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Climate change and an iconic Florida bird

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The Florida scrub-jay is a medium-sized bird native to Florida, known for its striking blue plumage and distinctive call. It is the only bird species that is entirely endemic to Florida, found mainly in the scrubby, sandy habitats of the central and southern part of the Sunshine State.

But extensive development, habitat fragmentation, and habitat degradation have caused the scrub-jay population to decline significantly over the past century. 

Another threat facing the Florida scrub-jay is climate change.  According to a new study by researchers from the Archbold Biological Station and the Cornell Lab of Ornithology, warmer winters driven by climate change are causing Florida scrub-jays to nest one week earlier than they did in 1981.  This seemingly innocuous change has reduced the number of offspring raised annually by 25% since 1981. 

The research team examined 37 years of data to assess the impacts of warming on reproductive efforts.  From 1981 to 2018, the average winter temperature at Archbold Biological Station in Florida increased by 2.5 degrees Fahrenheit.  Despite increases in the number of nests built and eggs laid over the longer breeding season, Florida scrub-jays are not producing more young. 

The researchers hypothesize that warmer temperatures make the nests susceptible to predation by snakes for a longer period of the Florida spring than in the past.  The findings, which were recently published in the journal Ornithology, suggest that climate change could dampen the success of conservation efforts for this threatened species.

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Long-term study reveals warming climates threaten Florida scrub-jay

Florida Scrub-Jay

Photo, posted October 15, 2018, courtesy of Judy Gallagher via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A sustainable and climate-friendly food

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Researchers predict that climate change will negatively impact the yield and nutritional quality of most staple food crops, including rice, corn, and soybeans, due to factors like extreme weather events, rising temperatures, and altered precipitation patterns, potentially leading to reduced food security globally.   

As a result, many experts contend that alternative food sources – like insect farming and seaweed aquaculture – are part of the solution.  Additionally, expanding production of climate resilient food crops will also have an important role to play in global food security.

According to a new international study led by researchers from University of Vienna in Austria, chickpeas – also known as garbanzo beans – are a drought-resistant legume plant with a high protein content that can help combat food insecurity amid climate change.

In the study, which was recently published in the journal Plant Biotechnology, the researchers investigated the natural variations of different chickpea genotypes and their resistance to drought stress and achieved promising results.  The research team managed to grow many different chickpea varieties under drought stress in a field experiment outside of Vienna. The results demonstrate that chickpeas are a great alternative legume plant that can complement grain farming systems in urban areas.

The study highlights how the decline of plant genetic diversity poses a major threat to plant productivity and harvests.  In fact, while there are approximately 7,000 edible crops, two-thirds of global food production is based on just nine crop species. 

According to the research team, highly nutritious and drought-resistant legumes such as chickpeas are a “food of the future.”

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Chickpeas – sustainable and climate-friendly foods of the future

Photo, posted March 21, 2020, courtesy of Ajay Suresh via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Forest crimes

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Wildlife trafficking is the world’s fourth largest form of organized crime, behind only drug trafficking, counterfeiting, and human trafficking.  When we hear about wildlife trafficking, we think of elephant ivory, rhino horns, tiger parts, and the like.  But so-called forest crimes, which includes poaching protected trees and illegal logging added up to somewhere between $30 billion and $100 billion during the period 2014-2018.  A 2020 report by the United Nations estimated that illegal trade just in rosewoods comprised more than 40% of the value of all trafficked species – animal and plant – during that time.

Even though rosewood comprises multiple tree species, world stocks of nearly all of them have been depleted through overexploitation. Rosewood is now protected worldwide, and some 300 species are under trade restrictions.

With a value of as much as $1.5 million per cubic meter, rosewood is at the center of a great deal of illegal activity, government corruption, and controversy.  A shipment of 30,000 illegally felled rosewood logs from Madagascar was seized at a port in Singapore in 2014. Those rosewood logs, worth at least $50 million, have been hung up in multiple legal proceedings and disputes ever since and remain in Singapore.

With huge financial stakes, it is perhaps not surprising that the U.N. estimates that as much as a third of the supposedly legal global timber trade involves illegally harvested wood.

