stanford

Decontaminating Drinking Water | Earth Wise

July 24, 2023 By EarthWise Leave a Comment

At least two billion people around the world often drink water that is contaminated with disease-causing microbes. Waterborne diseases are responsible for two million deaths each year, mostly among children under the age of five.

There are various ways to decontaminate water, including chemicals that can themselves produce toxic byproducts as well as using ultraviolet light, which takes fairly long to disinfect the water and requires a source of electricity.

Scientists at Stanford University and the SLAC National Accelerator Laboratory have recently invented a low-cost, recyclable powder that kills thousands of waterborne bacteria every second when the water containing it is exposed to ordinary sunlight. The discovery of this ultrafast disinfectant could be a tremendous benefit to the nearly 30% of the world’s population with no reliable access to safe drinking water.

The new disinfectant is a harmless metallic powder that works by absorbing both ultraviolet and high-energy visible light from the sun. It consists of nano-sized flakes of aluminum oxide, molybdenum sulfide, copper, and iron oxide. The key innovation is that when these four metallic ingredients are immersed in water, they all function together by reacting with the surrounding water and generating chemicals that quickly kill bacteria. The chemicals themselves don’t last long. They quickly break down in the water leaving completely safe drinking water.

The nontoxic powder is recyclable. It can be removed from water with a magnet. It can also be reused at least 30 times. Apart from its uses in less developed parts of the world, it could be valuable for hikers and backpackers who want to drink water from natural sources of unknown quality.

**********

Web Links

New nontoxic powder uses sunlight to quickly disinfect contaminated drinking water

Photo, posted February 27, 2013, courtesy of Petras Gagilas via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar Power At Night | Earth Wise

March 16, 2023 By EarthWise Leave a Comment

The use of solar power has grown tremendously in recent years as it has declined in price and become far more competitive with other forms of electricity generation. Its fundamental drawback, of course, is that it only works when the sun is shining. Solar panels don’t produce any power at night. That is, until now, apparently.

A team of engineers at Stanford University have developed a new kind of solar cell that is capable of generating at least some electricity at night. Published in the journal Applied Physics Letters, the research describes a device that can be a continuous renewable power source for both day and nighttime.

The device incorporates a thermoelectric generator that produces electricity from the small difference in temperature between the ambient air and the solar cell itself. The amount of power produced is far less than the solar cell generates from sunlight, but the device can provide nighttime standby lighting and power in off-grid and mini-grid applications.

Mini-grid applications are independent electricity networks that are used for small populations that may be too isolated to be connected to the main power grid. Nearly 600 million people in Africa currently live without access to electricity, primarily in rural areas. A standalone solar system operating independently of any power grid can meet many electricity needs such as phone charging and lighting, but such systems may not be able to handle large electrical need such as powering machinery and agricultural equipment. Mini-grids are larger installations that can provide power to a small rural community.

With innovations like the new Stanford device, a solar mini-grid may be able to keep running at some level even at night.

**********

Web Links

Solar panels that can generate electricity at night have been developed at Stanford

Photo, posted December 15, 2021, courtesy of Pete via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fake Meat And Climate | Earth Wise

March 10, 2023 By EarthWise 1 Comment

Investors have poured billions of dollars into efforts to replace animal proteins with plant-based substitutes or even laboratory-grown animal cells. Replacing meats with these products is certainly a favorable development for the climate, but it is not likely to offset livestock agriculture’s climate and land use impacts anytime soon.

According to research at Stanford University, even optimistic estimates are that only something like 5% of dietary protein will come from these technologies by 2030. That just isn’t fast enough to put a real dent in the food-related emissions problem.

Stanford environmental scientist David Lobell suggests that there should be much more focus on reducing emissions of animal-based systems. There really hasn’t been much effort in this area because it is only recently that the climate impact of animal agriculture has been a topic of public concern. One problem is that it is difficult for investors to monetize investments in approaches for lowering animal agriculture emissions. These might include alternative feeds or supplements or vaccinations that inhibit methane-producing microorganisms in animals’ digestive systems.

Another approach to the problem is changing the mix of animal proteins in people’s diets. Chicken and pork are half as bad as dairy per pound of protein, and about one-tenth as bad as beef, in terms of emissions.

Dairy is a major issue. There has been quite a lot of progress in increasing the use of dairy-free milk, but over the past 40 years, Americans have cut their consumption of milk in half but doubled their consumption of cheese. Progress in dairy-free cheese has not been anywhere near as successful as that of dairy-free milk. But new products are entering the marketplace all the time.

