Pollution In This World

Air pollution linked to diabetes and hypertension in African-American women

noreply@blogger.com (maidul) — Fri, 06 Jan 2012 12:48:00 +0000

The incidence of type 2 diabetes and hypertension increases with cumulative levels of exposure to nitrogen oxides, according to a new study led by researchers from the Slone Epidemiology Center (SEC) at Boston University. The study, which appears online in the journal Circulation, was led by Patricia Coogan, D.Sc., associate professor of epidemiology at the Boston University School of Public Health and the SEC.
While it is well established that air pollution increases the risks of acute cardiovascular events such as stroke and myocardial infarction, it is not known whether exposure increases the risk of chronic diseases like diabetes and hypertension. However, emerging findings from laboratory and clinical studies suggest that air pollution may predispose to both conditions.

Researchers assessed the risks of incident hypertension and diabetes associated with exposure to nitrogen oxides (NOx) and particulate matter (PM2.5) in a cohort of approximately 4,000 African American women living in Los Angeles. NOx are indicators of traffic-related air pollution. From 1995-2005, 531 incident cases of hypertension and 183 incident cases of diabetes occurred among the participants in the Los Angeles area. The risk of diabetes increased by a significant 24 percent, and the risk of hypertension by 11 percent, for each 12 ppb increase in exposure to NOx. There also were suggestive increases in risks of both diseases associated with exposure to (PM2.5), but the evidence for this was weaker than for NOx.
According to the researchers, two previous follow-up studies have suggested that traffic-related pollution increased the incidence of diabetes, but no African Americans were included. "A link between air pollution and the risks of diabetes and hypertension is of particular importance to African American women, because the incidence of both conditions is almost twice as high in African American women as in white women and African Americans live in more highly polluted areas than white Americans," said Patricia Coogan, D.Sc., the study's lead author. "In addition, even a modest effect of air pollutants on the risks of hypertension and diabetes will have significant public health impact due to the high incidence of these conditions and the ubiquity of exposure to air pollution," she added.

Benefits of new air quality rules greatly outweigh costs

noreply@blogger.com (maidul) — Mon, 26 Dec 2011 08:35:00 +0000

A report by researchers at Columbia University's Mailman School of Public Health provides an expanded review of six new air quality regulations proposed or recently adopted by the U.S. Environmental Protection Agency's (EPA). These include the first national standards for reducing dangerous emissions of mercury and other toxic pollutants from power plants. Though the cost of implementing the new regulations is estimated to be about $195 billion over the next 20 years or so, the economic, environmental and health benefits amount to well over $1 trillion, considerably outweighing the control costs, according to the report, which was issued by the Joint Center for Political and Economic Studies, a non-profit think tank based in Washington, D.C.
Patrick L. Kinney, ScD, professor of Environmental Health Sciences and director of Columbia University's Mailman School of Public Health's Program on Climate and Health, and MPH candidate Amruta Nori-Sarma also examined the role that environmental justice issues play in the development of EPA regulations. The researchers further analyzed the findings in light of a recent poll conducted by the Joint Center on climate change, health and conservation behaviors.

Building on the data from EPA, the report finds that six new air quality regulations would offer benefits and savings in doctors' visits, hospitalizations, and a reduction in cases of bronchitis, respiratory illness, and aggravated asthma particularly for African American populations and residents in vulnerable communities. The rules analyzed include the Heavy-duty Vehicles Greenhouse Gas (GHG) Emissions Standards, the 2017-2025 Model Year Light-Duty Vehicle GHG Emissions and Café Standards, the Utility Air Toxics Rule, the Cross-State Air Pollution Rule, the Boiler MACT, and the standards of Performance for Petroleum Refineries
The paper highlights the importance of the two motor vehicle rules, since urban air pollution tends to be dominated by motor vehicle emissions. The most beneficial of these rules is the light-duty vehicle rule, which will cost an estimated $140 billion but bring about $561 billion in benefits that include billions of barrels of oil saved, reduced emissions, and the health benefits related to non-greenhouse gas pollutants over the lifetime of vehicles sold between 2017 and 2025. According to the analysis, these will yield net societal benefits of $421 billion.
The findings also show that Cross-State Air Pollution Rule will provide significant health and environmental benefits to low income, minority, and tribal individuals in both rural areas and inner cities in the regions affected by the rule.
The poll, which surveyed 1500 African American adults in Atlanta, Cleveland and Philadelphia, asked respondents about issues related to air quality, climate change and the need for new regulations.
Among the poll's key findings:

A solid majority (59%) of African Americans polled in the three cities believe that global warming is causing serious problems
84% of respondents want the federal government to take strong action to deal with global warming
80% support EPA's Toxics Rule
40% described the air quality where they lived as excellent or good, while 59% said the air quality where they lived was fair or poor
83% believe that environmental factors such as air pollution play a major role in causing asthma in children

The authors believe that the close correspondence between public opinion and analytical findings pointing to the health and economic benefits of further air quality improvements should provide a strong mandate for action by the federal government.

Saving millions of lives and protecting our climate through clean cooking options

noreply@blogger.com (maidul) — Tue, 29 Nov 2011 12:21:00 +0000

For many people in the developing world getting enough food to eat is a persistent challenge. However the challenge does not stop there. A new issue of the international journal Energy Policy details the human and environmental cost of cooking food using the only energy source available to many people, woody biomass.
The Special Issue explores the type of decision frameworks that are needed to guide policy development for clean cooking fuels and to ensure that the provision of clean energy becomes a central component of sustainable development. Additionally, it presents a research agenda and an action agenda to facilitate the development and adoption of cleaner cooking fuels and technologies and analyses why past programs to improve access to clean cooking fuels have succeeded or failed.
Universal access to clean energy is a stated goal of the United Nations and is a key entry point for reducing emissions of black carbon and other particulates - known to negatively impact the climate. The scale of the issue and opportunity to minimise emissions through adoption of clean cooking fuels and stoves was highlighted in a new report from the UN Environment Program released on Friday 25th November and will be a focus of discussions at the UNFCCC climate talks commencing in Durban today.

While the use of biomass for cooking is in itself not a cause for concern, it is the unsustainable harvesting and dirty and inefficient burning of the wood that inhibits social and economic development, harms the environment, and takes a significant toll on human health. Latest estimates from the International Institute for Applied Systems Analysis (IIASA) indicate that in 2005, over 2 million people, mostly woman and children, died prematurely due to household air pollution – soot and other particles that are emitted when biomass is burned indoors in poorly ventilated environments.
“The collection and burning of woody biomass to cook food has consequences on many levels,” says co editor of the Special Issue and a lead author Shonali Pachauri from IIASA. “It traps women [in particular] in poverty as they must devote much of their time to wood collection. It affects the environment and climate due to deforestation and the emission of black carbon and greenhouse gases that result from burning, and tragically it is costing the lives of many woman and children in the developing world, predominantly in India, sub-Saharan African nations and China.”
The articles presented in the Special Issue consider the options for transitioning the nearly 2.7 billion people globally who are reliant on traditional biomass fuels to cleaner cooking fuels, such as LPG, biogas, ethanol and biodiesel, as well as electricity. “Much of the emphasis to date has been on increasing access to electricity, which while important may be too slow a path and may not address cooking energy needs (electricity is rarely used for cooking in many developing countries). Providing improved cooking stoves to households will have an immediate positive impact on people and the environment.
The issue presents new research findings on many issues associated with resolving the challenge of improving access to clean fuels and cookstoves including; how to measure and monitor energy poverty; an evaluation of the health and climate benefits of cookstove replacement options; how to improve the likelihood of adoption and sustained use of cleaner cooking stoves and fuels, and a cost - benefit analysis of reducing indoor air pollution. The research draws strongly on case studies conducted in India, Nepal, Kenya, Sudan, Indonesia and Mexico.
The issue also refers to several significant and recent initiatives established to raise awareness and improve access to clean cooking options and explains why they may or may not succeed. One example is the Global Alliance for Clean Cookstoves, an international program established in 2010 with a goal of equipping 100 million homes with clean cooking stoves and fuel by 2020. The program is based on the idea that carbon credits will encourage the adoption of clean cooking stoves. However, experience to date suggests that only international players with good contacts to international institutions will be able to access this money. This raises questions about how likely the program is to be adopted and persist at the community level, but also raises the more important issue of how business and the policy communities must work with communities to facilitate change. The articles included in this Special Issue reflect discussions that were held at an Istanbul Workshop in 2008 as part of the annual conference of the International Association for Energy Economics. Participants included the public and private sector as well as NGOs and donor organizations representing Asia, Africa and OECD countries. The Workshop brought energy economists and policy makers together to better understand the knowledge deficit when it comes to overcoming energy poverty and the enormous opportunities for the business, research and international development communities to work together to overcome this pervasive and harmful issue.
Universal access to clean energy remains a key goal of organizations like the United Nations and is a significant impediment to attainment of the UN Millennium Development Goals. It is also key to achieving other global objectives with regards to climate change mitigation and ecosystem management. The research presented in this issue helps to inform how to achieve access for all.
Reference: Energy Policy Vol 39 (2011) Household cooking fuels and technologies in developing countries. Shonali Pachauri, Hisham Zerriffi, Wesley Foell, Daniel Spreng (Editors).