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How Traffickers Got Away with the Biggest Rosewood Heist in History

Photo, posted April 19, 2010, courtesy of Dinesh Valke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wildlife crossings

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Every year, there are one to two million collisions between motor vehicles and large animals in the U.S.  About 200 people are killed annually.  Counting smaller vertebrates, around a million animals are killed by vehicles each day.  Research has shown that global warming is triggering widespread species redistribution.  As a result, more and more animals are on the move, changing their habitats to escape warming temperatures and climate extremes.

This situation has created renewed interest in creating wildlife crossings.  These are various kinds of structures that allow animals to traverse human-made barriers like highways.  They include such things as a grassy overpass that allows pronghorn to run across a highway in Wyoming and a long underpass that allows tigers to scamper beneath a highway in India.

In the U.S., there are more than 1,000 wildlife crossings and there are more being built all the time.  Data shows that they are highly effective.  A study of wildlife crossings on Highway 9 through the Blue River Valley in Colorado found that they reduced wildlife-vehicle collisions by nearly 90%. 

Wildlife crossing structures can be expensive to build, costing between $500,000 and $6 million, but research has shown that the money saved by avoiding crashes can recoup these costs in just a few years along with the fact that they potentially save lives.  Federal funding is largely distributed based on areas with the highest number of wildlife-vehicle collisions, which is crucial for addressing public safety issues.  However, a recent study suggests that future proposals need to incorporate climate-driven changes in animal behavior and habitat.

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As Climate Changes Fuels Animal Movement, Will These Structures Still Help Species Cross the Road?

Photo, posted April 5, 2017, courtesy of Jeffrey Beall via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Climate-smart coffee

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Do you crave that morning cup of coffee?  You’re not alone, and not by a long shot.  In fact, more than 2.2 billion cups of coffee are consumed globally every day. 

The existing coffee market is dominated by two species: Coffea arabica and Coffea canephora (the latter commonly called robusta).  Historically, coffee drinkers have preferred Arabica beans for their specific flavor and aroma. 

But climate change is threatening many crops around the world, and maybe none more so than coffee.  In fact, an alarming 50% of suitable coffee-growing land is projected to be lost by 2050.  As a result, scientists see two alternatives to supplement Arabica: either adapt coffee farming practices to new environments, or focus on coffee species that are more resilient.

According to a new study led by researchers from the University of Florida, Robusta coffee might be a good candidate to augment Arabica.   The researchers evaluated Robusta and Arabica for multiple traits in three high-altitude locations in Brazil over five years.

The study, which was recently published in the journal Crop Science, found that Robusta is highly adaptable and grows in high-altitude regions, which means it combines good production and flavor scores.  According to the researchers, Robusta can combine the following three elements for coffee cultivars: Sustainability (produce more with fewer inputs), quality (good flavor to meet consumer demand), and plasticity (capacity to adapt to new production systems).

Following these favorable findings with Robusta in Brazil, the scientists will test whether the species can grow in Florida.

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Robust and smart: Inference on phenotypic plasticity of Coffea canephora reveals adaptation to alternative environments

UF scientists study how to bring you ‘climate-smart coffee’

Photo, posted May 23, 2013, courtesy of McKay Savage via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Better wood for storing carbon

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Scientists have discovered a new type of wood that is highly efficient at storing carbon.  A comprehensive survey of the microscopic structure of the wood from many species of trees revealed that there is a type of wood that is neither softwood, such as pine and conifers, or hardwood, such as oak, ash, and birch.

The scientists from Cambridge University and Jagiellonian University in Poland analyzed some of the world’s most iconic trees using electron microscopy to survey their microscopic structure.

They found that tulip trees, which are related to magnolias and can grow over 100 feet tall, have a unique type of wood.  The trees, which diverged from magnolias far back to a time when atmospheric CO2 concentrations were low, grow very tall and very quickly.  These features were an adaptation to those conditions and result in the ability to store larger concentrations of carbon to compensate based on their microstructure.  The elementary units of wood are known as macrofibrils, and tulip trees have much larger macrofibrils than hardwoods but smaller than those of softwoods.  This unusual intermediate structure makes the trees highly effective at carbon storage.