**********

Web Links

Is fake meat a real solution? Stanford expert explains

Photo, posted June 17, 2019, courtesy of Christolph Scholz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Whales Eating Plastic | Earth Wise

December 1, 2022 By EarthWise Leave a Comment

Plastic waste has been accumulating in the world’s oceans in greater and greater quantities and much of it is in the form of microplastic particles. Many kinds of whales – the largest creatures on Earth – feed by gulping up mouthfuls of krill and other tiny creatures and then straining the seawater through bristly filter structures called baleens. As they do this, they are likely to be swallowing large amounts of plastic.

Scientists at Stanford University recently estimated just how much plastic whales are ingesting by tracking the foraging behavior of 65 humpback whales, 29 fin whales, and 126 blue whales in the Pacific Ocean. Each of the whales was tagged with a camera, microphone, and GPS device suction-cupped to their back.

After accounting for the concentration of microplastics in parts of the Pacific Ocean, the researchers were able to estimate the amount of plastic the whales were consuming. Humpback whales likely consume 4 million microplastic pieces each day, adding up to about 38 pounds of plastic waste. Fin whales swallow an estimated 6 million pieces each – amounting to 57 pounds of plastic. Blue whales, which are the largest creatures on Earth, eat an estimated 10 million microplastic pieces, or as much as 95 pounds of plastic waste each day.

Despite their enormous size, whales actually eat rather low on the food chain, which puts them close to where the plastic is in the water. Krill eats plastic and whales eat the krill. Many marine animals are at risk of eating microplastics, but whales are unique in that they can consume so much of it. It is just one more way in which the ocean plastic situation is a global crisis.

**********

Web Links

Blue Whales Swallowing 95 Pounds of Plastic Daily, Scientists Estimate

Photo, posted October 21, 2005, courtesy of Tobias Begemann via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wildfire Smoke And Air Quality | Earth Wise

November 1, 2022 By EarthWise Leave a Comment

According to a new study published by Stanford University, the average number of people in the U.S. exposed to unhealthy levels of airborne particulates at least one day a year has increased 27-fold over the last decade as a result of wildfires.

Millions of Americans are now routinely exposed to plumes of wildfire smoke that sometimes travel thousands of miles across the country. Accumulations of deeply unhealthy air have emerged mainly in the West, where increasingly intense wildfires have become all too common. Six of the seven largest wildfires in California recorded history have occurred since 2020.

Wildfire smoke has resulted in school closures, flight postponements, and even cancelled concerts. Overall, the regression in air quality has undone much of the clean air progress that has taken place since the advent of the Clean Air Act in 1970.

Wildfire smoke has added about 5 micrograms of PM 2.5 particles per cubic meter of air on average in many places in the West. This is a substantial increase from national levels, which are a total of about 10 micrograms per cubic meter and mostly result from emissions from cars, trucks, and power plants.

A decade ago, fewer than 500,000 Americans were exposed to any days of an air quality index of 100 or more due to smoke, which is a level that is deemed unhealthy. In 2020, 25 million Americans were in areas with such levels at least one day during the year.

Ordinarily, if people don’t live near a highway or power plant, their air quality is likely to be pretty good. But incursion from wildfire smoke is changing that, and the trend is likely to increase.

**********

Web Links

Number of Americans Exposed to Harmful Wildfire Smoke Has Increased 27-Fold

Photo, posted August 19, 2013, courtesy of Mike Lewelling / National Park Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Cheap Material For Carbon Capture | Earth Wise

September 12, 2022 By EarthWise Leave a Comment

The recently passed Inflation Reduction Act includes significant support for carbon capture technologies. Eliminating fossil fuel burning is essential for halting climate change, but in the interim, methods for capturing emissions of carbon dioxide and either storing it or turning it into usable products are increasingly necessary.

There are a variety of techniques being developed for carbon capture but at this point, none of them are commercially viable. The best technique in use today involves piping flue gases through chemicals called liquid amines, which bind CO2. The process requires large amounts of energy to release the bound carbon dioxide so it can be concentrated and stored. As a result, it is complicated and expensive.