Climate change will show which animals can take the heat

noreply@blogger.com (maidul) — Sat, 01 Oct 2011 08:04:00 +0000

As climate change continues to take hold this century, which species will be able to take the heat? Researchers at Brown University, in simulations examining species and their projected range, show that animals' ability to withstand fluctuations in temperature during their climate-induced journeys will be a crucial determinant of their ultimate survival.
In a new study based on simulations examining species and their projected range, researchers at Brown University argue that whether an animal can make it to a final, climate-friendly destination isn't a simple matter of being able to travel a long way. It’s the extent to which the creatures can withstand rapid fluctuations in climate along the way that will determine whether they complete the journey.

In a paper in Ecology Letters, Regan Early and Dov Sax examined the projected “climate paths” of 15 amphibians in the western United States to the year 2100. Using well-known climate forecasting models to extrapolate decades-long changes for specific locations, the researchers determined that more than half of the species would become extinct or endangered. The reason, they find, is that the climate undergoes swings in temperature that can trap species at different points in their travels. It’s the severity or duration of those climate swings, coupled with the given creature’s persistence, that determines their fate.
“Our work shows that it’s not just how fast you disperse, but also your ability to tolerate unfavorable climate for decadal periods that will limit the ability of many species to shift their ranges,” said Sax, assistant professor of biology in the Department of Ecology and Evolutionary Biology. “As a consequence, many species that aren’t currently of conservation concern are likely to become endangered by the end of the century.”
The researchers chose to study frogs, salamanders, and toads because their living areas are known and their susceptibility to temperature changes has been well studied. Based on that information, they modeled the migratory paths for each creature, estimating their travels to be about 15 miles per decade. The climate models showed fluctuations in temperatures in different decades severe enough that four creatures would become extinct, while four other species would become endangered at the least. The other seven would “fare OK,” Early said, “but they all lose out a lot.”
The temperature swings can cause a species to be stopped in its tracks, which means that it has to do double time when the climate becomes more favorable. “Instead of getting warmer, it can get cooler,” said Early, the paper’s lead author, of the climate forecasts. “That means that species can take two steps forward, but may be forced to take one step backward, because the climate may become unsuitable for them. Unfortunately, if they take a step back, they have to make up all of that ground. That’s what causes the gaps in the climate path.”
The study is unique also in that it considers at species’ ability to weather adverse intervals. Early and Sax said unfavorable climate lasting a decade would put the species in a bind. If the interval lasted two decades or more, it was likely the species would become extinct. “We’ve identified one critical piece of information that no one’s really thought about, and that is what’s the ability of species to persist under non-optimal conditions,” Sax said. "If you move to those conditions, can it hang on for a while? The answer will vary for different species.”
Rapid changes to climate already being witnessed underscores the study’s value. A growing number of scientists believe climate change is intensifying so quickly that the planet is hurtling toward a sixth mass extinction in history — and the first widespread perishing of creatures since the dinosaurs’ reign ended some 65 million years ago. For the first time, species are grappling not just with projected temperatures not seen for the last 2 million years but also with a human-shaped landscape that has compromised and fragmented animals’ natural habitats.
Confronted with these realities, Early and Sax say wildlife managers may need to entertain the idea of relocating species, an approach that is being hotly debated in conservation circles. “This study suggests that there are a lot of species that won’t be able to take care of themselves,” Sax said. “Ultimately, this work suggests that habitat corridors will be ineffective for many species and that we may instead need to consider using managed relocation more frequently than has been previously considered.”
Brown University, the U.S. Forest Service and the Portuguese Foundation of Science and Technology funded the research.

Steep increase in global CO2 emissions despite reductions by industrialized countries

noreply@blogger.com (maidul) — Wed, 21 Sep 2011 18:19:00 +0000

Global emissions of carbon dioxide (CO2) – the main cause of global warming – increased by 45 % between 1990 and 2010, and reached an all-time high of 33 billion tonnes in 2010. Increased energy efficiency, nuclear energy and the growing contribution of renewable energy are not compensating for the globally increasing demand for power and transport, which is strongest in developing countries.
This increase took place despite emission reductions in industrialised countries during the same period. Even though different countries show widely variable emission trends, industrialised countries are likely to meet the collective Kyoto target of a 5.2 % reduction of greenhouse gas emissions by 2012 as a group, partly thanks to large emission reductions from economies in transition in the early nineties and more recent reductions due to the 2008-2009 recession. These figures were published today in the report "Long-term trend in global CO2 emissions," prepared by the European Commission's Joint Research Centre and PBL Netherlands Environmental Assessment Agency.

The report, which is based on recent results from the Emissions Database for Global Atmospheric Research (EDGAR) and latest statistics for energy use and other activities, shows large national differences between industrialised countries. Over the period 1990-2010, in the EU-27 and Russia CO2 emissions decreased by 7% and 28% respectively, while the USA's emissions increased by 5% and the Japanese emissions remained more or less constant. The industrialised countries that have ratified the Kyoto Protocol (so called 'ratifying Annex 1 countries') and the USA, in 1990 caused about two-thirds of global CO2 emissions. Their share of global emissions has now fallen to less than half the global total.
Continued growth in the developing countries and emerging economies and economic recovery by the industrialised countries are the main reasons for a record breaking 5.8% increase in global CO2 emissions between 2009 and 2010. Most major economies contributed to this increase, led by China, USA, India and EU-27 with increases of 10%, 4%, 9% and 3% respectively. The increase is significant even when compared to 2008, when global CO2 emissions were at their highest before the global financial crisis. It can be noted that in EU-27, CO2 emissions remain lower in absolute terms than they were before the crisis (4.0 billion tonnes in 2010 as compared to 4.2 billion tonnes in 2007).
At present, the USA emits 16.9 tonnes CO2 per capita per year, over twice as much as the EU-27 with 8.1 tonnes. By comparison, Chinese per capita CO2 emissions of 6.8 tonnes are still below the EU-27 average, but now equal those of Italy. It should be noted that the average figures for China and EU-27 hide significant regional differences.
Long term global growth in CO2 emissions continues to be driven by power generation and road transport, both in industrial and developing countries. Globally, they account for about 40% and 15% respectively of the current total and both have consistent long-term annual growth rates of between 2.5% and 5%.
Throughout the Kyoto Protocol period, industrialised countries have made efforts to change their energy sources mix. Between 1990 and 2010 they reduced their dependence on coal (from 25% to 20% of total energy production) and oil (from 38% to 36.5%), and shifted towards natural gas (which increased from 23% to 27 %), nuclear energy (from 8% to 9%) and renewable energy (from 6.5% to 8%). In addition they made progress in energy savings, for example by insulation of buildings, more energy-efficient end-use devices and higher fuel efficiencies.
The report shows that the current efforts to change the mix of energy sources cannot yet compensate for the ever increasing global demand for power and transport. This needs to be considered in future years in all efforts to mitigate the growth of global greenhouse gas emissions, as desired by the UN Framework Convention on Climate Change, the Bali Action Plan and the Cancún agreements.
Source : European Commission Joint Research Centre

Deep oceans may mask global warming

noreply@blogger.com (maidul) — Tue, 20 Sep 2011 15:07:00 +0000

Earth's deep oceans may absorb enough heat at times to flatten the rate of global warming for periods of as long as a decade--even in the midst of longer-term warming. This according to a new analysis led by scientists at the National Center for Atmospheric Research (NCAR).
The study, based on computer simulations of global climate, points to ocean layers deeper than 1,000 feet as the main location of the "missing heat" during periods such as the past decade when global air temperatures showed little trend.
The findings also suggest that several more intervals like this can be expected over the next century, even as the trend toward overall warming continues.
"We will see global warming go through hiatus periods in the future," says NCAR's Gerald Meehl, lead author of the study.

"However, these periods would likely last only about a decade or so, and warming would then resume. This study illustrates one reason why global temperatures do not simply rise in a straight line."
The research, by scientists at NCAR and the Bureau of Meteorology in Australia, was published online Sunday in Nature Climate Change.
Funding for the study came from the National Science Foundation (NSF), NCAR's sponsor.
"The research shows that the natural variability of the climate system can produce periods of a decade or more in which Earth's temperature does not rise, despite an increase in greenhouse gas concentrations," says Eric DeWeaver, program director in NSF's Division of Atmospheric and Geospace Sciences.
"These scientists make a compelling case that the excess energy entering the climate system due to greenhouse gas increases may not be immediately realized as warmer surface temperatures, as it can go into the deep ocean instead."
The 2000s were Earth's warmest decade in more than a century of weather records.
However, the single-year mark for warmest global temperature, which had been set in 1998, remained unmatched until 2010.
Yet emissions of greenhouse gases continued to climb during this period, and satellite measurements showed that the discrepancy between incoming sunshine and outgoing radiation from Earth actually increased.
This implied that heat was building up somewhere on Earth, according to a 2010 study by NCAR researchers Kevin Trenberth and John Fasullo.
The two scientists, who are both co-authors on the new study, suggested that the oceans might be storing some of the heat that would otherwise go toward other processes, such as warming the atmosphere or land, or melting more ice and snow.
Observations from a global network of buoys showed some warming in the upper ocean, but not enough to account for the global build-up of heat.
Although scientists suspected the deep oceans were playing a role, few measurements were available to confirm that hypothesis.
To track where the heat was going, Meehl and colleagues used a powerful software tool known as the Community Climate System Model, which was developed by scientists at NCAR and the Department of Energy with colleagues at other organizations.
Using the model's ability to portray complex interactions between the atmosphere, land, oceans and sea ice, they performed five simulations of global temperatures.
The simulations, which were based on projections of future greenhouse gas emissions from human activities, indicated that temperatures would rise by several degrees during this century.
But each simulation also showed periods in which temperatures would stabilize for about a decade before climbing again.
For example, one simulation showed the global average rising by about 2.5 degrees Fahrenheit (1.4 degrees Celsius) between 2000 and 2100, but with two decade-long hiatus periods during the century.
During these hiatus periods, simulations showed that extra energy entered the oceans, with deeper layers absorbing a disproportionate amount of heat due to changes in oceanic circulation.
The vast area of ocean below about 1,000 feet (300 meters) warmed by 18 percent to 19 percent more during hiatus periods than at other times.
In contrast, the shallower global ocean above 1,000 feet warmed by 60 percent less than during non-hiatus periods in the simulation.
"This study suggests the missing energy has indeed been buried in the ocean," Trenberth says. "The heat has not disappeared and so it cannot be ignored. It must have consequences."
The simulations also indicated that the oceanic warming during hiatus periods has a regional signature.
During a hiatus, average sea-surface temperatures decrease across the tropical Pacific, while they tend to increase at higher latitudes, especially in the Atlantic, where surface waters converge to push heat into deeper oceanic layers.
These patterns are similar to those observed during a La Niña event, according to Meehl.
He adds that El Niño and La Niña events can be overlaid on top of a hiatus-related pattern.
Global temperatures tend to drop slightly during La Niña, as cooler waters reach the surface of the tropical Pacific, and they rise slightly during El Niño, when those waters are warmer.
"The main hiatus in observed warming has corresponded with La Niña conditions, which is consistent with the simulations," Trenberth says.
Source: National Science Foundation

