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Protected Areas Are Not Protecting Insects | Earth Wise

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Insects can be found in every environment on Earth and play crucial roles in the planet’s ecosystems.  In fact, Biologist E. O. Wilson once said that “if all mankind were to disappear, the world would regenerate back to the rich state of equilibrium that existed ten thousand years ago.  If insects were to vanish, the environment would collapse into chaos.”

While his statement may sound extreme, it’s really not an exaggeration.  Insects are critical to most ecosystems.  They pollinate more than 80% of plants – both those we eat and those that provide food and habitat for other species.  Insects are also a food source themselves, eaten by other insects, birds, fish, and mammals. Without insects, we wouldn’t have the rich biodiversity that supports life on earth today. 

But insect populations are collapsing around the globe, and they continue to be overlooked by conservation efforts.  Protected areas, like national parks, refuges, and sanctuaries, can safeguard threatened species, but only if those threatened species actually live within the protected areas. 

According to a new study recently published in the journal One Earth, 76% of insect species are not adequately covered by protected areas, including several critically endangered insects such as the dinosaur ant, crimson Hawaiian damselfly, and harnessed tiger moth. Alarmingly, the populations of 1,876 species do not overlap with protected areas at all.

Insects have been historically overlooked by conservation programs and need to be included in future conservation assessments. 

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Protected areas fail to safeguard more than 75% of global insect species

Photo, posted August 21, 2014, courtesy of Andy Reago & Chrissy McClarren via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Elephants And Global Warming | Earth Wise

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A study by researchers at Saint Louis University has found that elephants play a key role in creating forests that store large amounts of atmospheric carbon and in maintaining the biodiversity of forests in Africa.  Since elephants are endangered, their status represents a significant threat to an ecosystem that is very important to the Earth’s climate.

The African rainforest contains trees with both low carbon density (light wood) and high carbon density (heavy wood).  High carbon density trees grow more slowly and can be crowded out by the faster growing low carbon density trees rising above them.  Elephants affect the relative abundance of these trees by feeding more on the low carbon density trees which are more palatable and nutritious.  This thinning of the forest allows the trees that sequester the most carbon to flourish.

Elephants are also excellent dispersers of the seeds of high carbon density trees.  Essentially, elephants are the gardeners of the forest.  They plant the forest with high carbon density trees and get rid of the weeds – in this case, the low carbon density trees.  According to the study, if elephants were to become extinct, the African rainforest – the second largest on earth – would gradually lose between six and nine percent of its ability to capture atmospheric carbon.

Elephants have been hunted by humans for millennia.   Gaining support for protecting them has mostly been driven by the argument that everybody loves elephants.  Focusing on their role in maintaining forest diversity has not driven much more action.  The hope is that the evidence of how important elephants are for climate mitigation will be taken seriously by policy makers to generate the support needed for improved elephant conservation.

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Can Elephants Save the Planet?

Photo, posted March 15, 2008, courtesy of Michelle Gadd/USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

How To Save Big Cats | Earth Wise

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Big cats are among the most widely recognized and admired animals in the world. But these charismatic predators face many and varied threats, including the loss of habitat and prey, conflicts with humans, poaching, and the illegal wildlife trade.

Researchers from the University of Reading in the U.K. have studied the fortunes of 50 species of large carnivores worldwide over the past 50 years.  They found that social and economic factors, such as quality of life, were more closely associated with declines of large carnivore species than purely environmental factors, like habitat loss.   

The study, which was recently published in the journal Nature Communications, suggests that the best way to save large carnivores, including lynx, bears, and lions, is to encourage a sustainable model of social and economic development instead of focusing exclusively on issues like climate change.  

While rapid economic development pushes species to the brink of extinction, it’s also delivered enormous improvements in the quality of human life. But the analysis suggests that once people achieve a high quality of life and economic development slows, a turning point is reached and persecuted species have a chance to recover.

According to the research team, the recovery is a result of both improved habitat protections in advanced economies and a more harmonious relationship between people and predators.  What would have once been considered a dangerous pest is now recognized as being an important part of both the ecosystem and culture.  

