Ruapehu eruption like ‘Groundhog Day’





Dr Shane Cronin, head of the Volcanic Risk Solutions Group
Dr Shane Cronin, head of the Volcanic Risk Solutions Group

Massey University volcanologist Dr Shane Cronin, head of the Volcanic Risk Solutions Group, says the latest eruption and lahar on Mt Ruapehu is just like the September 1995 eruption.



“It’s like Groundhog Day. It’s just like the eruption in 1995. It’s quite spectacular. There are tonnes of black material around the Crater Lake. This seems to be made up of crater lake water, freshly erupted rock and rock from older eruptions. There has been a snow slurry lahar, which has flowed down the Whangaehu valley side of the mountain.”



Dr Cronin and his students from the Institute of Natural Resources drove to the Central Plateau on Tuesday night as soon as he heard about the eruption and spent the night camped by a lahar monitoring station at the base of Mt Ruapehu. They are now downloading data from monitoring instruments across the mountain, collecting samples and data and measuring the flow of the lahar around the lake. The instruments were purchased in December as part of a $720,000 Marsden Fund project led by Dr Cronin and Dr Vern Manville from the Institute of Geological and Nuclear Sciences (GNS).



“Our efforts yesterday included surveying precisely the levels of the lahars down the Whangaehu channel. The lahar deposits are an unusual mix of snow, mud and rock – like in ’95. There were at least three flows down the valley and our instruments installed for the Marsden Fund research project (on the March 2007 flow) seem all to have worked in capturing the flows as they passed.


He says the Whangaehu lahars were probably in total only about 15 per cent of the size of the March 18 lahar and were more or less confined to the upper mountain.



Eleven staff and students from the volcanic response group studied the lahar yesterday with 10 staying on today to concentrate on the northern flanks of the mountain, near the ski field, as well as working on more details of the Whangaehu lahars.



Dr Cronin says the technique used to gather information about the internal dynamics of the lahar, using seismometers, will be used to enhance predictive models being developed by the group. Dr Cronin says the difference between the lahar earlier this year and yesterday’s event is that this lahar was caused by an eruption, rather than a breaching of the Crater Lake wall. Because the event was eruption-related, he says, the early warning systems may not have measured the event accurately and he is hoping the monitoring equipment, still on the mountain after the March event, will prove to be more reliable.

Clues to End of the Last Ice Age


In contrast to what is often inferred from the geologic record, carbon dioxide did not cause the end of the last ice age, a new USC study published in Science suggests.



“There has been this continual reference to the correspondence between CO2 and climate change as reflected in ice core records as justification for the role of CO2 in climate change,” said paleoclimatologist Lowell Stott, the study’s lead author and a professor of earth sciences at USC College.



“You can no longer argue that CO2 alone caused the end of the ice ages.”



Deep-sea temperatures warmed about 1,300 years before the tropical surface ocean and well before the rise in atmospheric CO2, the study found. The finding suggests the rise in greenhouse gas was likely a result of warming – but not its main cause.



However, the study does not question the fact that CO2 plays a key role in climate.



“I don’t want anyone to leave thinking that this is evidence that CO2 doesn’t affect climate,” Stott cautioned. “It does, but the important point is that CO2 is not the beginning and end of climate change.”



While an increase in atmospheric CO2 and the end of the ice ages occurred at roughly the same time, scientists have debated whether CO2 caused the warming or was released later by an already warming sea.



The best estimate from other studies of when CO2 began to rise is no earlier than 18,000 years ago. Yet this study shows that the deep sea, which reflects a good picture of oceanic temperature trends, started warming about 19,000 years ago.



“What this means is that a lot of energy went into the ocean long before the rise in atmospheric CO2,” Stott said.



But where did this energy come from? Evidence pointed southward.



Water’s salinity and temperature are properties that can be used to trace its origin – and the warming deep water appeared to come from the Antarctic Ocean, the scientists wrote.



This water then was transported northward over 1,000 years via well-known deep-sea currents, a conclusion supported by carbon-dating evidence.



In addition, the researchers noted that the increases in deep-sea temperature coincided with the retreat of Antarctic sea ice, both occurring 19,000 years ago, before the northern hemisphere’s ice retreat began.


Finally, Stott and colleagues found a correlation between melting Antarctic sea ice and increased springtime solar radiation over Antarctica, suggesting this was the energy source.



As the sun pumped in heat, the warming accelerated because of sea-ice albedo feedbacks, in which retreating ice exposes more of the ocean that can absorb heat from the sun, much like a dark T-shirt on a hot day, and this results in more melting.



In addition, the authors’ model showed how changed ocean conditions may have been responsible for the release of CO2 from the ocean into the atmosphere, which like the albedo feedbacks, also accelerated the warming.



The link between the sun and ice age cycles is not new. The theory of Milankovitch cycles states that periodic changes in Earth’s orbit cause increased summertime solar radiation in the northern hemisphere, which controls ice size.



