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Not All Eggs In One Basket | Earth Wise

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Sea turtles lay their eggs in burrows on sandy beaches.  Many species lay their eggs on the exact same beach year after year.  On average, sea turtles lay over 100 eggs in a nest and produce between 2 and 8 nests per season.

Animals that produce such large numbers of eggs have this reproductive strategy because so few survive to adulthood.   Sea turtle eggs and hatchlings face numerous threats including powerful storms, poachers, marauding birds, and more.  Estimates are that only one in thousand sea turtle eggs leads to an adult turtle.

A recent study by the University of South Florida looked at the reproductive strategy of loggerhead sea turtles nesting on Keewaydin Island off the southwestern Gulf coast of Florida.  The researchers found that individual females lay numerous clutches of eggs in locations as much as six miles apart from each other to increase the chance that some of their offspring will survive.

As the saying goes, nesting loggerhead turtles don’t lay all their eggs in one basket.  The researchers compare the turtles’ strategy to investing in a mutual fund.  The female turtles divide their resources among many stocks rather than investing everything in a single stock.

During their 50-year lifetime, a single female loggerhead will produce over 4,000 eggs and scatter them at 40 different sites.  This strategy helps reduce the risk of complete reproductive failure caused by hurricanes and thunderstorms that could wash out or flood all their clutches.  The combination of unpredictable patterns of nests over time and space results in nearly two-thirds of loggerhead sea turtle hatchlings making it into the Gulf of Mexico.  The species still faces significant challenges but it is doing its part to try to survive.

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Not all in one basket: Loggerhead sea turtles lay eggs in multiple locations to improve reproductive success

Photo, posted January 27, 2012, courtesy of Jeroen Looye via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Aircraft Emissions And Climate Change | Earth Wise

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The aviation industry accounts for about 2.4% of global carbon dioxide emissions.  If the aviation industry was a country, it would place sixth in emissions, between Japan and Germany.

According to scientists at the University of Reading in the United Kingdom, aviation industry emissions could be reduced by simply better surfing the wind.  The researchers found that commercial flights between New York and London could have used up to 16% less fuel if they had made better use of the fast-moving winds at altitude.

The study, which was recently published in the journal Environmental Research Letters, analyzed approximately 35,000 flights in both directions between New York and London last winter.  The researchers compared how much fuel was burned during these flights to how much less fuel would have been burned by flying into or around the eastward jet stream air currents. 

They found that taking better advantage of the winds would have saved about 125 miles worth of fuel per flight on average.  The fuel saving per flight was 1.7% when flying west to New York, and 2.5% when flying east to London. 

New satellites will soon allow transatlantic flights to be tracked more accurately.  This should afford aircraft more flexibility in their flight paths, allowing them to better follow tailwinds and avoid headwinds. 

Upgrading aircraft or switching to greener fuels are two other ways that the aviation industry can reduce emissions, but those things are costly and take time to implement.  Optimizing flight paths is cheaper and offers immediate benefits.  

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Aircraft could cut emissions by better surfing the wind

Photo, posted May 16, 2011, courtesy of Cory W. Watts 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.

Rivers Changing Color | Earth Wise

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A recent study, published in Geophysical Research Letters, found that one-third of large American rivers have had significant changes of color over the past 30 years.  Rivers can appear to be shades of blue, green, and yellow and we tend to expect healthy rivers to have colors in shades of blue.  According to the new study, only 6% of American rivers are dominantly blue.

The study looked at 235,000 Landsat images taken from 1984 to 2018.  The results are that 56% of rivers studied were dominantly yellow, 38% dominantly green, and 6% blue.  Over the 34 years studied, 33% of the rivers had significant changes in color. About 21% became greener and 12% more yellow. 

The chief causes of color changes in rivers are farm fertilizer runoff, dams, efforts to fight soil erosion, and climate change.  Climate change increases water temperature and rain-related runoff.

Color changes are not necessarily a sign of poor river health, but dramatic changes could point to issues that need attention.  A river can change color based on the amount of sediment, algae, or dissolved organic carbon in the water.   If a river becomes greener, it can often mean large algae blooms are present that cause oxygen loss and can produce toxins.  On the other hand, rivers that are getting less yellow demonstrate the success of regulations to prevent soil erosion.

