Carbon Dioxide In Atmosphere Can Now Be Measured From Space

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ScienceDaily (Apr. 12, 2009) — INESC Porto developed a technology, together with ESA – European Space Agency, that enables a more effective measurement of gases in the atmosphere comparatively to the currently used techniques. With this technology, it will be possible to measure gases, such as carbon dioxide, methane, nitrous oxide and ozone – the gases responsible for global warming and greenhouse effects.

The system developed by INESC Porto’s Optoelectronics and Electronic System Unit (UOSE) has a high potential of applicability in satellites due to its efficiency, compactness and reduced volume and mass. The satellites equipped with INESC Porto’s optical fibre filters will be able to detect pollutant gases in the Earth’s atmosphere in concentrations less than 1 km high, at an altitude of 400 km.
The partnership between INESC Porto and ESA started in 2006 and is now showing its first signs of success with the development of an optical fibre filter that is capable of measuring carbon dioxide levels from space.
Other than carbon dioxide, this technology is capable of providing a precise measurement of other pollutant gases, such as methane gas, nitrous oxide and ozone, besides measuring levels of humidity, atmospheric pressure, temperature and wind speed. Thus, this is an essential tool made in Portugal for research on climate change, a step forward to the control of greenhouse gases in the battle against global warming.
If it is applied to satellites, the filter developed by INESC Porto is capable of monitoring all kinds of pollutant gas concentrations less than 1 km high, 50 km wide, at an altitude of 400 km. Unlike what the currently used technologies - atmospheric balloons and airplanes equipped for that purpose -provide, with the filters created by INESC Porto, it will be possible to map the atmosphere three-dimensionally, with a higher resolution and from a single position.
The technology's potential of application in orbital systems and scientific missions has to do with its unique features: efficiency, compactness and reduced volume and mass. The technology developed by INESC Porto consists of an ultra-narrow spectral tuneable and heat-reflecting filter based on optical fibre technology that can be used in order to monitor the atmosphere with the reflection of laser impulses. Using the radiation's time of flight and absorption, it will be possible to extract profiles of pollutant gas concentrations in the atmosphere.
Adapted from materials provided by INESC PORTO.

Potential To Amass More Carbon In Eastern North American Forests

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ScienceDaily (Apr. 11, 2009) — With climate change looming, the hunt for places that can soak up carbon dioxide from the atmosphere is on.

