Tag Archives: greenhouse

Persian Gulf could experience deadly heat: MIT Study

Detailed climate simulation shows a threshold of survivability could be crossed without mitigation measures.

By David Chandler


CAMBRIDGE, Mass.–Within this century, parts of the Persian Gulf region could be hit with unprecedented events of deadly heat as a result of climate change, according to a study of high-resolution climate models.

The research reveals details of a business-as-usual scenario for greenhouse gas emissions, but also shows that curbing emissions could forestall these deadly temperature extremes.

The study, published today in the journal Nature Climate Change, was carried out by Elfatih Eltahir, a professor of civil and environmental engineering at MIT, and Jeremy Pal PhD ’01 at Loyola Marymount University. They conclude that conditions in the Persian Gulf region, including its shallow water and intense sun, make it “a specific regional hotspot where climate change, in absence of significant mitigation, is likely to severely impact human habitability in the future.”

Running high-resolution versions of standard climate models, Eltahir and Pal found that many major cities in the region could exceed a tipping point for human survival, even in shaded and well-ventilated spaces. Eltahir says this threshold “has, as far as we know … never been reported for any location on Earth.”

That tipping point involves a measurement called the “wet-bulb temperature” that combines temperature and humidity, reflecting conditions the human body could maintain without artificial cooling. That threshold for survival for more than six unprotected hours is 35 degrees Celsius, or about 95 degrees Fahrenheit, according to recently published research. (The equivalent number in the National Weather Service’s more commonly used “heat index” would be about 165 F.)

This limit was almost reached this summer, at the end of an extreme, weeklong heat wave in the region: On July 31, the wet-bulb temperature in Bandahr Mashrahr, Iran, hit 34.6 C — just a fraction below the threshold, for an hour or less.

But the severe danger to human health and life occurs when such temperatures are sustained for several hours, Eltahir says — which the models show would occur several times in a 30-year period toward the end of the century under the business-as-usual scenario used as a benchmark by the Intergovernmental Panel on Climate Change.

The Persian Gulf region is especially vulnerable, the researchers say, because of a combination of low elevations, clear sky, water body that increases heat absorption, and the shallowness of the Persian Gulf itself, which produces high water temperatures that lead to strong evaporation and very high humidity.

The models show that by the latter part of this century, major cities such as Doha, Qatar, Abu Dhabi, and Dubai in the United Arab Emirates, and Bandar Abbas, Iran, could exceed the 35 C threshold several times over a 30-year period. What’s more, Eltahir says, hot summer conditions that now occur once every 20 days or so “will characterize the usual summer day in the future.”

While the other side of the Arabian Peninsula, adjacent to the Red Sea, would see less extreme heat, the projections show that dangerous extremes are also likely there, reaching wet-bulb temperatures of 32 to 34 C. This could be a particular concern, the authors note, because the annual Hajj, or annual Islamic pilgrimage to Mecca — when as many as 2 million pilgrims take part in rituals that include standing outdoors for a full day of prayer — sometimes occurs during these hot months.

While many in the Persian Gulf’s wealthier states might be able to adapt to new climate extremes, poorer areas, such as Yemen, might be less able to cope with such extremes, the authors say.

The research was supported by the Kuwait Foundation for the Advancement of Science.

Source: MIT News Office

The DC-8 airborne laboratory is one of several NASA aircraft that will fly in support of five new investigations into how different aspects of the interconnected Earth system influence climate change.
Image Credit: NASA

NASA Airborne Campaigns Tackle Climate Questions from Africa to Arctic

Five new NASA airborne field campaigns will take to the skies starting in 2015 to investigate how long-range air pollution, warming ocean waters, and fires in Africa affect our climate.

These studies into several incompletely understood Earth system processes were competitively-selected as part of NASA’s Earth Venture-class projects. Each project is funded at a total cost of no more than $30 million over five years. This funding includes initial development, field campaigns and analysis of data.

This is NASA’s second series of Earth Venture suborbital investigations — regularly solicited, quick-turnaround projects recommended by the National Research Council in 2007. The first series of five projects was selected in 2010.

“These new investigations address a variety of key scientific questions critical to advancing our understanding of how Earth works,” said Jack Kaye, associate director for research in NASA’s Earth Science Division in Washington. “These innovative airborne experiments will let us probe inside processes and locations in unprecedented detail that complements what we can do with our fleet of Earth-observing satellites.”