The study of river colors can pinpoint which rivers are undergoing rapid environmental change.  What the study does not provide is information on water quality.  Water quality measurements will be important to determine the health of many of the rapidly changing rivers.

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One Third of U.S. Rivers Changed Their Color, Three Decades of Satellite Images Show

Photo, posted July 6, 2016, courtesy of Jeffrey Beall via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Hudson River Tidal Marshes And Sea Level Rise | Earth Wise

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A new study at the University of Massachusetts Amherst looked at the resilience of Hudson River Estuary marshes to rising sea levels.  They observed that these marshes are growing upward at a rate two or three times faster than sea level rise, suggesting that they should be resilient to accelerated sea level rise in the future.

The study documented the fact that more than half of Hudson River tidal marshes actually formed since 1850.  In that year, the river channel was straightened, and a riverside railroad, berms, jetties and human-made islands of dredged soil were built.  All of these human-made features trapped sediment and created backwaters that often turned into marshes.

The research centered on seven sites spanning more than 100 miles of the Hudson Estuary from Wall Street up to Albany.  Although these marshes were an unintended result of early industrial development, they serve to protect the shoreline and provide rich ecosystems in terms of direct ecological and human benefits.  Marshes are a first line of defense against coastal flooding, provide an essential habitat for juvenile commercial fish species, store huge amounts of carbon that mitigates climate change, provide habitat for migratory birds, and filter nutrients coming off the land.

The study determined that such marches form relatively quickly.  When sediment is readily available, freshwater tidal wetlands can develop rapidly in sheltered settings.   There is concern that marshes globally will be drowned by rising sea levels, but this Hudson River case study shows how marshes may be able to resist the rising seas.  The research will help guide future land acquisition and land conservation strategies for areas adjacent to the river.

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New Study Finds More than Half of Hudson River Tidal Marshes were Created Accidentally by Humans; Resilient Against Sea Level Rise

Photo, posted December 4, 2008, courtesy of Daina Dajevskis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Compost And Landfills | Earth Wise

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Composting is popular as a way to keep solid waste out of landfills and many people turn much of their kitchen waste into rich soil amendments.   Cities and towns across the country have composting programs that collect waste from residents to produce large quantities of compost rather than adding the waste to landfills.  A new study from North Carolina State University looked into the environmental benefits of actually using compost at landfills.

Most municipal composting programs require that the compost they produce gets used “beneficially”.  The new research shows that using compost as an alternative daily cover at landfills is competitive and often superior to the use of compost as a soil amendment in terms of its environmental benefits.

Landfills apply a layer of daily cover to reduce odors, reduce windblown debris, and keep vermin out of landfill waste.  Federal regulations require six inches of soil as a daily cover.

Compost from food waste in particular is not always suitable for soil amendment in gardens and agricultural fields because it often contains broken glass and other contaminants.

The North Carolina State study looked at the environmental impact of using compost as daily cover in landfills compared with its use as a soil amendment.  They looked at global warming potential, acidification potential, eutrophication (which is the amount of nutrients released to ground and surface water), cumulative energy demand, and the depletion of resources.

The study concluded that using compost as landfill daily cover is environmentally superior with regard to eutrophication, acidification, and global warming potential.  On the other hand, soil amendment was better in terms of resource depletion and cumulative energy demand.

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Applying Compost to Landfills Could Have Environmental Benefits

Photo, posted April 22, 2008, courtesy of Alachua County via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Non-Native Plants And Insect Decline | Earth Wise

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Global insect populations have been in decline since the beginning of the 20th century.  The decline accelerated during the 1950s and 1960s, and it has reached alarming levels during the past 20 years.

The causes of plummeting insect populations include habitat destruction, deforestation, climate change, light pollution, and the rise of industrial agriculture.  This so-called insect apocalypse is being mirrored by a bird Armageddon because so many bird species depend on insects for their diets.

A still controversial, but increasingly likely factor in the decline of insect populations is the spread of non-native plants in agriculture, agroforestry, and horticulture.  A recent study published in the journal Ecological Entomology presents recent data supporting the proposition that the widespread displacement of native plants is a key cause of insect declines. 

Many insects depend on a limited number of plants for survival.  In many cases, insects’ diets are restricted to a single plant family.  When native host plants dwindle or disappear from an area, the population of insects that depend on those plants shrinks.

