Natural variation: Warm North Atlantic Ocean promotes extreme winters in US and Europe

The extreme cold weather observed across Europe and the east coast of the US in recent winters could be partly down to natural, long-term variations in sea surface temperatures, according to a new study published today.Researchers from the University of California Irvine have shown that a phenomenon known as the Atlantic Multidecadal Oscillation (AMO) — a natural pattern of variation in North Atlantic sea surface temperatures that switches between a positive and negative phase every 60-70 years — can affect an atmospheric circulation pattern, known as the North Atlantic Oscillation (NAO), that influences the temperature and precipitation over the Northern Hemisphere in winter.When the AMO is in its positive phase and the sea surface temperatures are warmer, the study has shown that the main effect in winter is to promote the negative phase of the NAO which leads to “blocking” episodes over the North Atlantic sector, allowing cold weather systems to exist over the eastern US and Europe.The results have been published today, Wednesday 2 April, in IOP Publishing’s journal Environmental Research Letters.To arrive at their results, the researchers combined observations from the past century with climate simulations of the atmospheric response to the AMO.According to their observations, sea surface temperatures in the Atlantic can be up to 1.5 C warmer in the Gulf Stream region during the positive phase of the AMO compared to the negative, colder phase. The climate simulations suggest that these specific anomalies in sea surface temperatures can play a predominant role in promoting the change in the NAO.Lead authors of the study Yannick Peings and Gudrun Magnusdottir said: “Our results indicate that the main effect of the positive AMO in winter is to promote the occurrence of the negative phase of the NAO. A negative NAO in winter usually goes hand-in-hand with cold weather in the eastern US and north-western Europe.”The observations also suggest that it takes around 10-15 years before the positive phase of AMO has any significant effect on the NAO. The reason for this lag is unknown; however, an explanation might be that AMO phases take time to develop fully.As the AMO has been in a positive phase since the early 1990s, it may have contributed to the extreme winters that both the US and Europe have experienced in recent years.The researchers warn, however, that the future evolution of the AMO remains uncertain, with many factors potentially affecting how it interacts with atmospheric circulation patterns, such as Arctic sea ice loss, changes in solar radiation, volcanic eruptions and concentrations of greenhouse gases in the atmosphere.The AMO also shows strong variability from one year to the next in addition to the changes seen every 60 – 70 years, which makes it difficult to attribute specific extreme winters to the AMO’s effects.Responding to the extreme weather that gripped the eastern coast of the US this winter, Yannick Peings continued: “Unlike the 2012/2013 winter, this winter had rather low values of the AMO index and the pattern of sea surface temperature anomalies was not consistent with the typical positive AMO pattern. Moreover, the NAO was mostly positive with a relatively mild winter over Europe.””Therefore it is unlikely that the positive AMO played a defining role on the east coast of the US, although further work is necessary to answer this question. Such an event is consistent with the large internal variability of the atmosphere, and other external forcings may have played a role.”Our future studies will look to compare the role of the AMO compared to Arctic sea ice anomalies, which have also been shown to affect atmospheric circulation patterns and promote colder, more extreme winters.”Story Source:The above story is based on materials provided by Institute of Physics. Note: Materials may be edited for content and length.

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Deforestation of sandy soils a greater climate threat

Deforestation may have far greater consequences for climate change in some soils than in others, according to new research led by Yale University scientists — a finding that could provide critical insights into which ecosystems must be managed with extra care because they are vulnerable to biodiversity loss and which ecosystems are more resilient to widespread tree removal.In a comprehensive analysis of soil collected from 11 distinct U.S. regions, from Hawaii to northern Alaska, researchers found that the extent to which deforestation disturbs underground microbial communities that regulate the loss of carbon into the atmosphere depends almost exclusively on the texture of the soil. The results were published in the journal Global Change Biology.”We were astonished that biodiversity changes were so strongly affected by soil texture and that it was such an overriding factor,” said Thomas Crowther, a postdoctoral fellow at the Yale School of Forestry & Environmental Studies and lead author of the study. “Texture overrode the effects of all the other variables that we thought might be important, including temperature, moisture, nutrient concentrations, and soil pH.”The study is a collaboration among Yale researchers and colleagues at the University of Boulder, Colorado and the University of Kentucky.A serious consequence of deforestation is extensive loss of carbon from the soil, a process regulated by subterranean microbial diversity. Drastic changes to the microbial community are expected to allow more CO2 to escape into the atmosphere, with the potential to exaggerate global warming.Specifically, the researchers found that deforestation dramatically alters microbial communities in sandy soils, but has minimal effects in muddy, clay-like soils, even after extensive tree removal.According to the researchers, particles in fine, clay-like soil seem to have a larger surface area to bind nutrients and water. This capacity might buffer soil microbes against the disturbance of forest removal, they said. In contrast, sandy soils have larger particles with less surface area, retaining fewer nutrients and less organic matter.”If you disrupt the community in a sandy soil, all of the nutrients the microbes rely on for food are leached away: they’re lost into the atmosphere, lost into rivers, lost through rain,” Crowther said. “But in clay-like soil, you can cut down the forest and the nutrients remain trapped tightly in the muddy clay.”The researchers also examined how the effects of deforestation on microbial biodiversity change over time. Contrary to their expectations, they found no correlation, even over the course of 200 years.”The effects are consistent, no matter how long ago deforestation happened,” Crowther said. “In a clay soil, you cut down the forest and the nutrients are retained for long periods of time and the community doesn’t change. …

