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Carbon Inequality | Earth Wise

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Everyone contributes to climate change through the generation of greenhouse gas emissions, but individual contributions vary greatly.   A study at the Paris School of Economics has determined that just 1 percent of the population is responsible for nearly a quarter of global carbon emissions growth since 1990.

The study estimated emissions from individuals’ consumption and their financial investments, and also from government spending in their country.  Individuals are responsible for carbon emissions as a result of their own activities, but they also bear their share of responsibility for the emissions of the firms that they own or invest in. 

In 2019, people living in sub-Saharan Africa produced an average of 1.8 tons of CO2 equivalent per capita.  In North America, the average per capita was more than 10 times higher.  Meanwhile, the top 10% of North America’s emitters produced more than 75 tons each.

From 1990 to 2019, the bottom 50% of emitters was responsible for just 16% of emissions growth, while the top 1% was responsible for 23%.  The top 0.1% saw emissions growth of 80%.

The inequality between rich and poor is driven more by inequality within countries than by inequality between countries.  This is particularly true for wealthy countries.  For example, over the study period, the top 1% saw their emissions grow by 26% while emissions actually declined 5-15% among low and middle earners even in wealthy nations.

Economic inequality drives a lot of the dynamics taking place within many countries around the world, and this even applies to pollution and greenhouse gas emissions.

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Global carbon inequality over 1990–2019

Photo, posted December 11, 2017, courtesy of Bernal Saborio via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Feeding Cows Seaweed | Earth Wise

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When cows digest their food, they burp, and when they burp, they release methane.  This is called enteric methane and it’s a real problem.  A single cow belches out 220 pounds of methane each year, which is the greenhouse gas equivalent of burning over 900 gallons of gasoline.  That’s more than the average car uses in a year.

Several studies have shown that feeding cows seaweed has the potential to substantially reduce the amount of methane in cow burps.  The latest comes from a trial that took place at the Straus Family Creamery, an organic dairy producer in Marin County, California.

The trial used a new seaweed-derived feed additive called Brominata.  Brominata is made of a red seaweed called Asparagopsis taxiformis.  The addition of the seaweed to the cows’ diets on the Straus farm resulted in an 52% average reduction in enteric methane emissions.  One cow in the study showed a reduction of 92%.

Cutting enteric methane emissions in half would be a huge improvement that would be quite difficult to achieve by convincing enough people to reduce meat and dairy consumption.

The California Air Resources Board has identified feed additives as an emissions-reduction strategy for the dairy industry.  There are now some synthetic feed additives that have been developed that reduce enteric methane, but they haven’tyet  received FDA approval for use in the U.S.  Brominata has been approved as Generally Regarded as Safe by the California Food and Drug Administration.  Whether it and similar seaweed-based feeds can be produced in sufficient quantity and without adverse environmental effects remains to be seen.  But it is an intriguing approach to solving a complicated problem.

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Feeding Cows Seaweed Reduces Their Methane Emissions, but California Farms Are a Long Way From Scaling Up the Practice

Photo, posted November 10, 2015, courtesy of Lance Cheung/USDA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Electricity From Bacteria | Earth Wise

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Microbiologists at Radboud University in the Netherlands have demonstrated in the laboratory that methane-consuming bacteria can generate electrical power.  Their study was recently published in the journal Frontiers in Microbiology.

The bacteria studied is called Candidatus Methanoperedens and in the natural environment it consumes methane in water sources that are contaminated with nitrogen including places like water-filled ditches and some lakes. The bacteria in the study make use of the nitrates in the water to break down and digest the methane. Methanogens, which are bacteria that reduce carbon dioxide to form methane, are the source of the methane in these places. 

The researchers exploited these complex interactions of bacteria to create a source of electrical power that is essentially a kind of battery with two terminals.  One of the terminals is a chemical terminal and one is a biological terminal.  They grew the bacteria on one of the electrodes where the bacteria donate electrons that result from its conversion of methane.  (Other microbiologists at the same institution had previously demonstrated electrical generation from a similar battery containing anammox bacteria that use ammonium rather than methane in their metabolic processing).

In the study, the Radboud scientists managed to convert 31% of the methane in the water into electricity but they are aiming at higher efficiencies. 