There are examples of insects that adopt introduced plants as food sources, such as silver-spotted skipper butterfly larvae feeding on invasive kudzu in the eastern U.S.  But generally, the widespread incursion of non-native plants is harmful to native insect populations.

Non-native plants are especially popular for horticulture.  Millions of acres of potential insect habitat have been transformed into food deserts for native insects.  The authors of the recent study recommend that Americans should extensively include native plants in their yards to help preserve insect diversity.

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How Non-Native Plants Are Contributing to a Global Insect Decline

Photo, posted May 2, 2004, courtesy of Bernard Spragg via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Once In A Lifetime Floods And Climate Change | Earth Wise

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Superstorm Sandy was the deadliest hurricane of 2012 and one of the most destructive hurricanes ever to hit the United States.  According to the National Oceanic and Atmospheric Administration, Superstorm Sandy caused an estimated $74.1 billion dollars in damages.  That figure made it the fourth-costliest storm in U.S. history, trailing only Hurricane Katrina in 2005 and hurricanes Harvey and Maria in 2017.  Superstorm Sandy affected 24 states and all of the eastern seaboard.  

New York was one of the states pummeled by Superstorm Sandy.  The storm brought flood-levels to the region that had not been seen in generations.  But according to a new study published in the journal Climatic Change, those flood levels could become much more common. 

Researchers at Stevens Institute of Technology have found that 100-year and 500-year flood levels could become regular occurrences by the end of the century for the thousands of homes surrounding Jamaica Bay, NY.  The researchers say climate change is the culprit.  

Using anticipated greenhouse gas concentration levels, the research team created simulations to find the probability of different flood levels being reached by the end of the century.  The researchers found that the historical 100-year flood level would become a one-year flood level by the year 2100.  500-year floods, like Superstorm Sandy, would become a four-year flood level by the end of the century. 

While this particular study is specific to Jamaica Bay, it does serve as an example of just how severe and costly the consequences of climate change will be.   

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Once in a lifetime floods to become regular occurrences by end of century

Photo, posted October 29, 2012, courtesy of Rachel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

 

Electronic Waste On The Decline | Earth Wise

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A new study published in the Journal of Industrial Ecology has found that the total mass of electronic waste generated by Americans has been declining since 2015.  Given that electronic devices are playing an ever-growing role in our lives, this finding seems rather surprising.  It also seems like pretty good news, but the underlying facts should dampen our level of enthusiasm.

The main reason for the decline is the disappearance of large, bulky cathode-ray tube televisions and computer monitors.  Since about 10 years ago, CRT displays have been on the decline in the waste stream, thereby leading to an overall decline in total e-waste mass.

Many state regulations with respect to e-waste recycling have targets based on product mass.  The regulations were typically designed to keep electronics with high levels of lead and mercury out of landfills.

At present, the more pertinent concern is how to recover valuable elements like cobalt (from lithium-ion batteries) and indium (from flat-panel displays).  These elements are not so environmentally toxic, but rather are relatively scarce in the earth’s crust. 

The main conclusion to be drawn from the declining mass of electronic waste is not that we are necessarily winning the battle against generating it but rather that e-waste is changing and regulations concerning it need to be rethought.  Focusing regulations on capturing critical elements not only would have significant economic benefits but also would be important in addressing geopolitical uncertainties that potentially could threaten what could be termed the mineral security of the U.S.

E-waste recycling is regulated at the state level and only half the states have e-waste recycling laws.  It may be time for more uniform policies across the country.

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Electronic Waste on the Decline, New Study Finds

Photo, posted January 22, 2013, courtesy of Thorsten Hartmann via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Caribbean Coral Reefs Under Siege | Earth Wise

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Coral reefs around the world have been suffering from warming seas and increasing acidification, both a result of human activity.  In the Caribbean, a new threat has emerged in the form of invasive algae.

New research published in Scientific Reports explains how an aggressive, crust-like alga is overgrowing shallow reefs and taking the place of coral that was damaged by powerful storms that exposed areas of the undersea rock where corals grew. 

Researchers from Oxford University, the Carnegie Institution, and California State University Northridge have been studying these peyssonnelid algal crusts, or PACs, for several years in the U.S. Virgin Islands.  The PAC has been out-competing coral larvae for surface space and then growing over the existing reef architecture, greatly damaging delicate reef ecosystems.

