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Insect declines in remote regions

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Insects play a crucial role in sustaining life on Earth.  They pollinate plants, recycle nutrients, and form the foundation of food webs in both terrestrial and freshwater ecosystems. Without insects, the rich biodiversity that supports our planet would not exist.

However, global studies show a widespread decline in both insect abundance and diversity. According to a new study by researchers from the University of North Carolina at Chapel Hill, insect populations are also shrinking in relatively undisturbed landscapes. 

The research team quantified the abundance of flying insects during 15 seasons between 2004 and 2024 in a subalpine meadow in Colorado, an area with decades of weather data and very little direct human activity. The results revealed an average annual decline of 6.6% in insect abundance, amounting to a 72% drop over the 20-year period. The study also linked these losses to rising summer temperatures.

Most previous studies of insect loss have focused on areas heavily influenced by agriculture or urbanization. This new research fills an important gap by showing that steep declines can occur even in pristine areas where human disturbance is minimal, suggesting that the changing climate may be a key driver. 

Mountain regions, which are home to many unique and locally-adapted species, are especially vulnerable. If these declines continue, the rich biodiversity found in high-altitude habitats could be in jeopardy.

The findings highlight the urgent need for broader and longer-term monitoring of insect populations and reinforce the importance of addressing climate change.  Even remote regions are not out of its reach.   

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Long-term decline in montane insects under warming summers

Insects are disappearing from the last places we thought were safe

Photo, posted July 16, 2019, courtesy of Tom Koerner / USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Reindeer grazing and forest carbon

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Northern forests store a third of the world’s carbon, acting as sinks for atmospheric carbon dioxide.  Forest carbon exchange is the process whereby forests sequester carbon dioxide from the atmosphere via photosynthesis, storing it in their wood, leaves, and roots, and releasing some carbon through decomposition and respiration.  This natural cycle in forests is a critical part of the global carbon cycle and is a key factor in the mitigation of climate change.

The carbon cycle in northern forests is affected by the depth of winter snow and its duration.  It turns out that other elements of the forest ecosystem play an important role as well.  Researchers at the University of Oulu in Finland measured the impact of reindeer grazing and snow depth in Finland’s coniferous forests over a five-year period. 

There are areas in northern Finland’s forests where reindeer grazing has been excluded for decades.  In these areas, shallow snow increased carbon release.  In the same locations, deeper snow decreased carbon release.  On the other hand, in areas where reindeer grazed, carbon release remained stable regardless of changes in snow cover. 

The researchers theorize that the substantially recovered lichen cover in the ungrazed areas influences soil temperature and moisture conditions.  When combined with changing snow conditions, these factors may affect soil decomposers and, therefore, the amount of carbon released. 

The essential conclusion of this work is that multiple elements of an ecosystem, such as reindeer grazing, can buffer ecosystem functions, such as carbon exchange.    In this case, reindeer play an important role in sustaining the biodiversity of northern ecosystems. 

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Reindeer grazing can mitigate the impacts of winter climate change on forest carbon release

Photo, posted December 17, 2015, courtesy of Eco Dalla Luna via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Tree plantings and climate impact

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Planting trees is a key strategy in the fight against climate change.  Trees absorb carbon dioxide, regulate temperature, support biodiversity, and improve air and water quality, offering benefits that extend well beyond their boundaries.

But according to a new study by researchers from University of California – Riverside, where those trees are planted makes a big difference.  The study, which was recently published in the journal Climate and Atmospheric Science, found that tree plantings are almost always a net positive for the climate because trees pull CO2 out of the atmosphere. But the impact of trees on temperature varies a lot by region.

In tropical regions, trees deliver the biggest cooling benefits.  They not only absorb carbon but also cool the air through a process called evapotranspiration.  Roots draw water from the soil, and when it evaporates from the leaves, it cools both the tree and the air around it.  This also raises humidity, which can lead to more clouds.  Both effects block some sunlight from reaching the ground, which adds to the cooling.