In Western Europe, slower economic development and an improved quality of life have allowed populations of grey wolves to increase 1,800% since the 1960s.

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Economics trump environment to save big cats, say ecologists

Photo, posted February 8, 2015, courtesy of Mathias Appel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Driving Electric Is Cheaper For Almost Everyone | Earth Wise

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A study by University of Michigan researchers found that about 90% of U.S. households would save money on fuel costs by owning an electric car rather than a gas-powered car.  So apart from the environmental benefits of electric cars, there are real economic benefits as well.

Both the price of gasoline and the price of electricity vary considerably across the country, so there are differences by location.  The study found that 71% of U.S. drivers would see their fuel expenses cut at least in half by driving an electric car.


Drivers in California, Washington, and New York would see the largest fuel savings as well as the biggest emissions reductions from a new electric car.  Those states have cleaner electric grids and a bigger gap between the cost of electricity and the cost of gas.

The study, published in the journal Environmental Research Letters, only looked at fuel costs and did not take into account the purchase cost of new cars.  Generally speaking, plug-in cars have higher sticker prices than gas-powered cars but multiple studies have shown that over their lifetimes, electric vehicles end up being cheaper to own than comparable gas-powered vehicles because of lower maintenance costs on top of the fuel savings.  The price gap between equivalent gas and electric cars continues to narrow in any case as the cost of batteries continues to decline.  On top of that, the recent expansion of federal tax credits on electric cars is making the vehicles cost-competitive right at the point of purchase.

Gasoline prices have come down considerably from their peak a year ago, but for almost everyone, it is still much cheaper to drive on electricity.

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Seven in 10 U.S. Drivers Could Halve Their Fuel Costs by Going Electric, Study Finds

Photo, posted April 23, 2022, courtesy of Pedrik via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Disappearing Glaciers | Earth Wise

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Glaciers are massive bodies of slowly moving ice.  Glaciers form on land, and represent the snows of centuries compressed over time.  They move slowly downward under the influence of their own weight and gravity. 

Most of the glaciers on the planet are found in the polar regions, including Antarctica, the Canadian Arctic, and Greenland.  Glaciers can also be found closer to the equator in mountain ranges, such as the Andes Mountain range in South America.  Glaciers are always changing, accumulating snow in the winter and losing ice to melting in the summer.  But in recent times, the melting has been outpacing the accumulation.

A new international study led by researchers at Carnegie Mellon University’s College of Engineering has produced new projections of glacier loss through the century under different emissions scenarios.  According to the projections, the world could lose as much as 41% of its total glacier mass this century – or as little as 26% – depending on climate change mitigation efforts. 

In a future with continued investments in fossil fuels (sometimes referred to as the “business as usual” scenario), more than 40% of the glacial mass will be gone by 2100, and more than 80% of glaciers by number could disappear.  Even in a best case scenario where the increase in global mean temperature is limited to 1.5° degrees Celsius relative to pre-industrial levels, more than 25% of glacial mass will be gone, and nearly 50% of glaciers by number will disappear.

Glaciers take a long time to respond to changes in climate.  A complete halt to emissions today would take anywhere from 30 to 100 years to be reflected in glacier mass loss rates.

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Team projects two out of three glaciers could be lost by 2100

Ice, Snow, and Glaciers and the Water Cycle

Photo, posted August 13, 2010, courtesy of Kimberly Vardeman via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

How Much Plastic Is Really In The Ocean? | Earth Wise

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The world has produced more than 6 billion tons of plastic to date and much of that has become waste that has not been recycled, incinerated, or otherwise properly contained.  A great deal of it has ended up in the oceans of the world.

Researchers at Kyushu University in Japan have done an analysis to assess just how much plastic has ended up in the ocean.  According to the study, nearly 28 million tons of plastic waste has entered the ocean and nearly two-thirds of that cannot be monitored.

Furthermore, the Kyushu analysis suggests that those 28 million tons are just the tip of the plastic waste iceberg.  Their findings are that there may be another 600 million tons of mismanaged plastic waste trapped on land – nearly 10% of all the plastic ever produced.

