Research team proposes new link to tropical African climate

Brown-led researchers and staff take cores from Lake Tanganyika, the world's second-deepest lake. Each core was 8 m (26 feet) long and taken at depths of 650 m (2,133 feet). The cores were collected in 2004 as part of the Nyanza Project and were analyzed in 2006 and 2007. - Credit: The Nyanza Project, University of Arizona
Brown-led researchers and staff take cores from Lake Tanganyika, the world’s second-deepest lake. Each core was 8 m (26 feet) long and taken at depths of 650 m (2,133 feet). The cores were collected in 2004 as part of the Nyanza Project and were analyzed in 2006 and 2007. – Credit: The Nyanza Project, University of Arizona

The Lake Tanganyika area, in southeast Africa, is home to nearly 130 million people living in four countries that bound the lake, the second deepest on Earth. Scientists have known that the region experiences dramatic wet and dry spells, and that rainfall profoundly affects the area’s people, who depend on it for agriculture, drinking water and hydroelectric power.

Scientists thought they knew what caused those rains: a season-following belt of clouds along the equator known as the Intertropical Convergence Zone (ITCZ). Specifically, they believed the ITCZ and rainfall and temperature patterns in the Lake Tanganyika area marched more or less in lockstep. When the ITCZ moved north of the equator during the northern summer, the heat (and moisture) would follow, depriving southeast Africa of moisture and rainfall. When the ITCZ moved south of the equator during the northern winter, the moisture followed, and southeast Africa got rain.

Now a Brown-led research team has discovered the ITCZ may not be the key to southeast Africa’s climate after all. Examining data from core sediments taken from Lake Tanganyika covering the last 60,000 years, the researchers report in this week’s Science Express that the region’s climate instead appears to be linked with ocean and atmospheric patterns in the Northern Hemisphere. The finding underscores the interconnectedness of the Earth’s climate – how weather in one part of the planet can affect local conditions half a world away.

The discovery also could help scientists understand how tropical Africa will respond to global warming, said Jessica Tierney, a graduate student in Brown’s Geological Sciences Department and the paper’s lead author.

“It just implies the sensitivity of rainfall in eastern Africa is really high,” Tierney said. “It doesn’t really take much to tip it.”

The researchers, including James Russell and Yongsong Huang of Brown’s Department of Geological Sciences faculty and scientists at the University of Arizona and the Royal Netherlands Institute for Sea Research, identified several time periods in which rainfall and temperature in southeast Africa did not correspond with the ITCZ’s location. One such period was the early Holocene, extending roughly from 11,000 years ago to 6,000 years ago, in which the ITCZ’s location north of the equator would have meant that tropical Africa would have been relatively dry. Instead, the team’s core samples showed the region had been wet.

Two other notable periods – about 34,000 years ago and about 58,000 years ago – showed similar discrepancies, the scientists reported.

In addition, the team found climatic changes that occurred during stadials (cold snaps that occur during glacial periods), such as during the Younger Dryas, suddenly swung rainfall patterns in southeast Africa. Some of those swings occurred in less than 300 years, the team reported.

“That’s really fast,” Tierney noted, adding it shows precipitation in the region is “jumpy” and could react abruptly to changes wrought by global warming.

While the scientists concluded the ITCZ is not the dominant player in shaping tropical African climate, they say more research is needed to determine what drives rainfall and temperature patterns there. They suspect that a combination of winter winds in northern Asia and sea surface temperatures in the Indian Ocean have something to do with it. Under this scenario, the winds emanating from Asia would pick up moisture from the Indian Ocean as they swept southward toward tropical Africa. The warmer the waters the winds passed over, the more moisture would be gathered, and thus, more rain would fall in southeast Africa. The theory would help explain the dry conditions in southeast Africa during the stadials, Tierney and Russell said, because Indian Ocean surface temperatures would be cooler, and less moisture would be picked up by the prevailing winds.

“What happens in southeast Africa appears to be really sensitive to the Indian Ocean’s climate,” Russell said.

The team examined past temperature in the region using a proxy called TEX86, developed by the Dutch contributing authors. To measure past precipitation, the researchers examined fatty acid compounds contained in plant leaf waxes stored in lakebed sediments – a relatively new proxy but considered by scientists to be a reliable gauge of charting past rainfall.