This approach represents a potential alternative to conventional biogas electricity generation.  In those installations, methane is produced by microorganisms digesting plant materials and the methane is subsequently burned to drive a turbine to generate power.  Those systems in fact have an efficiency of less than 50%.  The researchers want to determine whether microorganisms can do a better job of generating electricity from biological sources than combustion and turbines can do.

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Bacteria generate electricity from methane

Photo, posted December 3, 2008, courtesy of Martin Sutherland via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Not Enough Buzz For Bees | Earth Wise

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The dramatic worldwide decline in bees and other pollinating insects represents a serious threat to the global food supply, but it isn’t really getting much attention in the mainstream news.  Close to 75% of the world’s crops for human consumption depend, at least in part, on pollinators for sustained production, yield, and quality.

A new study by researchers at the University of Illinois Urbana-Champaign looked at nearly 25 million news items from six prominent sources, including The New York Times, The Washington Post, the Associated Press, as well as three overseas English-language news services.  The study found “vanishingly low levels of attention to pollinator population topics”, even compared with what many people consider to be the limited coverage of climate change.

The study made use of the Global News Index, which is a unique database of millions of news items from thousands of global sources published over decades.  It may be the largest academic study of the evolving nature of news coverage ever performed.

Even though the entomological community is highly focused on the impending pollinator crisis, the public is not paying much attention.  It is not even indifference; it is just that people don’t even know about it.

The majority of studies on pollinator decline have been done in Europe and North America, which means we don’t even know how serious the problem is given that most insect biodiversity is in the tropics.

Public awareness is important because individuals can make a difference by their decisions about what flowers to plant in their gardens, which weeds to tolerate in their yards, and how to manage insect pests.

The loss of pollinators is a very serious problem, and it is not likely to get enough attention if people don’t know about it.

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Pollinators not getting the ‘buzz’ they need in news coverage

Photo, posted December 28, 2006, courtesy of Alpha via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Costs Of Mislabeled Seafood | Earth Wise

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Seafood is the world’s most highly traded food commodity and reports of seafood mislabeling have become increasingly common over time.  A new study by Arizona State University looked at the environmental effects of mislabeled seafood.

What is mislabeled seafood?  Sometimes the snapper you were served was really Pacific Ocean Perch.  Maybe grouper was really whitefin weakfish.  Many times white leg shrimp are actually giant tiger prawns.

Approximately 190,000 to 250,000 tons of mislabeled seafood are sold in the U.S. each year, or 3.4 to 4.3% of consumed seafood.  Previous studies focused on the economic aspects of getting cheaper fish when paying for more expensive fish.  The new research looks at the environmental costs associated with mislabeled seafood.

Substituted seafood is 28% more likely to be imported from other countries, which may have weaker environmental laws than the U.S.  In the United States, fishery management is pretty good.  There is strong monitoring and enforcement to support limits on fishing.  Metrics like fish abundance, fishing mortality, bycatch, and discards are all monitored.  In many other places, this is not the case.

To really evaluate the overall effects of seafood mislabeling, one has to take into account both the rates of substitution and the levels of consumption. 

Consuming fish from a well-managed fishery should not have a negative impact in terms of the population now or in the future.  But even inadvertently consuming fish from poorly managed fisheries in not sustainable.  It is good to get your seafood from a trusted source.

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ASU Study Looks At The Environmental Effects Of Purchasing, Consuming Mislabeled Fish

Photo, posted August 1, 2014, courtesy of Ralph Daily via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Shifting Climate Attitudes – Even In Texas | Earth Wise

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Any conversation about climate policy and energy in the United States has to take Texas into consideration.  Texas leads the nation in energy production, providing more than one-fifth of U.S. domestically produced energy.  Texas also uses more energy than any other state and accounts for almost one-seventh of total U.S. energy consumption.  The state’s industrial sector, which includes petroleum refining and chemical manufacturing, accounts for almost half of Texas energy consumption.

As a result, longstanding skepticism among Texans toward the climate movement has represented a real impediment in developing and implementing effective climate policy in this country.  But according to new research at the University of Houston, attitudes in Texas have changed and now mirror those in the rest of the United States.

About 80% of Americans believe that climate change is happening, and now about 81% of Texans hold the same view.  Two out of three Americans are worried about climate change; more than 60% of Texans agree.

Nationwide, 55% agree that the oil and gas industries have deliberately misled people on climate change; 49% of Texans agree. 64% of Americans say hydraulic fracking has a negative effect on the environment and 61% of Texans agree.  People everywhere are willing to pay more for carbon-neutral energy, and a higher premium for gasoline as well.