NASA's Aqua satellite sees tropical storms Nate, Lee, fires

noreply@blogger.com (maidul) — Sun, 11 Sep 2011 11:38:00 +0000

Tropical Storm Nate is perched to make landfall in Mexico this weekend, and warnings are in effect. Nate is one of three major weather events around the Gulf of Mexico today, and NASA's Aqua satellite captured all three in one image.
Raging wildfires are occurring in Texas while the remnant clouds from Tropical Storm Lee in the northern Gulf of Mexico were also seen by Aqua.One satellite image taken by the Atmospheric Infrared Sounder instrument that flies aboard NASA's Aqua satellite captured the two tropical systems and smoke from the Texas fires on Sept. 8 at 19:05 UTC (3:05 p.m. EDT). The image shows Tropical Storm Nate was still lingering along the eastern Mexico coastline, the western edge of the remnants of Tropical Storm Lee (around a low pressure area centered over Indiana) appeared in the northern Gulf and smoke plumes from Texas wildfires.

The largest plume appeared light brown in color and was from the Bear Creek fire.
Current forecasts from the National Hurricane Center take Nate on a westward track and away from Texas that would benefit from the rains to combat the wildfires.
A Tropical storm warning is in effect from Chilitepec to Celestun and a Hurricane Watch is in effect from Tampico to Veracruz. A Tropical Storm Watch is in effect from Celestun to Progreso, from Veracruz to Punta El Lagarto, and from Tampico to La Cruz, Mexico.
On Friday, Sept. 9 at 11 a.m. EDT, Tropical Storm Nate was still not moving much in the Bay of Campeche. Nate was crawling to the northwest near 2 mph (4kmh). Nate was centered about 140 miles (225 km) west-northwest of Campeche, Mexico near 20.3 North and 92.6 West. Because tropical-storm-force winds extend 105 miles (165 km) from the center, Campeche is not yet experiencing them. Nate's maximum sustained winds had climbed to 65 mph (100 kmh) and the National Hurricane Center (NHC) expects Nate to reach hurricane status later today or Saturday, Sept. 10. Nate is a compact storm, over 210 miles in diameter.
Tropical Storm conditions are expected in the warning areas today and rainfall from 4 to 6 inches with isolated amounts up to 12 inches are possible over the Mexican states of Campeche and Tabasco, and over southern Veracruz today. Storm surge levels are expected to raise the water levels by 1 to 3 feet along the coast in the warning area.The NHC is forecasting Nate to become a hurricane and continue moving to the northwest, then turn west and make landfall in Mexico this weekend.

Source: http://www.nasa.gov/goddard

Study finds local temperature influences belief in global warming

noreply@blogger.com (maidul) — Sun, 29 May 2011 03:39:00 +0000

A study by Columbia Business School Professor Eric Johnson, co-director of the Center for Decision Sciences (http://www4.gsb.columbia.edu/decisionsciences) at Columbia Business School, Ye Li, a postdoctoral researcher at the Center for Decision Sciences, and Lisa Zaval, a Columbia graduate student in psychology, found that those who thought the current day was warmer than usual were more likely to believe in and feel concern about global warming than those who thought the day was unusually cold. The study, recently featured in Psychological Science, explains why public belief in global warming can fluctuate, since people can base their thinking off of the day's temperature. The researchers behind this study are also affiliated with Columbia University's Center for Research on Environmental Decisions, CRED (http://www.cred.columbia.edu/).

The team surveyed about 1,200 people in the United States and Australia in three different studies in order to determine their opinions about global warming and whether the temperature on the day of the study was warmer or cooler than usual. Respondents who thought that day was warmer than usual were more concerned about global warming than respondents who thought that day was colder than usual.
"Global warming is so complex, it appears some people are ready to be persuaded by whether their own day is warmer or cooler than usual, rather than think about whether the entire world is becoming warmer or cooler," said lead author Ye Li. "It is striking that society has spent so much money, time and effort educating people about this issue, yet people are still so easily influenced."
The study also revealed that respondents were fairly good at knowing if it was unusually hot or cold--perceptions correlated with reality three quarters of the time. While politics, gender and age all had the predicted influences – for instance, on the researchers' 1-to-4 scale of belief in global warming, Democrats were 1.5 points higher than Republicans – after controlling for the other factors, the researchers found that perceived temperatures still had nearly two-thirds the power as political belief, and six times the power as gender.
These results join a growing body of work that shows how irrelevant environmental information, such as the current weather, can affect judgments and opinions on climate change.

Chemical found in crude oil linked to congenital heart disease

noreply@blogger.com (maidul) — Sun, 01 May 2011 15:44:00 +0000

While it may be years before the health effects of the 2010 oil spill in the Gulf of Mexico are known, a new study shows that fetal exposure to a chemical found in crude oil is associated with an increased risk of congenital heart disease (CHD).
The study, to be presented Saturday, April 30, at the Pediatric Academic Societies (PAS) annual meeting in Denver, also showed that babies who had been exposed in utero to a chemical found in cleaning agents and spot removers were at increased risk of CHD.
Environmental causes of CHD have been suspected, and animal studies have suggested certain chemicals may cause CHD, a problem with the heart's structure and function due to abnormal heart development before birth.
"Congenital heart disease is a major cause of childhood death and life-long health problems," said D. Gail McCarver, MD, FAAP, lead author of the study and professor of pediatrics at the Medical College of Wisconsin and Children's Research Institute, Milwaukee. "Thus, identifying risk factors contributing to CHD is important to public health."

Dr. McCarver and her colleagues sought to determine whether human fetal exposure to solvents is associated with increased risk for CHD. The researchers tested samples of meconium, or fetal stool, from 135 newborns with CHD and 432 newborns without CHD. Meconium has been used to assess fetal exposure to illicit drugs such as cocaine. Seventeen compounds were measured in meconium samples using methods that detect very low levels of chemicals.
Additional data collected included race of the mothers and infants, family history for CHD, and maternal alcohol, tobacco, vitamin and drug use.
Infants with chromosomal abnormalities known to be linked to CHD, and babies of diabetic mothers were excluded from the study.
Results showed that 82 percent of infants had evidence of intrauterine exposure to one or more of the solvents measured.
Among white infants, but not black infants, fetal exposure to ethyl benzene was associated with a four-fold increased risk of CHD. In addition, exposure to trichloroethylene was associated with a two-fold increased risk for CHD among white infants and an eight-fold increased risk among black infants.
"This is the first report that exposure to ethyl benzene, a compound present in crude oil, was associated with CHD," Dr. McCarver said. Humans also can be exposed to ethyl benzene through inhalation of motor vehicle emissions, gasoline pump vapors and cigarette smoke.
"The association with ethyl benzene exposure is concerning, particularly considering recent oil spills," she said. "However, additional confirmatory studies are needed."
The study also adds to existing concerns about trichloroethylene (TCE). "This is of particular importance because TCE is a commonly used degreasing agent, which also is present in many cleaners and spot removers. TCE also has been the most common chemical identified around hazardous waste sites," Dr. McCarver said.
"Limiting known maternal exposure to this compound during early pregnancy appears prudent, particularly among those at increased CHD risk," Dr. McCarver concluded.
Source

Climate change from black carbon depends on altitude

noreply@blogger.com (maidul) — Sun, 17 Apr 2011 16:22:00 +0000

Palo Alto, CA—Scientists have known for decades that black carbon aerosols add to global warming. These airborne particles made of sooty carbon are believed to be among the largest man-made contributors to global warming because they absorb solar radiation and heat the atmosphere. New research from Carnegie's Long Cao and Ken Caldeira, along with colleagues George Ban-Weiss and Govindasamy Bala, quantifies how black carbon's impact on climate depends on its altitude in the atmosphere. Their work, published online by the journal Climate Dynamics, could have important implications for combating global climate change.
Black carbon is emitted from diesel engines and burning wood, among other sources. In the atmosphere, it acts as an absorbing aerosol—a particle that absorbs the sun's heating rays. (Other types of aerosols reflect the sunlight back out into space, providing a cooling effect.) The climate effect of black carbon is difficult to quantify because these particles heat the air around them, affecting clouds even before they begin to heat the land and ocean surface.