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A more potent greenhouse gas than carbon dioxide, methane emissions will leap as Earth warms

While carbon dioxide is typically painted as the bad boy of greenhouse gases, methane is roughly 30 times more potent as a heat-trapping gas. New research in the journal Nature indicates that for each degree that Earth’s temperature rises, the amount of methane entering the atmosphere from microorganisms dwelling in lake sediment and freshwater wetlands — the primary sources of the gas — will increase several times. As temperatures rise, the relative increase of methane emissions will outpace that of carbon dioxide from these sources, the researchers report.The findings condense the complex and varied process by which methane — currently the third most prevalent greenhouse gas after carbon dioxide and water vapor — enters the atmosphere into a measurement scientists can use, explained co-author Cristian Gudasz, a visiting postdoctoral research associate in Princeton’s Department of Ecology and Evolutionary Biology. In freshwater systems, methane is produced as microorganisms digest organic matter, a process known as “methanogenesis.” This process hinges on a slew of temperature, chemical, physical and ecological factors that can bedevil scientists working to model how Earth’s systems will contribute, and respond, to a hotter future.The researchers’ findings suggest that methane emissions from freshwater systems will likely rise with the global temperature, Gudasz said. But to not know the extent of methane contribution from such a widely dispersed ecosystem that includes lakes, swamps, marshes and rice paddies leaves a glaring hole in climate projections.”The freshwater systems we talk about in our paper are an important component to the climate system,” Gudasz said. “There is more and more evidence that they have a contribution to the methane emissions. Methane produced from natural or humanmade freshwater systems will increase with temperature.”To provide a simple and accurate way for climate modelers to account for methanogenesis, Gudasz and his co-authors analyzed nearly 1,600 measurements of temperature and methane emissions from 127 freshwater ecosystems across the globe.The researchers found that a common effect emerged from those studies: freshwater methane generation very much thrives on high temperatures. Methane emissions at 0 degrees Celsius would rise 57 times higher when the temperature reached 30 degrees Celsius, the researchers report. For those inclined to model it, the researchers’ results translated to a temperature dependence of 0.96 electron volts (eV), an indication of the temperature-sensitivity of the methane-emitting ecosystems.”We all want to make predictions about greenhouse gas emissions and their impact on global warming,” Gudasz said. “Looking across these scales and constraining them as we have in this paper will allow us to make better predictions.”Story Source:The above story is based on materials provided by Princeton University. …

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Amazon inhales more carbon than it emits, NASA finds

A new NASA-led study seven years in the making has confirmed that natural forests in the Amazon remove more carbon dioxide from the atmosphere than they emit, therefore reducing global warming. This finding resolves a long-standing debate about a key component of the overall carbon balance of the Amazon basin.The Amazon’s carbon balance is a matter of life and death: living trees take carbon dioxide out of the air as they grow, and dead trees put the greenhouse gas back into the air as they decompose. The new study, published in Nature Communications on March 18, is the first to measure tree deaths caused by natural processes throughout the Amazon forest, even in remote areas where no data have been collected at ground level.Fernando Esprito-Santo of NASA’s Jet Propulsion Laboratory, Pasadena, Calif., lead author of the study, created new techniques to analyze satellite and other data. He found that each year, dead Amazonian trees emit an estimated 1.9 billion tons (1.7 billion metric tons) of carbon to the atmosphere. To compare this with Amazon carbon absorption, the researchers used censuses of forest growth and different modeling scenarios that accounted for uncertainties. In every scenario, carbon absorption by living trees outweighed emissions from the dead ones, indicating that the prevailing effect in natural forests of the Amazon is absorption.Until now, scientists had only been able to estimate the Amazon’s carbon balance from limited observations in small forest areas called plots. On these plots, the forest removes more carbon than it emits, but the scientific community has been vigorously debating how well the plots represent all the natural processes in the huge Amazon region. That debate began with the discovery in the 1990s that large areas of the forest can be killed off by intense storms in events called blowdowns.Esprito-Santo said that the idea for the study arose from a 2006 workshop where scientists from several nations came together to identify NASA satellite instruments that might help them better understand the carbon cycle of the Amazon. In the years since then, he worked with 21 coauthors in five nations to measure the carbon impacts of tree deaths in the Amazon from all natural causes — from large-area blowdowns to single trees that died of old age. He used airborne lidar data, satellite images, and a 10-year set of plot measurements collected by the University of Leeds, England, under the leadership of Emanuel Gloor and Oliver Phillips. …

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Reindeer grazing may counteract effects of climate warming on tundra carbon sink

Local reindeer grazing history is an important determinant in the response of an ecosystem’s carbon sink to climate warming, say researchers at the Arctic Centre of the University of Lapland. Their study was published in the journal Nature Climate Change on 16 March 2014. The research project has been funded by the Academy of Finland.The consequences of global climate warming on ecosystem carbon sink in tundra are of great interest, because carbon that is currently stored in tundra soils may be released to the atmosphere in a warmer climate. This could contribute to atmospheric carbon dioxide concentration, and thus create a positive feedback that intensifies global change.A major portion of the Arctic is grazed by reindeer. In northernmost Europe, the reindeer was domesticated a few centuries ago. In a field experiment in northern Norway, the effects of experimental warming were compared between lightly and heavily grazed tundra. The grazing history between these areas had varied for the past 50 years. Carbon balances showed that under the current climate, lightly grazed, dwarf-shrub-dominated tundra were a stronger carbon sink than heavily grazed, graminoid-dominated tundra. However, warming decreased the carbon sink in lightly grazed tundra, but had no effect in heavily grazed tundra. Thus, tundra with a long history of intensive grazing showed a weak response to climate warming.The main reason for this grazer-induced difference was that in heavily grazed tundra, graminoids with rapid growth rates were able to increase their photosynthesis and carbon fixation under increased temperatures. …