Based on the research, it may be the case that tulip trees will end up being useful for carbon capture plantations – tree plantings specifically for the purpose of mitigating the effects of climate change.  Some east Asian countries are already using various tulip tree species in plantations for locking in carbon.  This was based on their large size and rapid growth, but it turns out that their novel wood structure may be the most compelling reason to use them.

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Scientists discover entirely new wood type that could be highly efficient at carbon storage

Photo, posted March 3, 2021, courtesy of Thomas Quine via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Species range and climate change

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The geographic range of a particular plant or animal species is the area in which it can be found during its lifetime.  The range of most species is limited by climatic factors, including temperature, precipitation, soil moisture, humidity, and wind.  Any changes in the magnitude or variability of these factors will impact the species living there. 

For example, a species sensitive to temperature may respond to a warmer climate by moving to cooler locations at higher latitudes or elevations. 

But not all species are able to move at the same speed.  According to an international research team led by scientists from the University of Massachusetts Amherst, non-native species are expanding their ranges many times faster than native species.

The researchers found that land-based plant and animal species need to be shifting their ranges by about two miles per year just to keep up with the rapid pace of the changing climate.  Marine species need to be moving about 1.7 miles per year.  However, native species are only managing to move about one mile per year on average.  

Non-native species, on the other hand, are spreading nearly 22 miles each year on their own.  Additionally, when the role humans play in assisting the spread of non-native species is factored in, the rate jumps to a whopping 1,170 miles per year.  This is more than 1,000 times faster than the rate at which native species are spreading.   

The researchers conclude that there is no chance for native species to keep up with climate change without human help.  Assisted migration needs to be on the table if native plants and animals are to survive.   

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Non-Native Plants and Animals Expanding Ranges 100 Times Faster than Native Species

Photo, posted April 10, 2011, courtesy of Bri Weldon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Averting a mass extinction

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There has been widespread concern that biodiversity is under siege and that we are in the beginnings of a sixth mass extinction in the long history of the Earth, this time caused by the actions of humanity.  There has been considerable debate about what can be done about it and solutions generally involve protecting large areas of the planet from human disruptions.  Some countries have set a target of protecting 30% of land and sea.

A new study by a broad coalition of conservation organizations and published in Frontiers in Science, concludes that humans can preserve much of the great diversity of life on Earth by setting aside just 1.2% of the planet for protection.

The experts mapped the wilderness available to rare and threatened plants and animals.  They then identified specific hotspots for rare wildlife that have yet to be protected.  They found a total of 16,825 such sites which nevertheless all together add up an area smaller than the state of Wisconsin.

Some scientists have been warning that by focusing too much on the size of protected lands, we are not necessarily safeguarding areas that are especially rich in wildlife.  The new study pushes for prioritizing hotspots for rare species, which the authors claim would be sufficient to stave off a sixth mass extinction.  The truth is that most species on Earth are rare, meaning that they are few in number or cover a small range, or both.

The study estimated that the cost of protecting the identified hotspot sites would be $263 billion, which is certainly a large amount of money.  But the authors point out that this sum to save global biodiversity is less than the yearly revenue of Shell Oil.

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To Avert a Mass Extinction, Protect 1 Percent of Earth

Photo, posted April 20, 2018, courtesy of Per Harald Olsen / AfricanBioServices via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Species and climate change

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Temperature extremes on Earth currently range from a low of -129°F to a high of 134°F.  But these climatic limits have changed throughout history.  In fact, during the last interglacial period 130,000 years ago, temperatures were warmer, resembling what we are projected to experience at the end of this century.

Species that evolved during such periods may possess pre-adaptations that could help them tolerate upcoming changes to the climate.  This factor is often overlooked by traditional statistical models predicting species’ responses to climate change.

But a new model, developed by researchers from Ifremer in France and Lausanne University in Switzerland, has taken this oversight into account, and reassessed the proportion of terrestrial and marine species threatened with extinction by climate change. 