The team's research involved idealized simulations of adding a theoretical megatonne of black carbon uniformly around the globe at different altitudes in the atmosphere. They found that the addition of black carbon near the land and ocean surface caused the surface to heat. As the altitude of black carbon increased, surface warming decreased. The addition of black carbon to the stratosphere caused the land and oceans to cool. This cooling occurred despite the fact that the black carbon caused the Earth as a whole to absorb more energy from the sun. When black carbon is high in the atmosphere, it can lose its energy to space while helping to shade the land and ocean surface.
"Black carbon lower in the atmosphere is more effective at warming the surface, even though black carbon particles at higher altitudes absorb more solar radiation," said Ban-Weiss, formerly of Carnegie and currently at Lawrence Berkeley National Laboratory. He continued: "Just analyzing instantaneous changes in absorption of radiation from black carbon cannot accurately predict changes in surface temperatures. If we want a consistent framework for predicting changes in surface air temperature from black carbon we need to account for rapid atmospheric responses in things like clouds."
Black carbon also had varying effects on precipitation. In the lower layers it increased precipitation and in the upper layers it decreased precipitation, a result of changes in atmospheric stability.
"We showed that black carbon near Earth's surface has the greatest effect on global warming. Unfortunately, this is exactly where we are putting most of the black carbon that we add to the atmosphere," Caldeira said. "This black carbon also often causes health problems, so cleaning up these emissions would help both the environment and human health."
Major sources of black carbon emissions into the lower atmosphere include forest fires, cooking stoves, and emissions from trucks and automobiles. Aircraft are a notable source of emissions to the upper atmosphere.
"This study points out the importance of understanding the complexities of how human activities affect the globe. If we want humans to live well while protecting the environment, we need to understand how our activities affect climate," Caldeira said.
Source

Algae and bacteria hogged oxygen after ancient mass extinction, slowing recovery of marine life

noreply@blogger.com (maidul) — Sun, 27 Mar 2011 16:49:00 +0000

A mass extinction is hard enough for Earth's biosphere to handle, but when you chase it with prolonged oxygen deprivation, the biota ends up with a hangover that can last millions of years.
Such was the situation with the greatest mass extinction in Earth's history 250 million years ago, when 90 percent of all marine animal species were wiped out, along with a huge proportion of plant, animal and insect species on land.
A massive amount of volcanism in Siberia is widely credited with driving the disaster, but even after the immense outpourings of lava and toxic gases tapered off, oxygen levels in the oceans, which had been depleted, remained low for about 5 million years, slowing life's recovery there to an unusual degree.
The reason for the lingering low oxygen levels has puzzled scientists, but now Stanford researchers have figured out what probably happened. By analyzing the chemical composition of some then-underwater limestone beds deposited over the course of the recovery in what is now southern China, they have determined that while it took several million years for most ecosystems in the ocean to recover, tiny single-celled algae and bacteria bounced back much more quickly.

In fact, according to biogeochemist Katja Meyer, the tiny organisms rebounded to such an extent that the bigger life forms couldn't catch a break – much less their breath – because the little ones were enjoying a sustained population explosion.
As the vast hordes of tiny dead organisms rotted, dissolved oxygen in the seawater was consumed by aerobic microbes involved in the decay process, leaving scant oxygen for larger organisms in what became an oxygen-depleted, or anoxic, environment.
The driver of the ongoing population boom appears to have been the massive amounts of carbon dioxide pumped into the atmosphere during the volcanism, Meyer said, which caused the world to warm.
"More warmth means an invigorated hydrological cycle, so you get more rain and this rain is also more acidic because there is more carbon dioxide dissolved in the rain," Meyer said.
The increased amounts of more acidic rain increased weathering of the land surface, which sent more nutrients into the ocean, which fueled explosions of life such as algae blooms.
"It is kind of counterintuitive that high productivity on the part of algae and bacteria would likely be generating these toxic geochemical conditions that prevent most of animal life from recovering from mass extinction," Meyer said.
But the process, she said, is basically the same as when excess runoff from fertilizers goes into a body of water, whether it's a pond on a golf course or the infamous dead zone in the Gulf of Mexico created by farm runoff carried down the Mississippi River.
"You get this giant bloom of algae and then it starts to smell bad as that algae decays, pulling oxygen out of the water and causing fish die-offs," Meyer said.
In spite of the almost inestimably high numbers of algae and bacteria living and dying during this time, there is little direct evidence of them in the fossil record because such tiny, soft-bodied creatures just don't preserve well.
So Meyer and her colleagues had to work with indirect evidence of the microorganisms to determine their abundance during the years after the mass extinction. The population proxy they used was the carbon present in the limestone.
Carbon – like all elements – comes in different varieties, called isotopes, distinguished by the number of neutrons each has in its nucleus. The researchers worked with two carbon isotopes, carbon 12, which has six neutrons, and carbon 13, which has seven.
Both isotopes are present in ocean water, but living things on Earth have always shown a preference for incorporating the lighter isotope, carbon 12, into their structures. Thus, where life is abundant, the ratio of carbon 13 to carbon 12 in seawater is higher than it is where there is no life.
Limestone records the composition of the seawater in which it was deposited, including the relative amounts of light and heavy carbon isotopes, so by analyzing the isotope ratio in the rocks, Meyer could infer the abundance of life in the water where the limestone formed.
Comparable modern environments, such as the Bahama Banks in the Caribbean Sea, where carbonate platforms similar to the limestones are forming, are typically teeming with life at the range of depths in which Meyer's limestones formed. In these environments, the ratio of carbon 13 to carbon 12 is generally constant from shallow to deep water.
But microorganisms are typically most abundant in shallow waters, so if marine life in the era after the mass extinction had been confined to algae and bacteria, then the shallower depths should show a markedly greater ratio of carbon 13 to carbon 12 than would be found at depth.
Meyer's analysis showed there was a difference of about 4 parts per thousand in carbon isotope ratios from the shallow waters to depths, roughly twice what it is today.
"We only see this gradient in the interval after the mass extinction prior to the recovery of animal life," said Meyer.
Meyer is the lead author of a research paper about the study published last month in Earth and Planetary Science Letters. The extinction 250 million years ago is known as the Permian-Triassic mass extinction, as it coincides with the end of the Permian period and the beginning of the Triassic period on the geologic time scale.
"It appears there was a huge amount of biological productivity in the shallow waters that was making the bottom waters uninhabitable for animals," said Jonathan Payne, assistant professor of geological and environmental sciences, who is a coauthor of the paper and in whose lab Meyer has been working.
"It looks like the whole recovery was slowed by having too much food available, rather than too little," Payne said. "Most of us think that if the biota isn't doing well, maybe we should feed it more. This is clearly an example where feeding it less would have been much better."
Funding for the research was provided by the National Science Foundation, Agouron Institute, American Chemical Society and National Geographic Society.

Hotspots of carbon confusion in Indonesia threaten to warm the world more quickly

noreply@blogger.com (maidul) — Mon, 28 Feb 2011 15:54:00 +0000

Indonesia has promised to become a world leader in reducing greenhouse gas emissions. In 2009, the president committed to a 26% reduction in greenhouse gas emissions by 2020 to below 'business-as-usual' levels. Of this total, 14% would have to come from reducing emissions from deforestation or forest degradation. Investments by foreign governments and other bodies are expected to raise total emission reduction from 26% to 41%.
While international negotiations on rules about how to reduce emissions and slow global warming are slow but ongoing, the Indonesian and Norwegian governments signed a letter of intent under which up to US$ 1 billion is available to assist in setting up a 'stop deforestation and forest degradation' system that also addresses peatland emissions. Part of the agreement is that Indonesia will implement a moratorium or 'two-year suspension on all new concessions for conversion of peat and natural forest'.
Promising as this may sound, the devil is in the detail. A lot depends on how 'peat' and 'natural forest' are defined and how rights are agreed upon. Strong lobbies from the forest and tree-crop plantation industry argue that the economy will be harmed if 'business as usual' is interrupted. According to news sources, definitions of 'natural forest' and 'peat' differ between drafts prepared by the Indonesian Government's emissions reduction taskforce and by the Ministry of Forestry. There are several key issues that need to be resolved.