Mitigation strategies for climate change are not well understood.  While 61% nationwide have heard of carbon taxes, less than half are familiar with carbon management, and only a third have heard of carbon pricing.

As the U.S. heads toward reengaging in efforts to address climate change, Texans appear to have caught up with the rest of the nation.

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Attitudes About Climate Change Are Shifting, Even in Texas

Photo, posted October 1, 2011, courtesy of Steve Rainwater via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Food Waste Into Wearables | Earth Wise

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A new startup company spun out of the University of Toronto wants to make clothing from food waste.  If they are successful, you may someday buy a shirt or a pair of gym shorts made from banana peels, rotten tomatoes, coffee grounds, or moldy bread.

A problem faced by the clothing industry is that most textiles are blended with synthetic and non-renewable fiber polyester, which makes them unrecyclable.  An alternative that has come on the scene in recent years is polylactic acid (or PLA), which is a decomposable bioplastic that is currently used for food packaging, medical implants, and 3D printing.  It is likely that a sustainable future for the fashion industry will depend on the ability to make use of biodegradable and carbon-neutral materials.

PLA is typically made from cornstalk, but the startup – called ALT TEX – does not want to rely on a crop already used for feedstock, human consumption, and alternative fuel.  Furthermore, there is no need to plant more corn when there is an abundant supply of unused post-industrial food waste from growers, producers, and retailers that contains the same biological building blocks for producing PLA.

ALT TEX has been conducting experiments using discarded apples to create a PLA-based fabric that is strong, durable, decomposable, and cost effective.  They are working with farmers and food suppliers to access their waste. If their efforts are successful, it would be possible to divert significant amounts of organic waste that currently emits the powerful greenhouse gas methane and instead enable the fashion industry to be more sustainable.

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Earth-friendly fashion: U of T startup turns food waste into wearables

Photo, posted August 30, 2019, courtesy of Ruth Hartnup via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Hydropower And Floating Solar | Earth Wise

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According to a new analysis by the National Renewable Energy Laboratory, hybrid systems of floating solar panels and hydroelectric plants have the potential to produce a significant portion of the world’s electricity.

According to their estimates, adding floating solar panels to bodies of water that host hydropower stations could produce up to 7.6 terawatts of power a year from the solar systems, resulting in about 10,600 terawatt-hours of energy.  The total global electricity consumption in 2018 was 22,300 terawatt-hours.  So, the potential in terms of the global appetite for electricity is very large.

This estimate is certainly optimistic.  It does not take into account economic feasibility or specific market demand.  What it does represent is an estimate of the technical and performance potential of floating photovoltaics at hydroelectric facilities.

Floating solar is just starting to be used in the U.S., but it has already caught on overseas where space for ground-mounted systems is at a greater premium. 

According to the NREL study, nearly 400,000 freshwater hydropower reservoirs across the globe could host floating PV sites that could be used in conjunction with the existing hydroelectric plants.  One important advantage of this approach is that the hybrid system would reduce transmission costs by linking to a common substation.  In addition, the two technologies could balance each other, with solar power taking up the slack in dry seasons and hydropower working well in rainy seasons.  In some places, pumped storage hydropower could be used to store excess solar generation.

There is great potential in hybrid floating solar/hydroelectric power.

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Untapped potential exists for blending hydropower, floating solar panels

Photo, posted April 12, 2009, courtesy of Alexis Nyal via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Fitness Trackers For Lobsters | Earth Wise

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The lobster industry is somewhat unique, at least in this country, in that it involves an animal food that is kept alive until it has reached the destination where it will be consumed or used.  As a result, the industry has to deal with a problem they call “shrink”, which is the mortality lobsters experience as they change hands from capture to kitchen.

Maine’s lobster industry has reached out to the University of Maine Lobster Institute along with collaborators at other institutions to help quantify and mitigate stress points in the lobster supply chain that reduce survival and profitability.

A 2-year project was funded by the National Oceanic and Atmospheric Administration to create miniature sensory devices – crustacean heart and activity trackers (called C-HATs).  These are essentially Fitbits for lobsters.  The noninvasive devices strapped on a lobster monitor its heart rate and movement as it passes from trap to on-board live tank to live storage crate to truck to wholesaler to retailer or processor.

