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Rivers And Climate Change | Earth Wise

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Our planet is heating up.  Scientists have concluded that the changing climate is primarily the result of increased greenhouse gas emissions from human activities.  Some of the effects of global climate change include thawing permafrost, rising seas, intensifying storms and wildfires, and warming oceans.   

According to a new study led by researchers from Penn State University, rivers are warming and losing oxygen even faster than oceans.  The study, which was recently published in the journal Nature Climate Change, found that warming occurred in 87% and oxygen loss occurred in 70% of the nearly 800 rivers studied.

The research team projects that within the next 70 years some river systems, especially those in the American South, will experience such low oxygen levels that the rivers could “induce acute death” for some fish species and threaten the aquatic diversity of river ecosystems. 

The research team used artificial intelligence and deep learning to analyze water quality data from nearly 800 rivers across the U.S. and central Europe.  The researchers found that rivers are warming up and deoxygenating faster than oceans, which could have serious implications for both aquatic life and humans.

While climate change has led to warming and oxygen loss in oceans and lakes around the world, the researchers did not expect to find warming and deoxygenation in shallower, flowing rivers.  Since life in water depends on temperature and dissolved oxygen, the researchers hope this study serves as a wake up call.  Warming and deoxygenating rivers have significant implications for water quality and the health of aquatic ecosystems worldwide.

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Rivers are rapidly warming, losing oxygen; aquatic life at risk

Photo, posted June 2, 2017, courtesy of Francisco Anzola via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

 Restoring Biocrusts | Earth Wise

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Biocrusts are complex ecosystems that form a thin layer on the surface of soils in arid and semiarid environments.  They are composed of variety of microbes including cyanobacteria, green algae, fungi, lichens, and mosses.  Biocrusts play a crucial role in maintaining soil health and ecosystem sustainability.

Biocrusts are under assault from human activities including agriculture, urbanization, and off-road vehicle use. Climate change is also placing stress on biocrusts, which are struggling to adapt to increasing temperatures.

Researchers at Arizona State University have proposed a novel approach to restoring healthy biocrusts.  Their idea is to make use of solar energy farms as nurseries for generating fresh biocrust.  The arrays of solar panels serve as shields from excessive heat and allow biocrusts to flourish and develop.  The newly generated biocrusts can then be used to replenish arid lands where the existing biocrusts have been damaged or destroyed.

When such biocrusts are harvested, the natural recovery process is rather slow, taking around six or eight years to fully recuperate.  But the researchers found that when harvested areas are reinoculated with the microbes, the biocrust cover can reach near-original levels within a year.

The ASU researchers demonstrated the viability of the approach in a three-year study at a solar farm in Arizona’s lower Sonoran Desert.  Based on their results, they conclude that the use of large solar farms for this purpose could provide a low-cost, low-impact, and high-capacity method to regenerate biocrusts and enable soil restoration on a regional scale.  They have dubbed their new approach as “crustivoltaics.”

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Using solar farms to generate fresh desert soil crust

Photo, posted March 12, 2023, courtesy of Eric Peterson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Seaweed On The Way | Earth Wise

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A type of seaweed called sargassum has long formed large blooms in the Atlantic Ocean.  It gets its name from the Sargasso Sea in the western Atlantic.  Since 2011, scientists have been tracking massive accumulations of the stuff each year that starts out off the coast of Africa and works its way across the Atlantic to end up in the Gulf of Mexico. 

The amount of sargassum present each year can shift depending on factors like changes in nutrients, rainfall, and wind conditions.  But since the 1980s, nitrogen content in the Atlantic has gone up by 45%.  This is likely due to human activities such as agriculture and fossil fuel production dumping materials into the rivers that feed into the ocean.

According to recent observations, the mass of seaweed now heading for Florida and other coastlines throughout the Gulf of Mexico may be the largest on record.  The giant blob of sargassum spans more than 5,000 miles in extent.  It is moving west and will pass through the Caribbean and up into the Gulf during the summer.  The seaweed is expected to become prevalent on beaches in Florida around July.