First, if the moratorium is limited to the 'kawasan hutan' (forest estate), one-third of current emissions from clearing or converting woody vegetation will remain unaccounted for. The institutional mandates and types of permits issued by the government differ between 'kawasan hutan' and the 'other land uses' category, however. Multi-strata agroforests managed by farmers used to cover approximately 10% of the country (or 20 million hectare) in 1990 but were reduced to about 17 million hectare by 2005, with further conversion continuing to this day. Part of this change is based on the economic incentives farmers perceive from conversion to monoculture farming and part is due to external pressure.
Second, the draft of the Ministry of Forestry aims to allow for new plantation concessions in logged forests, where tree planting or conversion to monocultural tree plantations is presented as forest improvement. The Ministry proposes a moratorium limited to protecting primary forests, and defines these as 'natural forests untouched by cultivation or silvicultural systems applied in forestry'. Part of Indonesia's logged-over (secondary) forest still has high carbon stocks and is important for biodiversity conservation. It would help if a map of Indonesia could clarify where the moratorium applies.
Third, peatlands are immense storage houses for carbon and their protection from drainage and fire play a crucial role in the reduction of carbon emissions. Peatlands occur both within and outside of the forest estate and are source of emissions whether forested or not. The Ministry of Forestry draft excluded any new concessions on peatlands deeper than three metre, but this is already illegal and yet still occurs. A further challenge is that existing maps of peat depth are not very accurate.
Fourth, laws, regulations and customary norms applied by different levels of government, the private sector and local communities have often conflicted in the past and continue to do so in the present. These conflicts hamper the application of any scheme and will need serious attention to resolve.
These issues are hot in peatland-rich Central Kalimantan, which has been selected by the Indonesian and Norwegian governments as the primary pilot province for the proposed emissions reduction scheme. Over the past few decades in the province, shifting national policies have shaped the distribution of power and the actual use of peatland, with hundreds of thousands of hectare cleared of forest in a failed attempt to create farmland.
Expectations of payments for carbon emission reduction are currently shaping decisions over natural resource management. But any actions to reduce emissions will need to appreciate the institutional complexity. Different levels of government and the private sector are attempting to influence policy and exercise power, each interpreting history, facts, rules and norms differently in support of their own claims.
The World Agroforestry Centre's research shows that the contesting claimants used the current contradictions and inconsistencies of Indonesian laws, multi-sector policies and the articulation of local property and customary rights for their own purposes. Legal arguments were not necessarily decisive in settling disputes and the lack of respect for legality contributed to confusion, undermining authority.
Furthermore, carbon rights in the area were not clear. They are at least as complex as the laws, regulations, layers of government, NGOs and private sector players that interact during the process that starts with a natural forest and ends with a landscape with few trees, high emissions but still high carbon stock, that is, the peatlands of Kalimantan.
A letter from Yayasan Petak Danum (Water Land Foundation, an NGO in Central Kalimantan) published on 27 February 2011 on red-monitor.org highlights the impact of these complexities on indigenous people's groups involved with one of the pilot projects designed to help reduce emissions in the province, the Kalimantan Forests and Climate Partnership. The World Agroforestry Centre conducted research into tenure and other issues for the Partnership in the early days of the project, which has been encapsulated in ASB Policybrief 21, Hot spots of confusion: contested policies and competing carbon claims in the peatlands of Central Kalimantan, Indonesia .
All this is also pertinent in a place like the Tripa swamp along the western coast of Aceh, where a block of dense swamp forest on peatland, high both in carbon stock and orangutan population density, is threatened by conversion to oil palm.
Part of the permits for such conversion exist but conflicts remain between local communities, local and national governments and private companies. The land status was changed a decade ago from 'watershed protection' forest to 'other land uses'. The forest is, therefore, outside the proposed definition of 'forest' under the emission reduction scheme yet it is exactly the type of carbon stock that the world wants saved.
If conversion to oil palm takes place, it will be widely seen as a failure of the moratorium and the international commitment made by Indonesia.
Recent studies by the World Agroforestry Centre, Yayasan Ekosistem Leuseur and PanEco provide details on the case.
Although it is a challenge to resolve all the above issues in a country the size of Indonesia, it can happen if a) the goal of reducing carbon emissions while supporting human wellbeing is kept in focus; b) the moratorium is clear and operational; and c) it goes beyond restating existing regulations that have not prevented 'business as usual'. This leads to several recommendations.
First, all forests, irrespective of their location and land status, should be included.
Second, logged forests should be included and protected under any emissions reduction scheme because they still contain high carbon stocks and substantial biodiversity.
Third, all peatlands should be included, irrespective of their depth.
Fourth, the definition of 'forest' should be made relevant to its purpose, which is to reduce carbon emissions by avoiding removing or decreasing woody vegetation.
Fifth, national and provincial governments are two among several contesting players and a negotiated settlement is needed rather than asserting a single legal authority.
Sixth, market-based implementation of an emissions reduction scheme will add confusion because unresolved carbon rights are an addition to the already complex layers of unresolved property rights. A 'co-investment' approach, in which all parties work together for human and environmental benefit at local and global levels, can contribute to resolving disputes on property rights and see more transparent use of state authority.
For the moratorium, a simple rule could be that it applies to new concessions on all lands, except those with an aboveground carbon stock of less than 35 tonne of carbon per hectare, and it applies to all peatlands regardless of the amount of above-ground carbon. This would be relatively easy to map and monitor. It would set clear rules to move forwards for now. It would buy time to think through the issues that relate to the lands that are included in the moratorium and refine rules in future as needed.
From www.worldagroforestry.org

Turtle populations affected by climate, habitat loss and overexploitation

noreply@blogger.com (maidul) — Wed, 02 Feb 2011 17:27:00 +0000

The sex of some species of turtles is determined by the temperature of the nest: warm nests produce females, cooler nests, males. And although turtles have been on the planet for about 220 million years, scientists now report that almost half of the turtle species is threatened. Turtle scientists are working to understand how global warming may affect turtle reproduction. To bring attention to this and other issues affecting turtles, researchers and other supporters have designated 2011 as the Year of the Turtle. Why should we be concerned about the loss of turtles?
"Turtles are centrally nested in the food web and are symbols of our natural heritage. They hold a significant role in many cultures. For example, in many southeast Asian cultures turtles are used for food, pets, and medicine," explains Deanna Olson, a research ecologist and co-chair of the Partners in Amphibian and Reptile Conservation steering committee spearheading the Year of the Turtle campaign.

Turtles (which include tortoises) are central to the food web. Sea turtles graze on the sea grass found on the ocean floor, helping to keep it short and healthy. Healthy sea grass in turn is an important breeding ground for many species of fish, shellfish, and crustaceans. The same processes hold for freshwater and land turtles. For example, turtles contribute to the health of marshes and wetlands, being important prey for a suite of predators. The Year of the Turtle activities, include a monthly newsletter showcasing research and conservation efforts, education and citizen science projects, turtle-themed art, literature, and cultural perspectives, says Olson, a scientist with the Forest Service's Pacific Northwest Research Station.
Olson also co-authored a report, "State of the Turtle," and created a new turtle mapping project for the United States. The report is being translated into other languages for use here and around the world.
"A French translation of the report is already completed, and groups from Bangladesh and Germany signed on recently to help promote turtle conservation, and new partners join us each week," explains Olson.
Here are a few quick facts about turtles:

About 50 percent of freshwater turtle species are threatened worldwide, more than any other animal group.
About 20 percent of all turtle species worldwide are found in North America.
Primary threats to turtles are habitat loss and exploitation.
Climate change patterns, altered temperatures, affected wetlands and stream flow all are key factors that affect turtle habitats.
Urban and suburban development causes turtles to be victims to fast-moving cars, farm machinery; turtles can also be unintentionally caught in fishing nets.

What can be done to conserve turtle populations?

Protect rare turtle species and their habitats.
Manage common turtle species and their habitats so they may remain common.
Manage crisis situations such as acute hazards (i.e., oil spills) and rare species in peril.

From http://www.fs.fed.us/pnw

How does your green roof garden grow?

noreply@blogger.com (maidul) — Fri, 31 Dec 2010 05:43:00 +0000

UNIVERSITY PARK, PA -- Growing plants on rooftops is an old concept that has evolved from simple sod roofing to roof gardens and new, lightweight "extensive green roofs". Modern green roofs have environmental and social benefits; they can reduce stormwater runoff, improve air quality, mitigate urban heat, reduce the demand for air conditioning and greenhouse gas emissions, and provide habitat for birds and wildlife. Long-used in urban planning in Europe, green roofs are becoming more popular in North America, and new research designed to promote the integration of green roofs into current and future buildings is burgeoning. Researchers from the Department of Horticulture at The Pennsylvania State University published a study in HortTechnology that evaluated the influence of substrate type and depth on establishment of five common green roof plants.

Plants suitable for extensive green roofs must tolerate extreme rooftop conditions, and the substrates in which they grow must meet both horticultural and structural requirements. Deeper substrates may retain more water for plants during dry periods, but they also weigh more, especially when near saturation. The study by Christine E. Thuring, Robert D. Berghage, and David J. Beattie was designed to evaluate the effects of substrate type and depth on the establishment and early growth of five plants popular in North American green roof designs.

The researchers hypothesized that early drought is more harmful for plants grown in shallow rather than deeper substrate depths, and that plants that survived early drought conditions would produce less shoot biomass than those subjected to late drought. Two stonecrops, one ice plant, and two herbaceous perennials were planted in three depths (30, 60, and 120 mm) of expanded shale and expanded clay, two commercially available green roof substrates. Study flats inside a plasticulture tunnel received three drought treatments: no drought, 2 weeks early drought, and 2 weeks late drought.

The two stonecrops performed well under most conditions, although tasteless stonecrop was stunted by early drought. Ice plant performed erratically and, along with maiden pink, poorly in face of drought during establishment. When subjected to any drought, the herbaceous perennials had the fewest survivors in the expanded shale. The study plants were most affected by substrate depth, except for maiden pink, which responded solely to drought. When subjected to early drought conditions, the herbaceous perennials did not survive in 30 mm of either substrate, or in 60 mm of expanded shale; early drought appeared to be more harmful to plant survival and performance than late drought. Although the stonecrops performed well in 60 mm of substrate when subjected to drought, their performance was superior in the expanded clay compared with shale.