In the study, which was recently published in the journal Nature Ecology and Evolution, the research team applied its model to nearly 25,000 terrestrial and marine species from around the world.  The researchers discovered that 49% of these species live in climate niches near the current climatic limits, and 86% could potentially extend beyond these limits. 

The most surprising result concerns tropical regions. While forecasts from traditional models estimate that the diversity of terrestrial species in tropical areas could decrease by 54% between now and 2041-2060, the new model predicts a more moderate decline of 39%.

The findings confirm the importance of taking urgent measures to mitigate climate change and its impact on biodiversity.

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Some species may better tolerate climate change than expected

Photo, posted October 23, 2015, courtesy of Anita Ritenour via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Declining pollinator populations

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Scientists have been sounding the alarm on the global struggle of pollinators for decades.  Many recent studies have highlighted alarming declines in pollinator populations, sparking concern about the potential negative impacts on ecosystems and agriculture.  Habitat loss, invasive species, and climate change are some of the factors linked to the population declines. But most pollinator research has focused on well-studied species in easily-accessible regions.

In a new study recently published in the journal PLOS One, a research team led by Northern Arizona University compiled data on four major families of bees and butterflies to create species distribution models, allowing them to assess changes over time and space across North America.

The researchers confirmed that bee and butterfly populations are declining in major regions of North America due to ongoing environmental changes, and found that significant gaps in pollinator research limit the ability to protect these species. 

The highest species richness was found along North America’s West Coast –  especially in California. But the models showed a decline in species richness over the past century in western North America.  In contrast, the research team found disproportionate increases in eastern North America.

Comparisons with climate data indicate that the pollinator population changes are at least partly due to the impacts of climate change, including prolonged drought and habitat degradation. 

The study identifies regions of declining populations where officials can prioritize conservation efforts, and highlights how improved monitoring methods could address the knowledge gaps on pollinator populations.

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Bee and butterfly records indicate diversity losses in western and southern North America, but extensive knowledge gaps remain

Bees and butterflies on the decline in western and southern North America

Photo, posted April 3, 2017, courtesy of Tracie Hall via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Deer vs. caribou

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The combination of a warming climate and human disruption of traditional habitats has been causing changes in the ranges of many animal species.  Over the past century, white-tailed deer have greatly expanded their range in North America.  Researchers from a group of Canadian institutions have been investigating the expansion of the deer in the boreal forest of Western Canada.  A five-year study used 300 wildlife cameras throughout the region to track the activities of large mammals.

Climate change has created milder winters and habitat alteration from forestry and energy exploration have created new food sources for deer. 

The expansion of deer in the forest has not been a good thing for the woodland caribou. The species was designated as threatened in 2002.  As of 2011, only 34,000 remained in the region.  Deer are ecosystem disruptors, in this case disrupting existing predator-prey dynamics.  Areas with more deer typically have more wolves and wolves are predators of caribou.  Deer can handle high predation rates, but the already threatened caribou cannot.

Understanding the relative roles of climate and human land use is essential in efforts to recover caribou populations.  It is complicated because further north, the climate becomes harsher and human land use decreases.  The debate over the relative effect of climate or habitat change is one of the most pressing issues facing ecologists globally as they pursue efforts for ecosystem restoration.

In any case, winter severity is expected to decline as climate change progresses.  Therefore, deer are expected to keep expanding northward and increasing in abundance, which means increasing risk to caribou.

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Deer are expanding north, and that’s not good for caribou

Photo, posted January 12, 2016, courtesy of Gerry via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Penguin detectives

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Emperor penguins, the tallest and heaviest of all living penguins, are also the most famous, being the subject of a very popular documentary film.  The ongoing loss of sea ice in Antarctica has led to unprecedented breeding failures in emperor penguin colonies. 

Since 2016, Antarctica has seen the four years with the lowest sea ice extent on record.  Between 2018 and 2022, 30% of the 62 known emperor penguin colonies were affected by partial or total sea ice loss.  Current predictions suggest that the population of emperor penguins will fall by 99% by the end of the century.

To monitor remote emperor penguin colonies, researchers use satellite images in which the brown stains of the birds’ guano stand out against the white ice and snow.

