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Fuel from Corn Waste

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A substantial amount of corn is grown in this country for the purpose of producing ethanol.  The value of doing so is debatable for many reasons.  Nevertheless, the majority of the corn crop is grown for food.  But along with all that corn, there is corn stover.  Stover is the dried stalks, leaves, and other plant parts that remain in the field after the corn itself has been harvested.  Corn stover is the largest quantity of biomass residue in the United States.  Around 250 million tons of it is produced annually and the majority of it is left unused.  Some is used for animal feed and other purposes and has monetary value, but much of it goes to waste.

Scientists at Washington State University have developed a way to produce low-cost sugar from stover that can be used to make biofuels and other bioproducts.

Corn stover is an abundant and cheap source of biomass, which holds great potential as a source of energy and valuable chemicals.  The challenge is to overcome the high cost of processing stover whose complex structural molecules like cellulose and lignin need to be broken down.

The new process uses potassium hydroxide and ammonium sulfite to convert stover into a sugar.  It is a mild-temperature process that allows enzymes to break down the cellulosic polymers in stover into sugar, which can then be fermented into biofuels.  The resulting sugar from the process would be cost-competitive with low-cost imported sugars. The researchers estimate that their patent-pending process could produce sugar that could be sold for as low as 28 cents per pound.

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Scientists discover a new way to convert corn waste into low-cost sugar for biofuel

Photo, posted August 30, 2012, courtesy of Idaho National Laboratory Bioenergy Program via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Feeding the future

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Climate change is already affecting the yields of major staple crops around the world, and researchers warn that the impacts will become more severe over time. Rising temperatures, shifting rainfall patterns, and more frequent extreme weather events are disrupting growing seasons and reducing agricultural productivity.

Addressing these growing threats requires rethinking how we grow, distribute, and consume food.  To kick off Climate Solutions Week, we wanted to examine some solutions that could make food systems more resilient, sustainable, and adaptable to our rapidly changing environment.

One solution is Climate-Smart Agriculture, which blends traditional practices with modern techniques to boost productivity while reducing greenhouse gas emissions. Methods like zero tillage, intercropping, and crop diversification could improve soil health, conserve water, and help farms withstand climate extremes.

Expanding the production of highly nutritious and climate resilient food crops – like millet, sorghum, teff, quinoa, chickpeas, and tepary beans – will also have an important role to play.  At the same time, reducing food waste through better storage, labeling, and surplus food re-use could help meet demand without increasing production pressure.

Agriculture is the largest user of freshwater globally, and climate change is intensifying water shortages.  Farmers will need to transition to water-efficient farming practices, including drip irrigation, rainwater harvesting, and the reuse of treated wastewater. 

Together, these solutions could help revolutionize the global food system to both feed a growing population and help protect the planet. 

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Climate-smart agriculture

Water for Prosperity and Peace

A Food For The Future

Photo, posted October 16, 2011, courtesy of Alliance of Bioversity International and CIAT via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Plastic from food waste

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Plastic waste management is a complicated business.  Most methods of recycling or breaking down plastic are costly and harmful to the environment.  The most common biodegradable alternatives – like paper straws – are less than ideal replacements.

There are many approaches to creating biodegradable plastics using feedstocks like seaweed, sugarcane, and other plant matter.  However, the resulting plastics often fall short compared with conventional petroleum-based plastics.

One type of bioplastic that is gaining popularity is polyhydroxyalkanoates, or PHA.  PHA is a plastic produced by microorganisms.  It is fully compostable or biodegradable but in other ways but looks, feels, and functions like regular plastic but without the environmental drawbacks.

PHA can be made using bacterial fermentation of a variety of feedstocks such as vegetable oils, sugars, starches, and even methane and wastewater.

Researchers at a startup from the University of Waterloo in Canada called MetaCycler BioInnovations have developed a process for producing PHA based on bacteria that has been engineered to convert waste from milk and cheese production.  This solution upcycles waste from the dairy industry into cost-effective, sustainable bio-based plastics. 

PHAs can be tailored to have a wide range of properties ranging from being rigid and tough to being quite flexible.  Therefore, they can be suitable for many applications including packaging, agricultural films, and consumer goods. 