The DC-8 airborne laboratory is one of several NASA aircraft that will fly in support of five new investigations into how different aspects of the interconnected Earth system influence climate change. Image Credit: NASA
The DC-8 airborne laboratory is one of several NASA aircraft that will fly in support of five new investigations into how different aspects of the interconnected Earth system influence climate change.
Image Credit: NASA

The five selected Earth Venture investigations are:

  • Atmospheric chemistry and air pollution – Steven Wofsy of Harvard University in Cambridge, Massachusetts, will lead the Atmospheric Tomography project to study the impact of human-produced air pollution on certain greenhouse gases. Airborne instruments will look at how atmospheric chemistry is transformed by various air pollutants and at the impact on methane and ozone which affect climate. Flights aboard NASA’s DC-8 will originate from the Armstrong Flight Research Center in Palmdale, California, fly north to the western Arctic, south to the South Pacific, east to the Atlantic, north to Greenland, and return to California across central North America.
  • Ecosystem changes in a warming ocean – Michael Behrenfeld of Oregon State University in Corvallis, Oregon, will lead the North Atlantic Aerosols and Marine Ecosystems Study, which seeks to improve predictions of how ocean ecosystems would change with ocean warming. The mission will study the annual life cycle of phytoplankton and the impact small airborne particles derived from marine organisms have on climate in the North Atlantic. The large annual phytoplankton bloom in this region may influence the Earth’s energy budget. Research flights by NASA’s C-130 aircraft from Wallops Flight Facility, Virginia, will be coordinated with a University-National Oceanographic Laboratory System (UNOLS) research vessel. UNOLS, located at the University of Rhode Island’s Graduate School of Oceanography in Narragansett, Rhode Island, is an organization of 62 academic institutions and national laboratories involved in oceanographic research.
  • Greenhouse gas sources – Kenneth Davis of Pennsylvania State University in University Park, will lead the Atmospheric Carbon and Transport-America project to quantify the sources of regional carbon dioxide, methane and other gases, and document how weather systems transport these gases in the atmosphere. The research goal is to improve identification and predictions of carbon dioxide and methane sources and sinks using spaceborne, airborne and ground-based data over the eastern United States. Research flights will use NASA’s C-130 from Wallops and the UC-12 from Langley Research Center in Hampton, Virginia.
  • African fires and Atlantic clouds – Jens Redemann of NASA’s Ames Research Center in Mountain View, California, will lead the Observations of Aerosols above Clouds and their Interactions project to probe how smoke particles from massive biomass burning in Africa influences cloud cover over the Atlantic. Particles from this seasonal burning that are lofted into the mid-troposphere and transported westward over the southeast Atlantic interact with permanent stratocumulus “climate radiators,” which are critical to the regional and global climate system. NASA aircraft, including a Wallops P-3 and an Armstrong ER-2, will be used to conduct the investigation flying out of Walvis Bay, Namibia.
  • Melting Greenland glaciers – Josh Willis of NASA’s Jet Propulsion Laboratory in Pasadena, California, will lead the Oceans Melting Greenland mission to investigate the role of warmer saltier Atlantic subsurface waters in Greenland glacier melting. The study will help pave the way for improved estimates of future sea level rise by observing changes in glacier melting where ice contacts seawater. Measurements of the ocean bottom as well as seawater properties around Greenland will be taken from ships and the air using several aircraft including a NASA S-3 from Glenn Research Center in Cleveland, Ohio, and Gulfstream III from Armstrong.

Seven NASA centers, 25 educational institutions, three U.S. government agencies and two industry partners are involved in these Earth Venture projects. The five investigations were selected from 33 proposals.

Earth Venture investigations are part of NASA’s Earth System Science Pathfinder program managed at Langley for NASA’s Science Mission Directorate in Washington. The missions in this program provide an innovative approach to address Earth science research with periodic windows of opportunity to accommodate new scientific priorities.

NASA monitors Earth’s vital signs from land, sea, air and space with a fleet of satellites and ambitious airborne and surface-based observation campaigns. With this information and computer analysis tools, NASA studies Earth’s interconnected systems to better see how our planet is changing. The agency shares this unique knowledge with the global community and works with institutions in the United States and around the world that contribute to understanding and protecting our home planet.

For more information about NASA’s Earth science activities, visit:


Source: NASA

Live longer? Save the planet? Better diet could nail both

New study shows healthier food choices could dramatically decrease environmental costs of agriculture

As cities and incomes increase around the world, so does consumption of refined sugars, refined fats, oils and resource- and land-intense agricultural products such as beef. A new study led by University of Minnesota ecologist David Tilman shows how a shift away from this trajectory and toward healthier traditional Mediterranean, pescatarian or vegetarian diets could not only boost human lifespan and quality of life, but also slash greenhouse gas emissions and save habitat for endangered species.