The researchers estimated that tropical tree plantings could cool regions like central Africa by as much as eight-tenths of a degree Fahrenheit. 

In contrast, planting trees at higher latitudes may have a slight warming effect.  Darker tree canopies absorb more sunlight, which can offset some of the cooling.  In some places, such as Canada and the northeastern U.S., trees may even increase fire risk.  But this does not mean trees in those regions are unhelpful.  They provide many other benefits for biodiversity, ecosystems, and the environment. 

But one thing is clear: planting trees in the tropics offers the strongest returns for the climate.

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Trees in the tropics cool more, burn less

Photo, posted September 15, 2024, courtesy of Jan Helebrant via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Migratory bison in Yellowstone

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Tens of millions of bison once migrated across the United States in enormous herds; tribal oral histories speak of it taking days for an entire herd to pass by.  These herds shaped the landscape and performed many ecosystem functions.  By the 1890s, the bison population had plummeted to fewer than 1,000 individuals.  Since then, dedicated conservation efforts – establishing protected areas and breeding programs – have led to the recovery of the species.  There are now about 400,000 bison, mostly existing in small, privately owned herds.

Yellowstone National Park is home to the last significant migratory bison herd.  Yellowstone was established as a national park in 1872 providing scientists with a unique opportunity to study how large grazing herbivores affect the landscape.  More than 5,000 bison live in the 3,500 square miles of the park. 

A 7-year study by researchers examined how bison change the soil and vegetation along their migratory route.  What looked like overgrazing turns out to allow plants to keep growing.  The bison graze and move on, increasing the density of microbes and nitrogen in the soil and significantly improving the nutrition for other herbivores.

The research validated what Indigenous peoples have known for many generations:  that bison helped shape this continent and having large numbers of them improve ecosystems for other animals as well.  Native American tribes would like to restore bison to their lands.  Whether some of the park fences might be removed to permit migration beyond official borders is under consideration.

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In Yellowstone, Migratory Bison Reawaken a Landscape

Photo, posted August 17, 2017, courtesy of Jacob W. Frank / NPS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The benefits of agroecology

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Agroecology focuses on sustainably managing agricultural systems by applying ecological principles.  The goal is to optimize the interactions between plants, animals, humans, and the environment.

A four-year study by the UK Centre for Ecology and Hydrology found that incorporating nature-friendly practices within farming increases biodiversity, pollination by bees, natural pest control, and the numbers of earthworms. 

The study compared three agricultural systems:  typical intensive agriculture, enhanced ecological farming, and maximized ecological farming.  Enhanced ecological farming involves planting wildflower field margins to provide habitat for bees, beetles, and spiders, and sowing overwinter cover crops to capture carbon and retain soil nutrients.  Optimized ecological farming adds planting in-field strips of wildflowers to attract beneficial insects and adding organic matter such as farmyard manure to improve soil health.

The ecological systems had increased populations of earthworms and pollinators, as well as natural predators of crop pests. 

The study concluded that while there are multiple benefits in terms of biodiversity, soil carbon, and crop yield when ecological farming systems are used, many farmers will be deterred from adopting agroecological farming practices and system because of the reduced profitability.  They argue that financial incentives such as subsidies are needed and are well worth it for the long-term sustainability of agriculture.

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Nature-friendly farming boosts biodiversity and yields but may require new subsidies 

Photo, posted July 27, 2023, courtesy of Judy Dean via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Green transit in London

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TfL – Transport for London – the operator of the transportation system in Britain’s capital city, has signed a deal with EDF Renewables to purchase electricity from a huge solar array to be erected next year in Essex.  TfL has the goal of powering 100% of its entire transit system – including its sprawling underground railway network – with renewable electricity by 2030.