Ice core studies confirm accuracy of climate models

An analysis has been completed of the global carbon cycle and climate for a 70,000 year period in the most recent Ice Age, showing a remarkable correlation between carbon dioxide levels and surprisingly abrupt changes in climate.

The findings, to be published this week in the online edition of the journal Science, shed further light on the fluctuations in greenhouse gases and climate in Earth’s past, and appear to confirm the validity of the types of computer models that are used to project a warmer climate in the future, researchers said.

“We’ve identified a consistent and coherent pattern of carbon dioxide fluctuations from the past and are able to observe the correlation of this to temperature in the northern and southern hemispheres,” said Ed Brook, an associate professor of geosciences at Oregon State University. “This is a global, interconnected system of ocean and atmosphere, and data like these help us better understand how it works.”

The analysis was made by studying the levels of carbon dioxide and other trace gases trapped as bubbles in ancient ice cores from Antarctica.

In the last Ice Age, as during most of Earth’s history, levels of carbon dioxide and climate change are intimately linked. Carbon dioxide tends to rise when climate warms, and the higher levels of carbon dioxide magnify the warming, Brook said. These natural cycles provide a “fingerprint” of how the carbon cycle responds to climate change.

In contrast to the relatively low levels of carbon dioxide in the Ice Age, the burning of fossil fuels since the Industrial Revolution has led to levels of greenhouse gases that by comparison are off the charts. The level of atmospheric carbon dioxide today is about 385 parts per million, or more than double that of some of the lower levels during the Ice Age. These changes have taken place at a speed and magnitude that has not occurred in hundreds of thousands of years, if not longer. Past studies of ice cores have suggested that Earth’s temperature can sometimes change amazingly fast, warming as much as 15 degrees in some regions within a couple of decades.

The question everyone wants to know is what all this will mean in terms of future climate change.

“Before humans were affecting the Earth, what we are finding is regular warm and cold cycles, which both began and ended fairly abruptly,” Brook said. “This study supports the theory that a key driver in all this is ocean currents and circulation patterns, which create different patterns of warm and cold climates depending on the strength of various parts of the global ocean circulation system.”

This issue is of more than academic interest – one of the primary circulation patterns is referred to scientifically as “meridional overturning circulation.” When that current is moving large amounts of warm water from the equator to the north, it helps to warm the high latitude parts of the Northern Hemisphere, and particularly the North Atlantic region. When the system stops or dramatically slows, as it has repeatedly in the past, Greenland and Europe get much colder while the Antarctic regions become warmer, Brook said.

“In every historic sequence we observed, the abrupt warming of Greenland occurred about when carbon dioxide was at maximum levels,” Brook said. “And that was during an Ice Age, and at levels of atmospheric carbon dioxide that are far lower than those we have today.”

Meteorites ‘behind volcanic eruptions’ say scientists

Gases that cause volcanoes to erupt may have spewed from meteorites that smashed into the earth billions of years ago, according to research presented at The BA Festival of Science in Liverpool today (Wednesday 10 September 2008).

Gases that cause volcanoes to erupt may have spewed from meteorites that smashed into the earth billions of years ago, according to research presented at The BA Festival of Science in Liverpool today (Wednesday 10 September 2008).

Research conducted by earth scientists at The University of Manchester in conjunction with other institutions, challenges the conventional belief of scientists that the earth’s earliest atmosphere came from solar nebular gases attracted and trapped by gravitational pull.

Gases are trapped in the deep earth and only released when rock is melted and volcanic eruptions and fire fountains occur, driven by the explosive expansion of these gases.

But putting gas into rock in the first place is hard and requires extreme conditions.

Researchers say a clue to how this actually happens is the release of ‘light’ helium – or the 3He isotope – from mid ocean ridges. Light helium is not produced on earth and somehow became trapped when the earth formed.

Scientists have previously argued that to put enough light helium into the deep earth to explain the volcanic emissions, the early earth was completely molten and surrounded by a dense atmosphere more like that around Jupiter than anything we see today.

But new research on neon gas led by Prof Chris Ballentine, Professor of Isotope Geochemistry in The School of Earth, Atmospheric and Environmental Sciences, casts serious doubt on this.

He said: “We have shown that the neon gas fingerprint expected for the captured solar nebula model is not matched.

“Instead we have found a meteorite signature, which suggests the massive early atmosphere is not trapped by gravitational attraction as originally thought but a result of meteorites spewing out gas on impact.