The study, published in the November 12 online edition of Nature by Tilman and graduate student Michael Clark, synthesized data on environmental costs of food production, diet trends, relationships between diet and health, and population growth. Their integrated analysis painted a striking picture of the human and environmental health costs of our current diet trajectory as well as how strategically modifying food choices could reduce not only incidence of type II diabetes, coronary heart disease and other chronic diseases, but global agricultural greenhouse gas emissions and habitat degradation, as well.

“We showed that the same dietary changes that can add about a decade to our lives can also prevent massive environmental damage,” said Tilman, a professor in the University’s College of Biological Sciences and resident fellow at the Institute on the Environment. “In particular, if the world were to adopt variations on three common diets, health would be greatly increased at the same time global greenhouse gas emissions were reduced by an amount equal to the current greenhouse gas emissions of all cars, trucks, planes, trains and ships. In addition, this dietary shift would prevent the destruction of an area of tropical forests and savannas as large as half of the United States.”

The researchers found that, as incomes increased between 1961 and 2009, people consumed more meat protein, empty calories and total calories per person. When these trends were combined with forecasts of population growth and income growth for the coming decades, the study predicted that diets in 2050 would contain fewer servings of fruits and vegetables, but about 60 percent more empty calories and 25 to 50 percent more pork, poultry, beef, dairy and eggs — a suite of changes that would increase incidence of type II diabetes, coronary heart disease and some cancers. Using life-cycle analyses of various food production systems, the study also calculated that, if current trends prevail, these 2050 diets would also lead to an 80 percent increase in global greenhouse gas emissions from food production as well as habitat destruction due to land clearing for agriculture around the world.

The study then compared health impacts of the global omnivorous diet with those reported for traditional Mediterranean, pescatarian and vegetarian diets. Adopting these alternative diets could reduce incidence of type II diabetes by about 25 percent, cancer by about 10 percent and death from heart disease by about 20 percent relative to the omnivore diet. Additionally, the adoption of these or similar alternative diets would prevent most or all of the increased greenhouse gas emissions and habitat destruction that would otherwise be caused by both current diet trends and increased global population.

The authors acknowledged that numerous factors go into diet choice, but also pointed out that the alternative diets already are part of the lives of countless people around the world. Noting that variations on the diets used in the scenario could potentially show even greater benefit, they concluded that “the evaluation and implementation of dietary solutions to the tightly linked diet-environment-health trilemma is a global challenge, and opportunity, of great environmental and public health importance.”

Tilman is a Regents Professor and McKnight Presidential Chair in Ecology in the College of Biological Sciences’ Department of Ecology, Evolution and Behavior and a resident fellow in the University of Minnesota’s Institute on the Environment, which seeks lasting solutions to Earth’s biggest challenges through research, partnerships and leadership development. Clark is currently a doctoral student in the College of Food, Agricultural and Natural Resource Sciences.

Source: University of Minnesota

Achieving agricultural sustainability through seawater

Even though our planet is called “Earth,” over 70% of its surface is composed of water. Our continued existence depends on this vital resource but it is a staggering fact that only 1% of that water is directly accessible for human use. That is mainly because about 98% of the world’s available water is salty. This means that merely “2% of the Earth’s water is fresh water; but half of it is frozen in the form of glaciers and icebergs,” as Mark Tester, Professor of Bioscience at KAUST and Principal Investigator of the Salt Lab, explains.

The scarcity of fresh water supplies, surface water found in lakes and rivers as well as underground sources, poses a major challenge in the face of a growing world population set to plateau at 9 billion people by 2050. Fresh water is an essential part of our agricultural production infrastructure required to feed ourselves. Indeed, no less than “70% of the water that we use on the planet is used for agriculture. Moreover, 40% of our food is produced under irrigation,” as Prof. Tester outlines.

Global climate change is compounding the problem of water scarcity by altering rainfall patterns, reducing rainfall in previously well watered regions. The already limited supply of fresh water is also increasingly affected by salinity. “It would be wonderful if we could unlock at least a fraction of the rest of the vast amount of the world’s water resources,” as Tester further posits.

“So, in the context of needing to produce 70% more food by 2050, we have to both stop the reduction of yield already suffered from brackish irrigation water, and also unlock some of the other 99% of the water that we’re not able to use at the moment. Both of these things call out for our ability to increase the salinity-tolerance of plants.”