A separate sensor-equipped device called the MockLobster travels along with the lobsters to log environmental conditions experienced, including temperature, light and dissolved oxygen levels.

The hope is to be able to get a good handle on the conditions lobsters experience from trap to market and learn where problems are likely to arise.  The researchers are also working to develop economical, standardized protocols to monitor water quality and the heath of lobsters during their movement through the supply chain.

The goal is to produce big improvements in the bottom lines of everyone along the supply chain along with big improvements in the health of the lobsters destined for market.

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Fitness trackers, environmental sensors prototyped to improve survival in the lobster supply chain 

Photo, posted August 29, 2015, courtesy of Adam Grimes via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Chocolate Is Good For The Heart | Earth Wise

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At last a good news story about what we eat, or more specifically, about what we like to eat.   According to research published recently in the European Journal of Preventive Cardiology, eating chocolate at least once a week is linked with a reduced risk of heart disease.

In the past, clinical studies have shown that chocolate is beneficial for both blood pressure and the lining of blood vessels.   The new study suggests that chocolate helps to keep the heart’s blood vessels healthy.

The researchers conducted a combined analysis of studies from the past five decades examining the association between chocolate consumption and coronary artery disease.  The analysis included data from over 300,000 participants who reported their chocolate consumption.  About 14,000 participants in the study ultimately developed coronary heart disease.  Compared with consuming chocolate less than once a week, eating chocolate more than once a week was associated with an 8% decreased risk of coronary heart disease.

Chocolate contains heart-healthy nutrients such as flavonoids, methylxanthines, polyphenols, and steric acid.  These substances may reduce inflammation and increase good (HDL) cholesterol.

The study did not examine whether any particular type of chocolate is more beneficial or whether there is an ideal portion size.  So, while chocolate appears to be promising for reducing the occurrence of coronary heart disease, it will require more research to determine how much and what kind of chocolate could be recommended.

Not to be spoilsports, but the doctors who conducted the study warned against overeating.  Eating large quantities of chocolate products laden with calories, sugar, milk and fat, is not a recommended path to improved health.

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Chocolate is good for the heart

Photo, posted February 22, 2014, courtesy of Jan David Hanrath via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Vehicle Electrification On The Rise | Earth Wise

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Nearly 70% of U.S. oil consumption is for transportation and transportation accounts for 28% of the country’s greenhouse gas emissions.  Therefore, technology improvements in transportation that can reduce emissions are a key element of combating climate change.  The highest impact strategy is the electrification of the transportation sector, and it is definitely accelerating.

Demand for electric vehicles is growing for multiple reasons.  These include long-term cost savings, tax incentives, declining battery costs, and greater environmental awareness.  This year, about 2.7 percent of global passenger vehicle sales will be for electric vehicles.  It is still a fairly small number, but that number is growing rapidly.  It is expected to be 10% in 2025, 28% in 2030, and more than half of all vehicle sales by 2040.  By that year, more than 30% of passenger vehicles on the road worldwide will be electric.  The numbers for electric buses, delivery vans and trucks, mopeds, scooters, and motorcycles are expected to be even higher.

The environmental impact of electrification will be significant in reducing carbon emissions and pollution in general.  Electric vehicles already reduce oil demand by a million barrels a day.  By the year 2040, they will displace nearly 18 million barrels of oil a day and reduce CO2 emissions by 2.5 billion tons per year.

Electric cars still face challenges.  They are still more expensive than gas-powered cars, but their cost-benefit analysis is changing rapidly as technology improvements and volume efficiencies drive down the cost of battery packs.  Analysts predict that electric vehicles will achieve price parity with internal combustion vehicles in as soon as two years but in any case within the next ten years.

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Electrification of transportation sector nears tipping point

Photo, posted May 7, 2020, courtesy of Mark Vletter via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Lifestyle And Carbon Footprint | Earth Wise

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Many studies have shown, to no great surprise, that affluent lifestyles lead to larger carbon footprints. Households in Switzerland enjoy a high standard of living and a team of researchers there has been studying the consumption and travel habits of Swiss citizens to better understand the impact of various factors on carbon footprint. Key factors include household composition and income, and whether the households are in the city or the countryside – even though, in the end, people’s lifestyles do not differ greatly from one environment to another. 