The seaweed provides food and protection for fishes, mammals, marine birds, crabs, sea turtles, and more.  But unfortunately, when sargassum hits the beaches, it piles up in mounds that can be difficult to walk through and eventually emits a gas that smells like rotten eggs.

Tourist destinations in the Caribbean region have their work cut out for them to remove seaweed that can pile up several feet deep.  For example, in Barbados, locals were using 1,600 dump trucks a day to clean their beaches.  Caribbean and Florida resorts spend millions of dollars each year to remove sargassum seaweed.

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A 5,000-mile-wide blob of seaweed is headed for Florida, threatening tourism across the Caribbean

Photo, posted February 24, 2020, courtesy of Bernard Dupont via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Protecting Wetlands | Earth Wise

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Wetlands are distinct ecosystems that are flooded or saturated by water, either permanently or seasonally.  They include mangroves, marshes, swamps, forested wetlands, bogs, wet prairies, and vernal pools.   The feature that most wetlands share is soil or substrate that is at least periodically saturated with or covered by water.

Wetlands are some of the most threatened ecosystems in the world.  While wetlands can be affected by a variety of natural stressors, including erosion, droughts, and storms, human activities have been the major driver of wetland decline. 

But according to a new study by researchers from McGill University in Canada, the global loss of wetland areas since 1700 has likely been overestimated.  The research team calculated that the area of wetland ecosystems around the world has declined 21-35% since 1700 as a result of human activities – far less than the 50-87% decline estimated in other studies.  The study’s focus beyond regions with historically high wetland losses and its avoidance of possibly misleading extrapolations likely resulted in the lower estimate.      

According to the study, which was published in the journal Nature, more than 2.1 million square miles of wetlands have been lost during the past 300 years – an area roughly the size of India.  The five countries with the highest wetland losses are the United States, China, India, Russia and Indonesia. 

But discovering that fewer wetlands have been historically lost than previously thought gives researchers a second chance to protect wetlands.  The findings of the study will help researchers prioritize global conservation and restoration actions.

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A second chance to protect wetlands

Photo, posted February 2, 2005, courtesy of Jan Tik 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

Cloud Seeding And The Western Drought | Earth Wise

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The massive megadrought affecting the American West is now considered to be the driest two-decade period in the past 1,200 years.  The lengthy drought has led to increased wildfires, reduced agricultural productivity, and reduced electricity generation by hydropower plants.  The historically low water levels in the largest two reservoirs in the U.S. – Lake Mead and Lake Powell – has triggered reductions in water allocations to Arizona, Nevada, and Mexico.

Several western states have expanded cloud seeding programs in an attempt to increase precipitation.  During the past two years, Idaho, Utah, Colorado, Wyoming, and California have all stepped up their cloud seeding efforts.  Outside of the US, the United Arab Emirates and China both have implemented massive cloud seeding programs.

A study by researchers at the University of Colorado and the National Center for Atmospheric Research looked at the ability of cloud seeding to increase snowfall.  The study unambiguously demonstrated that cloud seeding can increase snowfall.  Just how effective it is in terms of how much additional snow seeding produces is less clear.

Given the dire need for water and the fact that cloud seeding is not especially expensive, governments and other users are not hesitating to make use of it.

Unfortunately, the study shed no light on the efficacy of warm weather seeding to produce rain.  There is in fact little evidence that seeding clouds to produce rain accomplishes very much.  Once again, the prevailing view is that it is worth trying.  There do not appear to be environmental downsides to seeding.

The hope is that cloud seeding may at least restore clouds to the state they had been in before industrial pollution and other human activities affected them.

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Can Cloud Seeding Help Quench the Thirst of the U.S. West?

Photo, posted November 21, 2013, courtesy of Sharon Tate Soberon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Capturing Methane To Feed Fish | Earth Wise

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Methane in the atmosphere is an extremely potent greenhouse gas.  Its warming potential is about 85 times that of carbon dioxide over a 20-year period.  It also worsens air quality by increasing atmospheric ozone.  Many human activities add methane to the atmosphere, notably emissions from landfills and oil and gas facilities.