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First animals oxygenated the ocean

The evolution of the first animals may have oxygenated the earth’s oceans — contrary to the traditional view that a rise in oxygen triggered their development.New research led by the University of Exeter contests the long held belief that oxygenation of the atmosphere and oceans was a pre-requisite for the evolution of complex life forms.The study, published today in the leading journal Nature Geoscience, builds on the recent work of scientists in Denmark who found that sponges — the first animals to evolve — require only small amounts of oxygen.Professor Tim Lenton of the University of Exeter, who led the new study, said: “There had been enough oxygen in ocean surface waters for over 1.5 billion years before the first animals evolved, but the dark depths of the ocean remained devoid of oxygen. We argue that the evolution of the first animals could have played a key role in the widespread oxygenation of the deep oceans. This in turn may have facilitated the evolution of more complex, mobile animals.”The researchers considered mechanisms by which the deep ocean could have been oxygenated during the Neoproterozoic Era (from 1,000 to 542 million years ago) without requiring an increase in atmospheric oxygen.Crucial to determining oxygen levels in the deep ocean is the balance of oxygen supply and demand. Demand for oxygen is created by the sinking of dead organic material into the deep ocean. The new study argues that the first animals reduced this supply of organic matter — both directly and indirectly.Sponges feed by pumping water through their bodies, filtering out tiny particles of organic matter from the water, and thus helping oxygenate the shelf seas that they live in. This naturally selects for larger phytoplankton — the tiny plants of the ocean — which sink faster, also reducing oxygen demand in the water.By oxygenating more of the bottom waters of shelf seas, the first filter-feeding animals inadvertently increased the removal of the essential nutrient phosphorus in the ocean. This in turn reduced the productivity of the whole ocean ecosystem, suppressing oxygen demand and thus oxygenating the deep ocean.A more oxygen-rich ocean created ideal conditions for more mobile animals to evolve, because they have a higher requirement for oxygen. These included the first predatory animals with guts that started to eat one another, marking the beginning of a modern marine biosphere, with the type of food webs we are familiar with today.Professor Lenton added: “The effects we predict suggest that the first animals, far from being a passive response to rising atmospheric oxygen, were the active agents that oxygenated the ocean around 600 million years ago. They created a world in which more complex animals could evolve, including our very distant ancestors.”Professor Simon Poulton of the University of Leeds, who is a co-author of the study, added: ″This study provides a plausible mechanism for ocean oxygenation without the requirement for a rise in atmospheric oxygen. It therefore questions whether the long-standing belief that there was a major rise in atmospheric oxygen at this time is correct. …

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Plasma plumes help shield Earth from damaging solar storms

Earth’s magnetic field, or magnetosphere, stretches from the planet’s core out into space, where it meets the solar wind, a stream of charged particles emitted by the sun. For the most part, the magnetosphere acts as a shield to protect Earth from this high-energy solar activity.But when this field comes into contact with the sun’s magnetic field — a process called “magnetic reconnection” — powerful electrical currents from the sun can stream into Earth’s atmosphere, whipping up geomagnetic storms and space weather phenomena that can affect high-altitude aircraft, as well as astronauts on the International Space Station.Now scientists at MIT and NASA have identified a process in Earth’s magnetosphere that reinforces its shielding effect, keeping incoming solar energy at bay.By combining observations from the ground and in space, the team observed a plume of low-energy plasma particles that essentially hitches a ride along magnetic field lines — streaming from Earth’s lower atmosphere up to the point, tens of thousands of kilometers above the surface, where the planet’s magnetic field connects with that of the sun. In this region, which the scientists call the “merging point,” the presence of cold, dense plasma slows magnetic reconnection, blunting the sun’s effects on Earth.”The Earth’s magnetic field protects life on the surface from the full impact of these solar outbursts,” says John Foster, associate director of MIT’s Haystack Observatory. “Reconnection strips away some of our magnetic shield and lets energy leak in, giving us large, violent storms. These plasmas get pulled into space and slow down the reconnection process, so the impact of the sun on the Earth is less violent.”Foster and his colleagues publish their results in this week’s issue of Science. The team includes Philip Erickson, principal research scientist at Haystack Observatory, as well as Brian Walsh and David Sibeck at NASA’s Goddard Space Flight Center.Mapping Earth’s magnetic shieldFor more than a decade, scientists at Haystack Observatory have studied plasma plume phenomena using a ground-based technique called GPS-TEC, in which scientists analyze radio signals transmitted from GPS satellites to more than 1,000 receivers on the ground. Large space-weather events, such as geomagnetic storms, can alter the incoming radio waves — a distortion that scientists can use to determine the concentration of plasma particles in the upper atmosphere. Using this data, they can produce two-dimensional global maps of atmospheric phenomena, such as plasma plumes.These ground-based observations have helped shed light on key characteristics of these plumes, such as how often they occur, and what makes some plumes stronger than others. But as Foster notes, this two-dimensional mapping technique gives an estimate only of what space weather might look like in the low-altitude regions of the magnetosphere. To get a more precise, three-dimensional picture of the entire magnetosphere would require observations directly from space.Toward this end, Foster approached Walsh with data showing a plasma plume emanating from Earth’s surface, and extending up into the lower layers of the magnetosphere, during a moderate solar storm in January 2013. …