Researchers at UC Berkeley, Stanford, and Texas A&M University have developed a carbon capture method using melamine, which is an inexpensive polymer used to make Formica, as well as low-cost dinnerware, industrial coatings, and other plastics. Porous melamine itself adsorbs CO2 to a limited extent. But the researchers discovered that adsorption could be much improved by adding the chemical DETA (diethylenetriamine) to bind the CO2. In addition, adding cyanuric acid increased the melamine pore size and radically improved CO2 capture efficiency even more.

The result is a material that is more efficient even than exotic carbon capture materials like metalorganic frameworks and is much cheaper and easier to make. The researchers aim to design equipment that can used in industrial facilities, attached to buildings and other structures, or even to the tailpipes of gas-powered vehicles.

**********

Web Links

A simple, cheap material for carbon capture, perhaps from tailpipes

Photo, posted June 10, 2006, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Methane Leaks Are Worse Than We Thought | Earth Wise

May 4, 2022 By EarthWise Leave a Comment

Methane leaking from oil and gas wells is a real problem for the environment because methane is far more potent at trapping heat than carbon dioxide. The EPA has estimated that about 1.4% of the methane produced by wells nationally leaks into the atmosphere. However, environmental experts and energy industry engineers have been concerned that leaks from mines, wells, refineries, storage facilities, and pipelines are vastly underreported. But until recently, there really wasn’t a good way to find out.

Researchers at Stanford University have developed a technique based on the use of hyperspectral cameras mounted to airplanes. The cameras measure sunlight reflected off of chemicals in the air that are invisible to the human eye. Each chemical, including methane, has a unique fingerprint. Using these sensors, methane is easy to spot and the technique can measure the output of individual wells.

The researchers performed a study of almost every oil and gas asset in the New Mexico Permian Basin, one of the largest and highest-producing oil and gas regions in the world. They surveyed the sites for an entire year. They estimate that more than 9% of all methane produced in the region is being leaked into the skies, far more than EPA estimates.

The positive outcome of the survey is that the researchers found that fewer than 4% of the 26,000 sites studied produced half of all the methane emissions observed. Being able to identify the so-called super-emitter sites and dealing with them could lead to a major improvement in the situation.

The new technique is more accurate, faster, and more cost-effective than current ways to monitor emissions.

**********

Web Links

Stanford-led study: Methane leaks are far worse than estimates, at least in New Mexico, but there’s hope

Photo, posted July 10, 2016, courtesy of Ken Lund via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Capturing Methane To Feed Fish | Earth Wise

December 30, 2021 By EarthWise Leave a Comment

Methane in the atmosphere is an extremely potent greenhouse gas. Its warming potential is about 85 times that of carbon dioxide over a 20-year period. It also worsens air quality by increasing atmospheric ozone. Many human activities add methane to the atmosphere, notably emissions from landfills and oil and gas facilities.

Capturing methane from these sources for subsequent use is currently uneconomical but new research from Stanford University analyzes the market for using the methane to feed bacteria to produce fishmeal.

Methane-consuming bacteria called methanotrophs can be grown in chilled, water-filled bioreactors containing pressurized methane, oxygen, and nutrients. The bacteria produce a protein-rich biomass that can be used as fishmeal in aquaculture. This could offset demand for fishmeal made from small fish or plant-based feeds that require land, water, and fertilizer.

Some companies already do this using natural gas provided by utility pipelines, but it would be far better for the environment to use methane emitted at large landfills, wastewater treatment plants, and oil and gas facilities.

Consumption of seafood has more than quadrupled since 1960, depleting wild fish stocks. Farmed fish now provide half of all the animal-sourced seafood we eat.

The Stanford research analyzed the cost of methanotrophic fishmeal production under various scenarios and found it to be very competitive with and in some cases considerably cheaper than current market prices for fishmeal.

According to the study, this process could profitably supply total global demand for fishmeal with methane captured in the U.S. alone.

**********

Web Links

Stanford researchers reveal how to turn a global warming liability into a profitable food security solution

Photo, posted April 30, 2017, courtesy of Artur Rydzewski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Whales As Ecosystem Engineers | Earth Wise

December 14, 2021 By EarthWise Leave a Comment

Researchers from Stanford University have been studying the role of large whales on ocean ecosystems with some surprising results.

From 1910 to 1970, people killed about 1.5 million baleen whales in the waters surrounding Antarctica. The whales were hunted for their blubber, baleen, and meat. Baleen is the filtering fringe that certain whales use instead of teeth to capture food from the ocean. A primary food source for these whales is krill, small shrimp-like creatures. One would assume that the decimation of the baleen whale population in the Southern Ocean would have led to a surge in krill populations. But the new research has found that the opposite is the case.