Capturing methane from these sources for subsequent use is currently uneconomical but new research from Stanford University analyzes the market for using the methane to feed bacteria to produce fishmeal.

Methane-consuming bacteria called methanotrophs can be grown in chilled, water-filled bioreactors containing pressurized methane, oxygen, and nutrients.  The bacteria produce a protein-rich biomass that can be used as fishmeal in aquaculture.  This could offset demand for fishmeal made from small fish or plant-based feeds that require land, water, and fertilizer.

Some companies already do this using natural gas provided by utility pipelines, but it would be far better for the environment to use methane emitted at large landfills, wastewater treatment plants, and oil and gas facilities.

Consumption of seafood has more than quadrupled since 1960, depleting wild fish stocks.  Farmed fish now provide half of all the animal-sourced seafood we eat.

The Stanford research analyzed the cost of methanotrophic fishmeal production under various scenarios and found it to be very competitive with and in some cases considerably cheaper than current market prices for fishmeal. 

According to the study, this process could profitably supply total global demand for fishmeal with methane captured in the U.S. alone.

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Stanford researchers reveal how to turn a global warming liability into a profitable food security solution

Photo, posted April 30, 2017, courtesy of Artur Rydzewski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Food And Greenhouse Gas Emissions | Earth Wise

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According to a study published in the journal Nature Food, the world’s food systems are responsible for more than one third of global greenhouse gas emissions caused by human activities. 

‘Eat Local’ is often recommended as a way to minimize the carbon footprint of our diet.  But from a climate impact perspective, eating local only has a significant impact if transportation is responsible for a large portion of a food’s final carbon footprint.  And in many cases, greenhouse gas emissions related to transportation make up only a small portion of the emissions from food and what we eat is far more important. 

There are massive differences in the greenhouse gas emissions of various foods. 

For example, producing one pound of beef generates 60 pounds of greenhouse gas emissions.  This is more than double the next closest food (lamb), and more than 60 times greater than some plant crops like corn and cassava. 

For most foods – especially the largest emitters – greenhouse gas emissions from land use change combined with the emissions from processes at the farm stage account for more than 80% of the environmental footprint.  Meanwhile, transportation accounts for less than 10%, and its contribution for the largest emitters is even smaller.  For example, transportation accounts for 0.5% of emissions from beef production.

Eating beef or lamb has many times the carbon footprint of most other foods.  It matters very little in terms of emissions whether it was grown locally or shipped from another part of the world.  It’s not the location that makes the carbon footprint of our dinner large.  It’s what is on our plate that matters.

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Food systems account for over one-third of global greenhouse gas emissions

You want to reduce the carbon footprint of your food?

Photo, posted November 7, 2018, courtesy of Preston Keres / USDA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Arctic Communities And Permafrost Thaw | Earth Wise

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Permafrost is frozen soil, rock or sediment that can be as much as a few thousand feet thick.  To qualify as permafrost , the material has to have been at or below the freezing point of water for two or more years.  Most of it is located in high latitudes in the Arctic and Antarctic regions.   Permafrost covers nearly a quarter of the exposed land in the Northern Hemisphere.

Permafrost contains enormous amounts of carbon in the form of frozen soil that includes remnants of plants and animals, in some cases that have been there for more than 20,000 years.

The Arctic region has been warming faster than any place else on earth and thawing permafrost is already unleashing methane and carbon dioxide to the atmosphere, adding to the global temperature rise.

Apart from the impact on the global climate, thawing permafrost is making the ground unstable and is causing serious problems for local communities.

Recent research using satellite observations provides an overview of the Arctic to identify communities and infrastructure that will be at risk over the next 30 years.

Using high-resolution data from the Copernicus Sentinel satellite missions along with ground-based data going back to 1997, researchers modeled the permafrost ground temperature trends and extrapolated them out to 2050.  The results were that 55% of the infrastructure currently located on permafrost and within 60 miles of the Arctic coastline – infrastructure on which many communities rely – is likely to be affected.