The forthcoming 1,000-acre solar facility will also transform low-quality farmland by incorporating the planting of trees and hedgerows as well as setting aside some areas for natural regeneration, attracting a greater number of species of plants and animals, expanding biodiversity in the area.  Looking after nature and protecting the environment are key elements in TfL’s contracts, in keeping with its wider goals to be greener, more sustainable, and well-adapted to climate change. 

The solar facility will generate 80 gigawatt-hours annually for the transit authority, roughly enough electricity to power 29,000 homes, comprising about 20% of its total output.  Powering the entire sprawling London underground railroad network is equivalent to powering 420,000 homes.  Over the course of the 15-year contract with EDF, TfL expects to save over 30,000 tons of carbon from its operations.

TfL plans to secure 70% of its electricity use from power purchase agreements for renewable electricity from various sources with the remainder from green tariffs.  The Mayor of London has set the goal for London to be a net zero carbon city by 2030.

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London Inches Closer to Running Transit System Entirely on Renewable Power

Photo, posted March 5, 2017, courtesy of Albert Koch via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rainforests and thunderstorms

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Tropical forests are dying at an alarming rate, and not just from deforestation. Even intact forests are losing trees, threatening biodiversity, carbon storage, and the global climate. While drought and rising temperatures are often blamed, new research points to a surprising culprit: thunderstorms.

These intense, short-lived convective storms, common in the tropics, are increasing due to climate change. With strong winds and lightning, they can snap trees, strip canopies, and kill even the most robust tree specimens.

In a perspective paper recently published in the journal Ecology Letters, a research team led by the Cary Institute of Ecosystem Studies argues that thunderstorms, often overlooked in carbon storage research, may be the leading cause of tree death in tropical forests. The research team estimates that storms have caused 30 to 60% of tree mortality in the past, a number that is likely rising as storm activity increases 5 to 25% each decade.

Including storm data in forest carbon studies changes the picture significantly. Earlier models showed that carbon levels dropped sharply when temperatures rose beyond a certain point. But when storm impacts were added, that pattern disappeared, suggesting that storms – not just heat – may be a key factor in carbon loss.

Understanding which species are most vulnerable is critical for reforestation and conservation efforts. Mature trees store the most carbon, so if they’re lost to storms, future forests may fall short of their carbon storage potential.

As storm activity increases each decade, the stakes grow higher.  Accounting for storms could reshape how we protect, restore, and plan for the future of our forests. 

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Are the Amazon’s biggest trees dying? Forest coroners investigate

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

Earth Wise is a production of WAMC Northeast Public Radio

Forest-based agroforestry

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Tree plantings have become a go-to climate solution for governments and conservation groups due to the carbon-storing potential of trees.  While planting new trees on open farmland would help capture additional carbon, a new study led by scientists from Yale School of the Environment suggests a powerful alternative: forest-based agroforestry.

Instead of clearing land for crops or starting fresh with new trees, forest-based agroforestry (or FAF) brings agriculture into existing forests.  Think fruits, nuts, and medicinal plants, for example, grown sustainably under a forest canopy – all while maintaining biodiversity and storing carbon.

According to the researchers, human activity in forests is often seen as harmful. But for thousands of years, Indigenous and local communities have managed forests in ways that actually strengthen them.

The study, which was recently published in the journal Nature Climate Change, found that FAF not only rivals tree planting in terms of climate benefits, but it can also generate income and support cultural practices tied to the land.

Despite these benefits, forest-based agroforestry receives far less funding and policy support due to two key misconceptions. It’s frequently confused with industrial systems focused on global commodity crops, and results from tropical regions are wrongly assumed to apply to temperate and boreal forests.

The researchers recommend including FAF in agroforestry policies, clearly distinguishing it from harmful industrial practices, and expanding research on FAF in temperate and boreal regions to guide better land management.

Forest-based agroforestry appears to be a natural climate solution hiding in plain sight.