The precipitous decline of large marine mammals has negatively impacted the health and productivity of ocean ecosystems.

New high-tech tagging devices that attach to whales for brief periods allow researchers to record their movements and activities. For the first time, it has been possible to accurately determine how much krill whales actually consume, and the answer is that they eat two to three times as much as previously thought. Interestingly, the same technology shows that fish-eating whales like humpbacks eat somewhat less than previously thought.

Baleen whales are essentially mobile krill processing plants. They eat the krill, digest it, and produce iron-laden excretions that are needed by phytoplankton, which comprise the bottom of the food chain that nourish krill and other small creatures. With fewer whales, there is less nourishment for the krill. In fact, based on the new data, estimates are that the historic abundance of krill in the Southern Ocean had to be about five times what it is today.

Whales are important ecosystem engineers.

**********

Web Links

Stanford researchers find whales are more important ecosystems engineers than previously thought

Photo, posted November 18, 2010, courtesy of Dr. Brandon Southall, NMFS/OPR via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tree-Planting Is Not Necessarily A Good Thing | Earth Wise

July 31, 2020 By EarthWise Leave a Comment

There is no question that forests have a major role in efforts to combat climate change as well as to slow biodiversity loss. As a result, tree-planting on a massive scale has gained traction as a strategy and there have been major commitments made to plant billions of trees around the world.

A new study at Stanford University has rigorously analyzed the potential effects of these efforts and has found some significant problems. For example, the Bonn Challenge, which seeks to restore an area of forest more than eight times the size of California over the next 10 years, has 80% of its commitments in the form of planting monoculture tree plantations or a limited mix of trees that produce fruit and rubber, rather than restoring natural forests. The problem is that plantations have significantly less potential for carbon sequestration, habitat creation, and erosion control than natural forests. The potential benefits of the planting dwindle further if planted trees replace natural flora – forests, grasslands, or savannahs – which are ecosystems that have evolved to support local biodiversity.

The study looked at previous policies that created subsidies for planting trees. Chile’s Decree Law, in effect from 1974 to 2012, has served as a model for similar policies in a number of countries. Those subsidies further reduced native forest cover by encouraging the establishment of plantations in places where forests might have naturally regenerated. The subsidies expanded the area covered by trees, but decreased the area of native forests.

The study recommends that nations should design and enforce their forest subsidy policies to avoid undesirable ecological impacts and actually promote the recovery of carbon- and biodiversity-rich ecosystems.

**********

Web Links

Poorly designed tree-planting campaigns could do more harm than good, according to Stanford researcher and others

Photo, posted April 28, 2016, courtesy of the U.S. Department of State via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

More Extreme Wildfire Seasons | Earth Wise

April 29, 2020 By EarthWise Leave a Comment

According to a new study led by researchers at Stanford University, autumn in California feels more like summer now as a result of climate change, and this hotter and drier weather increases the risk of longer and more dangerous wildfire seasons.

The research team, whose work was recently published in the journal Environmental Research Letters, found that the frequency of extreme fire weather conditions in the fall in California has doubled since the early 1980s. Average temperatures during the season have increased by more than 2 degrees Fahrenheit, and rainfall has fallen by approximately 30%. The most pronounced warming has occurred in the late summer and early fall. That finding means that tinder-dry conditions coincide with the strong “Diablo” and “Santa Ana” winds that are typical in California at this time of year.

In recent years, these conditions have fed large and fast-moving wildfires across California. The state’s two largest wildfires, two most destructive wildfires, and the most deadly wildfire all occurred during 2017 and 2018, resulting in more than 150 deaths and $50 billion in damage.

Because summertime has typically been peak fire season, the recent spate of autumn fires is putting a strain on firefighting resources and funding. The ongoing COVID-19 pandemic could further strain emergency resources. Since fire-prone regions have historically shared wildfire-fighting resources throughout the year, the consequences of California’s extended wildfire season could have a global impact. (For example, California’s recent autumn wildfires have coincided with the beginning of wildfires in Australia).

The researchers highlight some opportunities to manage the intensifying wildfire risk in California, including limiting the trajectory of global warming in keeping with the targets identified in the United Nations’ Paris agreement.

