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Volcanic Aerosols, Not Pollutants, Tamped Down Recent Earth Warming

A team led by the University of Colorado Boulder looking for clues about why Earth did not warm as much as scientists expected between 2000 and 2010 now thinks the culprits are hiding in plain sight -- dozens of volcanoes spewing sulfur dioxide.

The study results essentially exonerate Asia, including India and China, two countries that are estimated to have increased their industrial sulfur dioxide emissions by about 60 percent from 2000 to 2010 through coal burning, said lead study author Ryan Neely, who led the research as part of his CU-Boulder doctoral thesis. Small amounts of sulfur dioxide emissions from Earth's surface eventually rise 12 to 20 miles into the stratospheric aerosol layer of the atmosphere, where chemical reactions create sulfuric acid and water particles that reflect sunlight back to space, cooling the planet.

Neely said previous observations suggest that increases in stratospheric aerosols since 2000 have counterbalanced as much as 25 percent of the warming scientists blame on human greenhouse gas emissions. "This new study indicates it is emissions from small to moderate volcanoes that have been slowing the warming of the planet," said Neely, a researcher at the Cooperative Institute for Research in Environmental Sciences, a joint venture of CU-Boulder and the National Oceanic and Atmospheric Administration.

A paper on the subject was published online in Geophysical Research Letters, a publication of the American Geophysical Union. Co-authors include Professors Brian Toon and Jeffrey Thayer from CU-Boulder; Susan Solomon, a former NOAA scientist now at the Massachusetts Institute of Technology; Jean Paul Vernier from NASA's Langley Research Center in Hampton, Va.; Catherine Alvarez, Karen Rosenlof and John Daniel from NOAA; and Jason English, Michael Mills and Charles Bardeen from the National Center for Atmospheric Research in Builder.

The new project was undertaken in part to resolve conflicting results of two recent studies on the origins of the sulfur dioxide in the stratosphere, including a 2009 study led by the late David Hoffman of NOAA indicating aerosol increases in the stratosphere may have come from rising emissions of sulfur dioxide from India and China. In contrast, a 2011 study led by Vernier -- who also provided essential observation data for the new GRL study -- showed moderate volcanic eruptions play a role in increasing particulates in the stratosphere, Neely said.

The new GRL study also builds on a 2011 study led by Solomon showing stratospheric aerosols offset about a quarter of the greenhouse effect warming on Earth during the past decade, said Neely, also a postdoctoral fellow in NCAR's Advanced Study Program.

The new study relies on long-term measurements of changes in the stratospheric aerosol layer's "optical depth," which is a measure of transparency, said Neely. Since 2000, the optical depth in the stratospheric aerosol layer has increased by about 4 to 7 percent, meaning it is slightly more opaque now than in previous years.

"The biggest implication here is that scientists need to pay more attention to small and moderate volcanic eruptions when trying to understand changes in Earth's climate," said Toon of CU-Boulder's Department of Atmospheric and Oceanic Sciences. "But overall these eruptions are not going to counter the greenhouse effect. Emissions of volcanic gases go up and down, helping to cool or heat the planet, while greenhouse gas emissions from human activity just continue to go up."

The research for the new study was funded in part through a NOAA/ ESRL-CIRES Graduate Fellowship to Neely. The National Science Foundation and NASA also provided funding for the research project. The Janus supercomputer is supported by NSF and CU-Boulder and is a joint effort of CU-Boulder, CU Denver and NCAR.

Source Story:Science Daily

M.Wassouf

Effects of Human Exposure to Hormone-Disrupting Chemicals Examined in Landmark United Nations Report

Many synthetic chemicals, untested for their disrupting effects on the hormone system, could have significant health implications according to the State of the Science of Endocrine Disrupting Chemicals, a new report by the United Nations Environment Programme (UNEP) and WHO.

The joint study calls for more research to understand fully the associations between endocrine disrupting chemicals (EDCs) -- found in many household and industrial products -- and specific diseases and disorders. The report notes that with more comprehensive assessments and better testing methods, potential disease risks could be reduced, with substantial savings to public health.

Human health depends on a well-functioning endocrine system to regulate the release of certain hormones that are essential for functions such as metabolism, growth and development, sleep and mood. Some substances known as endocrine disruptors can alter the function(s) of this hormonal system increasing the risk of adverse health effects. Some EDCs occur naturally, while synthetic varieties can be found in pesticides, electronics, personal care products and cosmetics. They can also be found as additives or contaminants in food.