Most human activity in the Arctic takes place along permafrost coasts.  Permafrost thaw is exposing these coasts to rapid change that threatens biodiversity and puts pressure on communities.

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Satellites pinpoint communities at risk of permafrost thaw

Photo, posted January 24, 2014, courtesy of Brandt Meixell / USGS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Peatlands And Greenhouse Gas Emissions | Earth Wise

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As the world seeks to reduce the greenhouse gas emissions that have been warming the climate, most of the focus has been on the primary contributors to the problem, such as the burning of fossil fuels.  But there are many smaller contributors to greenhouse gas emissions that individually play only a minor role but collectively add up to significant amounts.  One of these is the emissions from peatlands.

Peatlands are a type of wetland that occur in almost every country on Earth, covering 3% of the global land surface.  They are terrestrial ecosystems in which waterlogged conditions prevent plant material from fully decomposing.  As a result, the production of organic matter exceeds its decomposition, which results in a net accumulation of peat.  Peatlands are, in fact, the largest natural terrestrial carbon store, storing more over 700 billion tons of carbon, more than all other types of vegetation combined.

Human activity, such as creating drainage in peatlands for agriculture and forest plantation, results in the release of over 1.6 billion tons of CO2 into the atmosphere each year. This constitutes 3% of all global greenhouse gas emissions caused by human activities.

Large numbers of people rely on peatlands for their livelihoods, so it is not reasonable for these emission-generating activities to be greatly curtailed.  But researchers at the University of Leicester in the UK analyzed the potential effects of cutting the current drainage depths in croplands and grasslands on peat in half and showed that this could reduce CO2 emissions by more than 500 million tons a year. This equates to one percent of all greenhouse gas emissions caused by human activities.

There are numerous opportunities to reduce emissions a little bit at a time.

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Better peatland management could cut half a billion tonnes of carbon

Photo, posted August 17, 2013, courtesy of Joshua Mayer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Heat-Related Deaths | Earth Wise

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According to a new study recently published in the journal Nature Climate Change, more than one-third of the world’s heat-related deaths each year are attributable to human-induced climate change. 

Researchers from the London School of Hygiene and Tropical Medicine in the UK  and the University of Bern in Switzerland analyzed data from 732 locations in 43 countries.  They took observed temperatures and compared them with 10 computer models simulating a world without climate change.  By applying this technique to their data, the researchers were able to calculate for the first time the actual contribution of anthropogenic climate change in increasing mortality risks due to heat.

The research team found that 37% of all heat-related deaths between 1991 and 2018 were attributable to the warming of the planet due to human activities.  This percentage was highest in South America, Central America, and South-East Asia. 

In the United States, 35% of heat deaths were found to be a result of climate change.  New York had the most heat-related deaths at 141, and Honolulu had the highest percentage of heat deaths attributable to climate change at 82%.

But scientists caution that this is only a small portion of the climate’s overall impact. Many more people die from other extreme weather amplified by climate change, including severe storms, floods, and droughts.  Heat-related death figures will grow exponentially as temperatures rise.

According to the research team, the study’s findings highlight the need to adopt stronger climate change mitigation strategies, and to implement interventions to protect people from the adverse consequences of heat exposure.    

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Global warming already responsible for one in three heat-related deaths

Photo, posted April 14, 2017, courtesy of Karim Bench 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.

Paying To Combat Climate Change | Earth Wise

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The majority of Americans believe that climate change is happening, that human activities are largely responsible, and are actually willing to put up their own money to help fight it.   Unfortunately, these views diverge sharply along party lines and, as in many other areas these days, the will of the overall majority has little influence on policy.

According to Yale University research, 73% of adults think that global warming in happening and 57% think it is mostly caused by human activities.  Furthermore, only 32% believe it is due to natural forces.