**********

Web Links

Researchers forecast longer, more extreme wildfire seasons

Photo, posted September 12, 2019, courtesy of the California National Guard via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Stretchable Batteries | Earth Wise

February 28, 2020 By EarthWise Leave a Comment

Wearable technology is an ever-increasing part of our world. Fitness trackers have become commonplace for people of all ages. Smart watches perform a growing range of functions. There are wearable health monitoring systems of many types for assisted living, elderly patients, and people with specific health problems. Virtual reality headsets are increasingly popular and there is now even smart technology footwear that is integrated with smartphones and mapping software.

The adoption of wearable electronics has so far been limited by their need to derive power from relatively bulky, rigid batteries that reduce comfort and even may present safety hazards related to chemical leakage or combustion. To date, there has not been a power source that can stretch and bend the way our bodies do, which would enable electronic designs that people can comfortably wear.

Researchers at Stanford have recently announced the development of a soft and stretchable battery that relies on a special type of plastic to store power more safely than the flammable formulations used in conventional batteries today.

The lithium ion batteries in our phones, computers, cameras and electric cars already make use of plastic electrolytes. These polymer electrolytes are in the form of flowable gels. The Stanford researchers developed a new polymer that is solid and stretchable rather than gooey and potentially leaky. But it still carries an electric charge and maintains a constant power output even when squeezed, folded or stretched to nearly twice its original length.

The prototype battery is thumbnail-sized and stores only about half as much energy for its size as a conventional battery. But the researchers are working to increase both the size and the energy density of the battery.

**********

Web Links

A new stretchable battery can power wearable electronics

Photo, posted November 28, 2016, courtesy of Timo Newton-Syms via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Fish And Ships

April 25, 2019 By EarthWise Leave a Comment

Solutions to overfishing of certain tuna and shark populations have been hindered by some significant unknowns: where the fishing is happening, and where the fish are. But researchers from Stanford University have recently shed some light on this mystery.

According to a paper recently published in the journal Science Advances, the researchers have developed a map of shark, tuna, and ship movements that could help ocean managers identify regions of the sea where vulnerable species may be at risk.

The researchers’ work builds on a 2018 study in which four years of satellite vessel movement data was used to develop a machine learning algorithm that mapped the footprint of 70,000 different fishing vessels around the world. In their paper, the researchers zeroed in on the activities of 900 vessels from 12 countries in the northeast Pacific Ocean to figure out to what degree fishing fleets, sharks, and tunas overlapped.

The researchers combined the vessel data with the ocean habitat preferences of sharks and tunas obtained from a decade-long tracking program called Tagging of Pacific Predators (or TOPP). According to the IUCN, most of the 876 individuals tagged in TOPP belong to species that are either threatened or near-threatened.

By synthesizing this data, researchers were able to map where sharks and tunas would have the highest overlap with commercial fishing vessels. Increasing the transparency of where fish meets fleets will allow ocean managers to determine where international protections may be needed.

The United Nations is currently developing the world’s first legally binding treaty to protect international waters. The Stanford University researchers hope their findings can help with this treaty’s formulation.

**********

Web Links

Tunas, sharks and ships at sea

Photo, posted June 20, 2011, courtesy of Mike Baird via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Droughts And Hydropower

February 7, 2019 By EarthWise Leave a Comment

Recent droughts in several western states have led to well-publicized problems including wildfires, loss of trees, and damage to crops. A lesser-known impact of drought conditions has been increases in emissions of carbon dioxide and harmful air pollutants from power generation.

When hydropower runs low in a drought, western states tend to ramp up power generation – and therefore emissions – from fossil fuels. According to a new study from Stanford University, droughts caused about 10 percent of the average annual carbon dioxide emissions from power generation in California, Idaho, Oregon and Washington between 2001 and 2015.

Water is used in electricity generation both directly for hydroelectric power and indirectly for cooling in thermoelectric power plants. When water for hydropower comes up short because of drought conditions, natural gas or coal-fired power plants are brought online to pick up the slack.

These drought-induced shifts in energy sources led to an estimated 100 million tons of carbon dioxide across 11 western states between 2001 and 2015. That is the equivalent of adding 1.4 million vehicles to the region’s roadways. California, whose legislature has mandated that the state be carbon-free by 2045, contributed about half of this total. Washington, which is considering a similar mandate, contributed nearly a quarter of the total.

Western states in recent years have suffered intense droughts that scientists expect to become more common as global warming continues to intensify. The new study indicates that in regions where clean, reliable hydropower has been an important part of the energy mix, it will be increasingly necessary to provide clean backup energy sources in order to meet emission reduction targets.

**********