The three most resilient species used in the study—saxifrage pink, white stonecrop, and tasteless stonecrop—always produced more shoot biomass with increasing substrate depth, regardless of water availability. A standout performer was saxifrage pink, which had an attractive appearance and persistent flowering habit, making it an excellent choice as a green roof plant.

The experiment illustrates how appropriate species selection in the design of unirrigated extensive green roofs may be directed by factors such as substrate type and depth, as well as anticipated drought conditions. "This experiment revealed the variability among drought-tolerant species to various treatments, as well as the different plant responses to substrate type during drought", concluded the scientists.

New technology to speed cleanup of nuclear-contaminated sites

noreply@blogger.com (maidul) — Fri, 31 Dec 2010 05:02:00 +0000

CORVALLIS, Ore. – Members of the engineering faculty at Oregon State University have invented a new type of radiation detection and measurement device that will be particularly useful for cleanup of sites with radioactive contamination, making the process faster, more accurate and less expensive.
A patent has been granted on this new type of radiation spectrometer, and the first production of devices will begin soon. The advance has also led to creation of a Corvallis-based spinoff company, Avicenna Instruments, based on the OSU research. The market for these instruments may ultimately be global, and thousands of them could be built, researchers say.
Hundreds of millions of dollars are spent on cleanup of some major sites contaminated by radioactivity, primarily from the historic production of nuclear weapons during and after World War II. These include the Hanford site in Washington, Savannah River site in South Carolina, and Oak Ridge National Laboratory in Tennessee.

“Unlike other detectors, this spectrometer is more efficient, and able to measure and quantify both gamma and beta radiation at the same time,” said David Hamby, an OSU professor of health physics. “Before this two different types of detectors and other chemical tests were needed in a time-consuming process.”
“This system will be able to provide accurate results in 15 minutes that previously might have taken half a day,” Hamby said. “That saves steps, time and money.”
The spectrometer, developed over 10 years by Hamby and Abi Farsoni, an assistant professor in the College of Engineering, can quickly tell the type and amount of radionuclides that are present in something like a soil sample – contaminants such as cesium 137 or strontium 90 - that were produced from reactor operations. And it can distinguish between gamma rays and beta particles, which is necessary to determine the level of contamination.
“Cleaning up radioactive contamination is something we can do, but the process is costly, and often the question when working in the field is how clean is clean enough,” Hamby said. “At some point the remaining level of radioactivity is not a concern. So we need the ability to do frequent and accurate testing to protect the environment while also controlling costs.”
This system should allow that, Hamby said, and may eventually be used in monitoring processes in the nuclear energy industry, or possibly medical applications in the use of radioactive tracers.
The OSU College of Engineering has contracted with Ludlum Instruments, a Sweetwater, Texas, manufacturer, to produce the first instruments, and the OSU Office of Technology Transfer is seeking a licensee for commercial development. The electronic systems for the spectrometers will be produced in Oregon by Avicenna Instruments, the researchers said.V5JXEUDZ37T7

Broken glass yields clues to climate change

noreply@blogger.com (maidul) — Tue, 28 Dec 2010 09:56:00 +0000

A study appearing this week in Proceedings of the National Academy of Sciences finds that microscopic particles of dust, emitted into the atmosphere when dirt breaks apart, follow similar fragment patterns to broken glass and other brittle objects. The research, by National Center for Atmospheric Research (NCAR) scientist Jasper Kok, suggests there are several times more dust particles in the atmosphere than previously thought, since shattered dirt appears to produce an unexpectedly high number of large dust fragments.
The finding has implications for understanding future climate change because dust plays a significant role in controlling the amount of solar energy in the atmosphere. Depending on their size and other characteristics, some dust particles reflect solar energy and cool the planet, while others trap energy as heat.

Shattered soil

Kok’s research focused on a type of airborne particle known as mineral dust. These particles are usually emitted when grains of sand are blown into soil, shattering dirt and sending fragments into the air. The fragments can be as large as about 50 microns in diameter, or about the thickness of a fine strand of human hair.
The smallest particles, which are classified as clay and are as tiny as 2 microns in diameter, remain in the atmosphere for about a week, circling much of the globe and exerting a cooling influence by reflecting heat from the Sun back into space. Larger particles, classified as silt, fall out of the atmosphere after a few days. The larger the particle, the more it will tend to have a heating effect on the atmosphere.
Kok’s research indicates that the ratio of silt particles to clay particles is two to eight times greater than represented in climate models.
Since climate scientists carefully calibrate the models to simulate the actual number of clay particles in the atmosphere, the paper suggests that models most likely err when it comes to the number of silt particles. Most of these larger particles swirl in the atmosphere within about 1,000 miles of desert regions, so adjusting their quantity in computer models should generate better projections of future climate in desert regions, such as the southwestern United States and northern Africa.
Additional research will be needed to determine whether future temperatures in those regions will increase more or less than currently indicated by computer models.
The study results also suggest that marine ecosystems, which draw down carbon dioxide from the atmosphere, may receive substantially more iron from airborne particles than previously estimated. The iron enhances biological activity, benefiting ocean food chains, including plants that take up carbon during photosynthesis.
In addition to influencing the amount of solar heat in the atmosphere, dust particles also get deposited on mountain snowpacks, where they absorb heat and accelerate melt.

Glass and dust: Common fracture patterns

Physicists have long known that certain brittle objects, such as glass or rocks, and even atomic nuclei, fracture in predictable patterns. The resulting fragments follow a certain range of sizes, with a predictable distribution of small, medium, and large pieces. Scientists refer to this type of pattern as scale invariance or self-similarity.
Physicists have devised mathematical formulas for the process by which cracks propagate in predictable ways as a brittle object breaks. Kok theorized that it would be possible to use these formulas to estimate the range of dust particle sizes. He turned to a 1983 study by Guillaume d’Almeida and Lothar Schüth from the Institute for Meteorology at the University of Mainz in Germany that measured the particle size distribution of arid soil.
By applying the formulas for fracture patterns of brittle objects to the soil measurements, Kok determined the size distribution of emitted dust particles. To his surprise, the formulas described measurements of dust particle sizes almost exactly.
“The idea that all these objects shatter in the same way is a beautiful thing, actually,” Kok says. “It’s nature’s way of creating order in chaos.”
Author: Jasper Kok
Publication: Proceedings of the National Academy of Sciences

Growing hypoxic zones reduce habitat for billfish and tuna

noreply@blogger.com (maidul) — Sat, 25 Dec 2010 03:16:00 +0000

Billfish and tuna, important commercial and recreational fish species, may be more vulnerable to fishing pressure because of shrinking habitat, according to a new study published by scientists from NOAA, The Billfish Foundation, and University of Miami Rosenstiel School of Marine and Atmospheric Science.
An expanding zone of low oxygen, known as a hypoxic zone, in the Atlantic Ocean is encroaching upon these species' preferred oxygen-abundant habitat, forcing them into shallower waters where they are more likely to be caught.
During the study, published recently in the journal Fisheries Oceanography, scientists tagged 79 sailfish and blue marlin with satellite tracking devices in the western North Atlantic, off south Florida and the Caribbean; and eastern tropical Atlantic, off the coast of West Africa. The pop off archival satellite tags monitored horizontal and vertical movement patterns. Researchers confirmed that billfish prefer oxygen rich waters closer to the surface and will actively avoid waters low in oxygen.

While these hypoxic zones occur naturally in many areas of the world's tropical and equatorial oceans, scientists are concerned because these zones are expanding and occurring closer to the sea surface, and are expected to continue to grow as sea temperatures rise.
"The hypoxic zone off West Africa, which covers virtually all the equatorial waters in the Atlantic Ocean, is roughly the size of the continental United States, and it's growing," said Dr. Eric D. Prince, NOAA's Fisheries Service research fishery biologist. "With the current cycle of climate change and accelerated global warming, we expect the size of this zone to increase, further reducing the available habitat for these fish."
Less available habitat can lead to more fish being caught since the fish are concentrated near the surface. Higher catch rates from these areas may give the false appearance of more abundant fish stocks. The shrinking availability of habitat and resulting increases to catch rates are important factors for scientists to consider when doing population assessments.
Researchers forecast that climate change and its associated rise in ocean temperatures will further increase the expansion of hypoxic zones in the world's oceans. As water temperature increases, the amount of oxygen dissolved in water decreases, further squeezing billfish into dwindling available habitat and exposing them to even higher levels of exploitation.

The ethics of biofuels

noreply@blogger.com (maidul) — Wed, 15 Dec 2010 15:46:00 +0000

In the world-wide race to develop energy sources that are seen as "green" because they are renewable and less greenhouse gas-intensive, sometimes the most basic questions remain unanswered.
In a paper released today by the School of Public Policy at the University of Calgary, authors Michal Moore, Senior Fellow, and Sarah M. Jordaan at Harvard University in the Department of Earth and Planetary Sciences, look at the basic question of whether these energy sources are ethical.
In addition to arguing that the greenhouse gas benefits of biofuel are overstated by many policymakers, the authors argue that there are four questions that need to be considered before encouraging and supporting the production of more biofuel.