A survey conducted in the U.S. in August found that more than two-thirds of Americans – actually 70% – indicated willingness to donate a percentage of their personal income to support the fight against climate change.

Breaking that down further, 28% were willing to provide less than 1% of their income, 33% were willing to contribute 1-5% of their income, 6% said they would give 6-10% of their income, and 3% said they would contribute more than 10% of their income.  On the other hand, roughly 30% indicated that they were unwilling to contribute.

The survey also looked at opinions on how the fight against climate change should be paid for.  The majority (59%) chose government incentives for both businesses and consumers.   Three other options each favored by over 40% of those surveyed were taxes, conservation programs, and business investments. 

Another finding of the survey was that 44% are dissatisfied with the job that the federal and state governments are doing to address climate change, 35% are somewhat satisfied, and only 21% are very or completely satisfied with the government’s role.

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Yale Climate Opinion Maps 2020

Two-thirds of Americans are willing to donate part of their income to fight climate change

Photo, posted April 29, 2017, courtesy of majunznk via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Monitoring Wildlife For Warning Signs of the Next Pandemic | Earth Wise

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According to the World Health Organization, the coronavirus that causes COVID-19 likely originated in wild bats near Wuhan, China, and may have been passed to a second animal species before infecting people.  Since then, according to data from Johns Hopkins University, more than 13 million people around the world have been infected by COVID-19 and about 600,000 have died. 

But despite the ever-present threat of a new virus sparking the next pandemic, there is currently no global system to screen for viruses in wild animals that could eventually spill over to humans. 

In an article recently published in the journal Science, a group of scientists is calling for the creation of a decentralized global system of wildlife surveillance.  The establishment of this global system could help identify viruses in wild animals that have the potential to infect and sicken people before another global disease outbreak begins. 

According to the scientists, coronaviruses alone have caused outbreaks in humans three times in the last 20 years:  SARS (or Severe Acute Respiratory Syndrome), MERS (or Middle East Respiratory Syndrome), and COVID-19. 

While it’s impossible to know today how often viruses jump from animals to humans, human activity is making such spillover events more and more likely.  For instance, many continue to develop wild animal habitat to build new homes or businesses.  Some catch wild animals and re-sell them either for consumption or as exotic pets.  Parts from these wild animals are often shipped around the world as trinkets or as ingredients for traditional medicines. 

A global system that could identify potentially harmful viruses before they jump to humans is technologically feasible, affordable, and clearly necessary. 

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COVID-19 Dashboard by the Center for Systems Science and Engineering (CSSE) at Johns Hopkins University (JHU)

Global wildlife surveillance could provide early warning for next pandemic

Photo, posted January 15, 2008, courtesy of Doug Beckers via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Earth Itself Is Quieter | Earth Wise

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Our stories often discuss how human activities change the natural environment.  With most of us confined to our homes, the lack of human activities is having profound effects on the environment.  We are talking about some of these this week.

With about a third of the world’s population sheltering in place, our planet is much quieter these days.  It isn’t just our machines, vehicles, and factories that are making less noise.  The earth itself is quieter.  There has been a reduction in the earth’s seismic vibrations.

According to the journal Nature, various human-powered movements contribute to the persistent vibration of the earth’s crust.  Things like engines firing up in factories, trains pulling into stations, and trucks barreling down highways all make contributions to seismic activity.  Taken individually, such things are insignificant, but taken together, they produce a background of seismic noise that makes it difficult for seismologists to detect natural signals such as volcanic activity and earthquake aftershocks.

With much human activity on pause during the coronavirus outbreak, seismologists across the globe are seeing significant reductions in background seismic noise levels.

This respite in seismic noise, for as long as it lasts, represents an opportunity for scientists to better study the natural activity in the earth’s crust. Researchers studying the impact of ocean waves to predict volcanic activity and those who triangulate the location of earthquake epicenters may be able to make more sensitive measurements than under normal conditions.

There are very few positive things one can say about the coronavirus crisis, but it is providing opportunities to study and observe aspects of the natural world that are ordinarily drowned out by the bustle of humanity.