A team of researchers at EPFL’s School of Architecture, Civil and Environmental Engineering analyzed data from Switzerland’s household budget survey for 2008, 2011 and 2014.  They combined that data with an environmentally extended input-output analysis to assess households’ carbon footprints by measuring their direct and indirect emissions.

Overall, households in the countryside have larger carbon footprints than those in the city, mainly because they travel more and use more energy in their homes. But urban households have larger carbon footprints than their rural counterparts when it comes to food, clothing, cultural activities and air travel.  

A household’s composition directly influences its carbon footprint. A two-person household has the largest per-capita carbon footprint, and it falls as the size of the family grows since many of the same resources are shared by more people. 

Income levels play an important role.  People consume without much thought because they can afford to and enjoy doing it. But there is a trend towards people becoming more conscious of their levels of consumption and trying to be more responsible in Switzerland.  Overall consumption has actually declined over the years studied.  

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Our carbon footprint is highly impacted by how we live

Photo, posted December 19, 2017, courtesy of Alexander Kozik via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Conspicuous Consumption

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Human civilization consumes vast amounts of material.   The Circle Economy think tank actually puts some numbers on it.  According to their latest report, the amount of material consumed by humanity has passed 100 billion tons every year.  So, on average, every person on Earth uses more than 13 tons of materials per year.

That number has quadrupled since 1970, which is far faster than the population, which has only doubled during that time.  In the past two years alone, consumption has jumped by more than 8%.  While this has been going on, the proportion being recycled has been falling.

Of the 100 billion tons of materials, half of the total is sand, clay, gravel, and cement used for building, along with other minerals used for fertilizer.  Coal, oil and gas make up 15% and metal ores 10%. The final quarter are plants and trees used for food and fuel.  About 40% of all materials are turned into housing.  A third of the annual materials consumed remain in use, such as in buildings or vehicles.  But 15% is emitted into the atmosphere as greenhouse gases and a third is treated as waste.

The global emergencies of climate change and disappearing wildlife have been driven by the unsustainable extraction of fossil fuels, metals, building materials, and trees.  The authors of the report warn that if we continue to treat the world’s resources as limitless, we are heading for a global disaster.

The Circle Economy think tank promotes the idea of a circular economy in which renewable energy supports systems where waste and pollution are reduced to zero.  Some nations are taking steps towards circular economies, while others are not.  This is a problem we can’t allow to be unaddressed.

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World Consumes 100 Billion Tons of Materials Every Year, Report Finds

Photo, posted March 13, 2015, courtesy of Joyce Cory via Flickr.

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Scottish Wind Power

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Scotland is a windy country.  Most wind turbines in the European Union produce electricity at an average of 25% of their maximum rated power as a result of the variability of wind resources.  The west and northern coasts of Scotland have an average capacity of 31% or more.  Some wind farms in Scotland have achieved more than 50% capacity over the course of a year.

As of the end of last year, Scotland had more than 8 GW of installed wind power capacity.  This included 7.8 GW of onshore wind and 623 MW of offshore wind generators.  Estimates are that more than 11 GW of onshore wind could be installed in Scotland.  The total offshore potential is far greater than that but would be much more expensive.  There are multiple large-scale wind farms proposed or under construction in Scotland.

All of this growth in wind power has led to some remarkable results.  During the first half of 2019, wind turbines in Scotland produced enough electricity to power every home in the country twice over.  Scottish wind farms generated nearly 10 million megawatt-hours between January and June, which is equal to the consumption of 4.5 million homes during that period.   That is enough to take care of all of Scotland’s homes plus a large portion of northern England’s. 

Scotland has set a target of generating half of its electricity from renewable sources by 2030 and decarbonizing its energy system almost entirely by 2050.  The recent performance of its wind power installations shows that the country might be able to reach its goal much sooner than anticipated.

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Scotland’s Wind Farms Generate Enough Electricity to Power Nearly 4.5 Million Homes

Photo, posted March 27, 2017, courtesy of Ian Dick via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Reducing Methane From Animals

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Methane emissions from ruminant livestock are currently estimated to be more than 100 million tons each year and, after rice agriculture, represent the biggest human-initiated methane source.  Given that fact, there is widespread encouragement for people to reduce their consumption of meat in order to reduce the amount of the potent greenhouse gas going into the atmosphere.

