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Elephants And Global Warming | Earth Wise

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A study by researchers at Saint Louis University has found that elephants play a key role in creating forests that store large amounts of atmospheric carbon and in maintaining the biodiversity of forests in Africa.  Since elephants are endangered, their status represents a significant threat to an ecosystem that is very important to the Earth’s climate.

The African rainforest contains trees with both low carbon density (light wood) and high carbon density (heavy wood).  High carbon density trees grow more slowly and can be crowded out by the faster growing low carbon density trees rising above them.  Elephants affect the relative abundance of these trees by feeding more on the low carbon density trees which are more palatable and nutritious.  This thinning of the forest allows the trees that sequester the most carbon to flourish.

Elephants are also excellent dispersers of the seeds of high carbon density trees.  Essentially, elephants are the gardeners of the forest.  They plant the forest with high carbon density trees and get rid of the weeds – in this case, the low carbon density trees.  According to the study, if elephants were to become extinct, the African rainforest – the second largest on earth – would gradually lose between six and nine percent of its ability to capture atmospheric carbon.

Elephants have been hunted by humans for millennia.   Gaining support for protecting them has mostly been driven by the argument that everybody loves elephants.  Focusing on their role in maintaining forest diversity has not driven much more action.  The hope is that the evidence of how important elephants are for climate mitigation will be taken seriously by policy makers to generate the support needed for improved elephant conservation.

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Can Elephants Save the Planet?

Photo, posted March 15, 2008, courtesy of Michelle Gadd/USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Chocolate And Deforestation | Earth Wise

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The world consumes 7.5 million tons of chocolate a year.   Americans spend an average of $145 a year per capita on chocolate.  And we are not even the world leaders.  The Swiss eat an average of 22 pounds per person and the overall European chocolate market is the world’s largest.

A market valued over $100 billion a year is bound to have its issues for the environment, human rights, and other social issues, and chocolate is no exception.  The global cacao industry grapples with problems with child labor, poverty, deforestation, sustainability and other environmental issues.  The response of companies across the industry varies greatly. A website called chocolatescorecard.com keeps track of how many in the industry are doing.

Recently, lawmakers in the European Union have been putting together a landmark legislative package that addresses deforestation risks in the supply chains of a number of commodities including cattle, timber, rubber, soy, palm oil, and cacao. The proposed law restricts companies that import cacao and sell chocolate to import only what doesn’t destroy or degrade forests. 

Voluntary promises by big chocolate makers to save forests in major cacao-producing countries (like Ivory Coast, Ghana, Indonesia, and Nigeria) are difficult to keep.  Farmers sell to brokers who sell to trading companies that then sell to chocolate makers.  Tracing the origins of chocolate is difficult.  Ultimately, fairly compensating farmers is the only way they are likely comply with deforestation regulations and there are unfortunately many pockets to fill before that is likely to happen.

It is up to consumers to encourage companies to do the right thing by making their buying choices appropriately.

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The Forest in Your Chocolate

The Chocolate Scorecard

Photo, posted January 12, 2010, courtesy of Lee McCoy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Rainforest Promises | Earth Wise

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The recent UN climate summit in Sharm el Sheikh, Egypt brought with it lots of pledges for action.   Among them was a promise from the three countries that are home to more than half of the world’s tropical rainforests to try to do something to protect them.

The ministers of Brazil, Indonesia, and the Democratic Republic of Congo signed an agreement pledging cooperation on sustainable management and conservation, restoration of critical ecosystems, and creation of economies that would ensure the health of both their people and their forests.

The plan has no financial backing of its own.  The countries are pledging to work together to establish a funding mechanism that could help to preserve the tropical forests that both help regulate the Earth’s climate and sustain a wide range of animals, plants, birds, and insects.

That such an agreement has come about at all is a result of the election of Luiz Lula da Silva as Brazilian president, replacing Jair Bolsonaro, who was famously an opponent of any and all environmental conservation or protections.  President Lula addressed the attendees of the climate summit promising that “Brazil is back.”   He described his country as having been in a cocoon for the past four years under his predecessor.  He declared that going forward, Brazil will be a force to combat climate change.  Given the importance of the Amazon rainforest, that is critical for the success of the world’s efforts.

Like all other issues on the table at the climate summit, the real challenge is not to come up with meaningful pledges on climate action, it is to be able to follow through on those pledges.  If past summits are any indication, that is not an easy task.

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Brazil, Indonesia and Congo Sign Rainforest Protection Pact

Photo, posted September 15, 2013, courtesy of Moises Silva Lima via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Deforestation-Free Pledges | Earth Wise

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Deforestation is the purposeful clearing of forested land. Forests are cut down to make space for animal grazing, agriculture, and to obtain wood for fuel, manufacturing, and construction. Deforestation has greatly altered landscapes around the world and continues to do so today. 