The Waterloo technology is a way to tackle the problems of both food waste and plastic pollution with one solution.

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Turning food waste into a new bioplastic

Photo, posted December 10, 2017, courtesy of Leonard J Matthews via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Green grout for stabilizing buildings

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We are all familiar with the grout that is used for tiles in our homes. We are less familiar with grout that is used to stabilize the soil beneath buildings.  Grouting is a process of ground improvement by injecting materials that can fill voids and cracks, strengthen and increase the bearing capacity of soil, and reduce permeability.

Traditional grouting methods have environmental downsides.  Most often, silica-based chemical grouts are used, and they are produced through energy-intensive processes that contribute substantially to carbon dioxide emissions.  As is the case for all materials and practices of the construction industry, developing sustainable, low-emission alternatives to conventional grouting materials has become an important priority.

Researchers from the Shibaura Institute of Technology in Japan have developed an innovative new grout material called Colloidal Silica Recovered from Geothermal Fluids.  This grout material enhances soil stabilization and simultaneously reduces the environmental impact of geothermal energy harvesting.

Geothermal energy production generates large amounts of silica-rich waste fluids which creates challenges for its maintenance and disposal.  The new grout repurposes this waste material thereby transforming an industrial byproduct into a valuable construction material.

The new grout material is particularly valuable in earthquake-prone regions, where soil stabilization is essential in preventing structural damage during seismic events.  In addition, the grout’s superior water-sealing properties makes it ideal for underground construction projects like tunnels, subways, and basements.  The new grout in an important step for the construction industry’s efforts to achieve carbon neutrality.

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From Waste to Wonder: Revolutionary Green Grout for Sustainable Construction Practices

Photo, posted July 8, 2011, courtesy of MTA Construction & Development Mega Projects via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rats and climate change

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Human activity has made rats one of the most prolific mammals on the planet. Our waste, buildings, and ships provide food, shelter, and transport.  In the United States alone, rats cost the country approximately $27 billion each year in damage to infrastructure, crops, and contaminated food supplies. Additionally, rats carry and spread over 50 zoonotic pathogens and parasites, impacting public health around the world.

Now, climate change is adding to the problem. According to a new study recently published in the journal Science Advances, urban rat populations are exploding as global temperatures rise.  The researchers found that Washington DC, San Francisco, Toronto, New York City, and Amsterdam had the greatest population increases.  In fact, over the past decade, rats increased by a whopping 390% in Washington DC, 300% in San Francisco, 186% in Toronto, and 162% in New York City.  The study, which examined data from 16 cities globally, found that 11 of them showed significant increases in rat numbers.

Only Tokyo, Louisville, and New Orleans bucked the trend with declining rat numbers.

According to the researchers, the best pest management strategies involve making the urban environment less rat-friendly as opposed to removing rodents that are already there.  An example would be putting trash in containers instead of bags on the street. 

There aren’t many perks to the changing climate – unless, of course, you’re a rat. 

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Increasing rat numbers in cities are linked to climate warming, urbanization, and human population

‘Perfect rat storm’: urban rodent numbers soar as the climate heats, study finds

Photo, posted September 25, 2018, courtesy of Tim Felce via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A green battery from industrial waste

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Flow batteries are rechargeable batteries in which liquid electrolytes flow through one or more chemical cells from one or more tanks.  The electrolytes are redox pairs, that is, chemical compounds that can reversibly undergo reduction and oxidation reactions.  The most common redox electrolytes include elements like vanadium, chromium, iron, zinc, and bromine.  Flow batteries can provide large amounts of both electrical power and stored energy based on the size of the electrolyte tanks.  As a result, they can be scaled up far more readily than other battery technologies. 

Flow batteries are safe, stable, long-lasting, and their electrolytes can easily be refilled.  They have significant potential for use in utility-scale storage for renewable energy systems.

Researchers at Northwestern University have developed a redox flow battery based on an organic industrial-scale waste product.  The material – triphenylphosphine oxide or TPPO – is produced in the thousands of tons each year.  It is byproduct of producing a variety of substances including some vitamins, pharmaceuticals, agrochemicals, and other bulk chemicals.  For the most part, TPPO is of little use and must be carefully discarded.

