise than melting of the Greeland ice sheet some 100,000 years ago