The study created models that simulate the processes by which plastics find their way into the ocean, get transported, and fragment into pieces.  According to their models, large plastics and smaller pieces of microplastics floating on the ocean surface each account for only about 3% of all ocean plastics.  Microplastics on beaches account for another 3%, and 23% of ocean plastic waste is larger plastic litter on the world’s shores.

These things account for only about a third of ocean plastic.  The rest of it is in locations that are impossible to monitor such as heavy plastics that settle on the seafloor because they are denser than seawater.  Half of plastic products made today are made from these heavy plastics.

Plastic pollution is not just a big problem; evidently it is a bigger problem than we thought.

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Visible ocean plastics just the tip of the iceberg

Photo, posted February 28, 2010, courtesy of Kevin Krejci via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Agriculture Turning Wild Plants Into Weeds | Earth Wise

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We often hear about the importance of native plants in the environment and how invasive species can wreak havoc with ecosystems.   But it turns out that human activities can change the characteristics of native species and create unexpected new problems.

Common waterhemp is plant native to North America that typically grows near lakes and streams.  It never used to be any kind of problem, but in recent times it has become nearly impossible to eradicate from farms as a result of genetic adaptations triggered by modern agriculture.

A study led by researchers at the University of British Columbia looked at waterhemp samples from modern farms and neighboring wetlands and compared them with historical samples dating back as far as 1820 stored in various museums.

In recent times, mutations in genes related to drought tolerance, rapid growth, and resistance to herbicides have resulted in waterhemp that has become a pervasive weed on farms.  These genetic shifts, scarcely ever seen in historical samples, have made the plant thrive among human agricultural activities and enable it to outcompete crops.

Genetic analysis of the plants showed that herbicide-resistant mutations that were mostly absent from historical samples stand out as factors that allow waterhemp to prosper in agricultural settings. There are some plants in natural habitats that have herbicide-resistant mutations, but in many cases, these mutations are actually harmful to the plants in the wild.

Understanding how plant adaptations occur on relatively short timescales is increasingly important as farming and climate  change continue to drive rapid plant evolution.

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How intensive agriculture turned a wild plant into a pervasive weed

Photo, posted February 16, 2016, courtesy of Aqua Mechanical via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Electric Cars And Cleaner Air | Earth Wise

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Cities are awash in microscopic soot and other pollutants from the tailpipes of vehicles.  Apart from contributing substantially to the warming of the planet, these emissions have a significant impact on human health.  Research at Cornell University has determined that the continued growth of electric cars will lead to cleaner air and reduced human mortality in most if not all U.S. metropolitan areas.

The study, published in Renewable and Sustainable Energy Reviews, estimated the health impact and consequential economic impact of cleaner air in American cities as a result of the transition to electric vehicles.

For example, by 2050, Los Angeles will have 1,163 fewer premature deaths annually, corresponding to $12.6 billion in economic health benefits.  Greater New York City could see 574 fewer deaths a year leading to $6.24 billion in associated economic gains.

Global sales of electric cars have grown steadily.  In 2016, they accounted for less than 1% of the market.  That share grew to 2.2% in 2018, 4.1% in 2020, and 6.6% in 2021.

In the U.S., electric cars accounted for 4.5% of sales in 2021, but in many cities, the numbers were much higher. 

These trends are likely to accelerate as a combination of government policies and major decisions by automakers drive a rapid transition to electrification.  While mitigating the effects of climate change continues to be the main driving force for that transition, the human health benefits will be a very significant reward for doing the right thing for the planet.

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Electric car sales drive toward cleaner air, less mortality

Photo, posted May 11, 2021, courtesy of Chris Yarzab via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Polar Bears and Tires | Earth Wise

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There is lots of interest in traction.  People want to find better ways to move across wet and frozen surfaces safely.   This applies to both the shoes on our feet and the tires on our cars. 

Researchers at the University of Akron along with colleagues at Syracuse University and at Bridgestone, the tire company, have been studying how many arctic animals can walk and run across the ice without slipping and falling.  Their research focused on the paws of polar bears.