However, this study suggests that the pace-keeper of ice sheet growth and retreat lies in the southern hemisphere’s spring rather than the northern hemisphere’s summer.



The conclusions underscore the importance of regional climate dynamics, Stott said. “Here is an example of how a regional climate response translated into a global climate change,” he explained.



Stott and colleagues arrived at their results by studying a unique sediment core from the western Pacific composed of fossilized surface-dwelling (planktonic) and bottom-dwelling (benthic) organisms.



These organisms – foraminifera – incorporate different isotopes of oxygen from ocean water into their calcite shells, depending on the temperature, and by measuring the change in these isotopes in shells of different ages, it is possible to reconstruct how the deep and surface ocean temperatures changed through time.



If CO2 caused the warming, one would expect surface temperatures to increase before deep-sea temperatures, since the heat slowly would spread from top to bottom. Instead, carbon-dating showed that the water used by the bottom-dwelling organisms began warming about 1,300 years before the water used by surface-dwelling ones, suggesting that the warming spread bottom-up instead.



“The climate dynamic is much more complex than simply saying that CO2 rises and the temperature warms,” Stott said. The complexities “have to be understood in order to appreciate how the climate system has changed in the past and how it will change in the future.”



Stott’s collaborators were Axel Timmermann of the University of Hawaii and Robert Thunell of the University of South Carolina. Stott was supported by the National Science Foundation and Timmerman by the International Pacific Research Center.



Stott is an expert in paleoclimatology and was a reviewer for the Intergovernmental Panel on Climate Change. He also recently co-authored a paper in Geophysical Research Letters tracing a 900-year history of monsoon variability in India.



The study, which analyzed isotopes in cave stalagmites, found correlations between recorded famines and monsoon failures, and found that some past monsoon failures appear to have lasted much longer than those that occurred during recorded history. The ongoing research is aimed at shedding light on the monsoon’s poorly understood but vital role in Earth’s climate.

Oxygen on Earth: 50 to 100 Million Years Earlier Than Scientists Thought





New findings reveal the importance of oxygen in the environment shortly before the deposition of this massive formation of iron oxide--rust--in the Hamersley Basin in Western Australia. - Photo Credit: A. D. Anbar, ASU
New findings reveal the importance of oxygen in the environment shortly before the deposition of this massive formation of iron oxide–rust–in the Hamersley Basin in Western Australia. – Photo Credit: A. D. Anbar, ASU

Scientists have found that traces of oxygen appeared in Earth’s atmosphere 50 to 100 million years earlier than previously thought–before what geologists call the “Great Oxidation Event.”



This event happened between 2.3 and 2.4 billion years ago, when most geoscientists think atmospheric oxygen rose sharply from very low levels. The amount of oxygen before that time has been uncertain.



Analyzing layers of sedimentary rock in a kilometer-long core sample from the Hamersley Basin in Western Australia, the researchers report finding evidence that a small but significant amount of oxygen–a whiff–was present in the oceans and possibly Earth’s atmosphere 2.5 billion years ago.



The data also suggest that oxygen was nearly undetectable just before that time. Their findings appear in a pair of papers in the Sept. 28 issue of the scientific journal Science. The National Science Foundation (NSF) funded the research.



“We seem to have captured a piece of time before the Great Oxidation Event during which the amount of oxygen was actually changing–caught in the act, as it were,” said Ariel Anbar, a biogeochemist at Arizona State University in Tempe.



Anbar led one of the teams of investigators and participated in another team led by Alan Jay Kaufman, a geochemist at the University of Maryland in College Park. The collaborators analyzed a drill core for geochemical and biological tracers representing the time just before the rise of atmospheric oxygen.



“We have compelling evidence for a shift in the oxidation state of the surface ocean 50 million years before the Great Oxidation Event,” said Kaufman. “These findings are a significant step in our understanding of the oxygenation of Earth. They link changes in the environment with changes in the biosphere.”



The project also brought together scientists from the University of Washington, University of California in Riverside and University of Alberta.



“These results are the culmination of a successful effort to recover suitable rock material, and to test hypotheses regarding the evolution of biogeochemical cycles on Earth in the time period after the appearance of life and prior to the Great Oxidation Event,” said Enriqueta Barrera, program director in NSF’s Division of Earth Sciences, which funded the research.



The work also received support from the Astrobiology Drilling Program (ADP) of the NASA Astrobiology Institute (NAI) and the Geological Survey of Western Australia.



In the summer of 2004, the scientists bored into the geologically-famous Hamersley Basin in Western Australia, extracting a core of sedimentary rock 908 meters (about 3,000 feet) long.



“The core provides a continuous record of environmental conditions, analogous to a tape recording,” explains Anbar. Because it was recovered from deep underground, it contains materials untouched by the atmosphere for billions of years.


Anbar and his research group began an analysis of selected bands of the late Archean Mt. McRae Shale found in the upper 200 meters of the drill core. They analyzed amounts of the trace metals molybdenum, rhenium and uranium. The amounts of these metals in oceans and sediments depends on the amount of oxygen in the environment.