Making Our Current Plants Better

Prof. Mark Tester and his group, as well as other KAUST faculty members’ groups, are actively conducting experimental research in the University’s well-equipped greenhouse to find solutions to tackle our expanding food security challenges.

“We need to raise our ability to increase food supply,” said Tester. “We need innovation in plant science, modern plant breeding (e.g. quantitative genetics) and genetic modification.”

Prof. Tester’s group is primarily focused on studying how salt-tolerant plants are able to survive in harsh environments and then using that knowledge to make less salt-tolerant plants grow better in difficult conditions.

“We are trying to improve plant yields in sub-optimal conditions – where the soil is salty or when the water used to irrigate the plants is salty,” as Prof. Tester clarifies. His group essentially looks at the “naturally occurring variability in plants.”

How are some plants naturally able to better grow in salty water while others are less able to thrive in saline conditions? “I want to know what genes are in those tough plants that are missing from the less tough plants,” said Tester.

A Greenhouse Like No Other

These efforts, combining the observation of naturally occurring variations, the discovery of characterizing genes, and the measuring of the salt tolerance of plants require that KAUST plant scientists be able to grow plants in a controlled environment. These tasks are performed in the KAUST Center for Desert Agriculture (CDA)’s high quality 1600-square-meter greenhouse.

Prof. Mark Tester pointed out a unique feature of the greenhouse: a seawater tank. “We can water plants with seawater in this greenhouse. That’s pretty unusual,” he exclaimed. The filtered seawater greatly facilitates salinity experiments.

Another particular feature of the CDA greenhouse, unique to it’s location in Saudi Arabia, is that the water is actually cooled as it arrives from the desalination plant. This is to prevent the water warming the roots of plants in the soil – roots are used to be in the cooler soil, and are particularly sensitive to being warmed.

Different Approaches to Tackling Abiotic Stress

Given the fact that a quarter of the food that we produce under irrigation is already affected by salinity, a number that is rising rapidly, finding effective ways to use seawater to grow plants is of primary importance.

Prof. Tester recognizes the value of research towards this common sustainable agriculture goal also being conducted by fellow KAUST faculty members such as Prof. Heribert Hirt, who looks at solutions to increase plants’ tolerance to drought and heat, and Prof. Magdy Mahfouz, whose research interests focus on genome-engineering across plant species.

“Together we form a package of different approaches. All the approaches are good. There’s no one right approach. One might be better than another for particular circumstances, but they can all make a valuable contribution to improving crop growth in tough conditions,” said Prof. Tester.

How Plant Science Can Improve Food Security

Among the plants being cultivated and studied in the CDA greenhouse are rice plants. Demonstrating some of the crops that have grown in this controlled environment, Prof. Tester points out how “this one species of rice feeds half of the planet. It’s really important because it feeds the poor half of the planet – mainly in Asia and Africa.”

Taking into account the vital importance of rice crops to continue feeding the world’s growing population, it’s particularly significant that rice plants, as most crop plants, are salt-sensitive. They are indeed easily negatively affected by high salinity.

So Prof. Mark Tester and his team are studying the more salt-tolerant crops, such as barley and tomatoes, in order to better understand how they tolerate salinity, and then use that knowledge to improve other vital crops for our increasing food demands.

For instance, his team is growing a particular type of tomatoes, found on the Galapagos Islands, which are amazingly able to grow right at the edge of the sea and flourish in saline water. “We’re trying to discover the genes that are in these Galapagos tomatoes that allow the plants to grow in these crazy tough conditions,” said Tester.

“We want to use that knowledge to make commercial tomatoes even tougher,” he adds. By extension, “we can then turn our attention to rice and potentially improve its salt-tolerance.”

Source : KAUST News

Stanford graduate student Ming Gong, left, and Professor Hongjie Dai have developed a low-cost electrolytic device that splits water into hydrogen and oxygen at room temperature. The device is powered by an ordinary AAA battery. (Mark Shwartz / Stanford Precourt Institute for Energy)

Stanford scientists develop water splitter that runs on ordinary AAA battery

Hongjie Dai and colleagues have developed a cheap, emissions-free device that uses a 1.5-volt battery to split water into hydrogen and oxygen. The hydrogen gas could be used to power fuel cells in zero-emissions vehicles.


