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How to make cities cooler

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In cities, the air, surface, and soil temperatures are almost always warmer than in rural areas. This is known as the urban heat island effect.  Urban heat islands occur when cities replace natural land cover with dense concentrations of pavement, buildings, and other surfaces that absorb and retain heat.

Urban planners around the world have been researching ways to reduce the effects of heat in cities.  For example, trees, green roofs, and vegetation can help reduce urban heat island effects by shading building surfaces, deflecting radiation from the sun, and releasing moisture into the atmosphere.

A new study led by researchers from the University of Surrey in the U.K. has analyzed how well various green spaces and waterways are able to cool down cities.  The study, which was recently published in the journal The Innovation, found that wetlands, parks, and even botanical gardens are among the best ways to keep cities cool.   

In fact, the researchers found that botanical gardens can cool city air by a whopping 9°F during heatwaves on average.  Wetlands can cool city air by 8.5°F on average, followed by rain gardens at 8.1°F, green walls at 7.4°F, street trees at 6.8°F, city farms at 6.3°F, city parks at 5.8°F, and reservoirs and playgrounds at 5.2°F. 

The researchers also found that cities can unlock even greater benefits by connecting green spaces into green corridors.  Greening projects can also help remove carbon emissions and prevent flooding.

The research team hopes its findings will help urban planners design more resilient cities. 

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Wetlands, parks and even botanical gardens among the best ways to cool cities during heatwaves

Photo, posted April 25, 2022, courtesy of Catherine Poh Huay Tan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The East Coast is sinking

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Most of the world’s largest cities are located in coastal regions and coastal regions are on the front lines of the climate crisis.  Human populations continue to migrate towards low-elevation coastal areas at the same time that sea level rise is accelerating.  Coastal communities worldwide are increasingly vulnerable to the dangers of flooding and erosion.  With these hazards occupying a great deal of attention, there has been less attention paid to the dangers of land subsidence.

A recent study by researchers at Virginia Tech and the US Geological Survey using satellite data shows that parts of America’s east coast are sinking, and the culprit is the withdrawal of too much water from the aquifers beneath these coastal areas.

A series of overlapping aquifers extends all the way from New Jersey to Florida along the coast, providing a reliable source of water for drinking, irrigation, and industrial uses.  Even though these areas get regular rainfall, the deeper aquifers can take hundreds or even thousands of years to refill once water is pumped out.  Once water is removed, soils can compress and collapse, causing the land surface to sink.

Cities that were built on drained marshland or on fill soil are especially vulnerable to compaction. 

Seal level rise is slow, but it is insidious and continuous.  Add land subsidence to the mix and effects multiply.  Places like Boston, New York, Washington DC, Roanoke, Savannah, Jacksonville, and Miami, among others, all are increasingly vulnerable to these coastal hazards.  The combined effects of sea level rise and subsidence may even triple the prospects for flooding areas over the next few decades.

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As Aquifers Are Depleted, Areas Along The East Coast Of The US Are Sinking

Photo, posted August 7, 2015, courtesy of Tracy Robillard / NRCS Oregon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Flower power in agriculture

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Agriculture is the world’s largest industry.  When managed sustainably, agricultural operations can provide many environmental benefits, such as protecting watersheds and habitats, and improving soil health and water quality.  Sustainable agriculture also embraces biodiversity by minimizing its impact on wild ecosystems and incorporating numerous plant and animal varieties into farm ecosystems.

A new study of farms in India has demonstrated the power of incorporating flowers into farming practices.  According to the research by ecologists from the University of Reading in the U.K. and the M.S. Swaminathan Research Foundation in India, planting flowers beside food crops attracts bees, boosts pollination, and improves both the yield and quality of crops.

 The study, which was recently published in the Journal of Applied Ecology, is the first of its kind in India.  The researchers focused on moringa – which is a nutrient-packed superfood native to South India, and bees – the plants’ essential pollinators. 

Working alongside farmers, the researchers planted marigold and red gram crops alongside moringa trees across 12 moringa orchards.  They found that flower-visiting insect numbers and diversity were 50% and 33% higher, respectively, in orchards with floral interventions compared to those without them.  Floral interventions also led to larger moringa pods and a 30% increase in harvestable fruits.