Obvious "sinks" for the greenhouse gas include the oceans and the enormous trees of tropical rainforests. But temperate forests also play a role, and new research now suggests they can store more carbon than previously thought.
In a study that drew on both historical and present-day datasets, Jeanine Rhemtulla of McGill University and David Mladenoff and Murray Clayton of University of Wisconsin-Madison quantified and compared the above-ground carbon held in the forest trees of Wisconsin just prior to European settlement and widespread logging, and the total carbon they contain today.
Writing in the current issue of the Proceedings of the National Academy of Sciences, the researchers report that despite decades of forest recovery, Wisconsin's woodlands still only hold about two-thirds the carbon of pre-settlement times — suggesting substantial room for them to accumulate more.
"There's probably more potential (to store carbon) than people were considering," says Mladenoff. "There's still a big difference between what was once there and what's there now."
He adds that the true storage potential is probably at least two-fold higher than what he and Rhemtulla calculated, since they factored in only the live, above-ground biomass of tree trunks and crowns, and not the carbon stored in roots and soil.
The results have implications not only for Wisconsin, but also for regions across eastern North America where forests were leveled historically to make room for agriculture, and then grew up again as settlers abandoned their farms and headed west. In Wisconsin, for example, forest biomass and carbon have been steadily recovering since the peak of agricultural clearing in the 1930s, while those in the northeastern U.S. have been rebounding for about 125 years.
Yet, it's precisely because many temperate forests have been recovering for so long that people tend to assume their potential as carbon sinks is "maxed out," says Mladenoff.
"Our results suggest we need to rethink this," he says. "Rather than there being an intrinsic limit on how much carbon a forest can store, how we use the forest — how much we log, how we manage — may be more important."
The findings come amid sweeping discussions of international carbon treaties and accounting systems that are designed to reduce CO2 emissions and combat climate change. In the future, for instance, countries might earn credits for maintaining carbon-rich old-growth forests, or replanting trees on lands logged off previously for agriculture.
Areas that once supported large amounts of forest biomass might also be good sites for growing plantations of hybrid poplar and other biofuels crops, says Mladenoff. But, he cautions, any move toward planting more land in trees must be weighed against competing social and economic factors, such as the need for farmland.
"The landscape is full," says Mladenoff. "So if we're going to add something like forests, we're going to need to take something out."
That certainly seems to be true in Wisconsin. Based on historic carbon levels, the researchers' analysis found that much of the best land for growing trees is the north-central region and along northern Lake Michigan. If those lands could be reforested to pre-settlement levels, the scientists estimate they could add 150 teragrams of carbon (150 million metric tons) to the state's current total of approximately 275 teragrams.
The problem, however, is that most of those lands are still being farmed, setting up an interesting dilemma for policy makers: how to weigh the current economic benefit of agriculture against the future environmental benefit of carbon storage.
"Because we often forget the invisible services, like climate regulation, that ecosystems provide to us for free, we don't usually factor them into our decision making," says Rhemtulla. "But this will need to change if we're going to find ways to meet our immediate needs without compromising critical services over the long term."
Journal reference:
Jeanine M. Rhemtulla, David J. Mladenoff, and Murray K. Clayton. Historical forest baselines reveal potential for continued carbon sequestration. Proceedings of the National Academy of Sciences, 2009; DOI: 10.1073/pnas.0810076106
Adapted from materials provided by University of Wisconsin-Madison.

New Link Between The Evolution Of Complex Life Forms On Earth And Nickel And Methane Gas

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ScienceDaily (Apr. 9, 2009) — The Earth's original atmosphere held very little oxygen. This began to change around 2.4 billion years ago when oxygen levels increased dramatically during what scientists call the "Great Oxidation Event." The cause of this event has puzzled scientists, but researchers writing in Nature have found indications in ancient sedimentary rocks that it may have been linked to a drop in the level of dissolved nickel in seawater.

"The Great Oxidation Event is what irreversibly changed surface environments on Earth and ultimately made advanced life possible," says research team member Dominic Papineau of the Carnegie Institution's Geophysical Laboratory. "It was a major turning point in the evolution of our planet, and we are getting closer to understanding how it occurred."
The researchers, led by Kurt Konhauser of the University of Alberta in Edmonton, analyzed the trace element composition of sedimentary rocks known as banded-iron formations, or BIFs, from dozens of different localities around the world, ranging in age from 3,800 to 550 million years. Banded iron formations are unique, water-laid deposits often found in extremely old rock strata that formed before the atmosphere or oceans contained abundant oxygen. As their name implies, they are made of alternating bands of iron and silicate minerals. They also contain minor amounts of nickel and other trace elements.
Nickel exists in today's oceans in trace amounts, but was up to 400 times more abundant in the Earth's primordial oceans. Methane-producing microorganisms, called methanogens, thrive in such environments, and the methane they released to the atmosphere might have prevented the buildup of oxygen gas, which would have reacted with the methane to produce carbon dioxide and water. A drop in nickel concentration would have led to a "nickel famine" for the methanogens, who rely on nickel-based enzymes for key metabolic processes. Algae and other organisms that release oxygen during photosynthesis use different enzymes, and so would have been less affected by the nickel famine. As a result, atmospheric methane would have declined, and the conditions for the rise of oxygen would have been set in place.
The researchers found that nickel levels in the BIFs began dropping around 2.7 billion years ago and by 2.5 billion years ago was about half its earlier value. "The timing fits very well. The drop in nickel could have set the stage for the Great Oxidation Event," says Papineau. "And from what we know about living methanogens, lower levels of nickel would have severely cut back methane production."
What caused the drop in nickel? The researchers point to geologic changes that were occurring during the interval. During earlier phases of the Earth's history, while its mantle was extremely hot, lavas from volcanic eruptions would have been relatively high in nickel. Erosion would have washed the nickel into the sea, keeping levels high. But as the mantle cooled, and the chemistry of lavas changed, volcanoes spewed out less nickel, and less would have found its way to the sea.
"The nickel connection was not something anyone had considered before," says Papineau. "It's just a trace element in seawater, but our study indicates that it may have had a huge impact on the Earth's environment and on the history of life."
Dominic Papineau's research is supported by the NASA Exobiology and Evolutionary Biology Program and from the Fond québécois de la recherche sur la nature et les technologies.
Journal reference:
Konhauser et al. Oceanic nickel depletion and a methanogen famine before the Great Oxidation Event. Nature, 2009; 458 (7239): 750 DOI: 10.1038/nature07858
Adapted from materials provided by Carnegie Institution.