The current market for redox flow batteries is very small but is expected to grow over time as the need for utility-scale energy storage continues to expand.  A battery technology based on a waste material that is already produced in high volume and that must otherwise be disposed of with caution would have significant advantages.

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Green battery discovery turns trash into treasure

Photo, posted January 12, 2015, courtesy of California Energy Commission via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Storing carbon in buildings

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According to a new study by researchers at the University of California, Davis and Stanford University, construction materials used in buildings have the potential to lock away billions of tons of carbon dioxide.  The study, published in Science, shows that storing CO2 in buildings could be a major contributor to efforts to reduce greenhouse gas emissions.

Overall efforts in carbon sequestration take carbon dioxide – either as it’s being produced or once it’s already in the atmosphere – and store it away.  Storing it might involve injecting it into underground caverns or deep in the ocean.  Alternatively, storing it might involve converting it into a stable form using chemical reactions.  These various strategies involve both practical challenges and potential environmental risks.

The new study suggests that many materials that are already produced in large quantities have the potential to store carbon dioxide.  These include concrete, asphalt, plastics, wood, and brick.  More than 30 billion tons of these materials are produced worldwide every year.

Ways to accomplish carbon storage include adding biochar into concrete, using artificial rocks loaded with carbon as concrete and asphalt aggregates, plastic and asphalt binders based on biomass instead of petroleum, and including biomass fiber into bricks. 

The largest potential is using carbonated aggregates to make concrete.  Concrete is by far the world’s most popular building material with more than 20 billion tons being produced each year.

The feedstocks for these ways to store carbon in building materials are mostly low-value waste materials, so the economics of implementing these carbon sequestering strategies are likely to be quite favorable.

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Storing Carbon in Buildings Could Help Address Climate Change

Photo, posted October 19, 2022, courtesy of Alexandre Prevot via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Curbing food waste

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According to the U.S. Department of Agriculture, as much as 40% of the food supply in the United States is wasted.  In fact, Americans generate more food waste than all but two countries.

To address this problem, the federal government announced a goal nearly a decade ago to cut food waste in half by 2030 compared to 2016 levels.  Doing so would bring food waste down to approximately 164 pounds per person annually.

However, according to a new study led by researchers from the University of California – Davis, since 2016, per capita food waste has actually increased instead of decreasing. 

The study, which was recently published in the journal Nature Food, looked at how state policies align with federal targets.  The research team found that state policies focus more on recycling methods, such as composting and anaerobic digestion, rather than on prevention and rescue strategies, like food donations or repurposing food for animal feed.

In 2021, the EPA revised its definition of food waste to no longer include recycling methods.  But when food is wasted, the resources used to grow the food, including energy, water, and fertilizer, are also wasted. 

In the study, the researchers analyzed state-level food waste reduction efforts across four areas: prevention, rescue, repurposing, and recycling.  They found that recycling policies offered the most potential for diversion. Despite this, most states still fell short of the federal goal of 164 pounds per person annually. 

According to the research team, more comprehensive policies to address food waste must be implemented as soon as possible.

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States Struggle to Curb Food Waste Despite Policies

Photo, posted June 28, 2021, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Growing safer potatoes

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We are often advised to avoid eating green areas on potatoes.  The green comes from chlorophyll that occurs naturally when potatoes are exposed to light.  It is harmless but when it is there, it can be accompanied by a natural toxin – a substance called solanine, which is a steroidal glycoalkaloid or SGA.  Sunlight can produce solanine as well as chlorophyll.  Solanine is produced by plants to protect them from insects. 

Solanine is bitter tasting so one is unlikely to consume much of it.  But consuming enough of it can lead to gastrointestinal complications like diarrhea, abdominal pain, vomiting, and sweating. 

Researchers at the University of California Riverside have discovered a way to eliminate toxic compounds from potatoes, making them safer to eat and easier to store.  They have identified a key genetic mechanism in the production of SGAs.  They found a specific protein that controls the production and believe it will be possible to control where and when SGAs are produced.  Thus, it may be possible to have SGAs present in the leaves of potato plants, thereby protecting them from insects, while having none in the potatoes themselves.  By limiting SGAs to non-edible parts of plants, they can be safer and more versatile plants.  For example, modified potatoes could be stored in sunny places without worry and would always be safe to eat.