India has many crops of high economic and nutritional value.  The study highlights how farmers can significantly improve crop pollination services and boost yields, while also managing their lands in a more sustainable manner.

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Flower power on Indian farms helps bees, boosts livelihoods

Floral interventions on farms boost pollinators and crop yields

Photo, posted June 24, 2008, courtesy of Jim via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Does vertically-grown food taste different?

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Vertical farming is a method of producing crops in vertically stacked layers or surfaces typically in a skyscraper, used warehouse, or shipping container.  Modern vertical farming uses indoor farming techniques and controlled-environment agriculture technology. 

Vertical farming has the potential to be one of the solutions to food insecurity in parts of the world where crop production is limited by climate change or other environmental factors.  Vertical farming reduces water and land use, reduces nutrient emissions, and could eliminate the need for pesticides.  It also allows more food to be grown locally and with higher yields.

But some critics of vertically-grown veggies say they look pale, artificial, and taste bland.  In the first study of its kind, a research team led by scientists from the University of Copenhagen in Denmark sought to investigate whether these consumer prejudices hold true.

The research team asked 190 participants to blind taste test arugula, baby spinach, pea shoots, basil, and parsley grown in vertical farming and compare the taste and appearance to those same leafy greens grown organically in soil. 

Overall, the organic greens grown traditionally narrowly beat out the vertically-grown ones in the study, but it was very close.  For example, when asked to rate arugula on a scale of 1-9 with 9 being best, the participants gave both types a 6.6.  There was no clear winner between basil, baby spinach, and pea shoots.  The only clear winner was organically-grown parsley. 

The study debunks some myths about vertically-grown food and should help pave the way for more widespread adoption of this efficient method to grow tasty and nutritious food. 

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A delicious surprise: Vertically farmed greens taste as good as organic ones

Photo, posted May 11, 2009, courtesy of Cliff Johnson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Groundwater loss

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Groundwater is the water found underground in the cracks and spaces in soil, sand, and rock.  It is held in aquifers and bubbles up naturally into springs, streams, and rivers, but also is pumped out for use by people.  Groundwater provides almost half the drinking water in the U.S. and is a main source of water for agriculture.

The world’s supply of groundwater is steadily declining.  The combination of climate change and human population growth is increasingly diminishing groundwater.

A study by the Desert Research Institute published in the journal Nature Communications has mapped the global permanent loss of aquifer storage capacity for the first time.  Computer modeling with advanced machine learning techniques has provided a detailed picture of the world’s groundwater situation.

The study found that global aquifer storage capacity is disappearing at a rate of 10 miles a year, about the size of 7,000 Great Pyramids of Giza.  The loss of groundwater storage is permanent, forever reducing the amount of water that can be captured and stored because the pumping of groundwater can cause the ground surface above to sink, collapsing the space where water can be stored.

About 75% of this subsidence is occurring over cropland and urban regions.  The United States, China, and Iran account for most of the global groundwater storage loss but many other places in the Middle East and Asia are experiencing significant groundwater withdrawal as well.

Most regions of the world do not have monitoring programs for groundwater pumping.  The study underscores the need to better understand this issue on a global scale and take appropriate action before it is too late.

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Scientists Map Loss of Groundwater Storage Around the World

Photo, posted August 7, 2015, courtesy of NRCS Oregon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wild pigs in the U.S.

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In the U.S., there are as many as nine million feral swine living in 38 states.  A conservative estimate indicates that they cause about $1.5 billion in property and agricultural damage each year in this country. 

Pigs were introduced to the United States centuries ago as a food source, but they quickly established wild populations. Feral domestic pigs bred with purebred Eurasian boar that were introduced for hunting, and these hybridized wild pigs spread across the landscape thanks to their prolific reproductive rates and willingness to eat just about anything.

When wild pigs forage, they upturn roots and soil with their snouts, damaging natural habitats and other animals. A 2021 study found that wild pigs are releasing over five million tons of carbon dioxide annually by uprooting carbon trapped in soil. 

As a result, many programs were implemented nationwide to try to reduce populations, usually through lethal methods. 

According to new research from the University of Georgia’s Savannah River Ecology Laboratory and Warnell School of Forestry and Natural Resources, recent conservation efforts have proven effective at controlling wild pig populations in the Southeastern U.S.  Within 24 months of the start of control efforts in the study area in South Carolina, the research team found a reduction of about 70% in relative abundance of pigs, and a corresponding decline in environmental rooting damage of about 99%.