The research being presented at The BA Festival by Prof Ballentine also suggests that sea water appears to be leaking into the deep earth, with half of the water in the earth’s mantle – the region of the earth between the crust and the core – estimated to come from this source.

Prof Ballentine said: “The second signature or gas ‘fingerprint’ we have found in the deep Earth is identical to that of seawater, which is itself unique in the solar system.

“The only explanation for this is that seawater trapped in ocean crust is being driven back down into the deep Earth in a tectonic process called subduction.”

This statement challenges the belief of many scientists who argue this is impossible. They say the water should be squeezed and melted out during the subduction process.

Professor Ballentine added: “This process has the potential to fundamentally change how scientists think Earth has behaved over time. Even a little bit of water added to rock in the deep earth makes it more plastic and allows movement of tectonic plates sitting on top to be quicker.

“The source and fate of atmospheres and water on planets is central to understanding the origin of life and the conditions that lead to our own planet looking as it does today. Our work provides evidence that changes our big picture understanding of how planetary systems acquire their volatile elements.”

The research team have drawn their conclusions after studying commercially produced volcanic CO2 gas from the Colorado Plateau in the US.

The Manchester team is currently using a new state of the art instrument funded by the Natural Environment Research Council (NERC) to identify whether or not they can see this ‘meteorite signature’ in other trace gases such as krypton and xenon isotopes.

Scientists at Manchester are also working with colleagues at the Carnegie Institute, Washington and The University of Michigan to understand how changing the water content of the mantle will change the way in which the Earth convects and drives continents over time.

Prof Ballentine will present ‘Where do volcanic gases come from? Using isotopes to investigate the origin of volatile elements within our planet’ at The BA Festival of Science in Liverpool today, Wednesday 10 September 2008, at a session starting at 9.30am.

Scientist uncovers miscalculation in geological undersea record

New study by Peter K. Swart published in PNAS compares 13C/12C records from carbonate platforms in 3 ocean basins

The precise timing of the origin of life on Earth and the changes in life during the past 4.5 billion years has been a subject of great controversy for the past century. The principal indicator of the amount of organic carbon produced by biological activity traditionally used is the ratio of the less abundant isotope of carbon, 13C, to the more abundant isotope, 12C. As plants preferentially incorporate 12C, during periods of high production of organic material the 13C/12C ratio of carbonate material becomes elevated. Using this principle, the history of organic material has been interpreted by geologists using the 13C/12C ratio of carbonates and organics, wherever these materials can be sampled and dated.

While this idea appears to be sound over the last 150 million years or so, prior to this time there are no open oceanic sediment records which record the 13C/12C ratio, and therefore, geologists are forced to use materials associated with carbonate platforms or epicontinental seas. In order to test whether platform-associated sediments are related to the global carbon cycle, a paper by University of Miami Professor Dr. Peter K. Swart appears in the Proceedings of the National Academy of Sciences. This paper examines changes over the past 10 million years at sites off the Bahamas (Atlantic Ocean), the Maldives (Indian Ocean), and Great Barrier Reef (Pacific Ocean). The variations in the 13C/12C ratio are synchronous at all of the sites studied, but are unrelated to the global change in the 13C/12C ratio.

It appears that records related to carbonate platforms which are often used throughout the early history of the Earth are not good recorders of the 13C/12C ratio in the open oceans. Hence, the work presented suggests that assumptions made previously about changes in the 13C/12C ratios of carbonate sediments in the geological record are incorrect.

“This study is a major step in terms of rethinking how geologists interpret variations in the 13C/12C ratio throughout Earth’s history. If the approach does not work over the past 10 million years, then why would it work during older time periods?” said Swart. “As a consequence of our findings, changes in 13C/12C records need to be reevaluated, conclusions regarding changes in the reservoirs of carbon will have to be reassessed, and some of the widely-held ideas regarding the elevation of CO2 during specific periods of the Earth’s geological history will have to be adjusted.”

May 2008 Earthquake in China Could Be Followed by Another Significant Rupture

Through computer modeling, researchers have calculated the shifting and changes in stress within earth's crust in the regions adjoining the May 2008 Wenchuan earthquake. (Toda, Lin, Meghraoui, and Stein, reprinted from Geophysical Research Letters)
Through computer modeling, researchers have calculated the shifting and changes in stress within earth’s crust in the regions adjoining the May 2008 Wenchuan earthquake. (Toda, Lin, Meghraoui, and Stein, reprinted from Geophysical Research Letters)

Researchers analyzing the May 2008 Wenchuan earthquake in China’s Sichuan province have found that geological stress has significantly increased on three major fault systems in the region. The magnitude 7.9 quake on May 12 has brought several nearby faults closer to failure and could trigger another major earthquake in the region.