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Agriculture in Forests Can Provide Climate and Economic Dividends

Photo, posted May 8, 2023, courtesy of Preston Keres / USDA Forest Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The coastal squeeze

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Globally, coastal areas are being squeezed between rising seas on one side and human development on the other.  The average distance from the high waterline to the first built-up area with human structures or paved roads is less than 400 yards around the world.  The narrower a coast, the sooner rising sea levels cause problems.

Narrow coasts have reduced ability to defend against storm surges and other weather events.  Construction close to the sea makes coastal areas extra vulnerable.  Narrow coasts are also bad news for biodiversity.  A study by the Royal Netherlands Institute for Sea Research investigated plant diversity in both the Netherlands and the United States.  They found that the wider the coast was, the greater the plant diversity.

In Florida and Georgia, whenever coastal zones reached a couple of kilometers in width, diversity increased rapidly.  In the Netherlands, only coastal areas at least 3.8 kilometers wide reached their maximum plant diversity, but such areas are rare.  Dutch sand dune areas are typically no more than a kilometer wide, leaving plant diversity at no more than half the possible level.

Limited biodiversity in narrow coastal strips can be somewhat boosted by nature management but would benefit much more by spatial planning.  In the Netherlands, a spot called The Sand Motor is where a gigantic amount of sand was deposited off the coast in 2011.  Since then, natural forces have spread it along the coast.  Such coastal expansion could increase biodiversity.  Biodiversity is not a luxury.  It makes for a better future for coastal defense, a healthy drinking water supply, and a better human food supply.

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Coastal squeeze is bad for biodiversity, and for us!

Photo, posted June 21, 2017, courtesy of Mark Bias via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The human impact on biodiversity

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Biodiversity is under threat.  More and more plant and animal species are disappearing and humans are to blame.  Humans cause biodiversity loss through habitat destruction, invasive species, pollution, direct exploitation, and climate change, all of which are significantly influenced by human activities.

But until now, drawing broad conclusions about human impacts on biodiversity has been difficult because a clear, global overview of how human activity affects nature across all species did not exist. Most studies have focused on specific places, impacts, or time periods.

To fill these research gaps, a research team from the University of Zurich in Switzerland and the Swiss Federal Institute of Aquatic Science and Technology conducted an unprecedented synthesis study.  The researchers compiled data from around 2,100 studies that compared biodiversity at almost 50,000 sites affected by humans with similar places that hadn’t been affected by humans. 

The synthesis study, which was recently published in the journal Nature, found humans are having a highly detrimental impact on biodiversity worldwide.  In fact, not only is the number of species declining, but the composition of species communities is also changing.  On average, the number of species at impacted sites was almost 20% lower than at unaffected sites.

The study, which is one of the largest ever conducted on this topic, highlights the widespread negative impact of human activities on nature, and emphasizes the need to consider all forms of life when assessing biodiversity loss. 

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The Devastating Human Impact on Biodiversity

Photo, posted November 19, 2014, courtesy of Green Mountain Girls Farm via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The dangers of deep sea mining

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The White House is considering an executive order that would fast-track permitting for deep-sea mining in international waters and allow mining companies to bypass a United Nations-backed review process.

Deep sea mining is the extraction of minerals from the seabed in the deep ocean.  Most of the interest is in what are known as polymetallic nodules, which are potato-sized mineral deposits that have built up in layers over thousands of years. They are located several miles below the surface, primarily in what is called the Clarion-Clipperton zone, which is an environmental management area of the Pacific Ocean about halfway between Mexico and Hawaii.

A new multiyear study led by UK’s National Oceanography Center and published in the journal Nature found that the site of a deep-sea mining test in 1979 still showed lower levels of biodiversity than in neighboring undisturbed sites 44 years later.

Much is not known about the undersea nodules.  We know that they produce oxygen.  If the nodules are removed, will that reduce the amount of oxygen in the deep sea and affect the organisms that live there?  If mining occurs, what effect will the metal-containing sediment plumes churned up by the mining process have? 

