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Paris and climate change

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Paris is associated with climate change by virtue of the 2015 international agreement seeking to limit the amount of warming taking place on the planet.  But Paris is well aware that the world is not making much progress in meeting the goals of that agreement and the French capital is already suffering from the impact of the warming climate.

France has had multiple heat waves this summer that have seen multiple record high temperatures across the country.  Eight of the 10 hottest summers recorded in Paris have occurred since 2015.

Paris officials have performed heat crisis simulations to learn what the effects of extreme heat situations would be.  One simulation looked at the impact of temperatures reaching 122 degrees.  The consequences to many of the city’s functions and systems would be dire.  This might seem outlandish, but in 2019, temperatures in Paris reached 109 degrees, and climate change is warming Europe at more than twice the global average.  With its zinc roofs, squares paved with stone, and highest population density in Europe, Paris is especially ill-suited to hot weather.

Paris is taking steps to prepare for a warmer future.  It is pulling up asphalt parking places and road centers to plant trees, 15,000 last winter alone.  It is putting up more shade structures and water misters.  Paris is insulating older buildings – 7,000 a year now and a goal to reach 40,000 a year by 2030.  Paris is registering isolated older or disabled people, so that they can be checked on during heat waves.

It is a race against time.  Paris is trying to prepare for the changes to come.

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Paris Braces for a Future of Possibly Paralyzing Heat

Photo, posted September 30, 2018, courtesy of Pedro Szekely via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wildfires and water quality

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Hotter and drier conditions driven by climate change are leading to an increasing number of wildfires in North America and around the world. The damage wildfires cause – to forests, homes, and communities – is well-known. But long after the flames are gone, the effects can linger, especially in rivers and streams, where water quality may suffer for years.

A new study by scientists at the CIRES institute at the University of Colorado Boulder analyzed more than 100,000 water samples from more than 500 sites across the Western U.S. and found that wildfires can degrade water quality for up to eight years after a fire. The research, which was recently published in the journal Nature Communications Earth & Environment, found elevated levels of organic carbon, nitrogen, phosphorus, sediment, and turbidity – the cloudiness of water – in basins affected by fire.

This large-scale analysis reveals watersheds take longer to recover from wildfires than previously thought, with widespread, long-lasting impacts often going undetected for years.

Organic carbon, phosphorus, and turbidity remain elevated for one to five years after a fire. Nitrogen and sediment levels stay notably high for up to eight years. Fire-driven impacts are worse in more forested areas.

Each watershed in the study responded differently depending on local conditions.  In some places, sediment levels surged to as much as 2,000 times normal levels, while others remained relatively unchanged.

The research team hopes its findings can help guide future planning efforts to improve wildfire resilience.

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Wildfires threaten water quality for years after they burn

Photo, posted April 6, 2017, courtesy of Bonnie Moreland 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

Deconstructing buildings

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An estimated 30 million tons of wood waste from construction and demolition in the U.S. ends up in landfills each year.  A growing number of cities have launched initiatives to reuse the wood instead.  It is a strategy to reduce carbon emissions, cut waste, and shift towards a circular economy.

For a long time, salvaged wood was a niche pursuit by people who valued the fine grain and enduring quality of older wood.  Reclaimed old-growth lumber offers character and strength.  These people pursued construction that uses wood with a story – timber recovered from historic structures, collapsing barns, and other demolished buildings.

Now, there are multiple companies in the business of salvaging wood from buildings.  Cities and businesses are embracing the use of reclaimed materials.   Ordinances in cities like Portland, Oregon, Boulder, Colorado, and San Antonio, Texas require older buildings to be taken apart for repurposing their materials.  Palo Alto, California has banned demolition completely. 

Portland was the first U.S. city to require old residential homes to be deconstructed.  After a decade, contractors have deconstructed more than 650 homes in the city, salvaging 2,000 tons of reusable wood.

Using reclaimed wood in local buildings stores carbon and reduces emissions by avoiding the need to cut new trees, process materials, and ship them long distances.

Deconstructing buildings is not a widely available skill.  Contractors have to be trained on how to dismantle buildings piece by piece.  But there is now a national registry of deconstruction trainers and a network of practitioners.