Plants have evolved ingenious ways to balance growth, reproduction, and defense.  Our growing understanding of these mechanisms can allow people to redesign crops to meet modern needs, increase food safety, and reduce food waste.

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Growing safer spuds: Removing toxins from potatoes

Photo, posted October 14, 2013, courtesy of Elton Morris via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Politics and plastic

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The world currently produces nearly half a billion tons of plastic each year.  This is more than twice the amount it produced 20 years ago.  Half of all plastics ever manufactured have been made in the past 20 years.  Plastic waste is everywhere.  About eight million tons of plastic waste escapes into the ocean each year.

Environmental groups have urged nations to adopt a legally binding treaty to address the ever-growing problem of plastic pollution. The United Nations climate conference in South Korea last month took up the issue of reaching agreement on such a treaty.  At what was supposed to be the final round of talks on the topic, delegates could not bridge wide differences on what such a treaty should contain.

The main bone of contention was whether the treaty should include limits on plastic production itself.  Saudi Arabia, Russia, Kuwait, and other oil-producing countries opposed any curbs on plastic production.   They also opposed the phase-out of harmful chemicals used in the production of plastic.

The Saudi delegation claimed that if the issue of plastic pollution is addressed, there should be no problem with producing plastics.  They said the problem is pollution itself, not plastics.  They proposed a focus on improving recycling and waste management.

Of course, preventing plastic pollution from occurring is an extremely challenging thing to do.  Delegates from countries pushing for a wide-ranging treaty – led by Rwanda – were unwilling to accept a toothless theory lacking real constraints on the plastics industry.

As the conference ended, delegates said that they would reconvene in future months to try again to produce a treaty.  No date or place has been announced.

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Nations Fail to Reach an Agreement on Plastic Pollution

Photo, posted February 4, 2023, courtesy of Ingrid Taylar via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rising methane emissions

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Methane is a colorless and odorless gas that occurs abundantly in nature and is also a product of certain human activities.  It’s a short-lived but highly potent greenhouse gas and, as a result, is a major driver of climate change.  In fact, methane heats the atmosphere nearly 90 times faster than carbon dioxide over a 20-year period. 

Despite a global pledge from more than 150 nations to reduce methane emissions by 30% this decade, methane emissions continue to rise.  In fact, according to a new paper led by researchers from Stanford University, total annual methane emissions have increased 20% over the past two decades. 

The paper, which was recently published in the journal Environmental Research Letters, found that atmospheric concentrations of methane today are more than 2.6 times higher than in pre-industrial times.  In fact, atmospheric methane concentrations are currently the highest they’ve been in at least 800,000 years.

Methane emissions from coal mining, oil and gas production and use, cattle and sheep ranching, and decomposing organic waste in landfills are responsible for driving the growth.  In 2020, the most recent year for which data was available, nearly 400 million tons – or about two-thirds – of global methane emissions came directly from human activities. 

Methane concentrations in Earth’s atmosphere have increased at record speed over the past five years.  According to the research team, only the European Union and possibly Australia seem to have decreased methane emissions from human activities over the past two decades.  This trend “cannot continue if we are to maintain a habitable climate.”

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Methane emissions are rising faster than ever

Photo, posted December 4, 2010, courtesy of Dani Mettler via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Revolution Wind installs first turbine

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Revolution Wind is an offshore wind farm being built by Rhode Island and Connecticut and is the first multi-state offshore wind farm in the United States.  Once completed, it will deliver 400 MW of power to Rhode Island and 304 MW of power to Connecticut.

Revolution Wind is a 50/50 partnership between Ørsted, the Danish multinational energy company, and Eversource, a major New England utility company.  The wind farm is located about 15 miles south of the Rhode Island coast and 32 miles southeast of Connecticut.  It is fairly close to the recently completed South Fork Wind, the first completed utility-scale offshore windfarm in the U.S. and was built by the same partnership.

The first Revolution Wind turbine was installed at the end of August and construction continues with the installation of foundations for the 65 turbines that will comprise the project.  More than three-quarters of the units were in place by the beginning of September.  Ships have also arrived on scene for cable-laying operations for the wind farm.  Onshore construction continues in North Kingstown, Rhode Island, on the project’s transmission system.  The turbines for the project are being assembled by local union labor in New London, Connecticut. 