Researchers at the British Antarctic Survey have launched the ‘Polar Observatory’ on the online citizen science website Zooniverse to recruit ‘penguin detectives’ to help validate the accuracy of satellite images in assessing penguin populations.

The online app contains drone photos taken over the Snow Hill penguin colony.  The images have been split into more than 300 10-meter squares.  Volunteers are asked to identify any adult and chick penguins in a given picture.  The results will be fed into machine learning algorithms to train the AI systems in automatically counting penguins in future surveys.

The project is a fun opportunity for aspiring conservationists and penguin lovers in general to help learn more about the future of the species.  Interested people can learn more on the Zooniverse website.

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‘Penguin detectives’ required for new counting app

Polar Observatory

Photo, posted October 7, 2017, courtesy of Christopher Michel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Good owls and bad owls

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In the forests of the Pacific Northwest, spotted owls have been the subject of environmental concern for more than 30 years.  Over the past 20 years, northern spotted owl populations have declined by up to 80% as the birds have faced marginalized territories and increasing numbers of wildfires.  Only about 3,000 of them remain on federal lands.  Spotted owls are picky eaters and are not very adaptable.

The barred owl, a larger and more ornery species, has been moving in on spotted owl turf for 50 years, competing for food and space, and out-reproducing them and chasing them out of their nesting spots.

A last-ditch effort to rescue the northern spotted owl from possible extinction has been proposed by the U.S. Fish and Wildlife Service.  The plan would be to eradicate up to half a million barred owls over the next 30 years in Washington, Oregon, and Northern California.  The owls would be dispatched using cheap and efficient methods, such as shotguns.

The concept of killing off vast numbers of barred owls is awful, and nobody likes the idea.  However, other strategies have failed, and time is running out.  The only way to preserve the northern spotted owl is to protect and increase its habitat and have fewer barred owls.

To say that the proposed plan is controversial is a massive understatement.  A coalition of 75 wildlife and animal welfare organizations described it as a “colossally reckless action.”

A central issue in the debate is whether humans are responsible for this situation and should try to rectify it or, despite our desire to protect the spotted owl, we should just let nature take its course.

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They Shoot Owls in California, Don’t They?

Photo, posted April 4, 2022, courtesy of Kyle Sullivan / BLM via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Climate change and fish migration

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The warming climate is changing the distribution of fish species.  Researchers at the University of Adelaide in Australia have observed that tropical fish species are moving into temperate Australian waters.

The Eastern Australian Current is strengthening as the climate warms and larvae of tropical fish are getting caught in the current and moving into more temperate regions.  These larvae would not normally survive in the cooler Australian ocean water, but the warming current keeps the baby fish warm and increases their chances for survival.  The fish migration observed in the study is an ongoing process that has strengthened in the last few decades due to ocean warming.

The novel populations of tropical fish in these temperate ecosystems are not having much impact at the present time, but they may do so in the future.  The water is still cooler than the fishes’ natural environment and therefore they do not grow to their maximum size.  As a result, they don’t represent stiff competition for the native species – at least not yet.

As the ocean temperatures continue to rise, these tropical species will eventually grow to their full size and their diets will overlap more and more with those of temperate fish species.  Tropical herbivores tend to overgraze temperate kelp while the impact of tropical fish that eat invertebrates is less well understood.  Tropical fish with varied diets are the most successful invaders.  The ultimate effects on temperate ecosystems remain to be seen but survival may become difficult for the native fish in rapidly warming temperate ocean environments.

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Tropical fish are invading Australian ocean water

Photo, posted March 28, 2017, courtesy of Ryan McMinds via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Hope for amphibians

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There are more than 7,000 known species of amphibians, the group of animals that includes frogs, toads, and salamanders.  Over the past 25 years, more than 90 species are believed to have gone extinct and at least 500 more have declining populations.

There are many factors contributing to the decline of amphibian populations but the most alarming is a fungus called Batrachochytrium dendrobatidis – or Bd – that ravages the skin of frogs and toads and eventually causes heart failure.  The fungus has been devastating amphibians on nearly every continent.

In a recent paper in the journal Current Biology, scientists at the University of California Riverside documented the discovery of a virus that infects Bd and could be engineered to control the fungal disease.

