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Are today’s refrigerants safe?

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Refrigeration is based on heat transfer mediums that absorb heat from the area being cooled and transfer it to the outside environment.

The earliest refrigerants were dangerous substances like ammonia.  In the 1930s, chlorofluorocarbons (CFCs) like Freon became the standard refrigerant for use in refrigeration systems and even in aerosol cans.  When these substances were found to be depleting the earth’s ozone layer, the Montreal Protocol dictated their phaseout and by the mid-1990s, CFCs were largely replaced by hydrofluorocarbons (HFCs).

HFCs don’t deplete the ozone layer, but they were eventually determined to be potent greenhouse gases, thousands of times more planet-warming than carbon dioxide.   As a result, the global phaseout of HFCs began in 2016, and have been increasingly replaced by hydrofluoroolefins (HFOs), which are considered a more environmentally-friendly alternative to all their predecessors.

Trying to not be surprised by additional unpleasant discoveries about refrigerants, researchers are studying the potential environmental impacts of HFOs.  Researchers at the University of New South Wales in Australia have found that HFOs can break down in the atmosphere and that some small amounts of the resultant products are in fact fluoroforms, which are the HFC with the greatest global warming potential and can stay in the atmosphere for up to 200 years.

That only a small amount of HFC gets into the atmosphere is good, but nevertheless it reveals that the consequences of replacing widely-used chemicals are not a simple matter to determine.

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Are our refrigerants safe? The lingering questions about the chemicals keeping us cool

Photo, posted July 19, 2021, courtesy of Vernon Air Conditioning via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A record year for solar and batteries

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According to a recent forecast from the U.S. Energy Information Administration, solar panels and batteries will account for more than 80% of new power capacity installed in the U.S. this year.  The record growth of these technologies is hastening the decline of coal power in this country.

Solar power alone will account for more than half of the country’s new power capacity and most of it will be in Texas and California.

Wind power is expected to provide only 12% of new capacity this year.  Wind is facing rising costs, lengthy permitting, public backlash, and clear opposition from the Trump administration which is determined to stifle its growth.

As renewable energy grows, coal power continues to decline.  The U.S. will retire twice as much coal power this year as it did last year, closing about 5% of the country’s capacity.  Not only are older coal plants shutting down; the remaining plants are generating less power.

One of the most significant changes in technology over the last few decades has been the massive drop in the cost of clean energy.  Solar photovoltaic costs have fallen by 90% in the past decade, onshore wind by 70%, and batteries by more than 90%.  The connection between cost reduction and volume has been very strong:  costs of these technologies have fallen by around 20% every time global cumulative capacity doubles.   Over the past 40 years, solar power has transformed from one of the most expensive electricity sources to the cheapest in many countries.  That trend is likely to continue.  Setting politics aside, market forces generally are the strongest driver.

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U.S. Solar and Batteries Headed for Record Year

Photo, posted December 16, 2024, courtesy of Bureau of Land Management California via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Microplastics and birds

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Microplastics are tiny plastic particles, less than 5 millimeters in size, that come from the breakdown of larger plastics, synthetic fibers, microbeads, and tire wear.  Microplastics are found in oceans, rivers, soil, and even the air we breathe. These particles can take hundreds of years to degrade, spreading across ecosystems and accumulating in unexpected places, such as deep-sea sediments and Arctic sea ice.

According to a new study by researchers from the University of Texas at Arlington, microscopic plastic pollutants drifting through the air are lodging in the lungs of birds.  These findings raise  significant concerns about the impact on their respiratory health, but also raise alarms about potential risks to human health.

Birds were chosen for the study because they are found in almost every corner of the world and often share environments with humans. 

In the study, the research team examined 56 different wild birds from 51 distinct species, all sampled from the Tianfu airport in western China.  The researchers found high concentrations of microplastics in bird lungs, with an average of 221 particles per species.  The most common types identified were chlorinated polyethylene, which is used for insulating pipes and wires, and butadiene rubber, which is a synthetic material in tires.

Although there is no established “safe” level of plastic particles in lung tissue, high levels of microplastics have been linked to serious health risks, including heart disease, cancer, respiratory issues, and fertility problems.

The study highlights an urgent need to tackle plastic pollution in the environment because of its far-reaching impact on ecosystems and human health.  