Geophysicists used computer models to calculate the changes in stress along the Xianshuihe, Kunlun, and Min Jiang faults-strike-slip faults like the San Andreas-which lie about 150 to 450 kilometers (90 to 280 miles) from the Longmen Shan rupture that caused the devastating quake. The research team also examined seismic activity in the region over the past decade.

They found that the May 12 event has doubled the probabilities of future earthquakes on these fault lines. Specifically, they estimated the probability of another earthquake of magnitude 6 or greater in the region is 57 to 71 percent over the next decade. There is an 8 to 12 percent chance of a quake larger than magnitude 7 in the next decade and 23-31 percent in the next 30 years.

The research team was led by Shinji Toda of the Geological Survey of Japan, and includes Jian Lin of the Woods Hole Oceanographic Institution (WHOI), Mustapha Meghraoui of the Institute of Geophysics in Strasbourg (France), and Ross Stein of the U.S. Geological Survey (USGS). Their findings were published September 9 in the online edition of the journal Geophysical Research Letters.

“One great earthquake seems to make the next one more likely, not less,” said Stein, who has been collaborating with Lin and Toda for nearly two decades. “We tend to think of earthquakes as relieving stress on a fault. That may be true for the one that ruptured, but not for the adjacent faults.”

In 1999, a 7.4 magnitude earthquake in Izmit, Turkey, was followed four months later by an M7.1 event in nearby Duzce. The devastating December 2004 Sumatra earthquake (M9.2) and tsunami were followed by an M8.7 quake three months later.

“Because the Tibetan Plateau is one of the most seismically active regions in the world, we believe there is credible evidence for a new major quake in this region,” said Lin, a senior scientist in WHOI’s Department of Geology and Geophysics. “The research community cannot forecast the timing of earthquakes, and there are still significant uncertainties in our models. But the Turkey and Sumatra events indicate that one major earthquake can indeed promote another.

Researchers see it as a domino-like effect, where the movement of one piece of Earth’s crust means that another piece must move up, down, or away. While the stress in the crust gets reduced in some locations, it is transferred to other faults nearby.

Large aftershocks that occurred on August 1 and 5 in the Sichuan region of China may fit with this predicted pattern.

“Earthquake prediction is a bit like the thundercloud and lightning,” Toda explained. “We can forecast that lightning will come from a thundercloud, but we cannot predict the exact time and place where the lightning will hit. With earthquakes, we can roughly forecast the probability of activity over broad ranges of time, magnitude, and location, but we cannot determine the exact value for any of these.”

On May 12, 2008, about 300 kilometers of the Longmen Shan fault zone ruptured in an earthquake that killed at least 69,000 people and left another 5 million homeless. It was the deadliest and strongest earthquake to hit China since the 1976 Tangshan earthquake, which killed at least 240,000.

As pieces of the Longman Shan fault slipped by as much as nine meters (28 feet) in the May quake, stress increased along the neighboring Xianshuihe, Kunlun, and Min Jiang faults, according to Toda and colleagues. All three faults have a history of large quakes, though portions of each have been quiet for most of the past century. All three faults were considered to be primed for an earthquake even before the recent events.

In addition to the broad prediction of earthquake triggering, the researchers have also forecasted the rate and distribution of seismic shocks greater than magnitude 6, a prediction that they plan to test from seismic stations over the next decade.

“Our paper predicts the change in the rate of small earthquakes for the faults in the region, and now we can test that prediction,” said Stein. “If the rate of shocks increases on the adjacent faults, then we can confirm at least part of our hypothesis that large shocks are also more likely. It may take time, but it is a testable hypothesis.”

In western China, the intrusion of the Indian sub-continent pushes the Tibetan Plateau up and over the older Sichuan Basin and other parts of the Eurasian continent. An estimated 33 percent of world’s continental earthquakes occur in China, even though it only occupies 7 percent of the planet’s land mass. Nearly 55 percent of all human loss to earthquakes occurs in China.