Wild pigs are basically a human-caused problem, and controlling their populations will require continued cooperation and collaboration. 

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Wild pig populations in U.S. can be managed

Wild Pigs And The Environment

Photo, posted January 28, 2013, courtesy of Don and Janet Beasley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A billion pound problem

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Nearly two billion pounds of pumpkins are grown each year in the U.S.  But we actually don’t eat the vast majority of them.  Instead, most pumpkins are carved or otherwise decorated, and placed on porches across the country during Halloween.  But now that the holiday has come and gone, what happens to all those sagging masterpieces?

Simply put, we usually just throw them out.  In the days after Halloween, as much as 1.3 billion pounds of pumpkin winds up in landfills.  When left there to decompose, the pumpkins produce methane, a potent greenhouse gas that affects climate change by contributing to increased warming. 

Here are some ways to keep pumpkins out of the landfills this year and make Halloween festivities more sustainable. 

If the pumpkin is still in good shape, use the outer, meaty part of the pumpkin to make a fresh version of pumpkin puree.  Pumpkin puree is a common ingredient in baked goods like muffins, breads, and pies, especially during this time of the year.  The pumpkin seeds can also be scooped out, rinsed, and salted or spiced, and then baked in the oven, resulting in a delicious snack.

Pumpkins also have the potential to turn into great soil through composting. Pumpkins are just over 90% water, which help naturally add moisture to compost piles that need to be damp to effectively decompose food waste.

If eating or composting the pumpkins isn’t an option, consider donating them to a local farm.  Farmers will often collect pumpkins as treats for their pigs, goats, and other animals. 

The scariest part of Halloween shouldn’t be the waste. 

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Halloween is over. Here’s the most sustainable way to get rid of your jack-o’-lanterns, pumpkins, and gourds

Say Boo to Landfills – Compost Your Pumpkin After Halloween!

Photo, posted November 4, 2010, courtesy of William Warby via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Controlled Environment Agriculture | Earth Wise

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The term “controlled environment agriculture” (or CEA) refers to any number of systems embodying a technology-based approach to farming.  CEA can range from simple shade structures to greenhouses to full indoor or vertical farms.  At the most advanced level, CEA systems are fully automated, closed loop systems with controlled lighting, water, and ventilation.   Many systems make use of hydroponics rather than traditional soil.

The goal of CEA systems is to provide optimum growing conditions for crops and prevent disease and pest damage. 

A recent study by the University of Surrey in the UK sought to understand the impact of using CEA systems to grow lettuce, which is a high-value crop that is often grown in such systems.

The study found that, on average, CEA methods produce double the crop yields compared to field-based agriculture.  They also found that the cultivation time of CEA yields was, on average, 40 days.  This compares with an average cultivation time of 60-120 days for field-based agriculture.  More specifically, production of lettuce using CEA was 50% faster in the summer and up to 300% faster in the winter.

Climate change presents many difficult challenges to society, not the least of which is its threat to food security.  Controlled environment agriculture could allow cultivation of crops in harsh environments and in the face of changing climates.  Quantifying the benefits CEA can have on yield and growth provides important information for advancing our understanding of where and when this technology can bring the most value to society. 

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Using artificial methods for growing crops could help solve global food security

Photo, posted February 24, 2013, courtesy of Cindy Kurman / Kurman Photography via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fungus And Carbon Storage | Earth Wise

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It is well-known that plants and trees store enormous amounts of carbon.  What has not been common knowledge is that the vast underground network of fungi across the world’s lands stores billions of tons carbon, roughly equivalent to 36% of yearly global fossil fuel emissions.

These mycorrhizal fungi form symbiotic relationships with almost all land plants.  The fungi transport carbon, converted by sugars and fats by plants, into soil.  They have been supporting life on land for at least 450 million years and form sprawling underground networks everywhere – even beneath roads, gardens, and houses – on every continent on earth.

An international team of scientists analyzed hundreds of studies looking at plant-soil processes to understand how much carbon is being stored by fungi on a global scale.  The findings, published in the journal Current Biology, revealed that over 13 billion tons of CO2 is transferred from plants to fungi each year, more than China emits annually.  This process transforms the soil beneath our feet to a massive carbon pool and constitutes the most effective carbon storage activity in the world.