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Birds breathe in dangerous plastics—and so do we

Photo, posted January 28, 2017, courtesy of Pete Richman via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Sand mining and the environment

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Sand mining is the world’s largest mining endeavor.  It is responsible for 85% of all mineral extraction.  It is also the least regulated, possibly the most corrupt, and likely the most environmentally destructive.  Sand is the second-most exploited natural resource in the world after water.  Its global use has tripled in the past two decades.  More than 50 billion tons of sand is extracted from the environment each year.

Sand plays a critical role in much of human development around the world.  It is a key ingredient of concrete, asphalt, glass, and electronics.  It is relatively cheap and relatively easy to extract.  But we use enormous amounts of it.

Sand mining is a major threat to rivers and marine ecosystems.  It is linked to coastal erosion, habitat destruction, the spread of invasive species, and damage to fisheries. 

The harm from sand mining is only beginning to attract widespread attention.  A recent study by an international group of scientists published in the journal One Earth identifies        threats posed by sand mining.  Sand extraction in marine environments remains largely overlooked, despite sand and sediment dredging being the second most widespread human activity in coastal areas after fishing.

Sand is generally seen as an inert, abundant material, but it is an essential resource that shapes coastal and marine ecosystems, protects shorelines, and sustains both ecosystems and coastal communities.  Sand extraction near populated coastlines is particularly problematic as climate change makes coastlines increasingly fragile.

Like all other resources on our planet, even sand cannot be taken for granted.  It must be responsibly managed.

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The rising tide of sand mining: a growing threat to marine life

Photo, posted February 7, 2013, courtesy of Pamela Spaugy / U.S. Army Corps of Engineers via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Tigers in India

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The Anthropocene is the term that describes the current era in Earth’s history when human activities are having a significant impact on the planet.  It is an epoch filled with species extinction and species attrition in both numbers and range.  The population of large carnivores are among the most affected species and recovering these animals that play important roles in ecosystems is a formidable challenge.

Tigers in Asia are a prime example of extirpation – removal of a species from a specific area.  They have been eliminated in more than 90% of their historic Asian range over the past century.  A new study, published in Science has found that tigers in India are making a comeback.

India’s National Tiger Conservation Authority estimates that between 2010 and 2022, India’s tiger population grew from 1,706 to 3,682.  Tigers are thriving not only on protected lands but also near some human communities.

Tigers are gone from poorer areas where poaching was prevalent and from areas affected by the violent conflict associated with India’s Maoist rebellion.  On the other hand, the big cats can be found near some prosperous communities where poaching is rare.  Farmers keep cattle in enclosures to protect them from tigers.  

The success in protecting tigers in India could provide some insights for Europe where wolves are making a comeback, and perhaps even in the American West where the resurgence of wolf populations is triggering a violent backlash.

Large predators can survive in the modern world with creative thinking and willingness to find a balance between protection and coexistence.

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India Doubled its Tiger Population in a Little More Than a Decade

Photo, posted January 8, 2014, courtesy of Roderick Eime via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The largest carbon removal plant

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Direct air capture (DAC) is process that removes carbon dioxide out of the air and stores it away where it can no longer trap heat in the atmosphere.  It is intended to be a way of getting rid of the greenhouse gases that have built up in the atmosphere.  In principle, it’s a great idea.  In practice, it is a huge challenge.

In 2017, a company called Climeworks became the first company to take carbon dioxide out of the air and sell it as a product for use in carbonated drinks and in greenhouses.  In 2021, the company opened a DAC plant called Orca in Iceland that captures CO2 and permanently stores it underground.  Clients like Microsoft pay Climeworks for doing this as a way of offsetting their own emissions.

Recently, Climeworks has started operating a new plant called Mammoth – also in Iceland – that will be able to capture about 10 times more carbon dioxide than Orca.  Iceland is a prime location for DAC technology because its abundant geothermal energy makes powering it cheap and environmentally friendly.

Mammoth, when fully operational, will remove about 36,000 tons of carbon dioxide a year, the largest DAC system in the world.  But there is a long, long way to go.  Microsoft alone emits nearly 13 million tons of carbon dioxide a year.

There are multiple DAC projects in development including several in the United States being funded by the Bipartisan Infrastructure Law.  The four DAC hubs being developed under the program are each supposed to have the capacity to capture at least a million metric tons of CO2 a year.

Whether DAC can make a real difference remains to be seen.