But an additional strategy to lower global methane emissions is to actually reduce the amount of methane produced by each animal.  To that end, researchers at the University of Otago in New Zealand have now identified new processes that control methane production in the stomachs of sheep and similar animals like cattle and deer.

They determined the specific microbes and enzymes that control the supply of hydrogen, which is the main energy source for methane producing microbes, known as methanogens.  Their work is focused on the development of small molecule inhibitors and vaccines to specifically target the production of methane by methanogens.  By reducing the supply of hydrogen to methanogens, it is possible to reduce animal methane emissions.

The research involved studying two types of sheep – those producing large amounts of methane and those producing less.  They found that the most active hydrogen-consuming microbes differed between the sheep.  Specifically, in the low methane emitting sheep, hydrogen consuming bacteria dominated over methanogens.

Ultimately, a strategy might emerge to introduce feed supplements that encourage non-methane producers to out-compete methanogens.  Controlling the supply of hydrogen to the methanogens will lead to reduced methane emissions. 

Having low-emission cattle would definitely help reduce the impact of agriculture on the climate.

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Scientists discover processes to lower methane emissions from animals

Photo, posted April 7, 2017, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

We’re Still Eating The Wrong Things

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A new study published in the Journal of the Academy of Nutrition and Dietetics has found that despite efforts to increase public awareness of health issues related to diet, the amount of processed meat consumed by Americans has remained unchanged in the past 18 years.  Furthermore, our intake of fish and shellfish has not increased.  One quarter of US adults are still eating more unprocessed read meat than the recommended level, and less than 15% meet the current guidelines for fish and shellfish consumption.

About the only positive note is that Americans are eating less beef and more chicken than they did 18 years ago and, in fact, for the first time, the consumption of poultry exceeds that of unprocessed red meat.

Accumulating evidence has linked excessive consumption of processed meat to increased risk of obesity, diabetes, cardiovascular diseases, and some cancers.  The study’s authors speculate that public awareness of these linkages is not widespread enough to affect change and, in any case, factors other than health – social, cultural, and economic – have greater influence over Americans’ food choices.  The top five consumed processed meats are luncheon meat, sausage, hot dogs, ham, and bacon.

The low consumption of fish and shellfish among U.S. adults could be due to high retail prices, lack of awareness of the health benefits, and concerns about mercury contamination in certain types of fish.

Future research is needed to identify barriers to reducing processed meat consumption and increased seafood consumption.  Policies such as nutrition quality standards, excise taxes, health warning labels, and other interventions need to be explored.

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Americans still eat too much processed meat and too little fish

Photo, posted January 28, 2014, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Microplastic Diet

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According to a new study published in the journal Environmental Science & Technology, Americans consume more than 70,000 microplastic particles every year from the food they eat, the water they drink, and the air they breathe.

While the health impacts of ingesting these tiny particles are largely unknown, there is the potential for the plastic to enter human tissues and cause an immune response or perhaps release toxic chemicals into the body.

The analysis by biologists at the University of Victoria in Canada examined data from 26 previous studies on microplastic contamination.  It found that Americans eat and drink an estimated 39,000 to 52,000 microplastic particles each year, depending on their age and sex.  The numbers jump to 74,000 to 121,000 when inhalation of microplastics is included.

Americans who drink water solely from plastic bottles consume an additional 90,000 particles annually, compared to only 4,000 particles for people who only drink tap water.

The researchers warn that their findings are likely to be drastic underestimates of the problem.  Several major U.S. food groups – including poultry, beef, dairy, grains, and vegetables – have not been studied for their microplastic contamination.  Thus, the estimate of microparticle ingestion is associated with only 15% of an average person’s caloric intake.  Furthermore, there is no assessment currently available for how much plastic might be entering our bodies from food packaging.

The report’s findings suggest that microplastics will continue to be found in the majority if not all items intended for human consumption.  Realistically, the only way to reduce the human consumption of microplastics will be to reduce the production and use of plastics.

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Americans Consume Tens of Thousands of Microplastic Particles Every Year

Photo, posted June 18, 2016, courtesy of Sirirat Kornsongkaew via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Bees And Plastic

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Wild bees in Argentina have recently been found to be constructing nests entirely made of flimsy plastic material left on farms and scientists don’t know why.

In 2017 and 2018, researchers at Argentina’s National Agricultural Technology Institute built wooden, artificial nests for wild bees.  These bee species burrow into nests to individually lay larvae rather than having a large hive with queens and workers.  The artificial nests provide hollow openings that bees generally fill with cut leaves, twigs, and mud.