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Coronavirus lockdowns across the globe are actually causing the Earth to move less

Photo, posted March 9, 2020, courtesy of Jeremy Segrottvia Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sea Turtles Prospering During The Shutdown | Earth Wise

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Our stories often discuss how human activities change the natural environment.  With most of us confined to our homes, the lack of human activities is having profound effects on the environment.  We are talking about some of these this week.

Seven different species of sea turtles are found in the world’s oceans and play important roles in marine ecosystems.  Over time, human activities have tipped the scales against the survival of these animals.  They have been hunted for their eggs, meat, skin, and shells and face habitat destruction and accidental capture in fishing gear.  Their nesting grounds in beaches are constantly disturbed and endangered by human activity.

With the beaches in Florida closed in the effort to stop the spread of coronavirus, there is less plastic waste, fewer people and vehicles, and fewer artificial lights on the beach that disorient emerging turtle hatchlings.  Because of all of these factors, sea turtles have been building their nests without disruptions.

In April, it was nesting season for leatherback turtles, the largest of all sea turtles. In May, loggerhead turtles arrive in Florida.  Later in the summer, green turtles will arrive.

It takes about 60 days for sea turtle eggs to incubate and to hatch.  During that period, lots of things can happen to a nest on an active beach – it can get trampled, people can dig it up, and artificial light can confuse the hatchlings as they try to find their way to the water.  With the current shutdown, it should be a productive nesting season for sea turtles.

On the other hand, when beaches reopen, there may well be a major influx of people flocking to the beach because they have been stuck indoors for an extended period of time.

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Sea turtles are thriving as coronavirus lockdown empties Florida beaches

Photo, posted August 9, 2016, courtesy of Florida Fish and Wildlife via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Lockdown Cleans Up Indian Air | Earth Wise

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Our stories often discuss how human activities change the natural environment.  With most of us confined to our homes, the lack of human activities is having profound effects on the environment.  We are talking about some of these this week.

India suffers from some of the worst air pollution in the world.  Of the most polluted cities in the world, 21 out of 30 were in India in 2019.  According to World Health Organization standards, at least 140 million people in India breathe air containing 10 times or more greater levels than the safe limit for pollutants.  Air pollution contributes to the premature death of 2 million Indians every year.

Half of India’s air pollution comes from industry, 27% from vehicles, and 17% from crop burning.  Crop burning is prevalent because it is much cheaper than mechanical tilling after the harvest.

On March 25, the Indian government placed its 1.3 billion citizens under a strict lockdown to reduce the spread of COVID-19.   The country-wide mandate decreased activity at factories and drastically reduced car, bus, truck, and airplane traffic.

Within one week, NASA satellite sensor observed aerosol levels at a 20-year low for this time of year in northern India.  Aerosols are tiny solid and liquid particles suspended in the air that reduce visibility and can damage the human lungs and heart.  Some aerosols have natural sources, such as dust storms, volcanic eruptions, and forest fires.  But many come from human activities such as the burning of fossil fuels and croplands.  Scientists expected to see changes in atmospheric conditions during the Indian lockdown, but the current changes are dramatic.  They also present a unique opportunity to separate how natural and human sources of aerosols affect the atmosphere.

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Airborne Particle Levels Plummet in Northern India

Photo, posted April 29, 2020, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wildlife Reclaims Yosemite National Park | Earth Wise

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Our stories often discuss how human activities change the natural environment.  With most of us confined to our homes, the lack of human activities is having profound effects on the environment.  We are talking about some of these this week.

Yosemite National park is normally awash in humanity – there were over 300,000 visitors in April of 2019 and typically 4 million people visit each year.  But as of March 20, the park was closed to tourists to prevent the spread of the coronavirus.  Only a skeleton crew of employees remains in the park.

Without all the people, wildlife is coming out of hiding.  It did so in previous park closures during government shutdowns, but those closures were pretty short.  This one is expected to be the longest on record.