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Deconstructing Buildings: The Quest for New Life for Old Wood

Photo, posted May 16, 2018, courtesy of Alexandre Prevot via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Planting trees to cool the planet

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Planting lots of trees is one of many strategies being pursued to combat climate change. Forests absorb carbon dioxide, provide shade, and help regulate temperatures. They also support biodiversity and improve air and water quality.

According to a new study by researchers from the University of California – Riverside, restoring forests to their pre-industrial extent could reduce global average temperatures by 0.34 degrees Celsius. That’s equivalent to about 25% of the warming the Earth has already experienced.

The study models restoring 4.6 million square miles of forest.  While previous studies have focused on the role trees play in removing carbon, this research adds that trees also alter atmospheric chemistry in ways that boost their cooling impact.

Trees release natural chemicals called BVOCs – biogenic volatile organic compounds – which interact in the atmosphere to form particles that reflect sunlight and promote cloud formation. These effects enhance the cooling impact of forests, especially in climate models that take these chemical reactions into account.

But not all reforestation is created equal. The benefits of reforestation vary by region, with tropical forests offering stronger cooling and fewer drawbacks.  Importantly, the researchers emphasize that meaningful climate benefits don’t require restoring every lost forest. Small, localized efforts can still shift regional climates.

While forest restoration can meaningfully aid climate efforts, the researchers stress that it must complement – not replace – fossil fuel reductions.

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Does planting trees really help cool the planet?

Photo, posted May 20, 2005, courtesy of Ben Britten via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Parks for bugs

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Urban areas can have a variety of green spaces:  gardens, parks, and roadside and median plantings.  It turns out that these spaces can serve as pollinator refuges.

A study by researchers at the University of British Columbia found that reducing lawn mowing and creating pollinator meadows – essentially parks for bugs – significantly boosts pollinator diversity and creates healthier and more resilient ecosystems.

The 3-year study surveyed pollinators in 18 urban parks across the city of Vancouver.  It compared parks where meadows were planted and mowing was restricted with parks that were kept as standard turfgrass lawns.

Parks with meadows saw an immediate increase in pollinator species – from 21 to 47 more wild bee and hoverfly species – compared to parks without meadows.  These increases continued over the entire three-year study period.

The researchers identified more than 100 species of wild bees and hoverflies and 35 of them were only found in parks with meadows.

People think of urban landscapes as poor environments for biodiversity, but this study demonstrated that even relatively small changes can have significant impacts.  Even a patchwork of small habitats can allow species to move freely and settle into multiple areas quickly.

The researchers had advice for urban residents as well.  They suggest that people reduce mowing, plant native flowering shrubs and trees, create diverse habitats that incorporate a variety of plants that bloom at different times, avoid pesticide use, and leave natural nesting sites for pollinators.

Preserving pollinators is an important task and having a few parks for bugs can really help.

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How ‘parks for bugs’ boost pollinators in Vancouver

Photo, posted September 19, 2011, courtesy of Eric Bridiers / U.S. Mission Geneva via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The problem of mountain lions

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Mountain lions – also known as pumas, cougars, and even sometimes panthers – are the most widely distributed wild land mammal in the world.  They are found from Canada to South America.  There are an estimated 30,000 mountain lions in the United States, mostly in the West, but there are also mountain lions from the Midwest to the East Coast. 

Unlike wolves or grizzly bears, mountain lions are not managed by the federal government; they are managed by states and state regulations vary greatly.  In some places, hunting mountain lions is banned completely; in other places, it is always open season.

As more people encroach on wild land – building homes and small farms, as well as hiking and biking – the numbers of encounters between people and mountain lions are increasing.  And when mountain lions lose their fear of people, there is trouble.

Since 1890, there have been at least 32 fatal mountain lion attacks on humans and more than 170 non-fatal attacks.  California has seen the most attacks in the last 40 years with 22 people injured and four killed.  Despite this, Californians passed a ballot initiative in 1990 that bans all hunting of mountain lions.