Deforestation is the second largest contributor to global greenhouse gas emissions, trailing only fossil fuel use. Deforestation can lead to all sorts of problems, including biodiversity loss, soil erosion, desertification, and flooding.  Deforestation also threatens peoples’ livelihoods and increases inequality and conflict.

As a result, many companies around the world have made pledges to remove deforestation from their supply chains.  In fact, more than 94 companies had adopted zero-deforestation commitments by 2021.  But while these companies are talking the talk, they don’t seem to be walking the walk. 

According to a new study recently published in the journal Environmental Research Letters, companies’ deforestation-free supply chain pledges have barely impacted forest clearance in the Amazon. 

The research team from the University of Cambridge, Boston University, ETH Zurich, and New York University found corporate pledges to not purchase soybeans grown on land deforested after 2006 have only reduced tree clearance in the Brazilian Amazon by 1.6% between 2006 and 2015.  The researchers found that if these pledges had been implemented, the current levels of deforestation in Brazil could be reduced by approximately 40%.  

According to the research team, the findings of the study indicate that private sector efforts are not enough to stop deforestation. Political leadership will also be vital to forest conservation efforts.

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Companies’ ‘deforestation-free’ supply chain pledges have barely impacted forest clearance in the Amazon, researchers say

Photo, posted November 18, 2020, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Moving Endangered Species | Earth Wise

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People have intentionally or accidentally introduced numerous invasive species to habitats around the world.  At the same time, the planet’s wildlife is in a steep decline.  A recent study estimated that the populations of over 5,000 vertebrate species have declined by an average of nearly 70% since 1970.  A United Nations report warns that human activity has threatened as many as a million species with extinction.

With all of this as a background, there is climate change that is altering the habitats of the world’s species – warming lakes and oceans, turning forests into grasslands, tundra into woodland, and melting glaciers.  In response to these changes, living things are rearranging themselves, migrating to more hospitable locations.  But many species are just not capable of finding more suitable habitats on their own.

Conservationists are now increasingly considering the use of assisted migration. In some cases, when a species’ critical habitat has been irreversibly altered or destroyed, agencies are establishing experimental populations outside of the species’ historical range.  Such actions are often deemed extreme but may be increasingly necessary.

However, clear-cut cases are relatively rare.  More likely, it is a more difficult judgement call as to whether assisted migration is a good idea or is possibly a threat to the ecosystem of the species’ new location.  The relative dearth of assisted migration experiments is less likely a result of legal barriers than it is a lack of scientific and societal consensus on the practice. Scientists are now trying to develop risk-analysis frameworks that various agencies can use in considering potential assisted migration experiments. 

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Last Resort: Moving Endangered Species in Order to Save Them

Photo, posted March 18, 2010, courtesy of Jean via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Trees Are Growing Bigger | Earth Wise

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The alarming rate of carbon dioxide flowing into the atmosphere is having a real and actually positive effect on plant life. Higher concentrations of carbon dioxide make plants more productive because photosynthesis makes use of the sun’s energy to synthesize sugar out of carbon dioxide and water.  Plants make use of the sugar both as a source of energy and as the basic building block for growth.  When carbon dioxide levels go up, plants can take it up faster, supercharging the rate of photosynthesis.

In a new study published in the journal Nature Communications, scientists at Ohio State University found that trees are feasting on decades of carbon dioxide emissions and are growing bigger as a result. 

The researchers tracked wood volume in 10 different tree groups from 1997 to 2017 and found that all of them except aspens and birches grew larger.  Over that time period, carbon dioxide levels climbed from 363 parts per million to 405 parts per million.  According to the study, each 1% increase in lifetime CO2 exposure for trees has led to more than a 1% increase in wood volume.

In the big picture, the news isn’t so positive.  The global warming caused by increasing carbon dioxide levels increasingly threatens the forests of the world.  It has led to worsening droughts, insect infestations, and wildfires.  So overall, increasing levels of carbon dioxide are by no means a good thing for the world’s trees.  However, since trees are growing bigger more quickly, it means that planting them is an increasingly cost-effective method for fighting climate change because the same number of trees can sequester more carbon.

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As Carbon Dioxide Grows More Abundant, Trees Are Growing Bigger, Study Finds

Photo, posted September 12, 2015, courtesy of Nicholas A. Tonelli via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Sea Urchins And Climate Change | Earth Wise

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There is a thriving population of black sea urchins in bubbling volcanic vents off the coast of Ishia, a small island in the Gulf of Naples.  The oceanic environment there is very acidic, high in carbon dioxide, and very warm.   The environment represents a proxy for what is gradually happening to oceans around the world.