The UN study, which is the most comprehensive report on EDCs to date, highlights some associations between exposure to EDCs and health problems including the potential for such chemicals to contribute to the development of non-descended testes in young males, breast cancer in women, prostate cancer in men, developmental effects on the nervous system in children, attention deficit /hyperactivity in children and thyroid cancer.

EDCs can enter the environment mainly through industrial and urban discharges, agricultural run-off and the burning and release of waste. Human exposure can occur via the ingestion of food, dust and water, inhalation of gases and particles in the air, and skin contact.

"Chemical products are increasingly part of modern life and support many national economies, but the unsound management of chemicals challenges the achievement of key development goals, and sustainable development for all," said UN Under Secretary-General and UNEP Executive Director Achim Steiner.

"Investing in new testing methods and research can enhance understanding of the costs of exposure to EDCs, and assist in reducing risks, maximizing benefits and spotlighting more intelligent options and alternatives that reflect a transition to a green economy," added Mr Steiner.

 

 

In addition to chemical exposure, other environmental and non-genetic factors such as age and nutrition could be among the reasons for any observed increases in disease and disorders. But pinpointing exact causes and effects is extremely difficult due to wide gaps in knowledge.

"We urgently need more research to obtain a fuller picture of the health and environment impacts of endocrine disruptors," said Dr Maria Neira, WHO's Director for Public Health and Environment. "The latest science shows that communities across the globe are being exposed to EDCs, and their associated risks. WHO will work with partners to establish research priorities to investigate links to EDCs and human health impacts in order to mitigate the risks. We all have a responsibility to protect future generations."

The report also raises similar concerns on the impact of EDCs on wildlife. In Alaska in the United States, exposure to such chemicals may contribute to reproductive defects, infertility and antler malformation in some deer populations. Population declines in species of otters and sea lions may also be partially due to their exposure to diverse mixtures of PCBs, the insecticide DDT, other persistent organic pollutants, and metals such as mercury. Meanwhile, bans and restrictions on the use of EDCs have been associated with the recovery of wildlife populations and a reduction in health problems.

Recommendations

The study makes a number of recommendations to improve global knowledge of these chemicals, reduce potential disease risks, and cut related costs. These include:

    Testing: known EDCs are only the 'tip of the iceberg' and more comprehensive testing methods are required to identify other possible endocrine disruptors, their sources, and routes of exposure.

    Research: more scientific evidence is needed to identify the effects of mixtures of EDCs on humans and wildlife (mainly from industrial by-products) to which humans and wildlife are increasingly exposed.

    Reporting: many sources of EDCs are not known because of insufficient reporting and information on chemicals in products, materials and goods.

    Collaboration: more data sharing between scientists and between countries can fill gaps in data, primarily in developing countries and emerging economies.

"Research has made great strides in the last ten years showing endocrine disruption to be far more extensive and complicated than realized a decade ago," said Professor Åke Bergman of Stockholm University and Chief Editor of the report. "As science continues to advance, it is time for both management of endocrine disrupting chemicals and further research on exposure and effects of these chemicals in wildlife and humans."

Source story: Science Daily

M.Wassouf

Environment Ministry, GORS to Enhance Cooperation

State Ministry for Environment Affairs and the General Organization of Remote Sensing (GORS) have agreed to enhance cooperation. In a recent meeting, both sides discussed the activities and projects being carried out jointly in accordance with the understanding memorandum signed between the two sides.

Minister of State for Environment Affairs Dr. Nazira Sarkis stressed the importance of technical and scientific cooperation and coordination between the ministry and the GORS to serve environmental issues and urged concerned parties to eliminate all obstacles hampering the implementation of joint projects. 

The Minister, who called for using digital maps and space images techniques to boost environment work, reiterated the ministry's readiness to put its potentials and expertise at the service of all plans aiming to carry out more joint projects, pointing out that the ministry has been keen to bolster cooperation and exchange expertise with other ministries and all environment-concerned bodies through signing understanding memos aiming to preserve environment.

The minister said these memos provide for implementing joint activities and adopting suitable procedures to enhance the situation of environment and achieve best investment of human and natural potentials within the framework of the scientific environmental work and sustainable development.

For his part, Director General of the GORS, Dr. Osama Ammar underscored the real partnership between the GORS and the ministry, embodied in exchanging expertise and discussing new ideas to improve the environmental situation.

During the meeting, the two sides followed up the implementation of joint projects and the discussed ways of overcoming the difficulties facing the implementation of some projects being carried out in Al-Sweida province and Al-Ghab plain area.

He underlined the importance of benefitting from the available national expertise in serving the environmental process and working out scientific studies that cope with world technical and scientific research development.