There are strategies to reduce habituation and instill fear of humans in mountain lions.  One is called “tree-and-free” that uses dogs to chase mountain lions up trees.  But there are opponents of this and other measures employed. 

The fact is that there are simply too many mountain lions living in close proximity to humans and peaceful coexistence is very difficult to achieve.  Places where hunting lions is permitted have few problems with them, but that is not a solution that is acceptable in many places.  It’s a difficult problem.

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Deadly Encounter: Mountain Lion Attacks Spark Controversy

Photo, posted March 26, 2013, courtesy of the USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rising seas are destroying buildings

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Alexandria is the second largest city in Egypt and is the largest city on the Mediterranean coast.  Its history goes back over 2,300 years and it was once home to a lighthouse that was among the Seven Wonders of the Ancient World and a Great Library that was the largest in the ancient world.  The modern city has more than 6 million residents but still has many historic buildings and ancient monuments.  But perhaps not for long.

Rising seas and intensifying storms are taking a toll on the ancient port city.  For centuries, Alexandria’s historic structures have endured earthquakes, storm surges, tsunamis, and more.  They are truly marvels of resilient engineering.  But now, climate change is undoing in decades what took millennia for humans to create.

Over the past two decades, the number of buildings collapsing in Alexandria has risen tenfold.   Buildings are collapsing from the bottom up as a rising water table weakens soil and erodes foundations.  Since 2001, Alexandria has seen 290 buildings collapse.  Comparing present-day satellite imagery with decades-old maps, the authors of a study by the Technical University of Munich have tracked the retreat of Alexandria’s shorelines to determine where seas have intruded into groundwater. The authors say that more than 7,000 buildings in Alexandria are at risk.  They call for building sand dunes and planting trees along the coast to block encroaching seawater.

The true cost of this gradual destruction goes far beyond bricks and mortar.  This is the gradual disappearance of historic coastal cities.  Alexandria is a warning for such cities around the world.

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In This Storied Egyptian City, Rising Seas are Causing Buildings to Crumble

Photo, posted September 11, 2012, courtesy of Sowr via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Hurricanes and wildfires

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Early March saw more than 200 wildfires break out in the southeastern U.S. – a busy start to the region’s annual fire season.  One fire in the Carolina Forest near Myrtle Beach scorched over 2,000 acres over a two-week period and firefighters were busy containing it and many other blazes.

Strong winds and an unusually long dry period have made fires more likely to ignite and be spread.  Lightning strikes, power line sparking, backyard fire pits and leaf burning all can lead to wildfires under these conditions.

A weather disaster last year may be helping to make this fire season worse than usual.  Hurricane Helene ravaged the Southeast last September, dumping more than a foot of rain in some locations and knocking over hundreds of thousands of acres of trees across the region.

Lots of dead trees lying on the ground allow sunlight to reach the ground and dry out all the biomass, including the trees.  All of this desiccated plant material acts as kindling, providing fuel for wildfires.  Fallen trees can be a fire nuisance for years after a hurricane, especially in the Southeast, where dried out pine needles are highly combustible.  All it takes is an ignition.

In addition, all the fallen trees represent an access issue for firefighters as the logs block roads needed to reach the fires.

Research has shown that climate change is fueling more intense fires in the West.  Whether the changing climate is having a major effect in the Southeast isn’t clear.  But droughts are expected to become more intense and more frequent in the Southeast because of climate change and that isn’t good news for the likelihood of wildfires.

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How Hurricanes Can Fuel Wildfires in the Southeast

Photo, posted March 5, 2025, courtesy of the U.S. Army National Guard / Roberto Di Giovine 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

Engineering plants to consume more carbon dioxide

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The most abundant protein on the planet is an enzyme called ribulose-1,5-bisphosphate carboxylase/oxygenase, better known as RuBisCO.  Its critical role in photosynthesis makes life as we know it on earth possible.  What it does is convert carbon dioxide from the atmosphere into the organic matter contained in plants.

Getting plants to take up more carbon dioxide from the atmosphere is a key strategy for mitigating climate change.  Planting lots of trees is one way to do it.  Another is to get individual plants to capture more carbon dioxide.