“Earthquakes do not kill people, buildings do,” said Lin, who was a high school student in China when the devastating Tangshan earthquake struck. “There needs to be widespread education in earthquake preparedness, as well as systematic inspection of buildings in these regions of heightened risk. Every new building inspection and evacuation plan could potentially save lives.”

“We hope the long-term forecasting allows the Chinese government to make it a priority to mitigate future damage,” Toda added. “We recommend that Chinese scientists carefully observe changes in seismicity by installing new seismometers in the region.”

Lin, Toda, and Stein were preparing to teach an earthquake modeling course to Meghraoui’s students and colleagues in France when the May 12 earthquake occurred. The researchers immediately went into action, working with an international group of scientists to analyze the new stresses on the system.

An early version of the manuscript by Toda et al was circulated to several dozen Chinese scientists and government officials as they sought to assess the risk of aftershocks in the weeks after the earthquake. Chinese government organizations and scientists are now examining the paper in detail.

“The recent quake reminded us that Earth scientists have a tremendous responsibility to work on issues of societal relevance,” said Lin. “We don’t want to create panic, but there is legitimate cause for concern and we have a major role to play in educating the public about what we know.”

Funding for this research was provided by the Charles D. Hollister Endowed Fund for Support of Innovative Research at WHOI and the EOST-Institut de Physique du Globe de Strasbourg, France.

Climate: New spin on ocean’s role

New studies of the Southern Ocean are revealing previously unknown features of giant spinning eddies that have a profound influence on marine life and on the world’s climate.

These massive swirling structures – the largest are known as gyres – can be thousands of kilometres across and can extend down as deep as 500 metres or more, a research team led by a UNSW mathematician, Dr Gary Froyland, has shown in the latest study published in Physical Review Letters.

“The water in the gyres does not mix well with the rest of the ocean, so for long periods these gyres can trap pollutants, nutrients, drifting plants and animals, and become physical barriers that divert even major ocean currents,” Dr Froyland says.

“In effect, they provide a kind of skeleton for global ocean flows. We’re only just beginning to get a grip on understanding their size, scale and functions, but we are sure that they have a major effect on marine biology and on the way that heat and carbon are distributed around the planet by the oceans.”

One of the best known large-scale gyres in the world’s oceans is that associated with the Gulf Stream in the North Atlantic, notes fellow researcher Professor Matthew England, co-director of the UNSW Climate Change Research Centre.

“This current pumps massive amounts of heat towards Europe, warming the atmosphere and giving the region a relatively mild climate: to see how important that is, you only have to compare Portugal’s climate to that of Nova Scotia, in Canada, which as roughly the same latitude,” says Professor England.

“After releasing heat to the atmosphere the waters re-circulate toward the equator, where they regain heat and rejoin the flow into the Gulf Stream. In this way the ocean’s gyres play a fundamental role in pumping heat poleward, and cooler waters back to the tropics. This moderates the planet’s extremes in climate in a profound way, reducing the equator-to-pole temperature gradients that would otherwise persist on an ocean-free planet.”

The East Australia Current has a similar, although more modest, impact on local climate on the Australia’s east coast. Eddies also regulate biologically important properties such as nutrient upwelling to the surface. They are also fundamental in mixing heat across the Antarctic Circumpolar Current.

The Australian team is working with German colleagues at the University of Paderborn and the Technical University of Dresden. The team discovered last year that these gyres can escape detection by traditional observational methods, which concentrate on scrutinising average water flow or sea surface height.

Instead of monitoring flow in the ocean point by point, the team applied a mathematical technique known as Lagrangian analysis, which allowed them to take into account all possible current movements simultaneously and pick out the least intensive mixing regions. Using computer simulations, they found that this technique clearly identified where gyres and eddies trap drifting surface material in the seas near Antarctica.

The work is presently being extended to assess how the three-dimensional flow in the gyres extends deep down into the ocean. This will reveal their potential to influence climate and marine life, Dr Froyland says.

Uncertainty Analysis Is Key to Predicting Severity of Floods, Sedimentation

People who live in flood-prone areas naturally aren’t thrilled about the uncertainty they must cope with each hurricane season, but research conducted by a University at Buffalo engineer is based on the idea that a better understanding of this uncertainty is key to helping mitigate damage from floods.

Christina Tsai, Ph.D., associate professor of civil, structural and environmental engineering in the UB School of Engineering and Applied Sciences, is developing new mathematical and computer models that will better reflect the uncertainty of flow events and the likelihood of sedimentation, providing emergency planners with more precise data.