The goal was to characterize the nature of the environment and life in the oceans leading up to the Great Oxidation Event.



“The Maryland group began seeing funny variations in the chemistry of sulfur along this stretch of the drill core,” said Anbar. “We sped up our research to see if we found variations in metal abundances in the same places – and we did.”



Finding evidence of oxygen some 50 to 100 million years earlier than what was previously known was completely unexpected, say the scientists.



For the first half of Earth’s 4.56-billion-year history, the environment held almost no oxygen, other than that bound to hydrogen in water or to silicon and other elements in rocks. “Then, some time between 2.3 and 2.4 billion years ago, oxygen rose sharply in the Earth’s atmosphere and oceans, during the ‘Great Oxidation Event,'” said Anbar.



The event was a major step in Earth’s history, said Anbar, but its cause remains unexplained. How did Earth’s atmosphere go from being oxygen-poor to oxygen-rich, why did it change so quickly, and why did its oxygen content stabilize at the present 21 percent?



“Studying the dynamics that gave rise to the presence of oxygen in Earth’s atmosphere deepens our appreciation of the complex interaction between biology and geochemistry,” said Carl Pilcher, director of the NAI. “The results support the idea that our planet and the life on it evolved together.”



One possibility for explaining the Great Oxidation Event is that the ancient ancestors of today’s plants first began to produce oxygen by photosynthesis at this time.



“What we have now are new lines of evidence for oxygen in the environment 50 to 100 million years before its big rise,” Anbar said. This discovery strengthens the notion that organisms produced oxygen long before the Great Oxidation Event, creating features in the geologic record such as banded iron formations, and that the rise of oxygen in the atmosphere was ultimately controlled by geological processes.



“This knowledge is relevant to today’s studies of environmental and climate issues because it helps us understand the interactions between biology, geology and the composition of the atmosphere,” Anbar said.



“It also has implications for the search for life on planets outside our solar system. In the near future the only way we can look for evidence of life in such far-off places is to look for the fingerprints of biology in the compositions of their atmospheres. We are not far off from being able to detect Earth-like planets elsewhere in the galaxy, and eventually, we will be able to use telescopes to measure the oxygen content of their atmospheres.”



Questions Anbar hopes to investigate include: if scientists find that no Earth-like planets have undergone Great Oxidation Events, what will that mean about life on Earth? Is it inevitable that the evolution of oxygen-producing organisms results in an oxygen-rich atmosphere?



And, he said: “Can we find evidence that oxygen was produced even earlier?”

Arctic heat wave stuns climate change researchers





Undergraduate Geography student Joshua See, a member of Queen's International Polar Year project surveys the shifting terrain on Melville Island caused by this summer's record high temperatures in the Arctic. Photo Courtesy: Scott Lamoureux
Undergraduate Geography student Joshua See, a member of Queen’s International Polar Year project surveys the shifting terrain on Melville Island caused by this summer’s record high temperatures in the Arctic. Photo Courtesy: Scott Lamoureux

Unprecedented warm temperatures in the High Arctic this past summer were so extreme that researchers with a Queen’s University-led climate change project have begun revising their forecasts.



“Everything has changed dramatically in the watershed we observed,” reports Geography professor Scott Lamoureux, the leader of an International Polar Year project announced yesterday in Nunavut by Indian and Northern Affairs Minister Chuck Strahl. “It’s something we’d envisioned for the future – but to see it happening now is quite remarkable.”



One of 44 Canadian research initiatives to receive a total of $100 million (IPY) research funding from the federal government, Dr. Lamoureux’s new four-year project on remote Melville Island in the northwest Arctic brings together scientists and educators from three Canadian universities and the territory of Nunavut. They are studying how the amount of water will vary as climate changes, and how that affects the water quality and ecosystem sustainability of plants and animals that depend on it.



The information will be key to improving models for predicting future climate change in the High Arctic, which is critical to the everyday living conditions of people living there, especially through the lakes and rivers where they obtain their drinking water.



Other members of the research team include, from the Queen’s Geography Department: Paul Treitz, Melissa Lafreniere and Neal Scott; Myrna Simpson and Andre Simpson from U of T; and Pierre Francus from INRS-ETE, Quebec. Linda Lamoureux of Kingston’s Martello School will work with the scientists to develop learning tools for schools in the north.



From their camp on Melville Island last July, where they recorded air temperatures over 20ºC (in an area with July temperatures that average 5ºC), the team watched in amazement as water from melting permafrost a metre below ground lubricated the topsoil, causing it to slide down slopes, clearing everything in its path and thrusting up ridges at the valley bottom “that piled up like a rug,” says Dr. Lamoureux, an expert in hydro-climatic variability and landscape processes. “The landscape was being torn to pieces, literally before our eyes. A major river was dammed by a slide along a 200-metre length of the channel. River flow will be changed for years, if not decades to come.”