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Ancient ‘great leap forward’ for life in the open ocean: Cyanobacteria sheds light on how complex life evolved on earth

Plankton in Earth’s oceans received a huge boost when microorganisms capable of creating soluble nitrogen ‘fertilizer’ directly from the atmosphere diversified and spread throughout the open ocean. This event occurred at around 800 million years ago and it changed forever how carbon was cycled in the ocean.It has long been believed that the appearance of complex multicellular life towards the end of the Precambrian (the geologic interval lasting up until 541 million years ago) was facilitated by an increase in oxygen, as revealed in the geological record. However, it has remained a mystery as to why oxygen increased at this particular time and what its relationship was to ‘Snowball Earth’ — the most extreme climatic changes Earth has ever experienced — which were also taking place around then.This new study shows that it could in fact be what was happening to nitrogen at this time that helps solve the mystery.The researchers, led by Dr Patricia Sanchez-Baracaldo of the University of Bristol, used genomic data to reconstruct the relationships between those cyanobacteria whose photosynthesis in the open ocean provided oxygen in quantities sufficient to be fundamental in the development of complex life on Earth.Some of these cyanobacteria were also able to transform atmospheric nitrogen into bioavailable nitrogen in sufficient quantities to contribute to the marine nitrogen cycle, delivering ‘nitrogen fertiliser’ to the ecosystem. Using molecular techniques, the team were able to date when these species first appeared in the geological record to around 800 million years ago.Dr Sanchez-Baracaldo, a Royal Society Dorothy Hodgkin Research Fellow in Bristol’s Schools of Biological and Geographical Sciences said: “We have known that oxygenic photosynthesis — the process by which microbes fix carbon dioxide into carbohydrates, splitting water and releasing oxygen as a by-product — first evolved in freshwater habitats more than 2.3 billion years ago. But it wasn’t until around 800 million years ago that these oxygenating cyanobacteria were able to colonise the vast oceans (two thirds of our planet) and be fertilised by enough bioavailable nitrogen to then produce oxygen — and carbohydrate food — at levels high enough to facilitate the next ‘great leap forward’ towards complex life.”Our study suggests that it may have been the fixing of this nitrogen ‘fertiliser’ in the oceans at this time that played a pivotal role in this key moment in the evolution of life on Earth.”Co-author, Professor Andy Ridgwell said: “The timing of the spread in nitrogen fixers in the open ocean occurs just prior to global glaciations and the appearance of animals. Although further work is required, these evolutionary changes may well have been related to, and perhaps provided a trigger for, the occurrence of extreme glaciation around this time as carbon was now being buried in the sediments on a much larger scale.”Dr Sanchez-Baracaldo added: “It’s very exciting to have been able to use state of the art genetic techniques to help solve an age-old mystery concerning one of the most important and pivotal moments in the evolution of life on Earth. In recent years, genomic data has been helping re-tell the story of the origins of life with increasing clarity and accuracy. It is a privilege to be contributing to our understanding of how microorganisms have contributed to make our planet habitable.”Story Source:The above story is based on materials provided by University of Bristol. Note: Materials may be edited for content and length.

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Fish biomass in the ocean may be 10 times higher than estimated: Stock of mesopelagic fish changes from 1,000 to 10,000 million tons

With a stock estimated at 1,000 million tons so far, mesopelagic fish dominate the total biomass of fish in the ocean. However, a team of researchers with the participation of the Spanish National Research Council (CSIC) has found that their abundance could be at least 10 times higher. The results, published in Nature Communications journal, are based on the acoustic observations conducted during the circumnavigation of the Malaspina Expedition.Mesopelagic fishes, such as lantern fishes (Myctophidae) and cyclothonids (Gonostomatidae), live in the twilight zone of the ocean, between 200 and 1,000 meters deep. They are the most numerous vertebrates of the biosphere, but also the great unknowns of the open ocean, since there are gaps in the knowledge of their biology, ecology, adaptation and global biomass.During the 32,000 nautical miles traveled during the circumnavigation, the researchers of the Malaspina Expedition (a project led by CSIC researcher Carlos Duarte) took measurements between 40N and 40S, from 200 to 1,000 meters deep, during the day.Duarte states: “Malaspina has provided us the unique opportunity to assess the stock of mesopelagic fish in the ocean. Until now we only had the data provided by trawling. It has recently been discovered that these fishes are able to detect the nets and run, which turns trawling into a biased tool when it comes to count its biomass.”Transport of organic carbonXabier Irigoyen, researcher from AZTI-Tecnalia and KAUST (Saudi Arabia) and head of this research, states: “The fact that the biomass of mesopelagic fish (and therefore also the total biomass of fishes) is at least 10 times higher than previously thought, has significant implications in the understanding of carbon fluxes in the ocean and the operation of which, so far, we considered ocean deserts.”Mesopelagic fish come up at night to the upper layers of the ocean to feed, whereas they go back down during the day in order to avoid being detected by their predators. This behaviour speeds up the transport of organic matter into the ocean, the engine of the biological pump that removes CO2 from the atmosphere, because instead of slowly sinking from the surface, it is rapidly transported to 500 and 700 meters deep and released in the form of feces.Irigoyen adds: “Mesopelagic fish accelerate the flux for actively transporting organic matter from the upper layers of the water column, where most of the organic carbon coming from the flow of sedimentary particles is lost. Their role in the biogeochemical cycles of ocean ecosystems and global ocean has to be reconsidered, as it is likely that they are breathing between 1% and 10% of the primary production in deep waters.”According to researchers, the excretion of material from the surface could partly explain the unexpected microbial respiration registered in these deep layers of the ocean. Mesopelagic fishes would act therefore as a link between plankton and top predators, and they would have a key role in reducing the oxygen from the depths of the open ocean.Story Source:The above story is based on materials provided by Spanish National Research Council (CSIC). Note: Materials may be edited for content and length.