Given that fungi have such a crucial role in mitigating carbon emissions, the researchers are recommending that fungi should be considered in biodiversity and conservation policies. More needs to be done in protecting the underground networks of mycorrhizal fungi. The UN has warned that human activities are degrading soils and that 90% of the world’s soils could be degraded by 2050.  Not only would this obviously be very bad for the productivity of crops and plants, but we now know this could be catastrophic for curbing climate change and rising temperatures.

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Fungi stores a third of carbon from fossil fuel emissions and could be essential to reaching net zero

Photo, posted May 28, 2023, courtesy of Geoff McKay via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Moss And Carbon Storage | Earth Wise

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All plants, including algae and cyanobacteria, carry out photosynthesis. During the process of photosynthesis, plants remove carbon dioxide from the air and release oxygen to the air.  As a result, plants play a crucial role in the fight against climate change. 

According to a new study recently published in the journal Nature Geoscience, mosses – those tiny plants often found on the ground or rocks – might be important antidotes to climate change.  The study, which was led by scientists from the University of New South Wales in Australia and the Institute of Natural Resources and Agrobiology in Spain, uncovered evidence that mosses have the potential to store a massive amount of carbon in the soil beneath them.

The researchers found that mosses sequester around seven billion tons more carbon in the soil than is stored in the bare patches of soil typically found near them.  To put that figure in perspective, that is six times the annual global carbon emissions caused by global land use change, which includes things like deforestation, urbanization, and mining.  The researchers also found that moss-covered soil possessed heightened levels of vital nutrients and fewer instances of soil-borne plant pathogens on average compared to moss-less soil.

Mosses cover an area of more than 3.6 million square miles, which is similar in size to Canada, and can thrive in challenging environments.  The widespread presence and hardiness of mosses is why they can have such a significant impact on soil biodiversity and carbon sequestration. 

The research team hopes future work will focus on understanding the role of all types of vegetation, not just mosses and trees, in capturing carbon.

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Study: Modest moss supports billions of tons of carbon storage

Photo, posted August 23, 2017, courtesy of Peter Handke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Saving Our Soil | Earth Wise

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The majority of food we eat is grown in topsoil, that carbon-rich, black soil that nurtures everything from carrots to watermelons.  The fertility of this soil has developed over eons.    

But over the past 160 years, the Midwestern United States has lost 63.4 billion tons of topsoil due to farming practices.  In fact, Midwestern topsoil is eroding between 10 and 1,000 times faster than it did in the pre-agricultural era.  The rate of erosion is 25 times greater than the rate at which topsoil forms.

According to new research from the University of Massachusetts-Amherst, this rapid and unsustainable rate of topsoil erosion can be drastically reduced by utilizing an agricultural method already in practice: No-till farming.  This method, which is currently practiced on 40% of cropland acres in the Midwest, can extend our current level of soil fertility for the next several centuries.   

In the study, which was recently published in the journal Earth’s Future, the research team looked at the current business-as-usual method, under which approximately 40% of the midwestern U.S.’s acres are no-till farmed, all the way up to 100% adoption of no-till methods. 

If the U.S.’s current agricultural practices remain largely unchanged, approximately 9.6 billion tons of topsoil will be lost over the next century alone.  However, approximately 95% of the erosion in the business-as-usual scenario could be prevented by adopting 100% no-till farming practices. 

Saving our soil by improving our farming methods has implications for everything from food security to climate change mitigation. 

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Saving Our Soil: How to Extend U.S. Breadbasket Fertility for Centuries

Photo, posted January 19, 2022, courtesy of Terri Dux via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Plastic Eating Fungus | Earth Wise

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More than five billion tons of plastic have accumulated on land and sea including the most remote regions of the planet as well as in the bodies of animals and humans.  There is a compelling need to recycle as much plastic as possible but doing so is a major challenge. Plastic comes in many varieties and breaking it down for reuse requires different methods for each.

Polypropylene is one of the biggest challenges for recycling.  It is a very common plastic used for all sorts of products including food containers, coat hangers, plastic wrap, toys, and much more. It accounts for roughly 28% of the world’s plastic waste, but only 1% of it is recycled.