Comparing this summer’s observations against aerial photos dating back to the 1950s, and the team’s monitoring of the area for the past five years, the research leader calls the present conditions “unprecedented” in scope and activity. What’s most interesting, he says, is that their findings represent the impact of just one exceptional summer.



“A considerable amount of vegetation has been disturbed and we observed a sharp rise in erosion and a change in sediment load in the river,” Dr. Lamoureux notes. “With warmer conditions and greater thaw depth predicted, the cumulative effect of this happening year after year could create huge problems for both the aquatic and land populations. This kind of disturbance also has important consequences for existing and future infrastructure in the region, like roads, pipelines and air strips.”



If this were to occur in more inhabited parts of Canada, it would be “catastrophic” in terms of land use and resources, he continues. “It would be like taking an area the size of Kingston and having 15 per cent of it disappear into Lake Ontario.”



The Queen’s-led project is working with other IPY research groups including: Arctic HYDRA, an international group investigating the impact of climate change on water in the Arctic; Science Pub, a Norwegian group working on broad research from science to public education about the impacts of global warming; and CiCAT, a University of British Columbia-led group of 48 researchers investigating the impacts of climate change on tundra vegetation.



International Polar Year (IPY) is the largest-ever international program of coordinated scientific research focused on the Arctic and Antarctic regions and the first in 50 years.

Scientists to forecast and respond to human health effects of climate change





Dust storm approaching Stratford, Texas, in 1935.
Dust storm approaching Stratford, Texas, in 1935.

Climate changes have jeopardized human health in the past, and are bound to do so again. The Dust Bowl of the 1930s, for example, led to many illnesses and deaths from breathing difficulties and malnutrition, and prompted westward migrations of people vying for scarce food, shelter, and work.



Future severe climate changes will likewise have major public health ramifications. Following a request from Gov. Christine Gregoire, Washington State Department of Health and University of Washington health researchers are analyzing the likely effects of climate change on the state over the next century. Their group is called the Climate Change and Human Health Impacts Team, and goes by the acronym CHIT.



Their assessments will be based on scenarios developed by the UW Climate Impacts Group, an interdisciplinary research effort to discern the effects on the Pacific Northwest of natural climate shifts as well as global warming. The findings on potential health effects will be presented to the governor and the state legislature. The researchers will recommend how to manage and mitigate, and perhaps prevent, anticipated public health problems.



This study is part of a broader project funded by the Washington State Department of Community, Trade and Economic Development and directed by Dr. Edward L. Miles, the Bloedel Professor of Marine Studies and Public Affairs at the UW. The project, which has been funded for two years, is called “A Comprehensive Assessment of the Impacts of Climate Change on the State of Washington.” Alongside public health, project teams will examine other areas vital to the life and livelihood of the state. These include agriculture, coasts, estuaries, and harbors; energy and hydroelectric power; forests, hydrology and water resources; salmon and ecosystems, and civil engineering infrastructures.



“Problems related to climate change in any of these areas could affect human health,” said Dr. Roger Rosenblatt, professor of family medicine and head of CHIT, “because the issues we are considering are interrelated.” He gave as an example the higher incidence of wildfires expected from global warming. Many people would be at risk for developing lung and heart problems from smoke and poor air quality caused by the fires, he said.



Rosenblatt mentioned that there are many studies about the consequences of climate change on natural resources, but few researchers have looked at the issues from the public health point of view. Bringing together earth scientists and medical scientists is essential for this to happen.



“We need to have better information on how the health of individuals and communities might be affected by what will inevitably happen if we continue on the present course, and what we as a society can do to lessen the threat to the human population,” Rosenblatt said. “My hope is that if people understand the consequences for themselves personally and for their families, they may be motivated to work to reduce global warming. When individuals realize their own well-being is at stake, they become more interested in environmental issues like air pollution control and energy conservation.”


The effects of climate change are anticipated to vary from one part of the world to another and from region to region in the United States. Global warming scenarios developed for Washington state forecast the possibilities of coastal erosion, a rise in sea level, flow of salt water into fresh water wells, higher temperatures, flooding from storms, poorer air and water quality, more forest fires, melting of mountain snow packs, and warming of streams. Climate refugees from other states and countries may attempt to move to Washington state if it remains one of the few places with tolerable conditions. The influx would swell the state’s population and increase the demand on its public health and medical services.



CHIT will try to determine the types of health problems most likely to arise as a result of climate change in Washington state, which populations would be the most vulnerable, and what might be done to change the course of events. They will then look at the feasibility, effectiveness, and cost of potential interventions. They are working in partnership with the Human Health Preparation and Adaptation Work Group, chaired by Gregg Grunenfelder, assistant secretary for environmental health for the Washington State Department of Health.