The bear population within the park has quadrupled and many larger animals – such as bobcats and coyotes – are congregating outside of cabins and other buildings and prowling empty roads and walkways instead of hanging back at the edges of human settlements. 

In addition, the air at Yosemite is cleaner due to the lack of exhaust and diesel, and Yosemite Valley is nearly silent, apart from natural sounds from the river and the wind.  According to some observers, the park’s current condition is probably similar to what visitors in the 19th century witnessed. 

The few park employees sheltering in place are taking advantage of the virtually unimpeded natural amenities of the park.  Many are hiking to its lakes and waterfalls, enjoying trails that are empty apart from animals.  As some of the people staying in the park have noted, one could not ask for a better place to be isolated.

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Coyotes, bobcats and bears: Wildlife is reclaiming Yosemite National Park

Photo, posted October 30, 2019, courtesy of Ania Mendrek via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Coronavirus Shutdowns And The Environment | Earth Wise

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Our stories often discuss how human activities change the natural environment.  With most of us confined to our homes, the lack of human activities is having profound effects on the environment.  We are talking about some of these this week.

The COVID-19 pandemic is a global catastrophe, but it has ironically been a boon for the environment.  By taking billions of people off the streets around the globe and slashing all forms of travel, the global environment has seen dramatic changes.

Sea turtles in many countries are prospering by not having to compete with humans for precious beach space.  Animals everywhere have more freedom to roam and are taking advantage of the opportunity. The Himalayas are visible from parts of India for the first time in decades.

Satellite imagery has shown dramatic drops in nitrogen dioxide emissions in China, where pollution from vehicles is a serious public health problem.  Similar reductions in air pollution are evident in India, Italy and even in Los Angeles.  The city that is notorious for its smog suddenly has pristine air.

In Venice, water in the canals has become clear in the absence of heavy boat traffic stirring up sediments from the bottom.  Wildlife that normally is invisible such as jellyfish are being spotted.

Not all the changes to animal behavior are desirable.  Some wildlife that have become dependent on humans as a source of food are becoming aggressive and are taking to the streets of cities to look for food.  Monkeys in Thailand are mobbing towns and brawling, hunting for things to eat.  Rats in New York City are fighting over suddenly meager food supplies.

In many ways, the natural world is reacting to much of humanity sheltering in place.

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On Earth Day 2020, coronavirus shutdowns are a gift to the environment

Photo, posted April 2, 2020, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Another Greenhouse Gas Record

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According to the World Meteorological Organization, levels of heat-trapping greenhouse gases in the atmosphere have reached yet another new record high.  Globally averaged concentrations of carbon dioxide reached 407.8 parts per million in 2018, up from 405.5 parts per million in 2017.

The increase year-over-year was similar to that from 2016 to 2017, and remains a little over the average for the last decade.  Global CO2 levels crossed the 400 parts per million threshold in 2015.

Concentrations of methane and nitrous oxide also increased by higher amounts than the average for the past decade, based on observations from the Global Atmosphere Watch network with stations all over the globe.

Since 1990, there has been a 43% increase in total radiative forcing – which is the warming effect on the climate from long-lived greenhouse gases. Carbon dioxide accounts for about 80% of this.  The report notes that the last time the Earth experienced this high a level of CO2 was 3 to 5 million years ago. At that time, global temperatures were 2 to 3 Celsius degrees higher and sea levels were 30 to 60 feet higher than now.

The report includes data on the isotopic analysis of the CO2 in the atmosphere.  CO2 produced by fossil fuel combustion comes from plant material from millions of years ago and does not contain radiocarbon, that is, carbon-14.  CO2 from natural sources contains radiocarbon produced by cosmic rays.  The increasing CO2 levels in the atmosphere contain decreasing levels of radiocarbon, indicating that the overall increase is largely due to human activities.

Overall, global efforts to date to reduce emissions have not been very successful, and this is borne out by the growing levels of carbon dioxide in the atmosphere.

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Greenhouse gas concentrations in atmosphere reach yet another high

Photo courtesy of Flickr.

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...)