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Converting land to agriculture reduces carbon uptake, study shows

University of Montana researchers examined the impact that converting natural land to cropland has on global vegetation growth, as measured by satellite-derived net primary production, or NPP. They found that measures of terrestrial vegetation growth actually decrease with agricultural conversion, which has important implications for terrestrial carbon storage.Postdoctoral researcher Bill Smith and UM faculty members Steve Running and Cory Cleveland, along with a former UM postdoctoral researcher and current USGS scientist Sasha Reed, used estimates of agricultural NPP and satellite-derived estimates of natural NPP to evaluate the impact of expanding agricultural land to meet needs for food and fiber. Terrestrial NPP represents the total annual growth of vegetation on the land, which is a critical factor that helps determine how much carbon can be absorbed and stored from the atmosphere.Their results show that agricultural conversion has reduced that productivity by approximately 7 percent. A small percentage of intensively managed, irrigated or fertilized agricultural land shows an increase in productivity. However, productivity is reduced in 88 percent of agricultural lands globally, with the largest reductions in former tropical forests and savannas.”Current forecasts suggest that global food demand will likely double by 2050,” Smith said. “We hope that this research will help to identify strategies that, from a carbon balance perspective, should be avoided due to the potential for severe degradation of global vegetation growth and carbon storage.”The research was published in Geophysical Research Letters and highlighted in the February 2014 issue of Nature Geoscience.Story Source:The above story is based on materials provided by The University of Montana. Note: Materials may be edited for content and length.

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Nature can, selectively, buffer human-caused global warming, say scientists

Can naturally occurring processes selectively buffer the full brunt of global warming caused by greenhouse gas emissions resulting from human activities?Yes, find researchers from the Hebrew University of Jerusalem, Johns Hopkins University in the US and NASA’s Goddard Space Flight Center.As the globe warms, ocean temperatures rise, leading to increased water vapor escaping into the atmosphere. Water vapor is the most important greenhouse gas, and its impact on climate is amplified in the stratosphere.In a detailed study, the researchers from the three institutions examined the causes of changes in the temperatures and water vapor in the tropical tropopause layer (TTL). The TTL is a critical region of our atmosphere with characteristics of both the troposphere below and the stratosphere above.The TTL can have significant influences on both atmospheric chemistry and climate, as its temperature determines how much water vapor can enter the stratosphere. Therefore, understanding any changes in the temperature of the TTL and what might be causing them is an important scientific question of significant societal relevance, say the researchers.The Israeli and US scientists used measurements from satellite observations and output from chemistry-climate models to understand recent temperature trends in the TTL. Temperature measurements show where significant changes have taken place since 1979.The satellite observations have shown that warming of the tropical Indian Ocean and tropical Western Pacific Ocean — with resulting increased precipitation and water vapor there — causes the opposite effect of cooling in the TTL region above the warming sea surface. Once the TTL cools, less water vapor is present in the TTL and also above in the stratosphere,Since water vapor is a very strong greenhouse gas, this effect leads to a negative feedback on climate change. That is, the increase in water vapor due to enhanced evaporation from the warming oceans is confined to the near- surface area, while the stratosphere becomes drier. Hence, this effect may actually slightly weaken the more dire forecasted aspects of an increasing warming of our climate, the scientists say.The researchers are Dr. Chaim Garfinkel of the Fredy and Nadine Herrmann Institute of Earth Sciences at the Hebrew University and formerly of Johns Hopkins University, Dr. D. …

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An Intricate Form of Cancer

An Intricate Form of CancerMesothelioma is an intricate form of cancer that grows in the covering around the lungs, heart, and abdomen. The disease is caused due to harmful mineral asbestos. Exposure to asbestos in the workplace, in schools where asbestos is used in the walls, at home while washing clothes with asbestos can lead to this dreadful disease. The most bizarre thing is that it is diagnosed after many years of exposure to asbestos.Asbestos is a cluster of minerals that is present in nature. It is remarkably resistant to heat. It was used on a large scale in various industries due its resourcefulness and power. Asbestos contact, in 80% cases is responsible for the dangerous disease. Asbestos when heated releases fibres in the atmosphere. These …

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Without plants, Earth would cook under billions of tons of additional carbon

Oct. 16, 2013 — Enhanced growth of Earth’s leafy greens during the 20th century has significantly slowed the planet’s transition to being red-hot, according to the first study to specify the extent to which plants have prevented climate change since pre-industrial times. Researchers based at Princeton University found that land ecosystems have kept the planet cooler by absorbing billions of tons of carbon, especially during the past 60 years.The planet’s land-based carbon “sink” — or carbon-storage capacity — has kept 186 billion to 192 billion tons of carbon out of the atmosphere since the mid-20th century, the researchers report in the Proceedings of the National Academy of Sciences. From the 1860s to the 1950s, land use by humans was a substantial source of the carbon entering the atmosphere because of deforestation and logging. After the 1950s, however, humans began to use land differently, such as by restoring forests and adopting agriculture that, while larger scale, is higher yield. At the same time, industries and automobiles continued to steadily emit carbon dioxide that contributed to a botanical boom. Although a greenhouse gas and pollutant, carbon dioxide also is a plant nutrient.Had Earth’s terrestrial ecosystems remained a carbon source they would have instead generated 65 billion to 82 billion tons of carbon in addition to the carbon that it would not have absorbed, the researchers found. That means a total of 251 billion to 274 billion additional tons of carbon would currently be in the atmosphere. That much carbon would have pushed the atmosphere’s current carbon dioxide concentration to 485 parts-per-million (ppm), the researchers report — well past the scientifically accepted threshold of 450 (ppm) at which Earth’s climate could drastically and irreversibly change. The current concentration is 400 ppm.Those “carbon savings” amount to a current average global temperature that is cooler by one-third of a degree Celsius (or a half-degree Fahrenheit), which would have been a sizeable jump, the researchers report. …