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The world’s largest carbon removal plant is here, and bigger ones are on the way

Photo credit: Climeworks

Earth Wise is a production of WAMC Northeast Public Radio

Removing Carbon With The Oceans | Earth Wise

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There is increasing concern that reducing carbon emissions alone will not be sufficient to stabilize the climate and that technologies that actively remove carbon dioxide from the air will be needed.  There has been a fair amount of analysis of the efficacy of storing carbon in agricultural soil and in forests, but there has not been comparable studies of the risks, benefits, and trade-offs of ocean-based strategies. 

The oceans currently absorb about a quarter of the world’s carbon dioxide emissions.  There are multiple ways in which oceans could be induced to store much more.  A new report from the National Academies of Sciences, Engineering, and Medicine looks at several ocean carbon dioxide removal strategies in terms of efficacy, potential costs, and potential environmental risks.

One approach involves adding nutrients to the ocean surface to increase photosynthesis by phytoplankton.  The approach has a medium to high chance of being effective and has medium environmental risks.

Another approach is large-scale seaweed farming that transports carbon to the deep ocean or into sediments.   It has medium efficacy chances but higher environmental risks.

Protection and restoration of coastal ecosystems including marine wildlife would have the lowest environmental risk but only low to medium efficacy.

Chemically altering ocean water to increase its alkalinity in order to enhance reactions that take up carbon dioxide would be highly effective but a medium environmental risk.

The report describes some other approaches as well.  It recommends a $125 million research program to better understand the technological challenges as well as the potential economic, social, and environmental impacts of increasing the oceans’ absorption of carbon dioxide.

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Oceans Could Be Harnessed to Remove Carbon From Air, Say U.S. Science Leaders

Photo, posted August 21, 2016, courtesy of Quinn Dombrowski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Coral Reefs And Fish Survival | Earth Wise

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The precarious state of the world’s coral reefs has been a highly visible subject for a decade or more.  Mostly what we hear about is the loss of some of the most beautiful sights on the planet. But there is far more at stake than scenic wonders.

The warming and acidifying of ocean waters are causing corals to increasingly bleach and often die.  Corals provide a unique food source for some species of fish and a three-dimensional habitat for many others.  The fish that depend on corals are often prey for fish that don’t depend directly on corals and so on up the food chain.

What happens to fish when coral reefs disappear?  The fish species that feed on corals will starve while others will seek alternative rocky habitats.

A new study by the University of Helsinki uses statistical methods to predict how fish diversity will respond to declines in coral diversity. It concludes that a future coral loss might cause a 40% reduction in reef fish diversity globally.  This is more than a loss of colorful sights for snorkelers; reef fishes provide essential protein for millions of people around the world.

The estimate of potential loss of fish species greatly exceeds the number of species known to depend directly or even indirectly on coral.  The implication is that coral reef food webs will begin to unravel if corals go extinct.  This unraveling is expected to be worse in some places than others.  The Central Pacific, for example, could lose 60% of its reef fish.

For both snorkelers and for the millions who depend upon reef fishes for food, the need for greater efforts to conserve and restore coral reefs is apparent.

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A fu­ture ocean that is too warm for cor­als might have half as many fish spe­cies

Photo, posted September 27, 2009, courtesy of Matt Kieffer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Offsetting Reef Acidification | Earth Wise

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The Great Barrier Reef is the world’s largest coral reef system.  It is composed of nearly 3,000 individual reefs and 900 islands covering an area of more than 130,000 square miles.  In recent times, it has been under unprecedented stress from ocean warming, tropical cyclones, sediment and nutrient runoff, marine pests, and ocean acidification.

Among these stressors, ocean acidification is one of the most significant threats to the long-term viability of the reef because acidification affects the ability of corals to rebuild and repair their structures and recover from bleaching events.

New research from CSIRO, Australia’s national science agency, studied the impact of artificial ocean alkalinization on the acidity of the waters in the Great Barrier Reef.  The idea is to inject a source of alkalinity into the ocean, an accelerated version of a natural process that occurs from the chemical weathering of minerals under the sea.

The results of the study, published in the journal Environmental Research Letters, are that injecting an alkalinizing agent into the ocean along the length of the Reef would make it possible to offset ten years’ worth of ocean acidification based on the present rate of human-generated carbon emissions.  Such an effort could use an abundant mineral resource like olivine, which is already mined near the Great Barrier Reef.  Releasing 30,000 tons a day of the alkalinizing agent from an existing shipping line from a bulk carrier would reach almost the whole of the Great Barrier Reef.