New corals actually prefer to settle on crusty surfaces created by a different type of algae called crustose algae, or CCA.  CCA acts as guideposts for coral larvae by producing biochemical signals as part of a microbial community that entice baby coral to affix itself.

In contrast, the destructive PAC algae exclude coral settlement. The researchers determined that the microbial community associated with PAC algae is deployed to deter grazing from fish and other marine creatures.  Unfortunately, it also deters coral.

Fragile coral ecosystems are already under assault by environmental pollution and global warming.  Now, in the aftermath of powerful hurricanes like Irma and Maria, algal crusts are taking over reef communities and posing an existential threat to Caribbean corals.

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An unusual microbiome characterises a spatially-aggressive crustose alga rapidly overgrowing shallow Caribbean reefs

Photo, posted January 11, 2015, courtesy of Falco Ermert via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Large Drop In U.S. Greenhouse Gas Emissions | Earth Wise

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Greenhouse gas emissions in the U.S. in 2020 are on track to be at their lowest level in nearly 30 years as a result of the COVID-19 pandemic.  U.S. emissions haven’t been this low since 1983, when the economy was not even 40% of its current size.

According to a new study by the research group BloombergNEF, U.S. emissions for the year will be 9% lower than they were in 2019, which will be the largest yearly drop on record.  The report also anticipates that whatever happens in the pandemic, 2021 emissions will be well below pre-COVID levels as well.

The pandemic has inadvertently put the U.S. back on track to meet its original commitments to the Paris Climate Agreement, despite the fact that we have pulled out the agreement.  The incoming administration plans to return the U.S. to the pact.

Overall, U.S. emissions have been trending downward since 2008, primarily as a result of the lower dependence of the power sector on coal.  The report estimates that in the absence of the pandemic, 2020 emissions would have been 1% lower than last year’s.

The dramatic drop in emissions is not really a great cause for celebration.  Achieving significant emission reductions through massive economic hardship and societal disruption does not point the way towards making progress on climate change.  The economic upturn that will undoubtedly occur when the pandemic loses its grip on the world will lead to rebounding levels of greenhouse gas emissions.  But as is the case with all major crises, the current situation does present a chance to turn this temporary downturn in emissions into a more permanent one by making appropriate investments and policy changes.

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Due to COVID-19, 2020 greenhouse gas emissions in the U.S. are predicted to drop to lowest level in three decades

Photo, posted January 13, 2013, courtesy of Onnola via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Dust And Himalayan Glaciers | Earth Wise

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Glaciers in the Himalayas have been melting and retreating, as have glaciers around the world.  As is the case elsewhere, human-driven climate change is a major factor.  But at the lofty heights of the Himalayas, warming temperatures are not the biggest culprit.  Black carbon – released into the air by burning fossil fuels or biomass such as plants, trees, and shrubs – darkens the snow and causes it to absorb more of the sun’s heat.  A recent study by an international team of scientist has identified another important factor:  dust.

An estimated 5 billion tons of desert dust enters the Earth’s atmosphere every year.  Dust from places like Saudi Arabia gets picked up by spring winds and gets deposited on the western sides of mountains, where it can make the air 10 times more polluted than most European cities.  Dust blows across industrial and desert areas in the Indian subcontinent and the Middle East and lands in the Himalayas.  According to the new study, this dust is often the dominant cause of snow melt in those areas.

Desert dust causes snow melt in the same way that black carbon does.   Dirty snow absorbs sunlight more easily than clean snow.

Desert dust is a natural part of Earth’s systems, but the amount of it in the atmosphere has steadily increased since the Industrial Revolution, when humans greatly expanded into desert areas and broke through surface crust that held large amounts of dust in place.

There is not much we can do about desert dust, short of eliminating deserts.  But the disappearance of the Himalayan ice pack – which sustains over a billion people – can be mitigated by reducing greenhouse gas emissions to address climate change .