Commercial operations at Revolution Wind will not begin until 2026.  Construction of the electrical substation necessary to connect the project to the regional electric grid is taking place on the site of a decommissioned naval air station and it is a time-consuming project because of the presence of buried waste and soil contamination.  The construction of the offshore wind farm itself will be completed in 2025.

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Revolution Wind installs first offshore turbine

Photo courtesy of Kate Ciembronowicz / Orsted via Revolution Wind.

Earth Wise is a production of WAMC Northeast Public Radio

Greenhouses and the environment

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The use of greenhouses around the world has been growing dramatically.  A new satellite mapping exercise estimated the total land area covered with permanent greenhouses at 3.2 million acres, which is an area the size of Connecticut.  More than half of this is in China, where the growth of greenhouses has been driven by the rapid urbanization of the country and by a more prosperous population increasingly consuming produce like tomatoes, cucumbers, peppers, and eggplants.

The intensive agricultural methods employed within greenhouses can be harmful to local environments because of overtaxing water supplies and by polluting rivers and soils with nutrients, pesticides, and plastic waste.  But the effects of vast areas of plastic coverings on local temperatures can be even more dramatic, and often beneficial.

There are so many plastic and glass roofs in many areas that they are reflecting sufficient amounts of solar radiation to cool local temperatures.  Greenhouse roofs increase the albedo – the reflectivity – of the land surface typically by a tenth.

All these greenhouses are just the tip of the albedo iceberg.  Many farms now temporarily cover crops with reflective plastic sheets.  If these coverings are included in the satellite survey, the total reflective area would be about ten times greater – roughly the size of New York State.

A study in Almeria, on the Mediterranean coast of Spain, which grows about 3 million tons of fruit and vegetables annually, determined the cooling effects of greenhouses.  Weather stations amid the greenhouses showed an average cooling of 1.3 degrees Fahrenheit compared with the surrounding area.

Greenhouses are an accidental and benign form of climate engineering. The cooling provided by greenhouses is similar to the effect of white roofs in urban areas. 

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Could the Global Boom in Greenhouses Help Cool the Planet?

Photo, posted September 6, 2017, courtesy of Lance Cheung / USDA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Barley plastic

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The durability, malleability, and low cost of plastics have made them ubiquitous.  Plastics are everywhere:  in packaging, clothing, and an endless variety of products.  As a result, they are everywhere in the environment and they tend to stay there, contaminating land and sea.  They are tough to recycle, and their production emits more carbon dioxide than all air traffic combined.  The search for viable substitutes for plastic is global and intensive.

Most common bioplastics are not an ideal solution.  They don’t break down that easily when tossed into the natural environment.  The process can take years. 

Researchers at the University of Copenhagen have invented a new material made from modified starch that can completely decompose in nature and can do so in only two months.  The material is made using natural plant material from crops and could be used for food packaging as well as many other things.

The new material is a biocomposite composed of several substances that decompose naturally.  The main ingredients are amylose and cellulose, common in many plants.  Amylose is extracted from crops like corn, potatoes, wheat, and barley.

The Danish researchers have developed a barley variety that produces pure amylose in its kernels.  Pure amylose is ideal because it is less likely to turn into a paste when it interacts with water. 

Combining the amylose with cellulose forms long, strong molecular chains, resulting in a durable, flexible material that can replace plastic in many applications.  The research team has founded a spinoff company and have applied for a patent for the new material.  It is unclear when the biofriendly barley-based plastic might be commercialized, but its potential is quite good.

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Researchers invent one hundred percent biodegradable “barley plastic”

Photo, posted May 20, 2010, courtesy of Frederick Lang Jr. via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Eliminating plastic shipping pillows

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Anyone who gets packages from Amazon is familiar with the plastic air pillows used to keep products safe in transit.  Amazon uses almost 15 billion of them a year in North America.

Environmentalists have been urging Amazon and other vendors to cut down on the use of plastic packaging. The air-filled plastic pillows are made from plastic film, which is the most common form of plastic litter found in the sea and in seabeds along the shore.  Plastic film can be deadly to wildlife such as sea turtles and sea birds.  Plastic film generally can’t be composted or recycled either.