In response to the declining health of coral reef ecosystems, many different intervention concepts and technologies are under consideration.  The goal of these would be to minimize environmental pressures and enhance the resilience of the ecosystems.

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Projected acidification of the Great Barrier Reef could be offset by ten years

Photo, posted August 4, 2019, courtesy of Larry Koester via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Regulating Plastic Pollution | Earth Wise

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Much of the world is united in the desire to do something about the problem of plastic waste.  But putting in place regulations that transcend national borders is complicated.

One hundred fifteen countries have established bans on plastic bags, but globally, there are seven different definitions of what is considered a plastic bag.  Things like bag thickness can determine whether something even counts as a plastic bag.  These differences create loopholes that enable illegal bags to be used.  For a global company like Nestle, which sells food products in 187 countries, it means complying with 187 different sets of national regulations on plastic packaging.

At least 100 nations have expressed support for a global plastic treaty.  Preliminary talks are dealing with issues like setting a specific date to eliminate plastic from spilling into the ocean, creating a harmonized set of definitions and standards, coordination of national targets and plans, and creating a fund to build waste management facilities where they are most needed in less developed countries.

New plastic waste is created at a rate of over 300 million tons a year.   To date, 75% of all plastic ever produced has become waste, and plastic production is expected to triple by 2050.

With public concern about plastic waste growing and increasing support by countries around the world, there is growing optimism that a global treaty to address plastic waste could be approved on a pace that could make a difference.  Negotiations for international treaties can drag on for a decade or more.  There is not that kind of time to spare in this case, so perhaps urgency will drive more efficient action.

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Global treaty to regulate plastic pollution gains momentum

Photo, posted February 3, 2015, courtesy of Thad Zajdowicz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Cleaning Up Diesel With Bacteria | Earth Wise

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Mothballed military outposts with piles of rusting oil drums are not an unusual sight in Greenland.  There are about 30 abandoned military installations in Greenland and diesel that was once used to operate generators and other machinery has, in many cases, seeped into the ground.

Removing tons of contaminated soil from these sites is incredibly resource-intensive involving the use of aircraft and ships, so it has not really been practical.  As a result, Danish Defense and the engineering company NIRAS instead conducted a five-year experiment to optimize the conditions for naturally occurring soil bacteria to break down the contaminating diesel.

The experiment was performed at Station 9117 Mestersvig, an abandoned military airfield on the coast of East Greenland.  Forty tons of diesel fuel contaminated the soil there.

The remediation method using bacteria is known as landfarming and has most often been applied in warmer climates around the world.  This was the first large-scale test under Arctic conditions.

Landfarming works by distributing contaminated soil in a thin layer, which is then plowed, fertilized, and oxygenated every year to optimize conditions for bacteria to degrade hydrocarbons.

The site was monitored by scientists from the University of Copenhagen, and they found that after five years, the bacteria had bioremediated as much as 82 percent of the 5,000 tons of contaminated soil on the site. 

Based on these results, it appears to be feasible for naturally occurring bacteria to be used to remediate contamination in all of the 30 deserted military installations in Greenland as well as in other Arctic sites contaminated by diesel pollution.

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Bacteria used to clean diesel-polluted soil in Greenland

Photo, posted September 6, 2013, courtesy of Maj. Matthew J. Sala/The U.S. Air National Guard via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sunscreen For Corals | Earth Wise

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Sunscreen from beachgoers entering ocean waters is one of the greatest threats to coral reefs and there are global efforts to reduce or eliminate the use of many of the most harmful chemicals people use to protect themselves from the sun’s rays.  However, scientists at the Smithsonian Conservation Biology Institute have found that some corals have a natural sunscreen of their own that helps protect them from the effects of climate change.

Hawaiian blue rice corals feature a deep blue pigment that is created by chromoprotein that filters out harmful ultraviolet radiation from the sun.  UV damage has harmful impacts to reproduction in many coral species, but it appears not to have the same effect on blue rice coral.

In a study published in Scientific Reports, Smithsonian researchers studied the devastating effects that bleaching had on brown rice coral in the Hawaiian bleaching events of 2014 and 2015.  During the same events, blue rice coral either recovered quickly or was not affected by the elevated ocean temperature at all.