A team led by Dr. Ann Marie Kimball, UW professor of epidemiology in the School of Public Health and Community Medicine and an expert on emerging diseases, will develop predictive models of the migration of disease-transmitting mammals, birds, insects, and parasites. Her team will forecast the speed of the spread of diseases such as malaria and West Nile Virus and their potential impact on Washington state. Dr. Katherine Carr, associate professor of family and child nursing and an expert on the effects of pollution on children, is looking at air quality and potential increases in lung disease and heart disease. Dr. Rich Fenske, professor of environmental and occupational health sciences, and director of the Pacific Northwest Agricultural Safety and Health Center, will examine heat stroke and medical problems adults and children may experience in farming and ranching communities.



Gains that America and the world have made in public health could be swept away by climate change, according to Rosenblatt. Homo sapiens was a successful species after the last interglacial age, because the climate stabilized into one that was optimal for humans, Rosenblatt explained. A major climate shift in either direction, hot or cold, would take many people out of the range in which their bodies can perform normally and civilizations can thrive.



Another human characteristic, Rosenblatt pointed out, is that people are adept at addressing immediate emergencies, such as a bridge collapse or the appearance of SARS, but they are dismal at responding to slow-moving disasters such as global warming.



“Climate change is a large train moving at us at a slow and steady speed,” Rosenblatt said, “We still have the opportunity to get off the tracks or stop the train.”

Arctic Sea Ice Bottoms Out For 2007, Shatters All Time Record Low





The minimum low Arctic sea ice extent for 2007 is about 460,000 square miles less than the previous minimum record, set in 2005. The area of lost sea ice is roughly the equivalent of the area of Texas and California combined.
The minimum low Arctic sea ice extent for 2007 is about 460,000 square miles less than the previous minimum record, set in 2005. The area of lost sea ice is roughly the equivalent of the area of Texas and California combined.

Scientists from the University of Colorado at Boulder’s National Snow and Ice Data Center said today that the extent of Arctic sea ice appears to have reached its minimum for 2007 on Sept. 16, shattering all previous lows since satellite record-keeping began nearly 30 years ago.



The Arctic sea ice extent on Sept. 16 stood at 1.59 million square miles, or 4.13 million square kilometers, as calculated using a five-day running average, according to the team. Compared to the long-term minimum average from 1979 to 2000, the new minimum extent was lower by about 1 million square miles — an area about the size of Alaska and Texas combined, or 10 United Kingdoms, they reported.



The minimum also breaks the previous minimum set on Sept. 20 and Sept. 21 of 2005 by about 460,000 square miles, an area roughly the size of Texas and California combined, or five United Kingdoms, they found. The sea ice extent is the total area of all Arctic regions where ice covers at least 15 percent of the ocean surface.



Scientists blame the declining Arctic sea ice on rising concentrations of greenhouse gases that have elevated temperatures from 2 degrees F to 7 degrees F across the arctic and strong natural variability in Arctic sea ice, said the researchers.


The CU-Boulder research group said determining the annual minimum sea ice is difficult until the melt season has decisively ended. But the team has recorded five days of little change, and even slight gains in Arctic sea ice extent this September, so reaching a lower minimum for 2007 seems unlikely, they reported.



Arctic sea ice generally reaches its minimum extent in September and its maximum extent in March. The researchers used satellite data from NASA, the National Oceanic and Atmospheric Administration and the U.S. Department of Defense, as well as data from Canadian satellites and weather observatories for the study.



The CU-Boulder research group is reporting the news on its ongoing blog, along with images and discussion, which can be found on the Web at: nsidc.org/news/press/2007_seaiceminimum/20070810_index.html.



“The amount of ice loss this year absolutely stunned us because it didn’t just beat all previous records, it completely shattered them,” said CU-Boulder senior scientist Mark Serreze of NSIDC.

Scientist tracks greenland meltwater





Many glaciologists believe that snow/ice melt in Greenland could equate to a 1 meter increase in ocean levels, something that would be devastating to a major portion of the human population
Many glaciologists believe that snow/ice melt in Greenland could equate to a 1 meter increase in ocean levels, something that would be devastating to a major portion of the human population

World oceans would rise 23 feet and flood many coastal areas if climate change melted the entire Greenland ice cap. And satellite images from 1980 onward reveal the surface of this vast ice sheet is warming, getting soggy and staying wet for longer periods every year.



However, preliminary research by The University of Montana and its partners suggests some of this meltwater does not reach the ocean to contribute to sea-level rise. Instead it infiltrates downward into colder snow and refreezes into ice layers that can be more than a foot thick. These layers are fragmented, so water can’t flow atop them for long before draining downward again and freezing in place.



“We are still working up our results, but so far this is good news concerning worries about Greenland’s role in the sea level rise we see happening today,” said UM glaciologist Joel Harper. “Since many of the ice layers that form during a year of heavy melt are discontinuous, the next year’s melt can’t travel along the ice layers as a means of escaping the ice sheet.”



He said it’s so dark and cold during Greenland winters that even with some winter warming the snowpack is still extremely cold going into summer, “and summer melting always will have a hard time warming a snowpack laden with cold dense ice layers.”