Rawaa Ghanam

Asteroid will come closer than satellites – but it's not the end of the world

Lump of rock 50 metres long will soar through sky at about 8 miles a second

Anyone happening to glance towards the heavens in a week's time and glimpses a 50-metre-long lump of rock hurtling ominously through the skies need not panic.

Although it will pass closer to us than any asteroid has for the past 15 years – closer even than the TV satellites that girdle the planet – NASA insists that 2012 DA14 will miss Earth by a good 17,100 miles (27,520km).

"No Earth impact is possible," said Donald Yeomans, an astronomer with the US space agency.

He also pointed out that the planet was bombarded by about 100 tonnes of space material every day.

"Basketball-sized objects come in daily," he said. "Volkswagen-sized objects come in every couple of weeks. As you get to larger and larger sizes the number of objects out there is less and less, so the frequency of hits goes down."

Yeomans added that asteroids as big as DA14, which is abou t 46 metres wide, are estimated to strike Earth about every 1,200 years.

"For objects of this size, this is the closest predicted encounter that we're aware of," he said.

The asteroid's closest approach will be at 7.24pm on 15 February, meaning that those gazing keenly at the dark skies of eastern Europe, Asia and Australia will stand the best chance of seeing it through telescopes or binoculars.

DA14, which was discovered last year by a group of amateur astronomers in Spain, will soar through the sky at about 8 miles a second. At that speed, an object of similar size on a collision course with Earth would strike with the force of about 2.4m tonnes of dynamite.

The last time that happened was in 1908 when an asteroid or comet exploded over Siberia, levelling 80m trees over 830sq miles.

"Although they wouldn't cause a global catastrophe if they impact the Earth, they still do a lot of regional destruction," said Lindley Johnson, who oversees the Near-Earth Object Observations Programme at Nasa headquarters in Washington DC.

NASA  finds and tracks all near-Earth objects that are 1km or larger in diameter. Their efforts are intended to give scientists and engineers as early a warning as possible so that steps can be taken to avert the kind of catastrophe that did for the dinosaurs.

About 66m years ago, a six-mile-wide object smashed into the Yucatán peninsula in Mexico, leading to the demise of not just the giant lizards, but also most of the plant and animal life on Earth.

Source: the Guardian

B.N

Ozone Thinning Has Changed Ocean Circulation

 

 

 

A hole in the Antarctic ozone layer has changed the way that waters in the southern oceans mix, a situation that has the potential to alter the amount of CO2 in the atmosphere and eventually could have an impact on global climate change, a Johns Hopkins earth scientist says.

In a paper published in this week's issue of the journal Science, Darryn W. Waugh and his team show that subtropical intermediate waters in the southern oceans have become "younger" as the upwelling, circumpolar waters have gotten "older" -- changes that are consistent with the fact that surface winds have strengthened as the ozone layer has thinned,according to Science Daily.

"This may sound entirely academic, but believe me, it's not," said Waugh, of the Morton K. Blaustein Department of Earth and Planetary Sciences at Johns Hopkins' Krieger School of Arts and Sciences. "This matters because the southern oceans play an important role in the uptake of heat and carbon dioxide, so any changes in southern ocean circulation have the potential to change the global climate."

Waugh's team used measurements taken from the early 1990s to the mid-to-late 2000s of the amount of a chemical compound known as "chlorofluorocarbon-12," or CFC-12, in the southern oceans. CFC-12 was first produced commercially in the 1930s and its concentration in the atmosphere increased rapidly until the 1990s when it was phased out by the Montreal Protocol on substances that deplete the ozone layer. (Prior to the Montreal Protocol, CFC-12 was used in products such as aerosol hairsprays and refrigerants and in air conditioning systems.

From those ocean measurements, Waugh's team was able to infer changes in how rapidly surface waters have mixed into the depths of the southern oceans. Because they knew that concentrations of CFCs at the ocean surface increased in tandem with those in the atmosphere, they were able to surmise that the higher the concentration of CFC-12 deeper in the ocean, the more recently those waters were at the surface.

The inferred age changes -- "younger" in the subtropics, "older" nearer the South Pole -- are consistent with the observed intensification of surface westerly winds, which have occurred primarily because of the Antarctic ozone hole, suggesting that stratospheric ozone depletion is the primary cause of the changes in ocean ventilation. As stratospheric ozone recovers over the next 50 years, the changes in ventilation may slow or reverse. The impact of continued increases in greenhouse gases in the atmosphere will also need to be considered, however. The combined impact of the two factors on the southern oceans' ventilation and uptake of heat and carbon is an open question.

R.S