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Supermarket bargains and food waste

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Food waste is a major global problem.  The UN estimates that one third of all food goes to waste.  Apart from the fact that this is happening in a world where many people don’t have enough to eat, food waste is both an economic and a climate problem.

Researchers from the University of Copenhagen and Southern Methodist University investigated how different types of grocery sales strategies affect people’s shopping and food waste.  The result was that bulk offers increase food sales by nearly 20%, but they also lead to increased food waste in people’s homes.

The study analyzed over 43,000 purchases of fresh vegetables in eight Swedish supermarkets.  When customers were offered “two-fer” offers, they bought significantly more than when only single items were available.  The attraction of a special offer can be strong.  But, according to a follow-up survey, food from bulk offers ended up in the trash more often.  People thought they were saving money, but often ended up buying more than they can eat.

The researchers tested two strategies for reducing overbuying.  One was to make the actual savings explicit by displaying the regular price next to the offer.  The second was to put a friendly reminder on the offer sign along the lines of “I’d love to come home with you if you eat me.”  Both of these approaches resulted in reduced sales of 9-11% compared to the original volume offer despite the sale price remaining the same. 

Clearly, small changes in marketing can make a big difference.  Supermarkets play a big role in the occurrence of food waste and they have the ability to help nudge consumers into better behavior.

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Good deals – bad for the climate: Supermarket volume discounts lead to food waste

Photo, posted November 13, 2006, courtesy of Josh Hallett via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Self-healing concrete

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Concrete is the most widely used building material on Earth.  It has a dangerous and costly flaw:  it cracks easily.  Cracks in concrete can lead to inconvenient damage or to catastrophic structural failures such as collapses of buildings, bridges, or highways.

Concrete is made by mixing crushed stone and sand with powdered clay and limestone and adding water.  The mixture hardens and once set becomes extremely strong.  However, natural forces like freeze-thaw cycles, drying shrinkage, and heavy loads can cause cracks.  Even very tiny cracks can allow liquids and gases to seep into embedded steel reinforcements causing corrosion and weakness. 

For over 30 years, researchers have investigated microbe-mediated self-healing concrete.  It involves introducing microbial healing agents into cracks and injecting nutrients for the healing agents to produce repair materials.  It is not a very practical solution.

Researchers at Texas A&M University have developed a technique inspired by the behavior of lichen systems. Their system, like lichen, uses a combination of cyanobacteria which turns air and sunlight into food, and filamentous fungi, which produces minerals that seal the cracks. 

In lab tests, the paired microbes were able to grow and produce crack-filling minerals even in challenging environments such as concrete.  If it is possible to produce concrete that can heal itself, it would significantly reduce maintenance costs, extend its longevity, and even protect lives through increased safety.

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Cracking the Code: Deciphering How Concrete Can Heal Itself

Photo, posted May 21, 2009, courtesy of DesignMag 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

La Niña has arrived

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After seven months of waiting following the end of the recent El Niño condition, La Niña finally showed up in the eastern Pacific Ocean in early December.

El Niño and La Niña are climate patterns in the Pacific Ocean that can affect weather worldwide.  Normally, trade winds in the Pacific blow west along the equator, taking warm water from South America towards Asia.  To replace the warm water, cold water rises from the depths.  During El Niño, trade winds weaken and warm water is pushed back east, toward the west coast of the Americas.  As a result, areas in the northern U.S. and Canada are dryer and warmer than usual.

During La Niña, trade winds are stronger than usual, pushing more warm water toward Asia.  This results in more upwelling of cooler water from the depths.  This tends to lead to drought in the southern U.S. and heavy rains and flooding in the Pacific Northwest and Canada.  During a La Niña year, winter temperatures are warmer than normal in the South and cooler than normal in the North.

According to the report published in January by NOAA, the La Niña that has arrived is not a particularly strong one.  Sea surface temperatures are only about 1.3 degrees Fahrenheit below average in the tropical Pacific.  The report also suggests that the La Niña condition may not stick around very long.

The El Niño-Southern Oscillation phenomenon adds a natural source of year-to-year variability in global temperatures.  The presence of La Niña for at least part of this year may temporarily keep the lid on rapidly climbing global temperatures.

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La Niña Is Here

Photo, posted November 23, 2011, courtesy of NASA Goddard Space Flight Center via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Forever chemicals in water

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So-called forever chemicals are pervasive in a wide range of products.  These are man-made substances called per- and polyfluoroalkyls or PFAS.  They get their unfortunate nickname because the chemical bonds in them are so strong that the compounds don’t break down for hundreds or even thousands of years.

PFAS compounds are used in makeup, dental floss, nonstick pans, food wrappers, pesticides, stain-resistant fabrics and carpets, firefighting foams, and more.  High level exposure to some of these chemicals has been linked to a variety of health problems include high cholesterol, liver and immune system damage, pregnancy problems, and kidney and testicular cancer.