The researchers were studying the population genetics of the Bd fungus with DNA sequencing technology and uncovered the virus inside the fungal genome.  Some strains of the fungus are infected with the virus and others are not.  They are now looking for insights into the ways that the virus operates to see how it gets into the fungal cells.  The goal is to engineer the virus to infect more strains of the fungus and potentially end the global amphibian pandemic.

Frogs and toads control bad insects, crop pests, and mosquitos.  If their populations around the world collapse, it could be devastating.  They are already having difficulty coping with warmer temperatures, stronger UV light, and worsening water quality in many places. 

Some amphibian species are already acquiring resistance to Bd.  The UCR researchers are hoping to assist nature in taking its course.

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Discovery could end global amphibian pandemic

Photo, posted August 25, 2010, courtesy of Kev Chapman via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Major species turnover forecasted for North American cities

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Climate change affects animal species in many ways.  It induces habitat loss, disrupts migration and breeding patterns, threatens marine life, and facilitates an increased spread of disease.  It may also affect where animals can be found in the future. 

According to a new study led by researchers from the University of Toronto Mississauga and Apex Resource Management Solutions in Canada, climate change may dramatically affect the animal species observed in North American cities by the end of the century.

The researchers used species distribution data combined with machine learning to study the impact of human-caused climate change on more than 2,000 animal species historically found in the 60 most populous North American cities. 

According to the research team, changes in biodiversity are brewing for almost every city it studied by the year 2100.  In fact, cities with a rich history of biodiversity are predicted to have the largest declines and fewest gains in species. Cooler and wetter cities like Quebec, Ottawa, Winnipeg, Kansas City, and Omaha are expected to welcome the most new species.  Warmer cities with higher precipitation – like cities in coastal California – are projected to lose the most species. 

More than 95% of bird and insect species are predicted to experience a change in the number of cities they call home.  Canines, most amphibians, and aquatic birds are expected to experience the greatest losses.  Toads, turtles, mice and pelicans are projected to become more common overall. 

The researchers hope their findings will encourage more efforts to protect biodiversity.

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North American cities may see a major species turnover by the end of the century

Photo, posted September 29, 2013, courtesy of Jonathan Kriz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

An ice-free Arctic

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According to a new study by Colorado University, Boulder, the Arctic could see summer days with practically no sea ice as soon as sometime in the next few years.  Earlier predictions for when the first ice-free day in the Arctic could occur were sometime well into the 2030s.

By mid-century, the Arctic is likely to see an entire month without floating sea ice.  This would likely be in September, when ice coverage is at its minimum.  By the end of the century, the ice-free season could last for many months during the year.

Technically, an ice-free Arctic does not mean zero ice in the water.  The working definition is less than 386,000 square miles of ice, which represents less than 20% of what the minimum ice coverage was in the 1980s. In recent years, the coverage has been about 1.25 million square miles.

Sea ice coverage is a big deal because many Arctic animals rely on sea ice for survival, including seals and polar bears.  With warmer ocean water, invasive fish species could move into the Arctic Ocean, upsetting local ecosystems.  Sea ice loss also is a risk for coastal communities because the ice buffers the impact of ocean waves on the coastal land.  As the ice retreats, ocean waves would get bigger, eroding the coasts.

At this point, an ice-free Arctic is basically inevitable, but its annual duration will depend on society’s efforts to reduce carbon emissions.  Lengthy periods of minimal sea ice would transform the Arctic into a completely different environment with global effects that are mostly highly undesirable.  However, Arctic sea ice is resilient and could return fairly quickly if the atmosphere cools down.

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The Arctic could become ‘ice-free’ within a decade

Photo, posted July 9, 2022, courtesy of Reiner Ehlers via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Mercury in tuna

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Mercury is found throughout the ocean, and there is at least some of it in any fish one might eat. It is an element found naturally in the environment, but it is also a byproduct of manmade pollution. Generally speaking, bigger fish tend to have higher mercury levels than smaller ones, because they are higher up in the food chain. The more small fish those big fish eat, the more mercury builds up in their bodies.  Tuna aren’t the biggest fish in the ocean, but they are very common in many people’s diets.