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Himalayan glaciers melting because of high-altitude dust

Photo, posted March 13, 2018, courtesy of Sarunas Burdulis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

More Plastic Pollution From The United States | Earth Wise

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A new study published in the journal Science Advances has revealed that the United States is contributing far more to coastal plastic pollution than was previously believed.  A previous study using 2010 data ranked the US 20th globally, in its contribution to ocean plastic pollution from mismanaged waste.  The new study ranks the U.S. third among the world’s countries.

The largest contributor to the discrepancy is that the earlier study did not account for plastic scrap exports.  Using plastic waste generation data from 2016 – which is the most recent global data available – the study’s authors calculated that more than half of all plastics collected for recycling in the US were shipped abroad.  This amounts to over 2 million tons.  Of this amount, some 88% went to countries struggling to effectively manage, recycle, or dispose of plastics, and between 15-25% was, in fact, low-value or contaminated, meaning that it was effectively unrecyclable.  When all of these factors were taken into account, the researchers estimated that a million tons of US-generated plastic waste ended up polluting the environment.  It just occurred beyond our own borders.

Overall, 2-3% of all plastic waste generated in the US – about a million tons – is either littered or illegally dumped into the domestic environment.  When this is combined with the exported waste, the US is responsible for more than 2 million tons of plastic waste being dumped into the environment.  About two-thirds of that ends up in coastal environments, where it is likely to enter the ocean by wind or through waterways.

The United States generates the most plastic waste of any country in the world.  Unfortunately, we have been operating under the illusion that we were doing a pretty good job of dealing with it.

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New Study Reveals United States a Top Source of Plastic Pollution in Coastal Environments

Photo, posted April 3, 2015, courtesy of Vaidehi Shah via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Toughest Beetle Of Them All | Earth Wise

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In 2015, UC Riverside materials scientists placed a mottled black beetle in a parking lot and ran it over with a Toyota Camry.  Twice.  Crushed beneath the wheels of a 3,500-pound sedan, the inch-long insect made it through without a scratch.

For the past five years, a group of scientists have been studying this remarkable bug, which has the splendid name of the diabolical ironclad beetle. Using a combination of advanced microscopy, mechanical testing, and computer simulations, the researchers have figured out the secret of this beetle’s crush resistance.

The beetle’s super-toughness lies in two armorlike structures called elytra that meet in a line, called a suture, running the length of the abdomen.  The suture acts like a jigsaw puzzle.  It connects various exoskeletal blades – the puzzle pieces – in the abdomen under the elytra.   These structural components can act in different ways.  The interconnecting blades lock to prevent themselves from pulling out of the suture.  The suture and blades delaminate, leading to a graceful deformation rather than catastrophic failure.  These strategies dissipate energy to circumvent fracturing.

The researchers found that the diabolical ironclad beetle – just had to say that name again – can take on an applied force of about 150 newtons, a load at least 39,000 times its body weight.  (That’s the equivalent of a 150-pound person resisting the crush of about 25 blue whales).

An ongoing challenge for structural engineering is how to join together different materials without limiting their ability to support loads.  The strategies evolved in these beetles may be applicable in gas turbines of aircraft, for example, where metals and composite materials are joined together with mechanical fasteners.   We can learn things from the toughest beetle of them all.

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Diabolical ironclad beetles inspire tougher joints for engineering applications

Photo, posted April 9, 2017, courtesy of Vahe Martirosyan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Pandemic Lockdowns And Carbon Emissions | Earth Wise

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The early months of the COVID-19 pandemic saw many human activities reduced to a fraction of what they were previously.  Notably, air pollution in major cities was dramatically lower than it had been in decades.  Now, a new study has looked at the effect of the pandemic shutdowns on carbon dioxide emissions.

An international team of climate scientists has published an assessment of carbon dioxide emissions by industry, transportation, and other sectors from January through June.  According to their measurements, this year’s pandemic lockdowns resulted in a 9% decline in emissions from 2019 levels.

An earlier study reported a 17% drop in CO2 emissions, but the new study was more comprehensive and detailed.

The new data includes estimates of day-by-day, sector-specific and country-level differences in CO2 emissions derived from frequently updated data sources, some of which are nearly in real-time.  It tracks the effects of COVID-19-related disruptions of human activities in China starting in February and in the United States and Europe in March through May.

The data revealed the resumption of emissions in many regions, such as in China, where they are now back to pre-pandemic levels.  Emissions in the Americas and Europe have been slower to recover, especially in the US, where COVID-19 hotspots are continuing to emerge. 