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How Earth’s rotation affects vortices in nature, such as hurricanes and ocean currents

Oct. 15, 2013 — What do smoke rings, tornadoes and the Great Red Spot of Jupiter have in common? They are all examples of vortices, regions within a fluid (liquid, gas or plasma) where the flow spins around an imaginary straight or curved axis. Understanding how geophysical (natural world) vortices behave can be critical for tasks such as weather forecasting and environmental pollution monitoring.In a new paper in the journal Physics of Fluids, researchers Junho Park and Paul Billant of the CNRS Laboratoire d’Hydrodynamique in France describe their study of one such geophysical vortex behavior, radiative instability, and how it is affected by two factors, density stratification and background rotation.Radiative instability is a phenomenon that alters the behavior of fluid flows and can deform a vortex. The “radiative” tag refers to the fact that it is an instability caused by the radiation of waves outward from a vortex.”These waves can exist as soon as there is a density stratification — a variation of densities — throughout the vertical column of the vortex,” Park said. “In this study, we have considered how background rotation — in this case, the rotation of the Earth — impacts them.”Examples of density stratification in nature, Park explained, include the decrease in air density as one moves higher in the atmosphere or the increase in water density due to salinity and temperature with increasing ocean depth. “So, the waves in our mathematical model are somewhat analogous to waves on the ocean surface,” he said. “Likewise, the impact from background rotation on our modeled waves serves as an equal for the impact of the Coriolis force caused by the Earth’s rotation.””What we learned from our models is that strong background rotation suppresses the radiative instability, a characteristic that had been expected but whose dynamics had never been studied precisely,” Park said. “We’ve now developed a sophisticated mathematical means to explain this phenomenon, and that’s important to being better able to study and understand the behavior of geophysical vortices such as hurricanes and ocean currents.”Park said that he and Billant next plan to study instability behaviors in vortices with non-columnar shapes. “For example,” he said, “there are pancake-shaped flows called Mediterranean eddies, or meddies, that would be worth studying since we know they affect the mixing of the components that make up the ocean ecosystem.”

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Plant community plays key role in controlling greenhouse gas emissions from carbon rich moorlands

Sep. 18, 2013 — Different moorland plants, particularly heather and cotton grass, can strongly influence climate warming effects on greenhouse gas emissions, researchers from Lancaster University, The University of Manchester and the Centre for Ecology & Hydrology have discovered.The findings, published this week in the journal Ecology Letters, show valuable carbon stores, which lie deep below peaty moorlands, are at risk from changes in climate and from land management techniques that alter plant diversity.But the study found that the make-up of the plant community could also play a key role in controlling greenhouse gas emissions from these carbon rich ecosystems, as not all vegetation types respond in the same way to warming.The research, supported by a Natural Environment Research Council (NERC) grant, took place at Moor House National Nature Reserve, high up in the North Pennines, a long-term, ecological monitoring site for the UK Environmental Change Network.The newly set up experimental site manipulated both temperature and the composition and diversity of vegetation at the same time, allowing the team to study the combined effects of these global change phenomena for the first time.Temperatures were increased by around 1°C using open-topped, passive warming chambers, specially built on site, which mimicked the predicted effects of global warming.The researchers found that when heather was present, warming increased the amount of CO2 taken up from the atmosphere, making the ecosystem a greater sink for this greenhouse gas. However, when cotton grass was present, the CO2 sink strength of system decreased with warming, and the amount of methane released increased.Professor Richard Bardgett, who led the research team, and has recently moved to The University of Manchester, said: “What surprised us was that changes in vegetation, which can result from land management or climate change itself, also had such a strong impact on greenhouse gas emissions and even changed the way that warming affected them.”In other words, the diversity and make-up of the vegetation, which can be altered by the way the land is farmed, can completely change the sink strength of the ecosystem for carbon dioxide. This means that the way we manage peat land vegetation will strongly influence the way that peat land carbon sink strength responds to future climate change.”Dr Sue Ward, the Senior Research Associate for the project at Lancaster Environment Centre, said: “Setting up this experiment allowed us to test how greenhouse gas emissions are affected by a combination of changes in climate and changes in plant communities.”By taking gas samples every month of the year, we were able to show that the types of plants growing in these ecosystems can modify the effects of increase in temperature.”Dr Ward said the study would be of interest and relevance to ecological and climate change scientists and policy makers.”Changes in vegetation as well as physical changes in climate should be taken into account when looking at how global change affects carbon cycling,” she added. “Otherwise a vital part is missing — the biology is a key ingredient.”Professor Nick Ostle, from the Centre for Ecology & Hydrology, a joint partner in the research, said: “This ‘real-world’ study of the response of peat lands to climate change is unique, making these findings even more important.”It seems that the identity of the plants present in these landscapes will exert a strong influence on the effect of climate warming on soil CO2 emissions back to the atmosphere. If this is true then we can expect similar responses in other carbon rich systems in the Arctic and Boreal regions.”