These questions are:

What is the effect of biofuel production on food costs, especially for poor populations?
Should more land be used for biofuel when the return of energy per acre is low? Are there better uses for that land?
In addition to worrying about the impact of global warming, should we not consider the impact on land of massively expanding biofuel production?
What are the other economic impacts of large scale production of biofuel?

"Policymakers, especially in the U.S., have been in a rush to expand biofuel protection," says Michal Moore. "But they need to start thinking outside of the box of climate change and the corn lobby."
"If policy is designed to create better outcomes for everyone, then we need to subject policy to ethical tests. In many respects, current policy around biofuels fails those tests."
From http://www.policyschool.ca

Conditioning reefs for the future

noreply@blogger.com (maidul) — Wed, 08 Dec 2010 15:27:00 +0000

In a world first, a new 'state of the art' climate change experimental facility has been completed at the University of Queensland's Heron Island Research Station.
The Climate Change Mesocosm (CCM) project led by Associate Professor Sophie Dove and Dr. David Kline from the Global Change Institute's Coral Reef Ecosystems Laboratory is one of the largest and most accurately controlled ocean acidification and warming experimental systems in the world and simulates ocean temperatures and acidification levels predicted to occur on coral reefs in the next 50 to 100 years.
Able to regulate both temperature and CO₂ levels prescribed by the 2100 IPCC scenarios in a highly controlled environment, the CCM system allows studies of climate change from the molecular to the ecosystem level.

"While similar to the "Free Ocean Carbon Enrichment" (FOCE) project, recently featured in Sir David Attenborough's documentary "Death of the Oceans", the CCM differs in that it regulates the temperature, in addition to, the acidification levels above and below the current ambient conditions of water on the reef" said Dr Dove.
It is unique in so far as the experimental controls allow variation with respect to real-time conditions of CO₂ and temperature measured in the adjacent deepwater of Wistari channel."
Conditions in the 72 experimental aquaria and 12 mini-reefs can then fluctuate a fixed amount above or below the ambient 'control' conditions, but importantly incorporate a day/night and seasonal variability."
The main components of the system are 4 x 7,500L custom built air-tight and insulated fibre-glass tanks or sumps which provide the necessary residence time of the water for the fine control of CO₂ and temperature.
Dr David Kline a research fellow with the GCI explains "We are simulating preindustrial ocean conditions of -100 ppm CO₂ and minus 1°C; a control treatment of current reef CO₂ and temperature; the "B1" IPCC scenario of + 220ppm CO₂ and +2°C, and an extreme "A1FI" scenario of +640 ppm CO₂, +4.5 °C."
"In the eight months the FOCE system has been on the reef flat we have noticed the corals exposed to the higher CO₂ levels look quite different. The types of algae are different and the growth rate of the coral appears to have slowed.
We expect to see similar results from the CCM experiments where reefal organisms respond to the dual influences of acidification and temperature."

Scientists: The fire in Israel is a typical example of climate change effects in the Mediterranean

noreply@blogger.com (maidul) — Wed, 08 Dec 2010 15:25:00 +0000

According to "Israel’s National Report on Climate Change", prepared by Pe’er and other members of Ben-Gurion University of the Negev on behalf of the Israeli Ministry of the Environmental Protection, the frequency, intensity and extent of the fires would increase due to the prolongation of droughts, increase in water evaporation and an increased frequency of intense heat waves. At a warming of 1.5 degrees by the year 2100, which is by now considered a conservative scenario, models predict the desert to expand northward by 300 to 500 kilometers to the north. Mediterranean ecosystems, such as the one occurring in the Carmel Mountains, would thus disappear from Israel. Forest fires in the Carmel mountain range in northern Israel was preceded by eight months of drought and occurred during a heat wave with temperatures around 30ºC. Normally, first rainfall should have come in September or October, and the maximal daily temperature at this time of year should be around 15-20ºC.

The Carmel mountain range, northern Israel, rises to 546 meters above Sea Level. The combination of high rainfall (average of 800 mm per year), mountainous landscape and little human-pressure have resulted in rich and diverse vegetation, including Israel’s largest natural pine forest. Therefore, large parts are nowadays protected within National Parks and Conservation Areas.
Dr. Guy Pe'er, currently a fellow at the Helmholtz Centre for Environmental Research (UFZ), Leipzig, has witnessed three forest fires in the year 1989 where large areas of the Carmel mountains were burnt, penetrating the outskirts of his native city of Haifa. "Following the fire I spent over a year studying the recovery process of the vegetation and the Mesopotamian fellow deer at the reintroduction centre at the Carmel forest. It was there that I've learned that fires are something natural and nature can recover if no further disturbances occur." Guy Pe'er is nevertheless overwhelmed by the intensity and extent of the fire: the largest fire in 1989 has destroyed an area which was ten times smaller than the current one.
The worst forest fire ever in the history of Israel has spanned a total area of 5000 hectares, taken the lives of 42 people and burned 250 houses down. Damages are estimated at more than 55 million €. Israel has since then been engaged in heavy debates on responsibility: how did the government, the ministers and the fire-brigade contribute to this failure? Guy Pe'er holds a different opinion, suggesting that the discussion should involve the longer and more substantial causes of this fire, namely climate change. "It’s a matter of our consumption, our society and habits. We consume more than we need and more than Earth can sustain, and by that we bring about climate change and risk our own future. Can we behave as responsible humans and change our habits?" says Pe’er. From the perspective of the Israeli conservation biologist the international politics should reflect this incident onto the ongoing UN conference on Climate Change in Cancun, and ensure that its decisions will finally lead to the mitigation of climate change. Because climate change is not fiction: Israelis these days have got a glimpse of what may awaits the coming generations.

Electrified nano filter promises to cut costs for clean drinking water

noreply@blogger.com (maidul) — Sat, 04 Dec 2010 13:20:00 +0000

With almost one billion people lacking access to clean, safe drinking water, scientists are reporting development and successful initial tests of an inexpensive new filtering technology that kills up to 98 percent of disease-causing bacteria in water in seconds without clogging. A report on the technology appears in Nano Letters, a monthly American Chemical Society journal.
Yi Cui and colleagues explain that most water purifiers work by trapping bacteria in tiny pores of filter material. Pushing water through those filters requires electric pumps and consumes a lot of energy. In addition, the filters can get clogged and must be changed periodically. The new material, in contrast, has relatively huge pores, which allow water to flow through easily. And it kills bacteria outright, rather than just trapping them.

The scientists knew that contact with silver and electricity can destroy bacteria, and decided to combine both approaches. They spread sub-microscopic silver nanowires onto cotton, and then added a coating of carbon nanotubes, which give the filter extra electrical conductivity. Tests of the material on E. coli-tainted water showed that the silver/electrified cotton killed up to 98 percent of the bacteria. The filter material never clogged, and the water flowed through it very quickly without any need for a pump. "Such technology could dramatically lower the cost of a wide array of filtration technologies for water as well as food, air, and pharmaceuticals where the need to frequently replace filters is a large cost and difficult challenge," their report states.

Neglected greenhouse gas discovered by atmosphere chemists

noreply@blogger.com (maidul) — Sat, 04 Dec 2010 13:19:00 +0000

One kilo of anaesthetic gas affects the climate as much as 1620 kilos of CO2. That has been shown by a recent study carried out by chemists from University of Copenhagen and NASA in collaboration with anaesthesiologists from the University of Michigan Medical School. The amount of gas needed for a single surgical procedure is not high, but in the US alone surgery related anaesthetics affected the climate as much as would one million cars.Tænk før bedøvelse
Analyses of the anaesthetics were carried out by Ole John Nielsen. He is a Professor of atmospheric chemistry at the University of Copenhagen, and he's got an important message for doctors.
"We studied three different gasses in regular use for anaesthesia, and they're not equally harmful," explains Professor Nielsen

All three are worse than CO2 but where the mildest ones Isoflurane and Sevoflurane have global warming potentials of 210 and 510 respectively, Desflurane the most harmful will cause 1620 times as much global warming as an equal amount of CO2, explains the professor.
The three anaesthetic gasses isofluran, desflurane and sevoflurane were studied at the Ford atmospheric laboratories in Michigan. Mads Andersen of NASA's Jet Propulsion Laboratories collaborated on the analyses with his former PhD supervisor Ole John Nielsen. He relates how he got the idea for the study while his wife was giving birth.

Freon is a compound that Andersen knows well. It got his supervisor Professor Nielsen on the scientific map. With a global warming potential of a whopping 11.000 the refrigerant Freon has been banned all over the world since 1992. When the search was on for an alternative to the harmful substance Nielsen analysed just how much heat was retained by new compounds, and how long they would stay in the atmosphere. His methods went to prove, that the refrigerant HFC134a had a global warming potential of 1.300 and left the atmosphere in just 14 years to freons 50 to 100 years.Det gode viger pladsen for det endnu bedre
HFC-134a has spared the atmosphere a considerable climate effect. But it too is being prohibited all across the European Union. And unless therapeutic arguments speak for using all three, sevoflurane should be the only legal anaesthetic gas as shown by the study done by NASA, Ford and the Department of Chemistry at the University of Copenhagen.