A recent study published in the journal Nature Geoscience has found that PFAS chemicals are showing up in water around the world.  The study looked at more than 45,000 water samples and found that about 31% of ground water tested that wasn’t even near any obvious source of PFAS contamination had levels of the chemicals that are considered harmful to human health by the EPA.  About 16% of surface water samples – streams, rivers, ponds, and lakes – also not near any known source, had similar hazardous PFAS levels.

The EPA has now imposed strict new drinking water limits for six types of PFAS.  Going forward, water systems are required to monitor for these chemicals and remove them if they are found above allowable levels.  The new rules make the United States one of the strictest countries in the world in terms of regulating PFAS in water.

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EPA puts limits on ‘forever chemicals’ in drinking water

Photo, posted May 5, 2020, courtesy of Brandon Shaw via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

El Niño Will Likely Return | Earth Wise

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El Niño, a weather phenomenon triggered by warm waters in the eastern Pacific, is likely to return this year, according to the World Meteorological Organization.  The Pacific has been in the cooler La Niña phase for the past 3 years, which is unusual, but that appears to be coming to a close.  According to the WMO, there is an 80% chance that the Pacific will shift to the El Niño phase before fall.

Record hot years typically coincide with El Niño, which adds to the ongoing warming trend in the climate.   There is not yet a clear picture of how strong the forthcoming El Niño event will be or how long it might last, but even a mild El Niño could affect precipitation and temperature patterns around the world.

The hottest year on record, 2016, occurred during a particularly strong El Niño.  Experts expect that 2024 is likely to see soaring temperatures again.  El Niño generally leads to drier conditions in Australia, Indonesia, and southern Asia, but greater amounts of rainfall in South America, the U.S., and parts of Africa.  Despite the presence of a cooling La Niña for the past three years, the last eight years have been the hottest on record.

El Niño and La Niña form an intermittent cycle known as the El Niño Southern Oscillation, or ENSO, that is highly influential in shaping the year-to-year variations in weather conditions around the world.  ENSO is a natural phenomenon and scientists are still trying to understand how human-caused climate change might be impacting the behavior and dynamics of the cycle.

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‘A New Spike’ in Global Temperatures in the Forecast

Photo, posted October 11, 2015, courtesy of Harshil Shah via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Much More Microplastics In The Ocean | Earth Wise

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We’ve been hearing more and more about plastic contamination (microplastics) in the ocean.  It is pulled from the nostrils of sea turtles, found in Antarctic waters, and tracked in increasing quantities in sedimentary layers dating back to the 1940s.  A new study by researchers from the Scripps Institution of Oceanography suggests that there could be a million times more pieces of plastic in the ocean than previously estimated.

Oceanographers found that some of the tiniest countable microplastic particles in seawater occur at much higher concentrations than previously measured.  Apparently, the traditional way of counting marine microplastics most likely misses the smallest particles, and therefore underestimates the number of particles by a factor of anywhere from 10,000 to a million.

The new measurements estimate that the oceans may be contaminated by 8 million pieces of so-called mini-microplastics per cubic meter of water.  Earlier studies that only looked at larger pieces of plastic found only 10 pieces per cubic meter. 

Microplastic studies typically trawl or pull a fine net behind a ship to collect samples.  But the meshes previously used could only capture plastics as small as 333 microns.  The new study found plastic particles as small as 10 microns, which is less than the width of a human hair.

Plastics keep breaking down into smaller and smaller particles, but they are so chemically strong that their chemical bonds don’t break down. They remain bits of plastic.  Scientists are concerned that these particles can get small enough to enter the human bloodstream.  The potential effects on human health are not well known and not extensively studied.

The problem of plastics just keeps getting bigger.

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Microplastics a million times more abundant in the ocean than previously thought

Photo courtesy of UC San Diego.

Earth Wise is a production of WAMC Northeast Public Radio.

Spider Silk

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Spider silk – the protein fiber spun by spiders to make webs, nests, cocoons, and wrapping for prey that they stash away – is a remarkable substance.  Its mechanical properties combine high tensile strength and high extensibility or ductility.  This allows spider silk to absorb a lot of energy before breaking.   It is stronger than steel, but not as strong as Kevlar, for example.  On the other hand, it is tougher than either.

[Read more…] about Spider Silk

Recycled Plastic Lumber

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One of the most notable success stories in recycling is that of structural plastic lumber.   The material is mostly polyethylene reinforced with stiff plastics or recycled composites.   Made from milk containers, coffee cups, and other recycled plastics, structural plastic lumber is lighter than steel, longer-lasting than natural lumber and strong enough to support 120-ton locomotives.

[Read more…] about Recycled Plastic Lumber

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