Sixty-three wooden nests were constructed and three were found lined entirely with plastic.  The bees carefully cut bits of plastic in the shape and size of fingernails and arranged them in an overlapping pattern in their nests.  The plastic seems to have come from plastic bags or films, which have a similar texture to the leaves bees ordinarily use to line their nests.  And, in fact, leaves were readily available to the bees making use of plastic.

This is the first time that bees have been seen making nests entirely out of plastic, but for years scientists have known bees were incorporating plastic into their building materials.  Research is needed to determine the potential impact plastic might have on bees, but the nest building shows that bees are highly adaptive to changing environments.

Plastic often forms a threat to wildlife in the form of microplastics that can be consumed.  But there is no evidence that bees are consuming plastic.  Some researchers have speculated that the plastic in bees’ nests may form a barrier against common nest issues like mold and parasites.

At this point, it is not clear whether it is a good thing or a bad thing that some bees are choosing plastic over natural materials, but it is certainly interesting.

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Wild bees are building their homes from plastic—and scientists aren’t sure why

Photo, posted December 12, 2014, courtesy of Judy Gallagher via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

100% Renewables Does Not Necessarily Mean Carbon-Free

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Hundreds of companies around the world have committed to use 100% renewable energy in order to fight climate change.  But a new study from Stanford University points out that 100% renewable energy does not necessarily mean 100% carbon-free energy.

The problem is that the carbon content of electricity can vary a lot over the course of a day in many locations.  Using yearly averages can overstate the carbon reductions associated with a particular power source, in some cases by significant amounts.

Suppose a California company purchases or generates enough solar power to match 100% or more of their electricity use over the course of the year.  In reality, it may generate far more electricity than it uses during the afternoon and sell the excess.  Then, at nighttime, it purchases power from the grid, which would be far more carbon-intensive if it involves the burning of fossil fuels.

But in Britain, for example, the situation is very different.  With a high reliance on wind power, grid carbon intensity is actually lower at night.  So very different consumption patterns over the course of a day would be less carbon-intensive.

If sufficient energy storage capacity can be implemented into the grid as well as suitable long-range transmission, these time-based fluctuations in the electricity supply could be ironed out.  Until such time, electricity consumers need to evaluate the environmental benefits of their renewable strategies on an hourly basis rather than using averages.  And the best strategies are entirely dependent upon the characteristics of the specific grid they interact with.  The need for this kind of analysis will only grow as renewable generation expands.  Transparent, precise and meaningful carbon accounting is necessary.

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100% renewables doesn’t equal zero-carbon energy, and the difference is growing

Photo, posted January 29, 2013, courtesy of U.S. Fish and Wildlife Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The U.S. Military And Climate Change

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According to new research by scientists from Durham University and Lancaster University, the United States military is one of the largest climate polluters.  The U.S. military consumes more liquid fuels and emits more greenhouse gases than most countries.  

The study, published in Transactions of the Institute of British Geographers, finds that if the U.S. military were a country, it would be the 47th largest emitter of greenhouse gases in the world, falling between Peru and Portugal.  And this only takes into account the emissions from its liquid fuel consumption.  For this study, the U.S. military’s 2015 consumption was compared with the 2014 World Bank country liquid fuel consumption. 

In 2017, the U.S. military purchased more than 269,000 barrels of oil a day, emitting more than 25,000 kt- CO2e by burning those fuels.  The Air Force accounted for $4.9 billion worth of this fuel, followed by the Navy at $2.8 billion, the Army at $947 million, and the Marines at $36 million. 

The Air Force and the Navy are not only the U.S. military’s largest purchasers of fuel, they also use the most polluting types of fuel.  The Air Force is the largest emitter of greenhouse gases at more than 13,000 kt CO2e, nearly double that of the Navy’s 7,800 kt CO2e. 

Despite this study’s findings and a general uptick in awareness, it’s unlikely that the U.S. military’s dependence on fossil fuels will change.  That’s because the military continues to pursue open-ended operations around the globe, and the lifecycle of its existing military equipment insures dependence on hydrocarbons for many years to come. 

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U.S. military consumes more hydrocarbons than most countries — massive hidden impact on climate

Photo, posted July 8, 2016, courtesy of Alan Wilson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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