Polypropylene is seldom recycled because it generally has a short life as a packaging material, and it often becomes contaminated by other materials and plastics.  Thus, it generally ends up in landfills.

Researchers at the University of Sydney in Australia have discovered that two common strains of fungi were able to successfully biodegrade polypropylene.  The fungi species – with unavoidable Latin names of Aspergillus terreus and Engyodontium album – are typically found in soil and plants.

The researchers found that the fungi were able to break down polypropylene after it had been pre-treated with either UV light or heat, by 21% over 30 days, and by 25-27% over 90 days.  This seems rather slow but compared with the nearly endless life of polypropylene in landfills, it is a major improvement.

The hope is that methods like this could ultimately reduce the amount of plastic polluting the environment by encouraging plastic to biodegrade naturally under the appropriate conditions.

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Fungi makes meal of hard to recycle plastic

Photo, posted March 5, 2010, courtesy of Kevin Krejci via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rare Earths And The Energy Transition | Earth Wise

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Limiting the rise in global temperature to no more than 1.5 degrees Celsius requires decarbonization.  This means slashing fossil fuel use, switching to renewable energy sources, and electrifying as many sectors of the economy as possible.  Doing these things requires huge numbers of wind turbines, solar panels, electric vehicles, and storage batteries.   All of them use rare earth elements and other critical metals.

The 17 rare earth elements are actually common, but they are called rare because they are seldom found in sufficient quantities to be extracted easily or economically. 

China once supplied 97% of the world’s rare earth elements as a result of government support, cheap labor, lax environmental regulations, and low prices.  Once the world started to realize the dangers of being so dependent on China, many countries began developing their own rare earth element production. (However, today China still produces 60-70% of the world’s rare earth elements).

It is difficult to mine rare earth elements without causing environmental damage.  The prevalent extraction techniques involve toxic chemicals that can leach into the environment and, because rare earths are often found near radioactive elements, mining often brings dangerous radioactive waste into the environment.

Researchers are working on ways to make rare earth mining more sustainable.  Some of these include biomining – which uses microbes to extract rare earths from ores, electrical methods to free rare earths from ores, and so-called agromining, which is growing plants that hyperaccumulate rare earths from the soil into their tissues.

Making rare earth mining more sustainable and less harmful to the environment is an essential part of the world’s future.

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The Energy Transition Will Need More Rare Earth Elements. Can We Secure Them Sustainably?

Photo, posted November 18, 2008, courtesy of the Oregon Department of Transportation via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Protecting Wetlands | Earth Wise

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Wetlands are distinct ecosystems that are flooded or saturated by water, either permanently or seasonally.  They include mangroves, marshes, swamps, forested wetlands, bogs, wet prairies, and vernal pools.   The feature that most wetlands share is soil or substrate that is at least periodically saturated with or covered by water.

Wetlands are some of the most threatened ecosystems in the world.  While wetlands can be affected by a variety of natural stressors, including erosion, droughts, and storms, human activities have been the major driver of wetland decline. 

But according to a new study by researchers from McGill University in Canada, the global loss of wetland areas since 1700 has likely been overestimated.  The research team calculated that the area of wetland ecosystems around the world has declined 21-35% since 1700 as a result of human activities – far less than the 50-87% decline estimated in other studies.  The study’s focus beyond regions with historically high wetland losses and its avoidance of possibly misleading extrapolations likely resulted in the lower estimate.      

According to the study, which was published in the journal Nature, more than 2.1 million square miles of wetlands have been lost during the past 300 years – an area roughly the size of India.  The five countries with the highest wetland losses are the United States, China, India, Russia and Indonesia. 

But discovering that fewer wetlands have been historically lost than previously thought gives researchers a second chance to protect wetlands.  The findings of the study will help researchers prioritize global conservation and restoration actions.

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A second chance to protect wetlands

Photo, posted February 2, 2005, courtesy of Jan Tik via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Energy From Rice Straw | Earth Wise

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Rice straw is produced as a byproduct of rice production.  Globally, as much as a billion tons of rice straw is produced each year, three-quarters of it in Asia.  Straw incorporation in soil for fertilization is not practical in most places because with multiple crops per year, there is not enough time for the material to decompose and become good fertilizer.  As a result, open-field straw burning is increasingly the standard practice.