Scientists at the University of Illinois have focused on getting plants to produce more RuBisCO which allows them to grow faster, consuming more carbon dioxide in the process.

Some plants are better than others at taking advantage of the earth’s rising carbon dioxide levels.  Among these are food crops like corn, sugarcane, and sorghum.  Such plants’ growth is not primarily limited by how much carbon dioxide is in the atmosphere but rather by how much RuBisCO is in their leaves.  The Illinois scientists tweaked genes in corn and sorghum to produce plants containing more RuBisCO.  Laboratory experiments on corn demonstrated faster corn growth.  Recent outdoor field experiments on sorghum demonstrated a 16% boost in its growth rate. 

Improving photosynthesis in this way is not only a potential strategy for increasing plants’ ability to combat climate change.  It is also a way to cope with the world’s increasing demand for food by producing crops that can grow larger and more quickly.

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Scientists Engineer Crops to Consume More Carbon Dioxide

Photo, posted April 12, 2016, courtesy of K-State Research and Extension 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

Planting trees in Europe

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Planting lots of trees is one of many strategies being pursued to combat climate change.  Trees are storehouses of carbon from the atmosphere and planting more of them helps remove carbon dioxide.  But trees do more than that.  Trees are natural air conditioners in cities.

Trees significantly cool urban environments by providing shade and via a process called evapotranspiration by which they release water vapor into the air, which provides cooling.  This helps mitigate the urban heat island effect. Areas under trees in cities can be as much as 25 degrees cooler than in unshaded areas covered in asphalt.

The city of Paris has laid out a plan to help the city prepare for increasing amounts of extreme heat.  The goal is to replace 60,000 parking spaces across the city with trees by the end of this decade.  The plan to rip up parking spaces is part of a greater aim to create more than 700 acres of green space by 2030.  The Paris plan also includes creating more car-free zones and installing reflective roofs on 1,000 public buildings.  Nearly 80% of the buildings in Paris have zinc roofs – an affordable, corrosion-resistant and pretty much inflammable innovation of the 19th century.  However, these roofs can heat up to 194 degrees on a summer day, transferring heat into largely uninsulated top-floor garrets below.

Elsewhere in Europe, Danish lawmakers have agreed on a plan to rewild 10% of the country’s farmland and plant one billion trees.   According to the Danish government, this plan would bring about the biggest change to the Danish landscape in over 100 years.

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To Cope with Extreme Heat, Paris Will Swap Parking Spaces for Trees

Photo, posted April 11, 2014, courtesy of Val H. via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Regrowing forests naturally

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Deforestation is one of the major causes of climate change and restoring and enhancing forests is a major activity around the world as a way to mitigate its effects.  There are high-profile initiatives to plant millions of trees, but these projects are often ill-conceived and poorly managed.

One of the most dramatic failures was the planting of over a million mangrove seedlings on the Filipino island of Luzon back in 2012.  A study 8 years later found that fewer than 2 percent of the trees had survived.  The rest died or were washed away.

The causes of failure in tree planting programs include planting of trees that become vulnerable to disease, competing demands for land, changing climate, planting in areas not previously forested, and a lack of aftercare including watering seedlings.

A multinational study recently published in Nature has found that forests could regrow naturally on more than 800,000 square miles of land around the tropics without the need for planting trees by hand.  This is an area larger than Mexico.

The researchers mapped areas where forests would be likely to regrow – areas where soils are healthy and where there is already forest nearby to supply seeds.  In some places, lands are so degraded that it is necessary to plant trees by hand, but this is costly and prone to failure.  Forests that regrow naturally tend to fare better and make better habitats for wildlife.

The effect of regrown forests on the climate would be very substantial.  If these forests were allowed to grow for three decades, they would absorb enough carbon to offset 50 years of emissions by Australia, the home of the lead researcher of the study. 

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Tropical Forests Could Regrow Naturally on Area the Size of Mexico

Photo, posted February 16, 2018, courtesy of Jason Houston / USAID 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

Megafires and orchard health

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The frequent and massive megafires in places like Canada and the American west have led to a lot of research on the impact of smoke on humans but there has been less study of the effects of smoke on plant health.  Researchers at the University of California, Davis have found that trees are just as vulnerable as humans are to the harmful effects of long-term exposure to smoke.