Harper was part of a six-person scientific expedition that ventured onto the Greenland ice sheet for a month during June and July. They lived in tents high atop the ice cap at about 6,600 feet in a white, featureless landscape swept by endless wind. To do its work, the group made 60- to 70-mile journeys down into the melt zone closer to Greenland’s west coast, using snowmobiles to pull scientific gear and expedition members on skis.



Harper said their research was funded by a $524,000 National Science Foundation grant. His project collaborators are Tad Pfeffer of the University of Colorado and Neil Humphrey of the University of Wyoming. Each scientist brought one graduate student to complete the team.



The researchers drilled 21 35-foot-long ice cores during the course of their work. They also dug many snow pits and did numerous experiments with colored dye to track meltwater flow. In addition, they installed two meteorological stations and used radar to map ice layers beneath the snow.



In five boreholes located in sequentially lower elevations across a 25-mile span, the team also installed vertical strings of temperature sensors to note melting and freezing events in the snow up to 35 feet deep. (When water freezes it releases heat – a thermal signature that can be detected.) Harper said the sensors – called thermisters – have their own power source and will record data until researchers retrieve them next year.



He compared the Greenland ice cap to pancake batter. In its middle at higher elevations there is more snowfall than melting. As more snow is poured on, it compresses the vast sheet, which flows outward toward the warmer coasts where there is more melting.



The team had two snowmobiles to haul six people and their gear down to the melt zones to do their research. The landscape is utterly devoid of landmarks, so they used global positioning systems to navigate during the three-hour traverses. Two scientists drove, while the rest were towed behind the snowmobiles on skis.



“While skiing, we put on every bit of clothing we had and an iPod because you were standing behind these snowmobiles for three hours or more,” Harper said. “We would use a bike tire as a harness clipped to the rope. So we would just stand there and try not to fall asleep as we were pulled along.”


Harper, who was a competitive skier as a youth in Colorado, also tried using a sail to kite ski across the ice cap. His power source was Greenland’s endless katabatic winds, which are caused by dense cold air atop the ice sheet flowing downward toward the warmer coasts.



“A lot of times it was too windy – you could get up to 30 mph no problem,” he said. “I could get screaming along – and I’m used to speed – but this was on the edge. I found it was too hard to navigate long distances with GPS when you are trying to fly the kite and not crash. It just wasn’t compatible with the whole group, so in the end it was more for fun.”



He said some of the melt zone contained barely wet snow, while others areas were a “slush swamp” of super-saturated snow that a person without skis could sink into like quicksand. The expedition had to make the long traverses from base camp because members didn’t dare camp in the melt zone. Too much thawing could bog down their snowmobiles and leave the researchers stranded in an area where ski planes can’t land. They might be stranded in the soggy snow until the next freeze.



“And if the snow machines would break, you couldn’t possibly ski back in a day,” he said. “It’s too far.”



Harper said his group will return next year to study another 75-mile stretch of the ice cap. They will start at the lowest elevation examined last summer and continue downward toward the coastal melt zone. The expedition will begin earlier in the year so the snow won’t be as treacherous at lower elevations.



“This is one reason why our results are preliminary,” he said. “We only have half the story. I suspect things might really be moving down below, but so far in the upper part of the ice sheet, we have thrown that out. In that area we found the melt is increasing every year, but it isn’t going anywhere.”



Harper said they decided to study the west side of the ice cap because it is accessible from the town of Kangerlussuaq, which is the logistics headquarters for science in Greenland. The ice they studied also is the headwaters of Jakobshavn, one of Greenland’s big calving glaciers that has increased speed in recent years. Their base camp was a three-hour plane ride from Kangerlussuaq.



“There was nothing special about our camp,” he said. “It was just some GPS coordinates we selected in the middle of nowhere. We got nailed by a big storm right after we arrived, but after that temperatures stayed between about 10 and 35 degrees Fahrenheit.”



Harper said their work might partially explain why Greenland isn’t a larger player in current sea-level rises despite its enormous ice cap. A 2007 article in the journal Science contends Greenland contributes about 0.5 millimeter to ocean level rise annually, while smaller glaciers scattered around the globe contribute 1.1 millimeter to sea-level rise.



“Other recent work shows that ice loss from small glaciers and ice caps like those in Montana dominate current sea-level rise and will likely continue to dominate sea-level increases for at least the next 50 years,” he said. “Since there are several hundred thousand small glaciers around the world, the sea-level rise we expect from them is still very significant.



“I don’t know of any glaciologist who thinks anything like a 6-meter (19.8 foot) sea-level rise is in the cards by the end of the century,” Harper said, “but even 1 meter – which is at the upper end of what we currently think might be possible – would be a very big deal.”