Scientists at Aston University in Birmingham in the UK are embarking on a project to convert rice straw in Indonesia into low-cost energy on a commercial scale.

Indonesia produces 100 million tons of rice waste each year, of which 60% is burned in open fields, causing air pollution. 

The Aston researchers are developing a biomass conversion process based on pyrolysis.  This involves heating the rice straw to high temperatures over 900 degrees Fahrenheit to break it down, producing vapor and solid products.  Both of these things can be used to generate electricity.

A new combustion engine designed by a company called Carnot Limited is capable of converting 70% of the thermal energy extracted from the rice straw into electricity.

Energy extracted in this way could help low and middle-income countries to create their own locally generated energy, thereby reducing emissions, creating jobs, and improving human health.   The biomass electricity is predicted to be cheaper than solar, geothermal, wind, coal, or even subsidized gas-generated power.

The Aston University project will help develop a business model that could support companies and communities to produce local, cheap energy in Indonesia and other countries with biomass capacity. 

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Aston University to help power Indonesia with affordable energy made from rice straw

Photo, posted September 11, 2006, courtesy of Kristen McQuillin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Agrivoltaics | Earth Wise

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According to a study last year at Oregon State University, co-developing land for both solar photovoltaic power and agriculture could provide 20% of total electricity generation in the United States with an investment of less than 1% of the annual U.S. budget.  Widespread installation of agrivoltaic systems could reduce carbon emissions by 330,000 tons annually and create more than 100,000 jobs in rural communities.

Agrivoltaics could provide the synergistic combination of more food, more energy, lower water demand, lower carbon emissions, and improved local prosperity.  The problem with agrivoltaics to date is that the existing implementations have used solar arrays designed strictly for electricity generation rather than to be used in combination with agriculture.  They are not that well suited to co-exist with growing crops or grazing animals.

A new project is underway at Oregon State that will help researchers to optimize agrivoltaic systems.  The five-acre Solar Harvest Project is being built at the university’s North Willamette Research and Extension Center in Aurora, Oregon in partnership with the Oregon Clean Power Cooperative. 

The solar array for the project is designed specifically for agrivoltaics research and uses panels that are more spread out and able to rotate to a near vertical position to allow farm equipment to pass through.  The project will allow researchers to study the impact of solar panels on soil health, water use, and plant physiology and yields.

Electricity generated from the 326-kW solar system will be available for purchase by Oregon State and community members. 

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Construction starts on Oregon State agrivoltaics farm that will merge agriculture and solar energy

Photo, posted April 5, 2020, courtesy of Sean Nealon / Oregon State University via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

What Is Healthy Soil? | Earth Wise

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Soil supports life by providing many critical ecosystem services.  For example, soil acts as a water filter, a growing medium, and provides habitat for billions of organisms.  Soil is also the foundation of our cities and towns, and the basis of global agroecosystems, which provide humans with feed, fiber, food, and fuel.

For all of these reasons and many more, having healthy soil is vital.  But what does soil health mean? And how should it be measured?

According to new analysis by researchers from Cranfield University and Nottingham University in the U.K., how we think about, measure, and study soil must change in order to better understand how to manage this resource effectively. 

While the term ‘soil health’ is widely used, it means different things to different people.  There is no single agreed upon way to gauge the overall health of soil. 

Current approaches to assess soil health measure individual soil properties and use findings  to assign a single number giving an overall score.  But according to the research team, this does not reflect the wider system perspective that’s needed to fully evaluate the health of soil over time.

Instead, the researchers propose a new system to assess soil health based on a hierarchical framework that takes in several measures, including signs of life, signs of function, signs of complexity, and signs of emergence, which is the extent to which soils recover from multiple stressors. 

This new approach, which can be applied to all soils, moves us closer to an interdisciplinary understanding of the whole picture of soil health.  After all, healthy soil is fundamental to our survival.

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We need to change how we think about soil

Photo, posted April 8, 2008, courtesy of Brian Boucheron via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Cleaning Up Forever Chemicals | Earth Wise

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PFAS, per- and polyfluoroalkyl substances, are chemical pollutants that threaten human health and ecosystem sustainability.  They are used in a wide range of applications including food wrappers and packaging, dental floss, firefighting foam, nonstick cookware, textiles, and electronics.  Over decades, these manufactured chemicals have leached into our soil, air, and water.  Chemical bonds in PFAS molecules are some of the strongest known, so the substances do not degrade easily in the environment.