Her work, called uncertainty analysis, is geared toward creating more precise predictions of how such extreme flow events near lakes and rivers will impact urban areas, through the development and use of fundamental engineering principles, mathematical models and numerical techniques.

While sophisticated deterministic models for sediment transport and water quality modeling are available nowadays, Tsai said, the predictions that they produce are likely to be associated with errors and uncertainty, as flooding and sediment transport involve a multitude of highly varying and random factors.

“Our ultimate goal is to provide emergency managers with new scientific tools that can help them to better determine the level of risk for local communities posed by extreme flow events, such as hurricane-induced floods,” she continued. “The new tools also will more precisely reflect how significant is the potential for specific levels of contamination and sedimentation in rivers and lakes.”

Changes in sedimentation as a result of floods can alter the natural morphology of bodies of water, leading to erosion and increased contamination near shorelines.

“The model I am proposing will treat contamination and sedimentation processes as random variables influenced by factors such as flow turbulence and the uncertainty surrounding when and how floods will occur,” she said. “As a result, it is likely to result in a more comprehensive description of these processes.”

Tsai’s project is the result of a prestigious $407,921 Faculty Early Career Development Award she received recently from the National Science Foundation. According to the NSF, the CAREER program recognizes and supports the early career-development activities of teacher-scholars “who are most likely to become the academic leaders of the 21st century.”

Her work is closely aligned with “Extreme Events: Mitigation and Response,” identified as one of UB’s academic strengths during the university’s UB 2020 strategic planning process.

The NSF grant also supports Tsai’s development of more quantitative courses in this area as well as increased exposure for students to cross-disciplinary training in mathematical geoscience.

Glaciologist Projects Sea Level Rise

Joel Harper, a University of Montana glaciologist, studies the melting and movement of the world’s ice sheets. For him, calving is what happens when ice sheets meet the ocean and break apart to form icebergs.

Now Harper and his research partners suggest there needs to be a whole lot more calving going on to make the direst climate-change predictions of sea level rise — sometimes suggested at 6 meters (19 feet) or more — come to fruition by 2100.

In fact, glaciers and ice sheets would have to reach never-recorded sustained speeds to make the most extreme ocean level rises come true according to the researchers’ new methodology, which is laid out in the Sept. 5 edition of the journal Science.

The latest Intergovernmental Panel on Climate Change report projects between 18 to 60 centimeters (7.2 to 24 inches) of sea level rise by 2100. But Harper said that projection has come under criticism for not including ice dynamics — how ice sometimes speeds up and calves more icebergs in response to lubrication from meltwater or warming ocean temperatures.

“We simply don’t understand the physics of ice dynamics well enough to make accurate model predictions,” he said. “There are just too many uncertainties. So what we did is flip the problem on its head.”

Admitting ice dynamics is an unknown, the researchers worked the problem backward. They asked, “What would the glaciers and ice fields have to do to produce 2 meters of sea level rise by 2100? To produce 5 meters of sea level rise or more?”

“We found you would need to have phenomenal calving,” said Harper, who has lived and worked on the Greenland ice cap the past two summers, studying the increased melting there.

He said for the Greenland ice sheet to produce 2 meters of worldwide sea level rise by 2100, the glaciers moving into the island’s calving fjords would have to increase their speed to 45.8 kilometers (28.4 miles) per year and sustain that speed until the end of the century.

“For some perspective, the mean velocity right now is about 1.2 kilometers per year,” Harper said. “So you would need a 40-something increase in the mean velocity. And this scenario includes increasing the surface melt rate by tenfold.”

He said scientists have never seen ice move 45.8 kilometers per year anywhere in the world.

“But we can’t prove that it’s impossible,” he said. “What we can say is that it’s not a good working hypothesis. We’ve seen some glaciers double their ice discharge, and some are going 12 kilometers per year. Fifteen kilometers per year is the fastest we’ve ever seen one of the Greenland outlet glaciers go, and that one already stopped doing that.”

So, armed with this new methodology for dealing with the uncertainty of ice dynamics, how high do Harper and his partners think world oceans will rise by 2100?

“We think they will rise between .8 and 2 meters (2.7 and 6.7 feet),” he said. “That includes plausible ice dynamics scenarios. To get to 2 meters, that basically requires instant ice acceleration to extreme conditions from Antarctica, Greenland, small glaciers and our biggest projection for thermal expansion of the oceans. And anything over 2 meters is basically untenable.”