Rising Surface Temperatures Drive Back Winter Ice in Barents Sea


Rising sea-surface temperatures in the Barents Sea, northeast of Scandinavia, are the prime cause of the retreating winter ice edge over the past 26 years, according to research by Jennifer Francis, associate research professor at Rutgers’ Institute of Marine and Coastal Sciences (IMCS). The recent decreases in winter ice cover is clear evidence that Arctic pack ice will continue on its trajectory of rapid decline, Francis said.



In a paper published in Geophysical Review Letters, Francis and Elias Hunter, a research specialist in Francis’ laboratory, found that the rising average winter-time sea-surface temperature of the Barents Sea – up 3 degrees Celsius since 1980 – is likely driven by increasing greenhouse gases, which in turn are melting more ice. Francis and Hunter used satellite information dating back 26 years to perform their study.



Scientists have known for some time that the extent of perpetual, summer ice cover in the Arctic has been shrinking, but until the past few years, the average amount of winter ice has been relatively steady. The winter ice amount is important because if it begins to decrease, scientists believe it is an indicator that enough extra heat from the sun is being absorbed in summer in new open water areas so that the ice grows less in winter and is more easily melted the following summer, leading to even less summer ice. The record-breaking ice loss this year is further, dramatic evidence that this process is underway. While satellites can see the recent winter ice retreat, no one knew until now what was driving the ice back. Francis said she and Hunter were surprised when they discovered that warming ocean temperatures – and not atmospheric effects – were the main source of winter ice retreat, and that the warming is linked to general rising temperatures of the Atlantic Ocean via the Gulf Stream, which brings Atlantic water into the Barents Sea. “In the Barents Sea, I expected more influence from atmospheric heating; but it [the retreat of the ice edge] seems to be governed almost entirely by warming from the ocean,” Francis said.


Should the warming trend continue — and all indications are that it will — there would be considerable economic and political implications. “Fishing, shipping, oil exploration will all be easier to do in the Arctic if there is less ice around for a shorter time,” Francis said.



Francis and Hunter were in for another surprise in the Bering Sea, between Alaska and Siberia. That sea is virtually cut off from the Pacific Ocean by the Aleutian Islands. The researchers expected the ice edge there to be pushed around by northerly and southerly winds, but that wasn’t the case. Instead, it was the strength or weakness of the Aleutian Low – a semi-permanent storm with predominantly easterly winds in much of the Bering Sea – that determined the ice edge. In years when the low was weak – when the east wind didn’t blow as hard – the ice edge crept farther south. In years when the east winds blew hard, the ice edge retreated northward. The strength of the Aleutian Low oscillates in cycles lasting 10 to 20 years, Francis said, and right now, appears to be in a weak cycle. That means that the ice edge in the Bering Sea, not exposed to the world’s ocean system like its Barents Sea counterpart, has not retreated as much. Computer models predict, however, that the Aleutian Low will strengthen as the global climate system adapts to increasing greenhouse gases.

Researchers Reassess Theories on Formation of Earth’s Atmosphere





Scientists propose that argon in our atmosphere came from the weathering of the upper crust and not the melting of the mantle
Scientists propose that argon in our atmosphere came from the weathering of the upper crust and not the melting of the mantle

Geochemists at Rensselaer Polytechnic Institute are challenging commonly held ideas about how gases are expelled from the Earth. Their theory, which is described in the Sept. 20 issue of the journal Nature, could change the way scientists view the formation of Earth’s atmosphere and those of our distant neighbors, Mars and Venus. Their data throw into doubt the timing and mechanism of atmospheric formation on terrestrial plants.



Lead by E. Bruce Watson, Institute Professor of Science at Rensselaer, the team has found strong evidence that argon atoms are tenaciously bound in the minerals of Earth’s mantle and move through these minerals at a much slower rate than previously thought. In fact, they found that even volcanic activity is unlikely to dislodge argon atoms from their resting places within the mantle. This is in direct contrast to widely held theories on how gases moved through early Earth to form our atmosphere and oceans, according to Watson.



Scientists believe that shortly after Earth was formed, it had a glowing surface of molten rock extending down hundreds of miles. As that surface cooled, a rigid crust was produced near the surface and solidified slowly downward to complete the now-solid planet. Some scientists have suggested that Earth lost all of its initial gases, either during the molten stage or as a consequence of a massive collision, and that the catastrophically expelled gases formed our early atmosphere and oceans. Others contend that this early “degassing” was incomplete, and that primordial gases still remain sequestered at great depth to this day. Watson’s new results support this latter theory.



“For the ‘deep-sequestration’ theory to be correct, certain gases would have to avoid escape to the atmosphere in the face of mantle convection and volcanism,” Watson said. “Our data suggest that argon does indeed stay trapped in the mantle even at extremely high temperatures, making it difficult for the Earth to continuously purge itself of argon produced by radioactive decay of potassium.”