The Davis researchers studied almond, pistachio, and walnut trees at 467 orchard sites in California’s Central Valley from 2018 to 2022.  In 2022, so-called megafires burned more than 4.2 million acres in California, pouring ash and smoke into the sky.  The researchers had been studying how trees store carbohydrates to cope with heat and drought. 

With the onset of the fires, they saw an opportunity to study how smoke affects carbohydrate levels.  Trees use stored carbohydrates to sustain them through winter dormancy and spring growth.  Trees produce carbohydrates via photosynthesis and thick smoke blocks the amount of light reaching the trees.  Beyond that, there are other aspects of wildfire smoke, such as particulate matter and ozone that appear to affect photosynthesis.

The team found that the smoke not only reduced the amount of carbohydrates in trees but also caused losses that continued even after the fires were extinguished.  This led to nut yield decreases of 15% up to 50% in some orchards.  The researchers expected to see some impact on the trees during periods when smoke was really dense but were not expecting the smoke to have such a lingering effect and result in a significant drop in yield.

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Smoke From Megafires Puts Orchard Trees at Risk

Photo, posted October 1, 2008, courtesy of Suzi Rosenberg via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Canadian wildfires and global emissions

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The wildfires that burned vast amounts of Canada’s boreal forests in 2023 produced enormous amounts of smoke that found its way into American cities, working its way down the eastern seaboard and even producing unsafe air in Florida.

Researchers at Cal Tech and the Jet Propulsion Laboratory analyzed the carbon emissions associated with these fires last year and found that they were greater than those of all but three countries:  China, the US, and India.

Boreal forests have historically been a natural defense against climate change by storing carbon in trees rather than adding carbon dioxide to the atmosphere.  The fires in Canada, fueled by hot and dry weather, were extraordinary when compared with historical records.  But such fires are likely to be increasingly common as the climate continues to warm.

However, the hot and dry weather that fueled the 2023 fires was exceptional in many ways, involving early snow melt and so-called flash droughts.  This year’s fires in Canada are still bigger than average, but so far have not been as destructive as last year’s. 

Canada has been warming at about twice the global rate.  The extreme temperatures last summer were a major factor in the fueling of the fires, which burned an area almost the size of Florida.

Forests absorb about a quarter of global carbon emissions, but the increasing frequency and intensity of fires are calling into question their ability to continue to do so.  Parts of the Canadian forests are not regrowing after fires as they have in the past, partly because blazes burn trees so frequently and intensely.

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Canada’s Wildfires Were a Top Global Emitter Last Year, Study Says

Photo, posted June 8, 2023, courtesy of the Metropolitan Transportation Authority via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Food, timber, and climate change

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The sights of coffee plantations in California and vineyards in Britain are becoming more common as the climate changes. But behind what sounds like a success story is a sobering one: climate change is shifting the regions suitable for growing food all around the world. 

According to a new study by researchers from the University of Cambridge, as crop growing shifts northwards, a squeeze will be put on the land needed to produce timber.  The timber these trees produce is used to make everything from paper and cardboard to furniture and buildings.

According to the study, which was recently published in the journal Nature Climate Change, more than 25% of existing forestry land – an area equivalent in size to India – will become more suitable for agriculture by the end of the century if climate change continues unabated.  Approximately 90% of this current forestry land is located in Canada, China, Russia, and the United States.    

Global timber production is worth more than $1.5 trillion every year.  Recent heat waves and wildfires have caused huge losses of timber forests around the world. 

According to the World Bank, the value of the global food system is estimated to be roughly $8 trillion annually.  Scientists expect climate change to cause some areas to become too hot for growing food, particularly in the tropics and southern Europe. 

With the global demand for food and the global demand for wood both projected to double by 2050, the increasing climate change-driven competition between the two is set to be an emerging issue in the coming decades. 

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Global timber supply threatened as climate change pushes cropland northwards

Do the costs of the global food system outweigh its monetary value?

Photo, posted October 24, 2018, courtesy of Bill Smith 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...)