Researchers from the University of Sydney have determined that the ability of sea urchins to prosper in such an environment means that these animals, which are already abundant in the Mediterranean Sea are likely to spread further afield as oceans continue to warm and become more acidic.  The Mediterranean Sea is warming 20% faster than the global average.

Sea urchins are already an environmental problem in many places around the world.  When their numbers increase disproportionately, they decimate kelp forests and algae, leading to the demise of other species that depend on these things for food or shelter.  The result is something called an urchin barren, which is a rocky, sandy, urchin-filled seafloor devoid of other life.

Urchin barrens are increasingly common in many places, including the east coast of Australia and the coastline in the Americas stretching from Nova Scotia to Chile.

In Australia, for example, sea urchin populations have multiplied, and their range has expanded considerably, overgrazing kelp and damaging abalone and lobster farms.

Tests run by the Sydney researchers found that it is difficult to stress sea urchins.  They appear to tolerate conditions that other creatures simply cannot.   The only real positive is that understanding the urchins’ remarkable survival abilities might offer insights into adaptations that other animals might need in order to survive as the oceans become warmer and more acidic.

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Colonising sea urchins can withstand hot, acidic seas

Photo, posted January 31, 2010, courtesy of Anna Barnett via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Reshaping Our Planet | Earth Wise

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Human activity – especially agriculture – has altered 70% of the land on our planet.  According to a new report from the United Nations, damage to the Earth’s lands has put the planet on “crisis footing”.

Our health, our economy, and our well-being depend on land.  The food we eat, the water we drink, and the air we breathe all rely on status of the land to at least some extent.

According to the report, up to 40% of the planet’s land is already degraded, affecting half of the people alive today.  At current rates, an additional area nearly the size of South America will be degraded by 2050.

Degradation of land occurs in various ways, including deforestation, desertification, and the loss of wetlands or grasslands.  All of these things are caused by human activities.  As forests, savannas, wetlands, and mangrove swamps are converted to agriculture or are lost to urban expansion, greenhouse gas emissions rapidly increase, adding to the effects of climate change.  The climate crisis, biodiversity loss, and land degradation are integrally linked.

Much of the blame for degraded landscapes is on humanity’s ever-expanding need for food and the modern farming systems that produce it.  The global food system is responsible for 80% of the world’s deforestation, 70% of freshwater use, and is the greatest driver of land-based biodiversity loss.  Modern agriculture has altered the face of the planet more than any other human activity.

The report urges efforts at restoration of land.  Restoration can take multiple forms, including planting forests and shrubs or grazing livestock and growing crops between trees instead of clearing existing forests.

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UN Report Says Humanity Has Altered 70 Percent of the Earth’s Land, Putting the Planet on a ‘Crisis Footing’

Photo, posted June 20, 2010, courtesy of Nicholas A. Tonelli via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Red Pandas And Climate Change | Earth Wise

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Red pandas are small mammals native to the mountainous forests of China, India, Nepal, Bhutan, and Myanmar.  Unlike their name suggests, they are not related to giant pandas.  In fact, red pandas are distant relatives of raccoons. Renowned for their tree-climbing abilities, red pandas live at moderately high elevations in the Himalayas where they forage widely for bamboo shoots and various fruits.

According to the International Union for the Conservation of Nature, red pandas are endangered.  Scientists estimate that there are less than 10,000 red pandas remaining in the wild today, and these numbers are continuing to fall. 

Habitat loss is the main threat to red panda’s survival.  Human expansion into the area, combined with the effects of climate change, has led to the fragmentation and loss of livable land.  Red pandas also face dangers from hunting and poaching.

According to new research recently published in the journal Landscape Ecology, human impacts are driving red pandas closer to extinction than previously thought.  Using GPS telemetry, a research team from the University of Queensland in Australia tracked red pandas in Nepal over a 12-month period.  The researchers found that human activities, such as infrastructure development, were causing red pandas to restrict their movements, which is further fragmenting their habitat and interfering with natural interactions between the animals. 

As the amount of wild forest dwindles, red pandas are being forced into situations where they must decide whether to live closer to predators or adapt to co-exist with humans.

The research team recommends minimizing human-induced disturbances in red panda habitats and to maintain habitat continuity in ecologically sensitive areas. 