Previous studies discovered that polar bears have papillae – little bumps on the pads of their feet – that provide improved traction on snow.  The new research also looked at the paws of other species of bear – brown bears and black bears – and found that these others also have papillae on their paw pads, but that those of polar bears are as much as 50% taller.  These taller bumps give the pads a 30-50% increase in frictional shear stress.

The research may lead to various applications. For example, snow tires typically have deeper treads, but the polar bear study may lead to some new designs that would improve traction.  People who do high-altitude climbing are interested in the research as are companies that deliver goods in bad weather.  Anyone who has to be out and about in bad weather would like to get a better grip.

There are various other animals with traction-improving adaptations that are probably worth studying.  These include dogs, wolves, foxes, and mountain goats.  The same researchers at Akron have also studied other animals with unique abilities to deal with challenging surfaces including geckos, spiders, and mussels.  The natural world is filled with examples of creatures who can easily function in environments that we humans find very challenging.

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UA researchers’ focus on tire traction leads to investigation of polar bear paws

Photo, posted March 2, 2008, courtesy of Sam Weng via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tick-Borne Pathogens In Canada | Earth Wise

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Measuring only three to five millimeters in size, tiny ticks are a big problem.  They are widely distributed in many parts of the world, especially in warm and humid climates.  Ticks are arachnids – not insects – meaning they’re more closely related to spiders than to flies or mosquitos.  They are external parasites that feast on the blood of birds, reptiles, amphibians, and mammals – including humans.

In the United States, ticks are responsible for spreading potentially life-threatening infectious diseases.  According to estimates from the Centers for Disease Control and Prevention, ticks infect more than 300,000 people with Lyme disease in the U.S. every year, and the numbers continue to rise.  Other common tick-borne diseases include anaplasmosis, babesiosis, Rocky Mountain Spotted Fever, and powassan encephalitis.

Ticks are becoming a problem in Canada as well.  According to a new study by researchers from McGill University and the University of Ottawa, tick-borne pathogens are on the rise in Central Canada – a region where ticks were never previously detected. 

In the study, the researchers collected ticks across Ontario and Quebec.  They found that five emerging pathogens were present across their study sites, including the pathogens that cause Lyme disease and babesiosis.  The researchers also found that pathogens can transmit in different ways.  Typically, pathogens are transmitted to a tick after feeding from the blood of an infected host, like a small mammal.  But the research team found evidence of pathogens that could be directly transmitted from adult female ticks to larval ticks.

According to the researchers, more comprehensive testing and tracking is needed to detect the spread and risks of tick-borne pathogens to humans and wildlife in Canada.

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Tick-borne pathogens increasingly widespread in Central Canada

Photo, posted May 4, 2009, courtesy of Jerry Kirkhart via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Carbon In The Congo Peatlands | Earth Wise

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The Congo peatlands in central Africa are the world’s largest tropical peatlands complex, occupying an area of 65,000 square miles, about the size of the entire state of Florida. Peatlands represent a huge store of carbon and therefore are important to the stability of the climate.

A study by scientists at the University of Leeds and University College London found that around the time that Stonehenge was built – about 5,000 years ago – there was an extended drying period in central Congo and the peatlands started emitting carbon dioxide rather than storing it.  Over the course of time, the climate in the area got wetter again and over the past 2,000 years, the Congo peatlands have been a place that takes large amounts of carbon out of the atmosphere.

The study utilized peat samples taken from beneath remote swamp forests to build a record of the vegetation and rainfall in the central Congo Basin over the past 17,500 years.

In a paper published in Nature, the researchers warn that if modern-day global warming produces extended droughts in the Congo region, history could repeat itself and the peatlands could once again become carbon emitters.  If that were to happen, over 30 billion tons of carbon could be released into the atmosphere.  That is the equivalent to the total global emissions from fossil fuel burning over a three-year period.

There is some evidence that dry seasons are lengthening in the Congo Basin, but it is unknown if these will continue.  In any case, the study reveals that peatlands are more vulnerable than previously thought and need to be protected.  They are some of the most wildlife and carbon-rich ecosystems on Earth.