The blue-pigmented corals had dramatically greater reproductive vigor than the brown-pigmented version.  The key factor appears to be the sun-screening ability of the blue pigment in the particular symbiotic algae that lives inside the coral tissue known as zooxanthellae.  The coral protects the algae and in turn the algae provide the coral with food in the form of sugars produced as a waste product from photosynthesis.  In the case of the blue version, the algae also produce sunscreen for the coral.

By better understanding the role UV-protective pigments play in mitigating the adverse effects of climate change and warming oceans, scientists can learn why some species are better equipped to survive in a changing environment.

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Smithsonian Conservation Biology Institute Scientists Find Corals’ Natural “Sunscreen” May Help Them Weather Climate Change

Photo, posted September 28, 2009, courtesy of Matt Kieffer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Takeout Food And Ocean Litter | Earth Wise

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The Covid-19 pandemic saw most of us making use of take-out or delivery services as our only access to restaurant food.  It was a valuable link to normal life.  But unfortunately, the packaging of takeout food is a major contributor to the global plastic waste problem that isn’t going to disappear just because people are returning to eating in restaurants.

A new analysis of more than 12 million items by UK researchers published in the journal Nature Sustainability has found that the majority of ocean litter collected around the world is in the form of takeout food items:  bags, wrappers, containers, straws and cutlery, aluminum cans, and plastic and glass bottles.  Eighty percent of all the items surveyed were made of plastic.

Wrappers and packaging tended to concentrate along coasts, gathering on the shore and the sea floor.  Takeout trash was rarer in the open ocean.  In those areas, fishing debris accounted for half of the litter.

The authors of the study argue that efforts to curb plastic waste should prioritize takeout food and beverage containers.  They recommend that avoidable takeout items, like single-use plastic bags, should be replaced with non-plastic and biodegradable materials.  The authors also recommended making plastic producers responsible for the collection and disposal of plastic products.

As of July 1, the European Union has banned the 10 most common plastic and Stryofoam products found on European beaches.  The EU is also establishing an active European market for recycled plastics based on the principles of extended producer responsibility.

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Takeout Food and Drink Containers Account for Bulk of Ocean Litter

Photo, posted September 14, 2009, courtesy of Susan White/USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Have We Reached Peak Internal Combustion Engine? | Earth Wise

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According to new analysis from Bloomberg New Energy Finance, global sales of gas-powered cars may well have peaked in 2017, representing a significant milestone in the transition to electric vehicles.

Demand for gas cars dropped in 2018 and 2019, and then plummeted in 2020 as a result of the coronavirus pandemic.  While sales are surely picking up as the pandemic ebbs, the increasing demand (and supply as well) for plug-in vehicles is likely to put gas-powered cars in a state of permanent decline.

Global EV sales are projected to go from 3.1 million last year to 14 million in 2025.  The growth is being driven by falling battery prices, government policies, and increasing choices of vehicles.  Virtually all automobile manufacturers are introducing electric vehicles over the next couple of years and increasing numbers of them are planning a complete transition to EVs in the near future.  Projections are that EVs will account for the majority of new car sales by 2035.

While all this progress is encouraging, there are still over a billion gas- and diesel-powered cars on the road and the fleet turns over slowly.  The current average operating life of cars here in the US is 12 years.

To reach the net-zero carbon emission goals by 2050 as many governments have mandated, additional policies and regulations will be needed.  For example, electric cars will need to account for essentially all new sales by 2035, not just the majority.  Reaching net-zero by mid-century will require all hands on deck, including trucks and heavy commercial vehicles that have barely started to become electrified.

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New Analysis Suggests We Have Already Hit Peak Internal Combustion Engine

Photo, posted December 23, 2017, courtesy of Davide Gambino via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Potential Of Artificial Photosynthesis | Earth Wise

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The sun is the primary source of energy on the earth.  Enough solar energy hits the earth in one hour to meet all of human civilization’s energy needs for an entire year.  The two leading forms of renewable energy – photovoltaic solar power and wind power – are ways of making use of the sun’s energy.  Wind power is indirectly provided by the sun; photovoltaic power uses sunlight to generate electricity.

The most efficient use of solar energy on the planet is one perfected by plants millions of years ago:  photosynthesis.  Photosynthesis is a complex sequence of processes by which plants convert sunlight and water into usable energy in the form of glucose.  Plants utilize a combination of pigments, proteins, enzymes, and metals to perform their magic.  If we can develop artificial photosynthesis, it would be a dramatic improvement of humans’ ability to power society cleanly and efficiently.  Whereas photovoltaics capture about 20% of the sun’s energy, photosynthesis stores 60% of the sun’s energy as chemical energy.