Satellite Snow Maps Help Reindeer Herders Adapt To A Changing Arctic

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ScienceDaily (Apr. 10, 2009) — Arctic reindeer herders are facing the challenges of adapting to climate change as a warmer Arctic climate makes it harder for herds to find food and navigate. To help them adapt, the ESA-backed Polar View initiative is providing them with satellite-based snow maps.

"Snow is of paramount importance for reindeer herding because its quality determines whether reindeer are able to access the pastures that lie beneath it for much of the year," said Anders Oskal, the Director of the International Centre for Reindeer Husbandry (ICR). "Detailed circumpolar snow information is, thus, becoming increasingly important following the recent changes in the Arctic climate."
Oskal is working with Sámi reindeer herders in Finnmark, Norway, to help them maintain and develop sustainable reindeer husbandry. According to him, Finnmark is the area of Norway that is predicted to experience the largest temperature increases, raising concerns about whether ice layers will form over pastures preventing reindeer from foraging.
For this reason, ICR partnered with Polar View to examine how satellite observations could help by gathering information on snow and snow change in a timely and accurate manner for such vast circumpolar regions. Under the Polar View initiative, Kongsberg Satellite Services (KSAT) have been providing snow melt maps for Norway and Sweden and Eurasia snow cover maps for the last 18 months.
"The experience so far has definitely been positive, and the reindeer herders are extremely interested in the future utilisation of Polar View products that can relate important information about local snow conditions," Oskal said. "These products could have important consequences for herders’ decisions regarding winter pasture quality and potential migration routes."
In addition to climate change, reindeer herders also have to face a loss of pastures due to infrastructure development, such as roads, hydroelectric power dams and cabin resorts. In the future, ICR and Polar View may partner again to monitor the different forms of land use change over time.
Products from Polar View have also been used as input for an International Polar Year Project – IPY EALÁT-Network Study – on reindeer herding and adaptation to climate change.
The two Polar View snow services are provided by KSAT in partnership with the Northern Research Institute, the Norwegian Computing Centre and the Finnish Meteorological Institute.
Polar View is supported by ESA and the European Commission (EC) with participation from the Canadian Space Agency. It was established under the Global Monitoring for Environment and Security (GMES) programme – a joint initiative between ESA and the EC to combine all available space- and ground-based information sources to develop an independent European environmental monitoring capacity from planetary to local scales.
Adapted from materials provided by European Space Agency.

Deep-sea Rocks Point To Early Oxygen On Earth

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ScienceDaily (Mar. 25, 2009) — Red jasper cored from layers 3.46 billion years old suggests that not only did the oceans contain abundant oxygen then, but that the atmosphere was as oxygen rich as it is today, according to geologists.