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Water discovered in remnants of extrasolar rocky world orbiting white dwarf

Oct. 10, 2013 — Astrophysicists have found the first evidence of a water-rich rocky planetary body outside our solar system in its shattered remains orbiting a white dwarf.A new study by scientists at the Universities of Warwick and Cambridge published in the journal Science analysed the dust and debris surrounding the white dwarf star GD61 170 light years away.Using observations obtained with the Hubble Space Telescope and the large Keck telescope on Hawaii, they found an excess of oxygen — a chemical signature that indicates that the debris had once been part of a bigger body originally composed of 26 per cent water by mass. By contrast, only approximately 0.023 per cent of Earth’s mass is water.Evidence for water outside our solar system has previously been found in the atmosphere of gas giants, but this study marks the first time it has been pinpointed in a rocky body, making it of significant interest in our understanding of the formation and evolution of habitable planets and life.We know from our own solar system that the dwarf planet Ceres contains ice buried beneath an outer crust, and the researchers draw a parallel between the two bodies. Scientists believe that bodies like Ceres were the source of the bulk of our own water on Earth.The researchers suggest it is most likely that the water detected around the white dwarf GD 61 came from a minor planet at least 90 km in diameter but potentially much bigger, that once orbited the parent star before it became a white dwarf.Like Ceres, the water was most likely in the form of ice below the planet’s surface. From the amount of rocks and water detected in the outer envelope of the white dwarf, the researchers estimate that the disrupted planetary body had a diameter of at least 90km.However, because their observations can only detect what is being accreted in recent history, the estimate of its mass is on the conservative side.It is likely that the object was as large as Vesta, the largest minor planet in the solar system. In its former life, GD 61 was a star somewhat bigger than our Sun, and host to a planetary system.About 200 million years ago, GD 61 entered its death throes and became a white dwarf, yet, parts of its planetary system survived. The water-rich minor planet was knocked out of its regular orbit and plunged into a very close orbit, where it was shredded by the star’s gravitational force. The researchers believe that destabilising the orbit of the minor planet requires a so far unseen, much larger planet going around the white dwarf.Professor Boris Gänsicke of the Department of Physics at the University of Warwick “At this stage in its existence, all that remains of this rocky body is simply dust and debris that has been pulled into the orbit of its dying parent star.”However this planetary graveyard swirling around the embers of its parent star is a rich source of information about its former life. “In these remnants lie chemical clues which point towards a previous existence as a water-rich terrestrial body.”Those two ingredients — a rocky surface and water — are key in the hunt for habitable planets outside our solar system so it’s very exciting to find them together for the first time outside our solar system.”Lead author Jay Farihi, from Cambridge’s Institute of Astronomy, said: “The finding of water in a large asteroid means the building blocks of habitable planets existed — and maybe still exist — in the GD 61 system, and likely also around substantial number of similar parent stars.”These water-rich building blocks, and the terrestrial planets they build, may in fact be common — a system cannot create things as big as asteroids and avoid building planets, and GD 61 had the ingredients to deliver lots of water to their surfaces,” Farihi said.”Our results demonstrate that there was definitely potential for habitable planets in this exoplanetary system.”For their analysis , the researchers used ultraviolet spectroscopy data obtained with the Cosmic Origins Spectrograph on board the Hubble Space Telescope of the white dwarf GD 61. As the atmosphere of Earth blocks the ultraviolet light, such study can only be carried out from space.Additional observations were obtained with the 10m large mirror of the W.M. …

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Delaying climate policy would triple short-term mitigation costs

Sep. 12, 2013 — Higher costs would in turn increase the threshold for decision-makers to start the transition to a low-carbon economy. Thus, to keep climate targets within reach it seems to be most relevant to not further postpone mitigation, the researchers conclude.”The transitional economic repercussions that would result if the switch towards a climate-friendly economy is delayed, are comparable to the costs of the financial crisis the world just experienced,” lead-author Gunnar Luderer says. The later climate policy implementation starts, the faster — hence the more expensive — emissions have to be reduced if states world-wide want to achieve the internationally agreed target of limiting global warming to 2 degrees above pre-industrial levels. A binding global agreement to implement the emissions reductions required to reach this target is currently still under negotiation, while global emissions have continued to rise.”For the first time, our study quantifies the short-term costs of tiptoeing when confronted with the climate challenge,” Luderer says. “Economists tend to look at how things balance out in the long-term, but decision-makers understandably worry about additional burdens for the people and businesses they are responsible for right now. So increased short-term costs due to delaying climate policy might deter decision-makers from starting the transformation. The initial costs of climate policies thus can be more relevant than the total costs.”Future energy price increases could be limitedThe researchers investigated a number of cost dimensions, including climate policy effects on energy prices. If emissions reductions are delayed beyond 2030, global energy price levels are likely to increase by 80 percent in the short term. Such price increases are of particular concern because of the burden they put on the world’s poor. …

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Global warming has increased risk of record heat