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Congo peatlands could release billions of tonnes of carbon

Photo, posted November 5, 2016, courtesy of Roni Ziade / Forest Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Deforestation-Free Pledges | Earth Wise

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Deforestation is the purposeful clearing of forested land. Forests are cut down to make space for animal grazing, agriculture, and to obtain wood for fuel, manufacturing, and construction. Deforestation has greatly altered landscapes around the world and continues to do so today. 

Deforestation is the second largest contributor to global greenhouse gas emissions, trailing only fossil fuel use. Deforestation can lead to all sorts of problems, including biodiversity loss, soil erosion, desertification, and flooding.  Deforestation also threatens peoples’ livelihoods and increases inequality and conflict.

As a result, many companies around the world have made pledges to remove deforestation from their supply chains.  In fact, more than 94 companies had adopted zero-deforestation commitments by 2021.  But while these companies are talking the talk, they don’t seem to be walking the walk. 

According to a new study recently published in the journal Environmental Research Letters, companies’ deforestation-free supply chain pledges have barely impacted forest clearance in the Amazon. 

The research team from the University of Cambridge, Boston University, ETH Zurich, and New York University found corporate pledges to not purchase soybeans grown on land deforested after 2006 have only reduced tree clearance in the Brazilian Amazon by 1.6% between 2006 and 2015.  The researchers found that if these pledges had been implemented, the current levels of deforestation in Brazil could be reduced by approximately 40%.  

According to the research team, the findings of the study indicate that private sector efforts are not enough to stop deforestation. Political leadership will also be vital to forest conservation efforts.

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Companies’ ‘deforestation-free’ supply chain pledges have barely impacted forest clearance in the Amazon, researchers say

Photo, posted November 18, 2020, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Perennial Rice | Earth Wise

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People have been cultivating rice for more than 9,000 years.  Cultivated rice is an annual crop which is often extended to two crops a year by a process called ratooning, which is cutting back annual rice to obtain a second, weaker harvest.

An extensive project involving multiple institutions in China, the U.S., and Australia has been developing perennial rice.  The researchers developed it through hybridization, crossing a type of Asian domesticated annual rice with a wild perennial rice from Africa.  Using modern genetic tools to identify candidate plants, the team identified a promising hybrid in 2007, planted large-scale field experiments in 2016, and released the first commercial perennial rice variety, called PR23, in 2018.

The researchers spent five years studying the performance of the perennial rice alongside annual rice on farms in China’s Yunnan Province.  For the most part, the yield of the perennial rice was equivalent to that of annual rice over a period of four years. 

Because farmers don’t have to plant rice each season, growing perennial rice requires almost 60% less labor and saves nearly half the costs of seed, fertilizer, and other inputs.

Perennial rice is already changing the lives of more than 55,000 smallholder farmers in southern China and Uganda.  The economic benefits vary by location, but overall profit increases ranged from 17% to 161% over annual rice.

There are already three perennial rice varieties available to farmers, but researchers aren’t done refining the crop.  They plan to use their methodology to enhance traits such as aroma, disease resistance, and drought tolerance to newer versions.

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Farmers in China, Uganda move to high-yielding, cost-saving perennial rice

Photo, posted February 25, 2002, courtesy of Matthieu Lelievre via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Mosquito Magnets | Earth Wise

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We’ve all probably had the experience of being in the great outdoors with other people and having some of them being nearly devoured by mosquitoes while others didn’t get bitten at all.  It seemed like some people are mosquito magnets while others just aren’t the insects’ cup of tea, so to speak.

There have been various theories proposed over the years including such things as it being a question of blood type, or it having to do with how close one’s blood vessels are to their skin surface.

A new study by the Howard Hughes Medical Institute and the Rockefeller University has uncovered what appears to be the real explanation.  According to the paper published in the journal Cell, certain body odors are the deciding factor.  Every person has a unique scent profile associated with different chemicals present on their skin.  The researchers found that people whose skin produces high levels of carboxylic acids are the most attractive to mosquitos.

The researchers collected scent samples from participants by having them wear silk stockings on their arms for six hours.  The nylons were then cut into pieces and the pieces exposed to mosquitos.  After several months of head-to-head battles between various nylon samples, the study clearly demonstrated that the samples from subjects with higher levels of carboxylic acids in the skin were far more attractive to mosquitos.