Researchers across the globe are working to develop artificial photosynthesis.  A group at Purdue university has been making progress in trying to mimic the ability of leaves to collect light and split water molecules to generate hydrogen. This is a critical step in photosynthesis that is accomplished by protein and pigment complexes known as “photosystems II”.  The Purdue group is experimenting with these proteins and various synthetic catalysts in order to try to develop artificial leaves based on abundant, nontoxic materials. 

It is likely to take a decade or more for artificial photosynthesis technology to become part of our energy system, but its ultimate potential is enormous.

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Soaking up the sun: Artificial photosynthesis promises a clean, sustainable source of energy

Photo, posted June 14, 2007, courtesy of Alex Holyoake via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tracking Ocean Plastics | Earth Wise

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Plastic pollution in the oceans is a major problem.  An estimated 8 million tons of plastic trash enters the ocean every year.  Most of it is broken up by sun and waves into microplastics, which are tiny bits that ride currents for hundreds or thousands of miles.  All of this debris is harmful to marine ecosystems, and it is both challenging to track and very difficult to clean up.

University of Michigan researchers have developed a new technique for spotting and tracking ocean microplastics across the globe.  The approach relies on the Cyclone Global Navigation Satellite System, or CYGNSS, which is a constellation of eight microsatellites launched in 2016 to monitor weather near large storm systems.  It turns out that the radar systems on CYGNSS that measure surface roughness to calculate the wind speed near the eyes of hurricanes can also be used to detect the presence of microplastics.

With the satellite measurements, the researchers have found that global microplastic concentrations tend to vary by season, peaking during the summer months.  For example, June and July are the peak months for the Great Pacific Garbage Patch.  The data also showed spikes in microplastic concentration at the mouth of China’s Yangtze River, long suspected to be a chief source of plastic pollution.  The researchers produced visualizations that show microplastic concentrations around the world.

The information provided by the new technique could help organizations that clean up microplastics to deploy ships and other resources more efficiently.  Data of single-point release of plastics, such as from rivers, may also be useful to UNESCO, which has sponsored a task force to find new ways to track the release of microplastics into the world’s waters.

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Ocean microplastics: First global view shows seasonal changes and sources

Photo, posted April 3, 2018, courtesy of Rey Perezoso via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Importance Of Double-Cropping | Earth Wise

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In agriculture, double-cropping is the practice of growing two or more crops or commodities on the same piece of land in the same calendar year.  In Brazil, grain production has increased more than fourfold between 1980 and 2016.  The country now stands as the world’s largest exporter of soybeans and the second largest exporter of corn.  There were two primary drivers of this increase in food production: cropland expansion and double-cropping. 

Cropland expansion has long been recognized as a key driver behind the increase in Brazil’s agricultural output.  But cropland expansion is also a threat to biodiversity by driving habitat loss, deforestation, and an increase in carbon emissions. 

A new study recently published in the journal Nature Food quantified for the first time the impact that double-cropping had on helping Brazil achieve its tremendous growth in grain production.  The international research team examined data from three key agricultural regions in Brazil: the Centre-West, Southeast-South, and Matopiba region.  These three regions accounted for 79% of soybean production and 85% of  corn production in 2016. 

Soybean fields account for more than one third of Brazil’s cropland.  While the increase in soybean production was largely a result of cropland expansion, the increase in corn production was a result of double-cropping. 

Between 2003 and 2016, the study found that double-cropping in Brazil offset the equivalent of approximately 190 million acres of arable land for corn production. (This is more than twice the annual harvested area of corn in the United States).

Double-cropping represents a way to produce more food without clearing more land. 

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The impact of double-cropping

Photo, posted July 15, 2009, courtesy of Daniel Bauer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Greenhouse Gas Emissions From Water Reservoirs | Earth Wise

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A new study by researchers from Washington State University and the University of Quebec at Montreal looked at greenhouse gas emissions from water reservoirs.  It is perhaps surprising to think that water reservoirs are a source of greenhouse gas emissions at all, but that much was already known.  The new study found that those emissions are actually around 29% higher than previously thought.