Leaking underground CO2 storage could contaminate drinking water

noreply@blogger.com (maidul) — Thu, 11 Nov 2010 16:35:00 +0000

Leaks from carbon dioxide injected deep underground to help fight climate change could bubble up into drinking water aquifers near the surface, driving up levels of contaminants in the water tenfold or more in some places, according to a study by Duke University scientists.
Based on a year-long analysis of core samples from four drinking water aquifers, "We found the potential for contamination is real, but there are ways to avoid or reduce the risk," says Robert B. Jackson, Nicholas Professor of Global Environmental Change and professor of biology at Duke.
"Geologic criteria that we identified in the study can help identify locations around the country that should be monitored or avoided," he says. "By no means would all sites be susceptible to problems of water quality."

Storing carbon dioxide deep below Earth's surface, a process known as geosequestration, is part of a suite of new carbon capture and storage (CCS) technologies being developed by governments and industries worldwide to reduce the amount of greenhouse gas emissions entering Earth's atmosphere. The still-evolving technologies are designed to capture and compress CO₂, emissions at their source – typically power plants and other industrial facilities – and transport the CO₂ to locations where it can be injected far below the Earth's surface for long-term storage. The U.S. Department of Energy, working with industry and academia, has begun the planning for at least seven regional CCS projects.
"The fear of drinking water contamination from CO₂ leaks is one of several sticking points about CCS and has contributed to local opposition to it," says Jackson, who directs Duke's Center on Global Change. "We examined the idea that if CO₂ leaked out slowly from deep formations, where might it negatively impact freshwater aquifers near the surface, and why."
Jackson and his postdoctoral fellow Mark G. Little collected core samples from four freshwater aquifers around the nation that overlie potential CCS sites and incubated the samples in their lab at Duke for a year, with CO₂ bubbling through them.
After a year's exposure to the CO₂, analysis of the samples showed that "there are a number of potential sites where CO₂ leaks drive contaminants up tenfold or more, in some cases to levels above the maximum contaminant loads set by the EPA for potable water," Jackson says. Three key factors – solid-phase metal mobility, carbonate buffering capacity and electron exchanges in the overlying freshwater aquifer – were found to influence the risk of drinking water contamination from underground carbon leaks.
The study also identified four markers that scientists can use to test for early warnings of potential carbon dioxide leaks. "Along with changes in carbonate concentration and acidity of the water, concentrations of manganese, iron and calcium could all be used as geochemical markers of a leak, as their concentration increase within two weeks of exposure to CO₂," Jackson says.

Extreme global warming in the ancient past

noreply@blogger.com (maidul) — Thu, 11 Nov 2010 04:54:00 +0000

Variations in atmosphere carbon dioxide around 40 million years ago were tightly coupled to changes in global temperature, according to new findings published in the journal Science. The study was led by scientists at Utrecht University, working with colleagues at the NIOZ Royal Netherlands Institute for Sea Research and the University of Southampton.
"Understanding the relationship between the Earth's climate and atmospheric carbon dioxide in the geological past can provide insight into the extent of future global warming expected to result from carbon dioxide emission caused by the activities of humans," said Dr Steven Bohaty of the University of Southampton's School of Ocean and Earth Science (SOES) based at the National Oceanography Centre in Southampton.
It has been known for some time that the long-term warmth of the Eocene (~56 to 34 million years ago) was associated with relatively high atmospheric carbon dioxide levels. However, scientists were previously unable to demonstrate tight-coupling between variations in atmospheric carbon dioxide and shorter-term changes in global climate.

To fill this gap in knowledge, the authors of the new study focused on one of the hottest episodes of Earth's climate history – the Middle Eocene Climatic Optimum (MECO), which occurred around 40 million years ago.
Algae use photosynthesis to harvest the energy of the sun, converting carbon dioxide and water into the organic molecules required for growth. Different isotopes of carbon are incorporated into these molecules depending on the environmental conditions under which algae grow. Ancient climate can therefore be reconstructed by analysing the carbon isotope ratios of molecules preserved in fossilised algae.
The researchers took this approach to reconstruct variations in carbon dioxide levels across the MECO warming event, using fossilised algae preserved in sediment cores extracted from the seafloor near Tasmania, Australia, by the Ocean Drilling Program. They refined their estimates of carbon dioxide levels using information on the past marine ecosystem derived from studying changes in the abundance of different groups of fossil plankton.
Their analyses indicate that MECO carbon dioxide levels must have at least doubled over a period of around 400,000 years. In conjunction with these findings, analyses using two independent molecular proxies for sea surface temperature show that the climate warmed by between 4 and 6 degrees Celsius over the same period.
"We found a close correspondence between carbon dioxide levels and sea surface temperature over the whole period, suggesting that increased amounts of carbon dioxide in the atmosphere played a major role in global warming during the MECO," said Bohaty.
The researchers consider it likely that elevated atmospheric carbon dioxide levels during the MECO resulted in increased global temperatures, rather than vice versa, arguing that the increase in carbon dioxide played the lead role.
"The change in carbon dioxide 40 million years ago was too large to have been the result of temperature change and associated feedbacks," said co-lead author Peter Bijl of Utrecht University. "Such a large change in carbon dioxide certainly provides a plausible explanation for the changes in Earth's temperature."
The researchers point out that the large increase in atmospheric carbon dioxide indicated by their analysis would have required a natural carbon source capable of injecting vast amounts of carbon into the atmosphere.
The rapid increase in atmospheric carbon dioxide levels around 40 million years ago approximately coincides with the rise of the Himalayas and may be related to the disappearance of an ocean between India and Asia as a result of plate tectonics – the large scale movements of the Earth's rocky shell (lithosphere). But, as explained by Professor Paul Pearson of Cardiff University in a perspective article accompanying the Science paper, the hunt is now on to discover the exact cause.

Volcanic eruptions affect rainfall over Asian monsoon region

noreply@blogger.com (maidul) — Mon, 08 Nov 2010 07:35:00 +0000

Scientists have long known that large volcanic explosions can affect the weather by spewing particles that block solar energy and cool the air.
Some suspect that extended "volcanic winters" from gigantic eruptions helped kill off dinosaurs and Neanderthals.
In the summer following Indonesia's 1815 Tambora eruption, frost wrecked crops as far away as New England, and the 1991 blowout of the Philippines' Mount Pinatubo lowered average global temperatures by 0.7 degrees F--enough to mask the effects of greenhouse gases for a year or so.
Now, in research funded by the National Science Foundation (NSF)'s Division of Atmospheric and Geospace Sciences, scientists have discovered that eruptions also affect rainfall over the Asian monsoon region, where seasonal storms water crops for nearly half of Earth's population.

Tree-ring researchers at Columbia University's Lamont-Doherty Earth Observatory (LDEO) showed that big eruptions tend to dry up much of Central Asia, but bring more rain to southeast Asian countries including Vietnam, Laos, Cambodia, Thailand and Myanmar--the opposite of what many climate models predict.
A paper reporting their results appears in an advance online version of the American Geophysical Union (AGU) journal Geophysical Research Letters.
The growth rings of some tree species can be correlated with rainfall. LDEO's Tree Ring Lab used tree rings from some 300 sites across Asia to measure the effects of 54 volcanic eruptions going back about 800 years.
The data came from LDEO's new 1,000-year tree-ring atlas of Asian weather, which has produced evidence of long, devastating droughts.
"We might think of the solid Earth and the atmosphere as two different things, but everything in the system is interconnected," said Kevin Anchukaitis, the paper's lead author. "Volcanoes can be important players in climate over time."
Large explosive eruptions send up sulfur compounds that turn into tiny sulfate particles high in the atmosphere, where they deflect solar radiation.
The resulting cooling on Earth's surface can last for months or years.
Not all eruptions have that effect, however. For instance, the continuing eruption of Indonesia's Merapi this fall has killed dozens, but this latest episode is probably not big enough by itself to effect large-scale weather changes, scientists believe.
As for rainfall, in the simplest models, lowered temperatures decrease evaporation of water from the surface to the air. Less water vapor translates to less rain.
But matters are greatly complicated by atmospheric circulation patterns, cyclic changes in temperatures over the oceans, and the shapes of land masses.
Until now, most climate models incorporating changes in the sun and the atmosphere have predicted that volcanic explosions would disrupt the monsoon by bringing less rain to southeast Asia--but the researchers found the opposite.
They studied several eruptions, including one in 1258 from an unknown tropical site, thought to be the largest of the last millennium; the 1600-1601 eruption of Peru's Huaynaputina; Tambora in 1815; the 1883 explosion of Indonesia's Krakatau; Mexico's El Chichón in 1982; and Pinatubo.
Tree rings showed that huge swaths of southern China, Mongolia and surrounding areas consistently dried up in the year or two following big events, while mainland southeast Asia received increased rain.
The researchers believe there are many possible factors involved.
"The data only recently became available to test the models," said Rosanne D'Arrigo, one of the paper's co-authors. "There's a lot of work to be done to understand how all these different forces interact."
In some episodes pinpointed by the study, it appears that strong cycles of the El Niño-Southern Oscillation, which drives temperatures over the Pacific and Indian Oceans and is thought to strongly affect the Asian monsoon, might have counteracted eruptions, lessening their drying or moistening effects. p>
But it could work the other way, too, said Anchukaitis; if atmospheric dynamics and volcanic eruptions come together with the right timing, they could reinforce one another--with drastic results.
"Then you get flooding or drought, and neither flooding nor drought is good for the people living in those regions," he said.
Ultimately, said Anchukaitis, such studies should help scientists refine models of how natural and man-made forces might act together to shift weather patterns--a vital question for all areas of the world.