The reduction in carbon emissions has been due mostly to transportation with fewer people driving to work and traveling by air.  Even by June, when lockdowns were easing, global emissions were still significantly reduced.  In any case, a pandemic is a highly undesirable and unwelcome way to reduce carbon emissions, but the data from this year does show that it is effective.

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Pandemic lockdowns caused steep and lasting carbon dioxide decline

Photo, posted August 7, 2020, courtesy of Michael Mueller via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Quiet In The Pandemic | Earth Wise

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The early months of the Covid-19 pandemic had dramatic effects on many aspects of our daily lives.  Vehicle traffic, air pollution, and many other aspects of modern life saw reduced levels not seen in decades.  It turns out that one of the things that saw reduced levels was people’s exposure to environmental noise.

According to University of Michigan researchers, daily average sound levels dropped in half during the time that local governments made announcements about social distancing and issued stay-at-home orders in March and April as compared to noise levels measured in January and February.

The data was acquired from the Apple Hearing Study, which looked at noise exposure data from volunteer Apple Watch users in Florida, New York, California, and Texas.  The analysis included more than half a million daily noise levels measured before and during the pandemic shutdown.

The noise reduction – 3 decibels, which is a factor of two in noise level – is considered to be quite large and could have a significant effect on people’s overall health outcomes over time.

The four states studied had differing responses in terms of stay-at-home orders.  Both California and New York both had really drastic reductions in sound that happened very quickly, whereas Florida and Texas had somewhat less of a reduction.

The study demonstrated the utility of everyday use of digital devices in evaluating daily behaviors and exposures.  This sort of analysis could allow researchers to begin describing what personal sound exposures are like for Americans who live in a certain state, or are of a certain age, or who do or don’t have hearing loss.  The Apple Hearing Study is continuing and is still accepting new participants.

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Stay-at-home orders cut noise exposure nearly in half

Photo, posted April 10, 2020, courtesy of Joey Zanotti via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Nitrous Oxide Is No Laughing Matter | Earth Wise

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Carbon dioxide is the most well-known of greenhouse gases.  But there are others deserving of their own spotlight.  Nitrous oxide is one of them.  It turns out that the same “laughing gas” once used by dentists as an anesthetic is pretty bad for the environment.  In fact, it’s more than 300 times more potent as a greenhouse gas than carbon dioxide, and it can remain in the atmosphere for more than 100 years.

According to a new study by a team of international scientists, rising nitrous oxide emissions around the world are jeopardizing the climate goals of the Paris Agreement.  The growing use of nitrogen fertilizers in global food production is increasing atmospheric concentrations of nitrous oxide.

The study, which was led by Auburn University and recently published in the journal Nature, finds that nitrous oxide emissions are increasing faster than any emission scenario developed by the Intergovernmental Panel on Climate Change.  The current trajectory would lead to global mean temperature increases well above 3°C from pre-industrial levels.  The Paris Agreement aims to limit global warming to less than 2°C.    

According to the study, nitrous oxide levels have risen 20% from pre-industrial levels, with the fastest growth observed in the last 50 years due to emissions from human activities.  The largest contributors to nitrous oxide emissions come from East Asia, South Asia, South America, and Africa.  The United States, China, and India dominate nitrous oxide emissions from synthetic fertilizers, while Africa and South America dominate releases of nitrous oxide from natural sources, like livestock manure. 

Nitrous oxide emissions pose an increasing threat to the climate.  

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Nitrous oxide emissions pose an increasing climate threat, study finds

Photo, posted April 22, 2012, courtesy of Bill Meier via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Essential Oils And Organic Crops | Earth Wise

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Essential oils are concentrated liquids extracted from plants.  They are called “essential” in the sense that they contain the essence of the fragrance that is characteristic of the plant.  Essential does not mean indispensable or usable by the human body.  But despite that fact, essential oils have been used in folk medicine throughout history. 

In recent times, essential oils have frequently been used in aromatherapy.  Generally speaking, medicinal uses of essential oils are controversial, and, in some cases, they have even been demonstrated to be dangerous.

Research has shown that essential oils have potential as natural pesticides.  Recently, the USDA has funded research into the use of essential oils to battle pests and diseases of organic crops.