Recently, Amazon announced that it will replace its plastic pillows with recycled paper filler in all its North American markets – the United States, Canada, and Mexico – which together account for more than 70% of the retailer’s global sales.  It is already making the switch in a big way and is working towards fully removing the plastic materials by the end of the year.

Replacing plastic packaging with paper is a definite improvement.  Paper is recyclable and biodegradable.  It isn’t perfect:  if it ends up in landfills, it can contribute to methane pollution as it biodegrades.  But, on the other hand, paper packaging is more likely to be recycled.

Stemming the tide of plastic waste is an ongoing effort by environmental and consumer groups.  There is pending legislation in New York that aims to reduce the use of plastic packaging by 50% over 12 years by requiring manufacturers to either replace it or pay fees.  The bill cleared the State Senate but has not come up to a vote in the Assembly.  Similar legislation has already been passed in California, Oregon, Maine, and Colorado.

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Amazon Says It Will Stop Using Puffy Plastic Shipping Pillows

Photo, posted November 20, 2018, courtesy of Todd Van Hoosear via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Minerals from seawater

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There are about 18,000 desalination plants around the world that take in 23 trillion gallons of water each year.  The plants produce more than 37 billion gallons of brine – enough to fill 50,000 Olympic-size swimming pools – every day.  Disposing of this brine is an ongoing challenge.  Dumping it into the ocean can damage marine ecosystems.  Inland desalination plants either bury this waste or inject it into wells, adding further cost and complexity to the already expensive process of desalination.

According to researchers at Oregon State University, this waste brine contains large amounts of copper, zinc, magnesium, lithium, and other valuable metals.  A company in Oakland, California called Magrathea Metals has started producing modest amounts of magnesium from waste brine in its pilot projects.  With support from the U.S. Defense Department, it is building a larger-scale facility to produce hundreds of tons of the metal over two to four years. 

Most of the world’s magnesium supply comes from China, where producing it requires burning lots of coal and utilizing lots of labor.  Magrathea’s brine mining makes use of off-peak wind and solar energy and is much less labor intensive.

No large-scale brine mining operations currently exist and when there are some, they might end up having negative environmental impacts.  But in principle, the process should produce valuable metals without the massive land disturbance, acid-mine drainage, and other pollution associated with traditional mining.  Brine mining could turn a growing waste problem into a valuable resource.

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In Seawater, Researchers See an Untapped Bounty of Critical Metals

Photo, posted February 18, 2017, courtesy of Jacob Vanderheyden via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Biochar and carbon

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Biochar is a charcoal-like substance that is made by burning organic materials like crop and forestry wastes in a controlled process called pyrolysis, which is burning in an oxygen-deprived environment.  Pyrolysis produces little or no contaminating fumes and results in a stable form of carbon that can’t easily escape into the atmosphere.  Biochar is a very efficient way to convert carbon into a stable form.

Adding charred biomass to improve soil quality has been done for thousands of years.  Indigenous people in the Amazon added charcoal, food residue, and other waste to their soil.  When mixed with soil, biochar creates favorable conditions for root growth and microbial activities, which reduces greenhouse gas emissions. 

Last year, 125,000 tons of carbon dioxide were removed worldwide in the durable carbon market, which is a carbon credit marketplace for carbon removal.  About 93% of that was in the form of biochar. 

Biochar represents a value-added way to deal with agricultural waste and also to make use of dead trees in forests that should be removed to lower the risk of wildfires caused by the presence of all that dry tinder material. 

A bill to fund biochar research is pending before the Senate Agricultural Committee.  It is a rare example of bipartisan legislation.

Biochar is currently expensive to make in the US because large amounts of biomass must be shipped to one of the fewer than 50 small-scale production facilities in the country.   But with appropriate infrastructure, biochar could play an important role in efforts to sequester carbon and combat climate change.

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Biochar Is ‘Low-Hanging Fruit’ for Sequestering Carbon and Combating Climate Change

Photo, posted September 3, 2019, courtesy of Tracy Robillard / NRCS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The carbon footprint of urban agriculture

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Urban agriculture – essentially farming within a city – has become increasingly popular worldwide.  It is intended to make cities and urban food systems more sustainable.  There are social and nutritional benefits to urban agriculture, but its carbon footprint has not been widely studied.