Increased mercury levels are a result of human activities like burning coal and mining which release methylmercury into the air.  It then finds its way into the oceans in rainwater.  Methylmercury is a particularly toxic chemical that affects the nervous system.  Environmental protection policies in recent decades have helped to reduce mercury pollution.

However, a recent study by French researchers looked at the mercury levels in tuna over the past 50 years.  They found that the levels have basically not changed since 1971.  As a result, they are calling for more restrictive environmental policies to further lower mercury pollution levels.

The researchers explained that the lowering of mercury airborne levels to date has not necessarily been ineffective.  They theorized that the static levels in tuna may be caused by the upward mixing of “legacy” mercury from deeper ocean water into the shallower depths where tropical tuna swim and feed.  It could very well take decades to dramatically reduce ocean mercury levels. 

Meanwhile, mercury content in tuna varies considerably by tuna type and source and there are both better and worse choices out there.  Consumers should learn the facts.

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Mercury levels in tuna remain nearly unchanged since 1971, study says

Photo, posted November 7, 2015, courtesy of Mussi Katz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Greenland is greening

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Despite their names, Iceland is very green, and Greenland is very icy.  But in Greenland, that is changing.  Temperatures in the world’s largest island are rising twice as fast as they are in the rest of the world and, as a result, the icy rocky landscape is turning increasingly green.

Satellite records reveal that over the last three decades Greenland has lost 11,000 square miles of ice, which is an area about the size of Massachusetts.  As the ice melts off, tundra and shrublands takes its place.  The ice melt moves sediment and silt and eventually wetlands and fenlands are formed.

Between the late 1980s and the late 2010s, the areas of Greenland covered by vegetation have more than doubled.  The new green areas cover roughly 33,000 square miles, which is an area the size of Maine.

Greenland’s dramatic changes are the result of the warming climate, but in turn, those changes are accelerating climate change.  Land covered with dark green vegetation absorbs more energy from the sun thereby warming the air whereas ice-covered landscapes reflect much of the sun’s energy back into space.  In addition, the rapidly expanding wetlands are a significant source of methane, which traps even more heat in the atmosphere.

Greenland is a poster child for the effects of climate change.  Its glaciers and icecaps are shrinking, glacier-fed lakes are expanding, permafrost lakes are draining, and rivers are transporting vast amounts of sediment and widening.  All of this is going on as its vegetation cover and species diversity is expanding.

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In Icy Greenland, Area Covered by Vegetation Has More Than Doubled in Size

Photo, posted September 20, 2019, courtesy of Amanda via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Is the Amazon rainforest nearing a tipping point?

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The Amazon rainforest is the largest rainforest in the world, covering more than 2.5 million square miles.  More than three million species live in the rainforest, which constitutes approximately 10% of the world’s known biodiversity.  The Amazon rainforest’s biodiversity is so rich that scientists are still discovering new species all the time. 

The Amazon rainforest absorbs huge amounts of carbon dioxide from Earth’s atmosphere, making it a key part of mitigating climate change.  But the amount of carbon dioxide absorbed by the Amazon rainforest today is 30% less than it was in the 1990s. 

Deforestation of the Amazon rainforest remains a major problem. Cattle ranching is the leading cause of deforestation, but industrial activities, such as the mining of oil and gas, copper, iron, and gold, are also to blame.

According to a new study recently published in the journal Nature, global warming may be interacting with regional rainfall and deforestation to accelerate forest loss in the Amazon.  In fact, it may be pushing the rainforest towards a partial or total collapse. 

The study, which was led by researchers from Federal University of Santa Catarina in Brazil and the University of Birmingham in the U.K., has identified the potential thresholds of these stressors, and highlighted how their combined effects could produce a tipping point for the Amazon rainforest. 

The findings are important because the Amazon rainforest plays a vital role in the global climate system.  By identifying the most important stressors on the rainforest environment, the researchers hope they can develop a plan to keep the Amazon rainforest resilient.

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Is the Amazon forest approaching a tipping point?

Photo, posted July 2, 2017, courtesy of Anna & Michal via 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...)