However, Harper stresses that a rise of even .8 meters is a huge deal. Raising the California Central Valley levees only .15 meter, for example, would cost more than $1 billion.

“We hope our research will help give people a better number to work with,” he said. “If we keep thinking along the lines of 6 meters of sea level rise by 2100, we would write off places that are actually savable. We could put our money into building massive walls where they aren’t needed instead of concentrating on other things.”

Harper said sea levels have come up at phenomenal rates in the past, but that hasn’t happened since the last Ice Age.

“All of Canada was covered by a vast ice sheet, and it was calving into the Hudson Bay, which was this huge gate,” he said. “We live in a different world today.”

Harper’s partners in the study and co-authors of the Science article are Tad Pfeffer of the Institute of Arctic and Alpine Research at the University of Colorado and Shad O’Neel of the Scripps Institution of Oceanography at the University of California, San Diego.

Major flooding risk could span decades after Chinese earthquake

Up to 20 million people are at increased risk of flooding and major power shortages in China’s massive Sichuan Basin.

Dr Alex Densmore, a geographer from Durham University, makes the observations on returning from carrying out investigative fieldwork in the China earthquake zone, where nearly 100,000 people were killed in May 2008.

Dr Densmore, who has been studying the active faults in Sichuan for the past eight years, says the risk from flooding and power shortages could occur over the next few decades or possibly centuries.

The biggest risk is posed by the ongoing landslides in Sichuan province, a common occurrence after major earthquakes such as these. Landslides cause rocks and sediment to be dumped in the river valleys, and this material then moves downstream to settle on river beds.

In some areas, river beds are already two to three metres higher due to the increased amounts of sediment after the earthquake. This means that during periods of heavy rains the rivers have greater potential to burst their banks — a risk that will last for decades to centuries.

There is also the potential for build up of sediment in the reservoirs behind the many dams in the area. These reservoirs then become useless for flood control or hydro-electric power generation.

These long term effects of the earthquake should be considered very carefully by the Chinese authorities, says Dr Densmore, who was “astounded and impressed” by the speed and efficiency of response to the earthquake’s short term effects.

Many mountain communities, who took the brunt of the disaster, have been relocated and re-housed into the 500 km-wide Sichuan Basin, which is perceived to be a safer area to live. Up to 20 million people live in the western part of the Basin, where the provincial capital, Chengdu, is also sited.

Thousands of those at risk have already been displaced from their homes due to May’s devastating earthquake.

Dr. Alex Densmore’s research in China is funded by The Natural Environment Research Council (NERC).

Dr Densmore, Director of Hazards Research at Durham University’s Institute of Hazard and Risk Research, said: “We were amazed at how fast the Chinese had responded to this disaster. Many of the people in the mountain areas have been resettled and there are big temporary housing communities with supplies of clean water, power, and access to food and transportation. It is a very impressive response and is a big contrast with how the US responded after Hurricane Katrina.

“However, while the short term response has been excellent, in the longer term they will need to have a well informed discussion about where to permanently move these communities.

“There is a significant risk of a major flooding disaster. At the moment it is very difficult to predict the exact nature of that risk but in ten years or so we may be in a better position. The enhanced risk due to the earthquake will persist for decades, possibly for up to 100 years.

“In the longer term, the authorities will need to look at issues such as moving people out of the flood plains and re-routing transportation links in areas where there are high risks of floods.”

Dr Densmore and his team have been studying the fault lines which caused the earthquake, and found that buildings which were directly on top of the fault line were almost always completely demolished, while others built near the fault were damaged but often remained standing.

He says that when or if it is time to rebuild the devastated towns, planners should consider establishing buffer zones around the fault lines, a practice followed in other places where there is high risk of earthquakes such as North America and Japan. Buildings of flexible materials such as wood and bamboo are preferable to rigid structures of bricks, concrete and mortar.

Scientists Testing New Method Of Storing Carbon Dioxide In Underground Coal Beds

New Mexico Tech researchers are conducting a large-scale experiment near Aztec, N.M. that will have a dramatic impact on future outlook on greenhouses gases, fossil fuels and the oil and gas industry.

Tech researchers are leading a team sequestering carbon dioxide into coal beds, while simultaneously recovering natural gas. The total funding of the three phases is about $90 million in grants from the U.S. Department of Energy and more than $30 million from other sources. Tech scientists are leading the project, with more than 20 partners, including other universities, national labs and industrial subcontractors.