Argon and other noble gases are tracer elements for scientists because they are very stable and do not change over time, although certain isotopes accumulate through radioactive decay. Unlike more promiscuous elements such as carbon and oxygen, which are constantly bonding and reacting with other elements, reliable argon and her sister noble gases (helium, neon, krypton, and xenon) remain virtually unchanged through the ages. Its steady personality makes argon an ideal marker for understanding the dynamics of Earth’s interior.



“By measuring the behavior of argon in minerals, we can begin to retrace the formation of Earth’s atmosphere and understand how and if complete degassing has occurred,” Watson explained.



Watson’s team, which includes Rensselaer postdoctoral researcher Jay B. Thomas and research professor Daniele J. Cherniak, developed reams of data in support of their emerging belief that argon resides stably in crystals and migrates slowly. “We realized from our initial results that these ideas might cause a stir,” Watson said. “So we wanted to make sure that we had substantial data supporting our case.”


The team heated magnesium silicate minerals found in Earth’s mantle, which is the region of Earth sandwiched between the upper crust and the central core, in an argon atmosphere. They used high temperature to simulate the intense heat deep within the Earth to see whether and how fast the argon atoms moved into the minerals. Argon was taken up by the minerals in unexpectedly large quantities, but at a slow rate.



“The results show that argon could stay in the mantle even after being exposed to extreme temperatures,” Watson said. “We can no longer assume that a partly melted region of the mantle will be stripped of all argon and, by extension, other noble gases.”



But there is some argon in our atmosphere – slightly less than 1 percent. If it didn’t shoot through the rocky mantle, how did it get into the atmosphere?



“We proposed that argon’s release to the atmosphere is through the weathering of the upper crust and not the melting of the mantle,” Watson said. “The oceanic crust is constantly being weathered by ocean water and the continental crust is rich in potassium, which decays to form argon.”



And what about the primordial argon that was trapped in the Earth billions of years ago? “Some of it is probably still down there,” Watson said.



Because Mars and Venus have mantle materials similar to those found on Earth, the theory could be key for understanding their atmospheres as well.



Watson and his team have already begun to test their theories on other noble gases, and they foresee similar results. “We may need to start reassessing our basic thinking on how the atmosphere and other large-scale systems were formed,” he said.



The research was funded by the National Science Foundation.

How The Discovery Of Geologic Time Changed Our View Of The World


In 1911 the discovery that the world was billions of years old changed our view of the world for ever.



Imagine trying to understand history without any dates. You know, for example, that the First World War came before the Second World War, but how long before? Was it tens, hundreds or even thousands of years before? In certain situations, before radiometric dating, there was no way of knowing.



By the end of the 19th century, many geologists still believed the age of the Earth to be a few thousand years old, as indicated by the Bible, while others considered it to be around 100 million years old, in line with calculations made by Lord Kelvin, the most prestigious physicist of his day.



Dr Cherry Lewis, University of Bristol, UK, said: “The age of the Earth was hugely important for people like Darwin who needed enormous amounts of time in which evolution could occur. As Thomas Huxley, Darwin’s chief advocate said: ‘Biology takes its time from Geology’.”



In 1898 Marie Curie discovered the phenomenon of radioactivity and by 1904 Ernest Rutherford, a physicist working in Britain, realised that the process of radioactive decay could be harnessed to date rocks.



It was against this background of dramatic and exciting scientific discoveries that a young Arthur Holmes (1890-1964) completed his schooling and won a scholarship to study physics at the Royal College of Science in London. There he developed the technique of dating rocks using the uranium-lead method and from the age of his oldest rock discovered that the Earth was at least 1.6 billion years old (1,600 million).


But geologists were not as happy with the new results as, perhaps, they should have been. As Holmes, writing in Nature in 1913, put it: “the geologist who ten years ago was embarrassed by the shortness of time allowed to him for the evolution of the Earth’s crust, is still more embarrassed with the superabundance with which he is now confronted”. It continued to be hotly debated for decades.



Cherry Lewis commented, “In the 1920s, as the age of the Earth crept up towards 3 billion years, this took it beyond the age of the Universe, then calculated to be only 1.8 billion years old. It was not until the 1950s that the age of the Universe was finally revised and put safely beyond the age of the Earth, which had at last reached its true age of 4.56 billion years. Physicists suddenly gained a new respect for geologists!”



In the 1920s the new theory of continental drift became the great scientific conundrum, and most geologists were unable to accept the concept due to the lack of a mechanism for driving the continents around the globe.



In 1928 Arthur Holmes showed how convection currents in the substratum (now called the mantle) underlying the continents could be this mechanism. This proved to be correct but it was another 40 years before his theories were accepted and the theory of plate tectonics became a reality.



The theory of plate tectonics has proved to be as important as the theory of evolution and the discovery of the structure of the atom, but without the discovery of how to quantify geologic time, confirmation of plate tectonics would not have been possible.



Today, few discussions in geology can occur without reference to geologic time and plate tectonics. They are both integral to our way of thinking about the world. Holmes died in 1964 having lived just long enough to see sea floor spreading confirm his ideas of continental drift.