U.S. organic food sales topped $50 billion in 2018 and fruits, vegetables, and other specialty crops combined make up more than a third of organic sales.  In order to meet consumer demand, farmers need ways to battle pests and diseases that often accompany organic crop growth.

A four-year project at the University of Hawaii at Manoa is entitled “Plant Safety, Horticultural Benefits, and Disease Efficacy of Essential Oils for Use in Organically Grown Fruit Crops:  From the Farm to the Consumer.”   The researchers will work with certified organic producers in Hawaii, Florida, South Carolina, Georgia, and California to evaluate the effectiveness of plant essential oils on major fruit pathogens such as avocado scab, anthracnose fungal disease, and powdery mildew on targeted tropical and temperate fruit crops such as avocado, mango, blueberry, and peach.

The goal is increase orchard productivity of the expanding organic fruit industry.

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Essential oils could keep pests, disease from organic crops

Photo, posted January 6, 2015, courtesy of Abi Porter via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Alien Species On The Rise | Earth Wise

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Alien species are species that are introduced, accidentally or intentionally, outside of their natural geographic range as a result of human activities.  More than 35,000 alien species have been recorded through 2005, which is the most recent year for which researchers have comprehensive global data. 

Some of the alien species go on to become invasive alien species, which can have damaging impacts on both ecosystems and economies.  In fact, alien species are one of the main drivers of plant and animal extinctions around the globe.  

According to a new study by an international research team involving University College London, the number of alien species, particularly insects, arthropods and birds, is expected to increase globally by 36% by 2050 when compared to 2005 levels.  The research was recently published in the journal Global Change Biology.

Using a mathematical model developed for the study, the researchers identified high levels of variations between regions.  For example, the largest increase in alien species by the middle of the century is expected in Europe, where numbers are predicted to jump by 64%.  The temperate regions of Asia, North America, and South America are also predicted to be hotspots of alien species.  The lowest relative increase in alien species is expected in Australia.

The researchers do not expect a reversal or slowdown in the spread of alien species.  In fact, with global transportation and trade forecasted to increase in the coming decades, they anticipate many new species will infiltrate non-native habitats by hitching rides as stowaways.   

According to the research team, it would take a concerted global effort with stricter regulations and more rigorous enforcement to slow the flow of new species. 

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Alien species to increase by 36% worldwide by 2050

Photo, posted October 3, 2016, courtesy of the Asian Carp Regional Coordinating Committee via Flickr. Photo credit: Ryan Hagerty/USFWS.

Earth Wise is a production of WAMC Northeast Public Radio.

Artificial Reefs As Havens For Marine Predators | Earth Wise

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Climate change, pollution, development and other stresses have accelerated the decline of reef ecosystems across much of the world’s oceans in recent years.  Large predators such as sharks, mackerels, barracudas, jacks and others that formerly fed around reefs have had to venture outside their normal migratory routes in search of suitable alternatives.

According to a new study by Duke University, marine predators have taken up residence at shipwrecks and other artificial reefs.  The study surveyed 30 sites along the North Carolina coast and found that predator densities were up to five times larger at the 14 artificial reefs surveyed than at the 16 natural reefs in the survey.

Shipwrecks, particularly those that rose between 4 and 10 meters up into the water column, were a big favorite of the fishes.  Some of those sites supported predator densities up to 11 times larger than natural reefs or low-profile artificial reefs.  The shipwrecks are basically high-rise timeshares in the sea.

The findings of the survey show that artificial reefs can support large predators, supplementing natural reefs if the design and placement of the artificial reefs are appropriate.  In addition, when it comes to designing artificial reefs, there appears to be a height advantage.  So, reefs either made from sunken ships or at least made to resemble them would be desirable.

Because undersea predators help maintain healthy and sustainable populations of species lower in the food web, providing suitable habitat for the predators is extremely important.  Based on the study, it appears that the strategic use of artificial reefs can be an effective way to help counter the increasing loss of natural habitat on the ocean bottom.

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Artificial Reefs Take on a Towering Presence as Havens for Marine Predators

Photo, posted July 29, 2014, courtesy of NOAA Photo Library via Flickr. Photo credit: Flower Garden Banks National Marine Sanctuary

Earth Wise is a production of WAMC Northeast Public Radio.

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)