The San Juan Basin project is part of Phase II of a three-phase project. The goal of the San Juan Basin injection project is to inject 35,000 tons of carbon dioxide during a six-month demonstration near Navajo City, N.M.

Phase III will involve a four-year injection project in Utah, sequestering up to 2.9 million tons of CO2 with a maximum rate of 1 million tons per year.

“Our purpose isn’t to make judgments about global warming,” said senior scientist Reid Grigg. “Our purpose is to engineer projects to sequester CO2. I believe what we are doing is sound engineering and sound science. If we inject CO2, we want to do it under sound scientific and sound engineering principles.”

The six-month injection project in the San Juan Basin is a precursor to a larger project near Price, Utah, with goal of injecting about 2.9 million tons of carbon dioxide to be injected into a geologic feature called the Farnham Dome.

“We need to do all sorts of things to solve the energy crisis,” he said. “To solve global warming, we need to look at carbon dioxide and we need to show that this can be done.”

Grigg, an engineer at New Mexico Tech, said the decade-long project is examining methods of sequestering CO2 into geological formations. The San Juan Basin coalbed methane site is one of three injection sites being used in Phase II.

In many coal deposits, methane or natural gas, is trapped within carbon deposits. When carbon dioxide is injected into the coal bed, the gas is absorbed by the coal, forcing methane out, Grigg said. Many coal beds in the United States are saturated with natural gas, but much of the gas is not extracted because methane is “stuck” in the coal. CO2 shares the same tendency to bind to coal. Laboratory tests show that coal preferentially absorbs CO2 over methane, with two molecules of carbon dioxide displacing one molecule of methane, Grigg said.

Until recently, the cost of injecting CO2 was more than the value of the produced methane. Recent price increases make the process cost-effective, Grigg said.”Just two years ago, the cost of injection was more than the price for methane,” Grigg said. “With the price of methane going up and people wanting to get rid of CO2, this process looks like a good sink to store CO2.”

At the San Juan Basin, there are three 20-foot layers of coal each separated by about 20 feet of rock at depths between 2,800 to 3,000 feet, Grigg said. One well was drilled, completed into the three coal zones where CO2 is presently being injecting into each layer, Grigg said.

As the San Juan Basin project proceeds, scientists are using pressure gauges, tiltmeters that record minute surface movement, tracers, seismic methods, and compositional sensors to track the movement of CO2, Grigg said.

“We have all kinds of nifty gadgets,” Grigg said. “One device was sensitive enough that we recorded the big earthquake in China on May 12.”

The project started with drilling the injection well in early May, with injection commencing on July 30. As the project proceeds, the rate of injection has been increasing, while project scientists track the surface pressure to ensure subsurface pressures do not exceed recommended levels.

Tech scientists at the Petroleum Research Recovery Center have been studying processes of injecting carbon dioxide into geological formations since the late 1970s, Grigg said. For the first 20 years, the studies concentrated on the industrial use of injected CO2 for enhanced oil recovery. In the late 1990s, the focus started to shift toward sequestration of CO2, using the same techniques. The long-term goal is to discover if carbon-dioxide can effectively be sequestered in geological formations. In cases like the San Juan Basin, the process is made more cost effective by the fact that the extracted natural gas is marketable.

Currently, researchers are using naturally-occurring carbon dioxide. Ultimately, Grigg said the process could be used to sequester manmade carbon dioxide – mostly from power plant emissions. Presently the largest problem is the cost of separating CO2 from other gases.

“We have a couple of methods of separating carbon dioxide from power plant emissions that work well,” he said. “The problem is that they cost a lot.”

Typically, power plant emissions are 85 percent nitrogen and 15 percent carbon dioxide. Scientists have devised methods to separate the two chemicals, but there is no market for nitrogen.

Grigg said the cost of separation is roughly 30 percent of the cost of power generation. In other words, for every 10 power plants, the industry would need three more power plants to produce enough energy to separate carbon dioxide from nitrogen.

New Mexico Institute of Mining and Technology is the lead organization of the U.S. Department of Energy’s Southwest Regional Partnership for Carbon Sequestration. The partnership includes the states of Colorado, New Mexico and Utah, as well as portions of Arizona, Kansas, Texas, Oklahoma, and Wyoming. The Southwest partnership is one of seven regional groups.