Overall, the researchers found that the world’s water reservoirs annually produce methane, carbon dioxide, and other greenhouse gases at an amount equivalent to 1.07 billion tons of carbon dioxide.   That is a small fraction of the 36 billion tons produced by fossil fuels and other industrial sources, but it is by no means a negligible amount.   In fact, it is more greenhouse gases than emitted by the entire country of Germany, which is the world’s sixth largest emitter.

Decomposing plant matter near the bottom of reservoirs fuels the production of methane, which is far more potent than carbon dioxide in warming the atmosphere.  This methane degassing accounts for about 40% of emissions from reservoirs.

The study is particularly important because it may be possible to reduce methane emissions from reservoirs by selectively only withdrawing water from near the reservoirs’ surface, which tends to be relatively methane-poor compared to greater depths.  In a related study, reducing withdrawal depth by 10 feet in a Malaysian reservoir reduced methane degassing emissions by 92%.

Human-generated greenhouse gas emissions come from a surprisingly wide range of sources and it is worthwhile studying as many of them as possible in the hope of finding additional ways to reduce the total.

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Greenhouse gas emissions from water reservoirs higher than previously expected

Photo, posted July 22, 2016, courtesy of Iain Merchant via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Hardier Corals For Endangered Reefs | Earth Wise

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Mass coral bleaching events are getting increasingly frequent as the oceans continue to warm, endangering coral reefs all over the world. The damage to Australia’s Great Barrier Reef has been enormous and in 2015, nearly half of Hawaii’s coral reefs were affected by a severe bleaching event.

Not all coral bleaching is permanent.  Corals can sometimes recover.  Some corals even seem to resist bleaching altogether.  Researchers from the University of Pennsylvania studied these resilient corals to see just how effective they are in resisting the effects of climate change.

Their experiments sought to determine whether corals that seem to resist bleaching can be moved to other locations and used as the seed stock to repopulate degraded reefs.

The researchers identified coral colonies that resisted bleaching during the 2015 Hawaiian bleaching event and collected samples from them.  They transplanted some of them to a second reef as well as putting other samples in laboratory tanks and simulating a bleaching event by raising the water temperature over a period of several days.

Careful tracking of the corals’ health showed that the bleaching-resistant corals stayed that way even in a new environment and under additional stress.  They also studied how well the corals reproduced and found that the corals that spent time in a favorable new site before being subjected to stress demonstrated greater fitness and improved reproduction.

The study indicates that coral transplantation using colonies known to be resistant to bleaching may be an effective way to buy some time in preserving the world’s coral reefs.  But global action on climate change is essential because even bleaching-resistant corals aren’t going to survive forever if ocean warming keeps increasing.

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Climate change-resistant corals could provide lifeline to battered reefs

Photo, posted November 29, 2012, courtesy of Robert Linsdell via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Pesticide From Beer | Earth Wise

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Researchers from the Neiker Basque Institute for Agricultural Research and Development in Spain have demonstrated that a combination of rapeseed cake and beer bagasse can be used to reduce populations of soil parasites and increase crop yields. 

Beer bagasse is spent brewers’ grain – the stuff that is left over after the beer is made.  Beer brewing generates substantial amounts of by-products, including large amounts of spent grain.  It already has some practical uses, including as a feedstock for biofuel, as a food additive, and it even has some medical uses.  But the new research has shown that the bagasse can be the basis for a biodisinfestation treatment to be used in agriculture.  The aim is to disinfect soils, protect soil microorganisms, and increase crop yields.

The actual material studied was a mixture of beer bagasse, rapeseed cake, and a generous amount of fresh cow manure.  The high nitrogen content of the mixture promotes the activity of beneficial microorganisms in the soil, which helps to break down organic matter and kill off nematodes and other parasites that damage crops.

Nematodes are common parasites that can penetrate plant roots to lay their eggs, which damages the root and prevents the plants from absorbing nutrients effectively.  Application of the bagasse-based mixture over 12 months increased crop yields by 15% and boosted healthy soil microbes.

The study demonstrated that agricultural byproducts can be an effective treatment for root-knot nematodes and other soil parasites, increase crop yields, and help promote sustainable food systems to reduce waste from the agricultural industry.  The researchers hope to identify other potential organic treatments for tackling soil parasite problems.

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Beer byproduct mixed with manure proves an excellent organic pesticide

Photo, posted July 1, 2011, courtesy of Quinn Dombrowski via Flickr.

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