This jasper or hematite-rich chert formed in ways similar to the way this rock forms around hydrothermal vents in the deep oceans today.
"Many people have assumed that the hematite in ancient rocks formed by the oxidation of siderite in the modern atmosphere," said Hiroshi Ohmoto, professor of geochemistry, Penn State. "That is why we wanted to drill deeper, below the water table and recover unweathered rocks."
The researchers drilled diagonally into the base of a hill in the Pilbara Craton in northwest Western Australia to obtain samples of jasper that could not have been exposed to the atmosphere or water. These jaspers could be dated to 3.46 billion years ago.
"Everyone agrees that this jasper is 3.46 billion years old," said Ohmoto. "If hematite were formed by the oxidation of siderite at any time, the hematite would be found on the outside of the siderite, but it is found inside," he reported in a recent issue of Nature Geoscience.
The next step was to determine if the hematite formed near the water's surface or in the depths. Iron compounds exposed to ultra violet light can form ferric hydroxide, which can sink to the bottom as tiny particles and then be converted to hematite at temperatures of at least 140 degrees Fahrenheit.
"There are a number of cases around the world where hematite is formed in this way," says Ohmoto. "So just because there is hematite, there is not necessarily oxygen in the water or the atmosphere."
The key to determining if ultra violet light or oxygen formed the hematite is the crystalline structure of the hematite itself. If the precursors of hematite were formed at the surface, the crystalline structure of the rock would have formed from small particles aggregating producing large crystals with lots of empty spaces between. Using transmission electron microscopy, the researchers did not find that crystalline structure.
"We found that the hematite from this core was made of a single crystal and therefore was not hematite made by ultra violet radiation," said Ohmoto.
This could only happen if the deep ocean contained oxygen and the iron rich fluids came into contact at high temperatures. Ohmoto and his team believe that this specific layer of hematite formed when a plume of heated water, like those found today at hydrothermal vents, converted the iron compounds into hematite using oxygen dissolved in the deep ocean water.
"This explains why this hematite is only found in areas with active submarine volcanism," said Ohmoto. "It also means that there was oxygen in the atmosphere 3.46 billion years ago, because the only mechanism for oxygen to exist in the deep oceans is for there to be oxygen in the atmosphere."
In fact, the researchers suggest that to have sufficient oxygen at depth, there had to be as much oxygen in the atmosphere 3.46 billion years ago as there is in today's atmosphere. To have this amount of oxygen, the Earth must have had oxygen producing organisms like cyanobacteria actively producing it, placing these organisms much earlier in Earth's history than previously thought.
"Usually, we look at the remnant of what we think is biological activity to understand the Earth's biology," said Ohmoto. "Our approach is unique because we look at the mineral ferric oxide to decipher biological activity."
Ohmoto suggests that this approach eliminates the problems trying to decide if carbon residues found in sediments were biologically created or simply chemical artifacts.
Other researchers on the study included Masamichi Hoashi, graduate student at Kagoshima University, Japan; Arthur H. Hickman, geologist with the Geological Survey of Western Australia; Satoshi Utsunomiya, Kyushu University, Japan, and David C. Bevacqua and Tsubasa Otake, former Penn State master's and doctoral students, Penn State; and Yumiko Watanabe, research associate, Penn State.
The NASA Astrobiology Institute supported this work.
Adapted from materials provided by Penn State.

Climate Warming Affects Antarctic Ice Sheet Stability

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ScienceDaily (Mar. 22, 2009) — A five-nation scientific team has published new evidence that even a slight rise in atmospheric concentrations of carbon dioxide, one of the gases that drives global warming, affects the stability of the West Antarctic Ice Sheet (WAIS). The massive WAIS covers the continent on the Pacific side of the Transantarctic Mountains. Any substantial melting of the ice sheet would cause a rise in global sea levels.