Humans produce the substance at much higher levels than other animals.  There is little one can do about their own levels.  Changing one’s diet or what soap they use doesn’t seem to make a difference. 

Perhaps researchers can come up with some method of breaking down carboxylic acids in the skin in the future.  Until such time, there are really people who are mosquito magnets.

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Some People Really Are Mosquito Magnets, and They’re Stuck That Way

Photo, posted September 4, 2014, courtesy of James Gathany / Centers for Disease Control via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Carbon Footprint Of Electric Vehicles | Earth Wise

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Electric vehicles are widely known to be the environmentally friendly alternative to internal combustion-based cars.   But there are skeptics who argue that EVs actually have a larger carbon footprint than nonelectric vehicles.  The argument is that the manufacturing and disposal of vehicle batteries is very carbon intensive.  They also point to the reliance on coal to produce the electricity that powers the cars.

These claims have led to multiple studies in the form of life-cycle analyses comparing the amount of greenhouse gases created by the production, use, and disposal of a battery electric vehicle to that associated with a gasoline-powered car of a similar size.

In short, the studies have found that while it is true that the production of a battery electric vehicle results in more emissions than a gasoline-powered one, this difference disappears as the vehicle is driven. 

According to a study conducted by the University of Michigan and financed by the Ford Motor Company, the emissions equation evens out in 1.4-1.5 years for sedans, 1.6-1.9 years for S.U.V.s, and about 1.6 years for pickup trucks.

Emissions from driving come from burning gas in the nonelectric vehicles and from the generation of electricity used by the battery-powered cars.  In the current average power mix across the U.S., driving an EV results in a 35% reduction in emissions.  However, it varies tremendously by location.  There are some places with very dirty power and some with very clean power.  But of the more than 3,000 counties in the U.S., only 78 end up with higher emissions from electric cars.  Of course, as the electric grid gets greener, the advantages of electric cars only become greater.

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E.V.s Start With a Bigger Carbon Footprint. But That Doesn’t Last.

Photo, posted May 21, 2022, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Bitcoin Mining And The Environment | Earth Wise

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Bitcoin mining, the process by which the prominent cryptocurrency is created, is well-known to be energy intensive, but the environmental impact of it has not been extensively studied.  People have described Bitcoin as ‘digital gold.’  A new analysis by researchers at the University of New Mexico has found that Bitcoin mining shouldn’t be compared to gold mining.  It is more appropriately compared to the creation of much more energy-intensive products such as beef, natural gas, and crude oil.

Furthermore, the study found that rather than becoming more sustainable over time, Bitcoin mining is becoming dirtier and more damaging to the climate as long as it relies upon fossil-fuel generated electricity.  Estimates are that in 2020, Bitcoin mining used 75.4 terawatt hours of electricity, which is more electricity than the entire country of Austria, as well as 150 other nations around the world.

The study looked at the economic cost of the air pollution and carbon emissions associated with Bitcoin mining and found that in many instances, the negative economic impact of creating a single Bitcoin is more than what the resultant coin is worth.

Based on the market value of Bitcoins, the cost of climate damage for that value is a little less that that of electricity produced by natural gas and gasoline produced from crude oil, but actually more than that of beef production.

There are multiple cryptocurrencies.  Ether is one that voluntarily switched away from so-called proof-of-work mining.  Whether Bitcoin or others will act similarly absent potential regulation remains to be seen.  Until such time, Bitcoin mining remains an increasingly dirty and damaging business.

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Technology: UNM researchers find Bitcoin mining is environmentally unsustainable

Photo, posted May 11, 2017, courtesy of Komers Real via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

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

Trees Are Growing Bigger | Earth Wise

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The alarming rate of carbon dioxide flowing into the atmosphere is having a real and actually positive effect on plant life. Higher concentrations of carbon dioxide make plants more productive because photosynthesis makes use of the sun’s energy to synthesize sugar out of carbon dioxide and water.  Plants make use of the sugar both as a source of energy and as the basic building block for growth.  When carbon dioxide levels go up, plants can take it up faster, supercharging the rate of photosynthesis.