The nodule fields sustain highly specialized animal and microbial communities.  More than 20 billion tons of nodules are estimated to lie on the seabed of the Clarion-Clipperton Zone.  If large-scale mining takes place, and there is much interest in that happening, it is important to find out what the impact will be on the ocean and its ecosystems because it is likely to be largely irreversible.

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Deep sea mining for rare metals impacts marine life for decades, scientists say

Photo, posted September 4, 2014, courtesy of James St. John via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Bad news for birds

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The 2025 U.S. State of the Birds report was released recently.   The report is produced by a coalition of leading science and conservation organizations.  The bottom line is that there have been continued widespread declines in American bird populations across all mainland and marine habitats. 

More than one-third of U.S. bird species are of high or moderate conservation concern.  Among these, 112 are tipping point species that have lost more than 50% of their populations over the last 50 years. 

Protecting bird species is not just about biodiversity and stewardship of nature.  Wild birds have surprisingly large economic impact.  Nearly 100 million Americans are engaged in birding activities which contribute substantially to local and state economies.  The 2022 National Survey of Fishing, Hunting, and Wildlife-Associated Recreation estimated that the total economic output related to bird watching activities was an amazing $279 billion and birding-related activities support 1.4 million jobs.  Bird watching and other encounters with nature are beneficial for human well-being, including reducing stress, anxiety, and depressive symptoms.

The rapid declines in birds are related to habitat loss, environmental degradation, and extreme weather events.  Moreover, if conditions are not healthy for birds, they are unlikely to be healthy for people as well.  Fortunately, many actions that are good for birds are good for us, so conservation efforts going forward are important.

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State of America’s birds: Population declines continue

Photo, posted October 30, 2018, courtesy of Shenandoah National Park via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Sharks and rays in a warming world

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Sharks and rays belong to a group of cartilaginous fish called elasmobranchs, which have been swimming in the world’s oceans for 450 million years. The resilient species have survived five mass extinction events, and are older than dinosaurs, trees, and Mount Everest. 

But despite their resilience, many species of sharks and rays today are threatened by human activities, including overfishing, habitat loss, and climate change.  In fact, according to a new study led by researchers from the University of Vienna in Austria, more than one third of the shark and ray species known today are severely under threat. 

The study, which was recently published in the journal Biology, found that higher carbon dioxide levels were having a negative effect on sharks and rays, ranging from impacts on the animals’ senses to changes in the skeleton during embryonic development.  An examination of fossil records found that higher CO2 levels had contributed to the extinction of individual shark and ray species in the past. 

But the study also found that global warming could be creating opportunities for sharks and rays.  Rising sea levels and higher temperatures have historically expanded shallow coastal habitats and warm waters, supporting species biodiversity.

But according to the research team, the rapid environmental changes, combined with the impacts from human activities, outpace the ability of sharks and rays to adapt, making it unlikely that they will benefit from global warming.

Protecting sharks and rays is crucial not only for their survival but also for maintaining entire ocean ecosystems. Without top predators, these ecosystems could collapse, impacting both marine life and the people and industries that depend on it.

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Sharks and rays benefit from global warming – but not from CO2 in the Oceans

Myths About Sharks and Rays

Photo, posted November 27, 2007, courtesy of Laszlo Ilyes via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Restoring English hedgerows

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Hedgerows are lines of different types of bushes and small trees growing very close together typically placed between fields or along the sides of roads in the countryside.  The network of hedges throughout rural England dates back to the Bronze Age, or even possibly Neolithic times.  As the first farmers began clearing areas of land for cultivation, they left strips of trees as boundaries.  Hedgerows act as field boundaries but also protect livestock, support biodiversity, and help mitigate climate change.

There are currently about 250,000 miles of hedgerows in England. However, about half of these important habitats were lost in the post-WWII years due to agricultural intensification.  Furthermore, a 2007 survey found that fewer than half of remaining hedgerows were judged to be in good structural condition.