Sep. 5, 2013 — Researchers calculate that intense heat like that in the summer of 2012 is up to four times more likely to occur now than in pre-industrial America, when there was much less carbon dioxide in the atmosphere.Drought shriveled crops in the Midwest, massive wildfires raged in the West and East Coast cities sweltered. The summer of 2012 was a season of epic proportions, especially July, the hottest month in the history of U.S. weather record keeping.And it’s likely that we’ll continue to see such calamitous weather.In the north-central and northeastern United States, extreme weather is more than four times as likely to occur than it was in the pre-industrial era, according to a new study by Noah Diffenbaugh, a Stanford associate professor of environmental Earth system science, and Martin Scherer, a research assistant in the department.Diffenbaugh and Scherer found strong evidence that the high levels of greenhouse gases now in the atmosphere have increased the likelihood of severe heat such as occurred in the United States in 2012.The researchers focused primarily on understanding the physical processes that created the hazardous weather. They looked at how rare those conditions were over the history of available weather records, going back over the last century.Then, using climate models, they quantified how the risk of such damaging weather has changed in the current climate of high greenhouse gas concentrations, as opposed to an era of significantly lower concentrations and no global warming. Their findings don’t pinpoint global warming as the cause of particular extreme weather events, but they do reveal the increasing risk of such events as the world warms.”Going forward, if we want to understand and manage climate risks, it’s more practically relevant to understand the likelihood of the hazard than to ask whether any particular disaster was caused by global warming,” Diffenbaugh said.In 2012 alone, the United States suffered 11 extreme weather events that each caused at least $1 billion in damage. “It’s clear that our greenhouse gas emissions have increased the likelihood of some kinds of extremes, and it’s clear that we’re not optimally adapted to that new climate,” Diffenbaugh said.While Diffenbaugh cautions against trying to determine whether global warming caused any individual extreme event, the observed global warming clearly appears to have affected the likelihood of record heat, according to Diffenbaugh and Scherer.The study, looking at the likelihood of July 2012 U.S. temperatures recurring, is part of a larger report edited by scientists at the National Oceanic and Atmospheric Administration (NOAA) and published Sept. 5 in the Bulletin of the American Meteorological Society. The report includes studies of a dozen 2012 extreme weather events by research teams around the world, about half of which found some evidence that human-caused climate change contributed to an extreme weather event.Close study of extreme weather events can help quantify the likelihood that society will face conditions similar to those that occurred in the summer of 2012, thereby informing efforts to reduce vulnerability and increase resilience. …

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Beetles modify emissions of greenhouse gases from cow pats

Aug. 22, 2013 — Cattle contribute to global warming by burping and farting large amounts of greenhouse gases. Some of the same gases are also emitted from cow pats on pastures. But now researchers from the University of Helsinki have found that beetles living in cow pats may reduce emissions of the key greenhouse gas — methane.Agriculture is one of the biggest sources of the anthropogenic greenhouse gases responsible for global warming. Among these, cattle farming for meat and milk are major sources of methane, a gas with a potent warming effect. Much of this methane comes from the guts of ruminating cattle, but some escapes from dung pats on pastures. Now researchers from the University of Helsinki have found that beetles living in the cow pats may reduce emissions of methane. The study has just been published in the journal PLoS ONE.Atte Penttilä, who undertook the study for his Masters, explains: “Cow pats offer a prime food for a large number of organisms. In fact, there are probably as many beetle species living in dung as there are bird species on this planet.”Of the dung beetles living in Northern Europe, most spend their entire lives within the dung pats. “We believe that these beetles exert much of their impact by simply digging around in the dung. …

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Soil carbon ‘blowing in the wind’

Aug. 6, 2013 — Australian soils are losing about 1.6 million tonnes of carbon per year from wind erosion and dust storms affecting agricultural productivity, our economy and carbon accounts, according to new research.Top soil is rich in nutrients and carbon but is increasingly being blown away by events such as the ‘Red Dawn’ in Sydney in 2009.When wind lifts carbon dust into the atmosphere it changes the amount and location of soil carbon.Some carbon falls back to the ground while some leaves Australia or ends up in the ocean.CSIRO research scientist Dr Adrian Chappell and an international team of experts in wind erosion and dust emission recently calculated the extent of these carbon dust emissions.”Carbon stored in our soils helps sustain plant growth. Our modelling shows that millions of tonnes of dust and carbon are blowing away, and it is uncertain where all that ends up,” Dr Chappell said.”We need to understand the impact of this dust carbon cycle to develop more accurate national and global estimates of carbon balances and to be able to prepare for life in a changing climate.”Australia’s carbon accounts, and even global carbon accounts, have not yet taken wind or water erosion into consideration and when this happens it could have significant impacts on how we manage our landscapes. While soil organic carbon lost through dust is not a major contributor to Australia’s total emissions, it is a major factor in our deteriorating soil health.”Carbon is an essential ingredient for the healthy soils which underpin Australia’s capability to produce enough food to feed 60 million people.Understanding the movement of carbon through the landscape is a necessity if we are to improve the quality of our soils and support farmers and land managers to store carbon.This is not an issue for Australia alone. Other countries will also need to know the fate of their wind-blown carbon; countries like the USA and China with larger dust emissions will likely face similar challenges when including wind borne dust in their carbon accounting.With the frequency and intensity of dust storms likely to increase in Australia, the impact of wind erosion would also increase.This redistribution of carbon needs to be better understood so we can improve our land management practices to better protect our soils.Recent research estimated that the ‘Red Dawn’ dust storm that passed over the eastern coast of Australia on 23 September 2009 cost the economy of New South Wales A$300 million, mainly for household cleaning and associated activities.The research paper “Soil organic carbon dust emission: an omitted global source of atmospheric CO2” was published in the latest issue of the journal Global Change Biology.

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