In 2015, American consumers will finally be able to purchase fuel cell cars from Toyota and other manufacturers. Although touted as zero-emissions vehicles, most of the cars will run on hydrogen made from natural gas, a fossil fuel that contributes to global warming.

Stanford graduate student Ming Gong, left, and Professor Hongjie Dai have developed a low-cost electrolytic device that splits water into hydrogen and oxygen at room temperature. The device is powered by an ordinary AAA battery. (Mark Shwartz / Stanford Precourt Institute for Energy)
Stanford graduate student Ming Gong, left, and Professor Hongjie Dai have developed a low-cost electrolytic device that splits water into hydrogen and oxygen at room temperature. The device is powered by an ordinary AAA battery. (Mark Shwartz / Stanford Precourt Institute for Energy)

Now scientists at Stanford University have developed a low-cost, emissions-free device that uses an ordinary AAA battery to produce hydrogen by water electrolysis.  The battery sends an electric current through two electrodes that split liquid water into hydrogen and oxygen gas. Unlike other water splitters that use precious-metal catalysts, the electrodes in the Stanford device are made of inexpensive and abundant nickel and iron.

“Using nickel and iron, which are cheap materials, we were able to make the electrocatalysts active enough to split water at room temperature with a single 1.5-volt battery,” said Hongjie Dai, a professor of chemistry at Stanford. “This is the first time anyone has used non-precious metal catalysts to split water at a voltage that low. It’s quite remarkable, because normally you need expensive metals, like platinum or iridium, to achieve that voltage.”

In addition to producing hydrogen, the novel water splitter could be used to make chlorine gas and sodium hydroxide, an important industrial chemical, according to Dai. He and his colleagues describe the new device in a study published in the Aug. 22 issue of the journal Nature Communications.

The promise of hydrogen

Automakers have long considered the hydrogen fuel cell a promising alternative to the gasoline engine.  Fuel cell technology is essentially water splitting in reverse. A fuel cell combines stored hydrogen gas with oxygen from the air to produce electricity, which powers the car. The only byproduct is water – unlike gasoline combustion, which emits carbon dioxide, a greenhouse gas.

Earlier this year, Hyundai began leasing fuel cell vehicles in Southern California. Toyota and Honda will begin selling fuel cell cars in 2015. Most of these vehicles will run on fuel manufactured at large industrial plants that produce hydrogen by combining very hot steam and natural gas, an energy-intensive process that releases carbon dioxide as a byproduct.

Splitting water to make hydrogen requires no fossil fuels and emits no greenhouse gases. But scientists have yet to develop an affordable, active water splitter with catalysts capable of working at industrial scales.

“It’s been a constant pursuit for decades to make low-cost electrocatalysts with high activity and long durability,” Dai said. “When we found out that a nickel-based catalyst is as effective as platinum, it came as a complete surprise.”

Saving energy and money

The discovery was made by Stanford graduate student Ming Gong, co-lead author of the study. “Ming discovered a nickel-metal/nickel-oxide structure that turns out to be more active than pure nickel metal or pure nickel oxide alone,” Dai said.  “This novel structure favors hydrogen electrocatalysis, but we still don’t fully understand the science behind it.”

The nickel/nickel-oxide catalyst significantly lowers the voltage required to split water, which could eventually save hydrogen producers billions of dollars in electricity costs, according to Gong. His next goal is to improve the durability of the device.

“The electrodes are fairly stable, but they do slowly decay over time,” he said. “The current device would probably run for days, but weeks or months would be preferable. That goal is achievable based on my most recent results”

The researchers also plan to develop a water splitter than runs on electricity produced by solar energy.

“Hydrogen is an ideal fuel for powering vehicles, buildings and storing renewable energy on the grid,” said Dai. “We’re very glad that we were able to make a catalyst that’s very active and low cost. This shows that through nanoscale engineering of materials we can really make a difference in how we make fuels and consume energy.”

Other authors of the study are Wu Zhou, Oak Ridge National Laboratory (co-lead author); Mingyun Guan, Meng-Chang Lin, Bo Zhang, Di-Yan Wang and Jiang Yang, Stanford; Mon-Che Tsai and Bing-Joe Wang, National Taiwan University of Science and Technology; Jiang Zhou and Yongfeng Hu, Canadian Light Source Inc.; and Stephen J. Pennycook, University of Tennessee.

Principal funding was provided by the Global Climate and Energy Project (GCEP) and the Precourt Institute for Energy at Stanford and by the U.S. Department of Energy.

Mark Shwartz writes about energy technology at the Precourt Institute for Energy at Stanford University.