There are high-tech, energy-intensive forms of urban agriculture, such as vertical farms and rooftop greenhouses.  But most urban farms are decidedly low-tech such as individual gardens managed by single farmers and community gardens managed by small groups of people.

A comprehensive international study led by the University of Michigan calculated the greenhouse gas emissions associated with the materials and activities of urban farms over their operating lives.  The emissions, expressed in the quantity of carbon dioxide equivalents produced per serving of food, were then compared to those of foods raised by conventional agriculture.

On average, food produced through urban agriculture emitted six times higher amounts of CO2 per serving than conventionally grown produce.

The study went on to recommend best practices crucial to making low-tech urban agriculture more carbon-competitive with conventional agriculture.  These include making use of infrastructure for more extended periods of time, making use of urban waste, and maximizing social and health benefits. 

Urban agriculture offers a variety of social, nutritional, and place-based environmental benefits and has its place in future sustainable cities.  It is important to implement it in ways that are most beneficial.

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Study finds that urban agriculture must be carefully planned to have climate benefits

Photo, posted July 27, 2016, courtesy of Sandra Cohen-Rose and Colin Rose via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Red mud and steel

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Most of us have never heard of red mud.  Otherwise known as bauxite residue, it is an industrial waste product generated by the most common process by which aluminum is made and the world produces 200 million tons of red mud each year.  The stuff is a significant environmental hazard being extremely alkaline and corrosive. Most of it ends up in large landfills and the costs associated with disposing of red mud are substantial.

Red mud is red because it contains large amounts of iron oxide, often as much as 60% of it.  Scientists at the Max-Planck Institute in Germany have developed a method for producing steel from red mud that is much less carbon intensive than traditional steel production and that is economically viable.

The scientists melt the red mud in an electric furnace powered in part by green hydrogen.  Running the furnace this way, even when using electricity from only partially renewable sources, results in far fewer greenhouse gas emissions as well as economic benefits.  In the furnace, liquid iron separates from the other liquid oxides and can be extracted easily.  The resultant iron is so pure that it can processed directly into steel.  The remaining metal oxides are no longer corrosive, and they solidify into a glass-like material that can have practical uses in construction.

There are 4 billion tons of red mud that have accumulated worldwide to date.  According to the researchers, their process could produce over 700 million tons of green steel from it, potentially saving 1.6 billion tons of carbon dioxide emissions. 

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Green steel from toxic red mud

Photo, posted September 7, 2021, courtesy of Healthy Gulf via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Bio-based products on the rise

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There is a growing global movement working towards replacing conventional synthetic products – ones that are toxic to make or use, difficult to recycle, and have large carbon footprints – with products made from plants, trees, or fungi that can be safely returned to the earth at the end of their useful life.  This so-called bioeconomy is in its infant stages, but there is increasing interest in turning successful research into manufactured products.

One example is nylon.  Nylon was created in the 1930s by DuPont.  It has been used and continues to be used in a wide range of products.  The problem with it is that it is made from petroleum, it doesn’t biodegrade, and producing it generates nitrous oxide, which is a problematic greenhouse gas.

A San Diego-based company called Genomatica has developed a plant-based nylon using biosynthesis, a process in which a genetically engineered microorganism ferments plant sugars to create a chemical intermediate that can be turned into the nylon-6 polymer, and then into textiles. 

The impetus for developing bio-based products includes the growing public disgust at the mounting environmental toll of plastic, not the least of which is that people and animals are increasingly ingesting it.  Coupled with this, there is a rapidly-growing torrent of funding, especially in the US and Europe, aimed at accelerating the transition away from products that are non-biodegradable, toxic, and that produce carbon emissions.   Last September saw the launch of the National Biotechnology and Biomanufacturing Initiative which will support research and development on such topics as the use of sustainable biomass and waste resources to make non-toxic, bio-based fuels, chemicals, and fertilizers.

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From Lab to Market: Bio-Based Products Are Gaining Momentum

Photo, posted May 27, 2010, courtesy of André C via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)