Studies have shown that at certain levels, PFAS chemicals can be harmful to humans and wildlife and have been associated with a wide variety of health problems.

Currently, the primary way to dispose of PFAS chemicals is to burn them, which is an expensive multistep process.  Even trace levels are toxic, so when they occur in water in low amounts, they need to be concentrated in order to be destroyed.

Researchers at Texas A&M University have developed a novel bioremediation technology for cleaning up PFAS.  It uses a plant-derived material to absorb the PFAS which is then eliminated by microbial fungi that literally eat the forever chemicals.

The sustainable plant material serves as a framework to adsorb the PFAS.  That material containing the adsorbed PFAS serves as food for the fungus.  Once the fungus has eaten it, the PFAS is gone. 

The EPA has established a nationwide program to monitor the occurrence and levels of PFAS in public water systems and is considering adding PFAS threshold levels to drinking water standards.  If this happens, the technology developed at Texas A&M may become an essential part of municipal water systems.

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Texas A&M AgriLife develops new bioremediation material to clean up ‘forever chemicals’

Photo, posted August 10, 2013, courtesy of Mike Mozart via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Progress On Artificial Photosynthesis | Earth Wise

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Photosynthesis is the process by which plants use the energy from sunlight to turn water and carbon dioxide into biomass and ultimately the foods we and other organisms eat.  Scientists at the University of California Riverside and the University of Delaware have found a way to create food from water and carbon dioxide without using biological photosynthesis and without needing sunlight.

The research, recently published in the journal Nature Food, uses a two-step electrocatalytic process to convert carbon dioxide, electricity, and water into acetate, which is the primary component of vinegar.   Food-producing microorganisms then consume the acetate in order to grow.   Solar panels are used to generate the electricity to power the electrocatalysis.  The result is a hybrid organic-inorganic system that is far more efficient in converting sunlight into food than biological photosynthesis.

The research showed that a wide range of food-producing organisms can be grown in the dark directly on the acetate output of the electrolyzer.  These include green algae, yeast, and the fungal mycelium that produce mushrooms.   Producing algae with this technology is about 4 times more energy efficient than growing it with photosynthesis.  Yeast production is about 18 times more energy efficient than the typical method of cultivating it using sugar extracted from corn.

Artificial photosynthesis has the potential to liberate agriculture from its complete dependence on the sun, opening the door to a wide range of possibilities for growing food under the increasingly difficult conditions imposed by the changing climate.

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Artificial photosynthesis can produce food without sunshine

Photo, posted September 7, 2016, courtesy of Kevin Doncaster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Methane From Thawing Permafrost | Earth Wise

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The Arctic permafrost contains a massive amount of carbon in the form of frozen soil, which contains remnants of plants and animals that died millennia ago.  Estimates are that there is 2 ½ times as much carbon trapped in this Arctic soil than there is in total in the atmosphere today.

As the Arctic warms, the permafrost is starting to thaw.  Once that happens, microbes begin to consume the previously frozen organic matter trapped in the soil.  As part of this process, the microbes produce large amounts of methane, which is an extremely potent greenhouse gas.   Thus, there continues to be great concern that wide-scale thawing of the permafrost would result in massive amounts of methane being released into the atmosphere.

A recent study in northern Sweden revealed a glimmer of hope.  The study gauged methane emissions from a swath of permafrost that thawed in the 1980s and another that thawed 10 or 15 years later. 

In the first area, as ice melted underground, water on the surface sank down into the soil.  As the surface dried out, new plants emerged that helped to keep methane emissions buried underground.

Grasses found in wet areas have straw-like structures that convey oxygen to their roots.  The straws also allow methane in the soil to escape into the atmosphere.  As the areas dry out, other plants lacking the straws can sometimes replace the grasses.  When methane can’t escape, soil bacteria break it down into carbon dioxide.

The result is that the permafrost releases only a tenth of the methane as expected.  The hope is that changes in plant cover driven by climate change may limit methane emissions from thawing permafrost.

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Thawing Permafrost In Sweden Releases Less Methane Than Feared, Study Finds

Photo, posted July 7, 2014, courtesy of NPS Climate Change Response via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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