The UK Centre for Ecology and Hydrology has set a target to create or restore 45,000 miles of hedgerow by 2050.  While the overall length of managed hedgerows in England has not changed much since 2007, the proportion in good structural condition has improved significantly and hedgerow height has increased.

England’s Department for Environment, Food & Rural Affairs aims to create or restore 30,000 miles of hedgerow by 2037.  However, the Climate Change Committee recommends that the national hedgerow network be increased by 40% by 2050 and the organization Natural England’s long-term aspiration is a 60% increase in hedgerow extent to support thriving plants and wildlife. 

For more information on this topic and other environmental news visit us at: earthwiseradio.org or Find us on Facebook.

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​​​​​​​Urgent need to enable more farmers and contractors to revive England’s network of hedgerows

Photo, posted May 27, 2016, courtesy of Dave S. via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar farms and pollinators

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Two important environmental challenges are finding some literal common ground:  the need to reduce carbon emissions and the fight to stave off global biodiversity collapse.  Both issues can be addressed at solar farms.

Solar energy is an important weapon in the battle against climate change.  But utility-scale solar farms take up large amounts of land.  Large-scale solar farms already take up nearly a thousand square miles of land in the US and will take up much more in the coming decades.

In the meantime, the biodiversity collapse is being driven in large part by habitat loss.

Given all this, solar farm operators, biologists, and environmentalists are teaming up to grow pollinator-friendly plants in and around solar farms. The plantings attract insects, birds and even mammals. The more plant diversity in the solar farms, the more environmental benefits can be achieved. 

There are costs associated with creating pollinator-friendly solar farms. Ideally, solar panels need to be installed at greater height than otherwise in order to permit growing many of the plants that attract bees and butterflies.  But there are economic benefits associated with attracting and sustaining pollinators.  On a cautionary note, there have already been cases of greenwashing, where solar operators claim environmental benefits far in excess of the scope of the actual efforts they have made. 

There are both governmental and non-governmental agencies seeking to assess and certify pollinator-friendly solar farms.  There is considerable variability in the ecological value of existing farms.  Pollinator-friendly solar farms are in their early days, but they have a lot to offer as a win-win strategy for the environment.

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Solar Farms Have a Superpower Beyond Clean Energy

Photo, posted December 4, 2014, courtesy of Juwi Renewable Energies Limited via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Deep sea mining

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Deep sea mining is the extraction of minerals from the ocean floor at depths greater than 660 feet and as much as 21,000 feet below the surface.  Active or extinct hydrothermal vents on the ocean floor create sulfide deposits which collect metals such as silver, gold, copper, manganese, cobalt, and zinc.  This forms polymetallic nodules – potato-sized rocklike deposits containing these valuable minerals.  There are literally trillions of these things scattered over wide areas of ocean floor.  The largest of these deposits are in the Pacific Ocean between Hawaii and Mexico in the Clarion Clipperton Fracture Zone.

Mining companies argue that land-based sources for valuable metals are running out and are critically needed for green technologies like batteries for electric vehicles and manufacturing solar panels and wind turbines.  They also claim that mining in the deep sea will be less environmentally damaging than land-based mining.

The deep sea is viewed by many as kind of a watery desert but there are actually diverse and rich ecosystems down there.  Most of the animals living in the depths are tiny, but that doesn’t make them any less important.  Many can live for a very long time.  Some invertebrates live for thousands of years.

There are currently no commercial deep sea mining operations underway.  Many countries have outlawed them.

The deep seas are the last mostly unexplored part of the Earth.  Deep sea mining will unquestionably be highly destructive to these environments.  We don’t really know what the impact of widespread deep sea mining might be, but the world continues to edge ever closer to allowing it to happen.

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Can We Mine the World’s Deep Ocean Without Destroying It?

Photo, posted March 30, 2018, courtesy of the NOAA Office of Ocean Exploration and Research 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

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

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...)