The research, which was published in the March 19 issue of the journal Nature, is based on investigations by a 56-member team of scientists conducted on a 1,280-meter (4,100-foot)-long sedimentary rock core taken from beneath the sea floor under Antarctica's Ross Ice Shelf during the first project of the ANDRILL (ANtarctic geological DRILLing) research program--the McMurdo Ice Shelf (MIS) Project.
"The sedimentary record from the ANDRILL project provides scientists with an important analogue that can be used to help predict how ice shelves and the massive WAIS will respond to future global warming over the next few centuries," said Ross Powell, a professor of geology at Northern Illinois University.
"The sedimentary record indicates that under global warming conditions that were similar to those projected to occur over the next century, protective ice shelves could shrink or even disappear and the WAIS would become vulnerable to melting," Powell said. "If the current warm period persists, the ice sheet could diminish substantially or even disappear over time. This would result in a potentially significant rise in sea levels."
ANDRILL--which involves scientists from the United States, New Zealand, Italy and Germany--refines previous findings about the relationship between atmospheric carbon dioxide concentration, atmospheric and oceanic temperatures, sea level rise and natural cycles in Earth's orbit around the Sun, through the study of sediment and rock cores that are a geological archive of past climate.
The dynamics of ice sheets, including WAIS, are not well understood, and improving scientists' comprehension of the mechanisms that control the growth, melting and movements of ice sheets was one of NSF's research priorities during the International Polar Year (IPY). The IPY field campaign, which officially ended March 2009, has been an intense scientific campaign to explore new frontiers in polar science, improve our understanding of the critical role of the polar regions in global processes, and educate students, teachers, and the public about the polar regions and their importance to the global system. NSF was the lead agency for U.S. IPY efforts.
The cores retrieved by ANDRILL researchers have allowed them to peer back in time to the Pliocene era, roughly 2 million to 5 million years ago. During that era, the Antarctic was in a natural climate state that was warmer than today and atmospheric carbon dioxide levels were higher. Data from the cores indicate the WAIS advanced and retreated numerous times in response to forcing driven by these climate cycles.
Powell and Tim Naish, director of Victoria University of Wellington's Antarctic Research Centre, served as co-chief scientists of the 2006-2007 ANDRILL project that retrieved the data and are lead authors in one of two companion studies published in Nature.
Naish said the new information gleaned from the core shows that changes in the tilt of Earth's rotational axis has played a major role in ocean warming that has driven repeated cycles of growth and retreat of the WAIS for the period in Earth's history between 3 million and 5 million years ago.
"It also appears that when atmospheric carbon dioxide concentrations reached 400 parts per million around four million years ago, the associated global warming amplified the effect of the Earth's axial tilt on the stability of the ice sheet," he said.
"Carbon dioxide concentration in the atmosphere is again approaching 400 parts per million," Naish said. "Geological archives, such as the ANDRILL core, highlight the risk that a significant body of permanent Antarctic ice could be lost within the next century as Earth's climate continues to warm. Based on ANDRILL data combined with computer models of ice sheet behavior, collapse of the entire WAIS is likely to occur on the order of 1,000 years, but recent studies show that melting has already begun."
The second ANDRILL study in Nature--led by David Pollard of Pennsylvania State University and Rob DeConto from University of Massachusetts--reports results from a computer model of the ice sheets. The model shows that each time the WAIS collapsed, some of the margins of the East Antarctic Ice Sheet also melted, and the combined effect was a global sea level rise of 7 meters above present-day levels.
Whether the beginnings of such a collapse could start 100 years from now or within the next millennium is hard to predict and depends on future atmospheric CO2 levels, the researchers said. However, the new information from ANDRILL contributes a missing piece of the puzzle as scientists try to refine their predictions of the effects of global warming.
The most recent report of the Intergovernmental Panel on Climate Change (IPCC) noted that because so little is understood about ice sheet behavior it is difficult to predict how ice sheets will contribute to sea level rise in a warming world. The behavior of ice sheets, the IPCC report said, is one of the major uncertainties in predicting exactly how the warming of the globe will affect human populations.
"From these combined data modeling studies, we can say that past warming events caused West Antarctic ice shelves and ice grounded below sea level to melt and disappear. The modeling suggests these collapses took one to a few thousand years," Pollard said.
Pollard and DeConto also underscored the role of ocean temperatures in melting of the ice.
"It's clear from our combined research using geological data and modeling that ocean temperatures play a key role," DeConto said. "The most substantial melting of protective ice shelves comes from beneath the ice, where it is in contact with seawater. We now need more data to determine what is happening to the underside of contemporary ice shelves."
The National Science Foundation (NSF), which manages the U.S. Antarctic Program (USAP), provided about $20 million in support of the ANDRILL program. The other ANDRILL national partners contributed an additional $10 million in science and logistics support.
The ANDRILL Science Management Office, located at the University of Nebraska-Lincoln, supports science planning and the activities of the international ANDRILL Science Committee (ASC). Antarctica New Zealand is the ANDRILL project operator and has developed the drilling system in collaboration with Alex Pyne at Victoria University of Wellington and Webster Drilling and Exploration.
The U.S. Antarctic Program and Raytheon Polar Services Corporation (RPSC) supported the science team at McMurdo Station and in the Crary Science and Engineering Laboratory, while Antarctica New Zealand supported the drilling team at Scott Base.
ANDRILL scientific studies are jointly supported by: the U.S. National Science Foundation, the New Zealand Foundation for Research, the Italian Antarctic Research Program, the German Science Foundation and the Alfred Wegener Institute.
Adapted from materials provided by National Science Foundation.