In a new study published in the journal Nature Communications, scientists at Ohio State University found that trees are feasting on decades of carbon dioxide emissions and are growing bigger as a result. 

The researchers tracked wood volume in 10 different tree groups from 1997 to 2017 and found that all of them except aspens and birches grew larger.  Over that time period, carbon dioxide levels climbed from 363 parts per million to 405 parts per million.  According to the study, each 1% increase in lifetime CO2 exposure for trees has led to more than a 1% increase in wood volume.

In the big picture, the news isn’t so positive.  The global warming caused by increasing carbon dioxide levels increasingly threatens the forests of the world.  It has led to worsening droughts, insect infestations, and wildfires.  So overall, increasing levels of carbon dioxide are by no means a good thing for the world’s trees.  However, since trees are growing bigger more quickly, it means that planting them is an increasingly cost-effective method for fighting climate change because the same number of trees can sequester more carbon.

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As Carbon Dioxide Grows More Abundant, Trees Are Growing Bigger, Study Finds

Photo, posted September 12, 2015, courtesy of Nicholas A. Tonelli via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wildfire Smoke And Air Quality | Earth Wise

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According to a new study published by Stanford University, the average number of people in the U.S. exposed to unhealthy levels of airborne particulates at least one day a year has increased 27-fold over the last decade as a result of wildfires.

Millions of Americans are now routinely exposed to plumes of wildfire smoke that sometimes travel thousands of miles across the country.  Accumulations of deeply unhealthy air have emerged mainly in the West, where increasingly intense wildfires have become all too common.  Six of the seven largest wildfires in California recorded history have occurred since 2020.

Wildfire smoke has resulted in school closures, flight postponements, and even cancelled concerts.  Overall, the regression in air quality has undone much of the clean air progress that has taken place since the advent of the Clean Air Act in 1970.

Wildfire smoke has added about 5 micrograms of PM 2.5 particles per cubic meter of air on average in many places in the West.  This is a substantial increase from national levels, which are a total of about 10 micrograms per cubic meter and mostly result from emissions from cars, trucks, and power plants.

A decade ago, fewer than 500,000 Americans were exposed to any days of an air quality index of 100 or more due to smoke, which is a level that is deemed unhealthy.  In 2020, 25 million Americans were in areas with such levels at least one day during the year.

Ordinarily, if people don’t live near a highway or power plant, their air quality is likely to be pretty good.  But incursion from wildfire smoke is changing that, and the trend is likely to increase.

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Number of Americans Exposed to Harmful Wildfire Smoke Has Increased 27-Fold

Photo, posted August 19, 2013, courtesy of Mike Lewelling / National Park Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Bengal Water Machine | Earth Wise

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Over the past three decades, the owners of 16 million small farms in the Bengal Basin of Bangladesh have been pumping shallow groundwater during dry seasons to irrigate rice paddies.  By lowering groundwater levels in this way during the dry season, the ability of leakage from rivers, lakes, and ponds to replenish the groundwater was greatly enhanced.   Capturing surface water not only improved the recovery of groundwater levels but only helped to reduce flooding during monsoons.

The net result of this enormous collective groundwater pumping by millions of farmers has been the creation of vast natural reservoirs underground that are comparable to what is contained by many of the world’s largest dams.   This system of sustaining irrigation has transformed what was previously a famine-prone country into a food-secure nation.

The details of this remarkable transformation have been laid out in a study by University College London recently published in the journal Science.  According to the study, over the course of 30 years, more than 75 cubic kilometers of fresh water was captured by this process, which is equivalent to the combined reservoirs of China’s Three Gorges Dam and the Hoover Dam in the U.S.

The authors of the study described the water cycling process as “The Bengal Water Machine” and argue that it can be a sustainable alternative to conventional approaches to seasonal river flow storage for irrigation, which typically involve dams and reservoirs.  Such approaches are difficult to implement in densely populated alluvial plains where sand, silt, and clay are laid down by annual floodwaters. 

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Millions of farmers “replumb” world’s largest delta

Photo, posted February 2, 2010, courtesy of Melanie Ko via Flickr.

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