Earth Science: Lithosphere Deformed And Fractured Under Indian Ocean Much Earlier Than Previously Thought

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ScienceDaily (Mar. 20, 2009) — The discovery by Indian and British scientists that the Earth’s strong outer shell – the ‘lithosphere’ – within the central Indian Ocean began to deform and fracture 15.4–13.9 million years ago, much earlier than previously thought, impacts our understanding of the birth of the Himalayas and the strengthening of the Indian-Asian monsoon.

India and Asia collided around 50 million years ago as a result of plate tectonics – the large-scale movements of the lithosphere, which continue to this day. The new study, published in the scientific journal Geology, focuses on the tectonics-related deformation of the lithosphere below the central Indian Ocean.
“Compression of the lithosphere has caused large-scale buckling and cracking,” says team member Professor Jon Bull of the University of Southampton’s School of Ocean and Earth Science based at the National Oceanography Centre; “The ocean floor has been systematically transformed into folds 100-300 kilometres long and 2,000-3,000 metres high, and there are also regularly spaced faults or fractures that are evident from seismic surveys and ocean drilling.”
The onset of this deformation marks the start of major geological uplift of the Himalayas and the Tibetan Plateau, some 4,000 km further to the north, due to stresses within the wider India-Asia area. Some studies indicate that it began around 8.0–7.5 million years ago, while others have indicated that it started before 8.0 million years ago, and perhaps much earlier.
This controversy has now been addressed by Professor Bull and his colleagues Dr Kolluru Krishna of the National Institute of Oceanography in India, and Dr Roger Scrutton of Edinburgh University. They have analysed seismic profiles of 293 faults in the accumulated sediments of the Bengal Fan. This is the world’s largest submarine fan, a delta-shaped accumulation of land-derived sediments covering the floor of the Bay of Bengal.
They demonstrate that deformation of the lithosphere within the central Indian Ocean started around 15.4–13.9 million years ago, much earlier than most previous estimates. This implies considerable Himalayan uplift before 8.0 million years ago, which is when many geologists believe that the strong seasonal winds of the India-Asia monsoon first started.
“However,” says Professor Bull, “the realisation that the onset of lithospheric deformation within the central Indian Ocean occurred much earlier fits in well with more recent evidence that the strengthening of the monsoon was linked to the early geological uplift of the Himalayas and Tibetan plateau up to 15-20 million years ago.”
Intensive deep-sea drilling within the Bengal Fan should provide better age estimates for the onset of deformation of the lithosphere in the central Indian Ocean and help settle the controversy.
The research was funded by India’s Council of Scientific and Industrial Research (CSIR), and the United Kingdom’s Royal Society and Natural Environment Research Council (NERC).
Adapted from materials provided by National Oceanography Centre, Southampton.