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Red pandas face a fractured future

IUCN: Red Panda

Photo, posted November 27, 2016, courtesy of Mathias Appel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Forests And Water | Earth Wise

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We hear a great deal about the environmental services provided by forests.  Deforestation is one of the major factors contributing to increasing levels of carbon dioxide in the atmosphere.  And, of course, forests – most notably rainforests – are major contributors to biodiversity.  A new study by the U.S. Forest Service looked at the role forests play in providing water for Americans.

According to the study, published in the journal Water Resources Research, forested lands across the U.S. provide 83 million Americans with at least half of their water.  125 million people – well over a third of the country – receive at least 10% of their water from forests.  Notably, in the drought-stricken western U.S., nearly 40 million people get more than half of their drinking water from forests that are increasingly threatened by wildfires.

The study looked at surface water sources for more than 5,000 public water systems.  It provides a critical update to the map of where our water comes from.  The study focused on surface waters such as lakes, rivers, and streams because it is too difficult to trace sources of groundwater on a national scale.  Included is a new database of inter-basin water transfers, which are how surface water moves from places where it is plentiful to where it is not.  Examples are the California Aqueduct and the Central Arizona Project which respectively supply Los Angeles and Phoenix with drinking water.  

In Los Angeles, 69% of the water coming in through inter-basin transfers originated in forested lands.  In Phoenix, the figure is 82%.  There are many urban communities that obtain more than half of their drinking water from inter-basin transfers.  Even far from forests, water from forests is essential for millions of Americans.

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U.S. Forests Provide 83 Million People with Half Their Water

Photo, posted September 26, 2016, courtesy of Don Graham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Historic Western Drought | Earth Wise

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The American Southwest has suffered from drought conditions since the year 2000.  The drought has reduced water supplies, devastated farmers and ranchers, and it has helped to fuel numerous wildfires across the region.  It has generally been considered to be worst in 500 years.

According to a recent analysis, the drought has become so severe that it has actually led to the driest two decades in at least 1,200 years and the changing climate is largely responsible.  The summer of 2021 was especially dry; about 2/3 of the West was in severe drought conditions.

Scientists at UCLA used tree ring data to gauge drought.  Based on that analysis, 2000-2021 is the driest 22-year period since 800 A.D. which is as far back as the data goes.

The study confirmed the role of temperature, more than precipitation, in driving exceptional droughts.  Precipitation levels can go up and down over time and can vary in different regions.  But the ongoing emissions of greenhouse gases into the atmosphere are causing temperatures to generally rise over time.  Warmer temperatures make the air more capable of pulling water out of the soil, out of vegetation, out of crops, and out of forests.  All of that makes drought conditions more severe.

A megadrought is generally considered to be one that is both severe and long.  But even during one, there can be wet years.  2005 was a notable one.  But there must be enough consecutive wet years to actually end a drought.

Several previous megadroughts over the past 1,200 years lasted as long as 30 years.  So, the current drought is in full swing and may go on for a long time to come.

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How Bad Is the Western Drought? Worst in 12 Centuries, Study Finds.

Photo, posted September 25, 2021, courtesy of David Sierralupe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Mercury In The Amazon Rainforest | Earth Wise

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Recent research has found that some of the highest levels of mercury pollution ever recorded are in a patch of pristine Amazonian rainforest.  The international team of researchers discovered that illegal goldmining in the Peruvian Amazon is the source of the pollution.

Illegal miners separate gold particles from river sediments using mercury.  Mercury binds to gold, forming pellets large enough to be caught in a sieve.   The pellets are then burned in open fire ovens, releasing the mercury to the atmosphere, leaving the gold behind.  The mercury smoke ends up being washed into the soil by rainfall, deposited onto the surface of leaves, or directly absorbed into leaf tissues.

Deforested areas had low levels of mercury, while the areas with the largest, densest old-growth trees captured huge volumes of atmospheric mercury, more than any other ecosystem studied in the entire world.  Mercury levels were directly related to leaf area index:  the denser the canopy, the more mercury it holds.  Birds from this area have up to twelve times more mercury in their systems than birds from less polluted areas.  Such high concentrations of mercury could provoke a decline of up to 30% in these birds’ reproductive success.

Small-scale artisanal gold mining is an important livelihood for local communities.  Eliminating it outright may not be a viable solution but coming up with ways to continue to provide a sustainable livelihood while protecting communities from poisonous pollution is essential.

In the meantime, the forests are doing an important service by capturing much of the mercury and preventing it from getting into the general atmosphere and endangering more people and animals.  Burning or harvesting the mercury-ridden trees would release the mercury back into the atmosphere.

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Modern Day Gold Rush Turns Pristine Rainforests into Heavily Polluted Mercury Sinks

Photo, posted August 24, 2016, courtesy of Anna and Michal via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Spring Is Coming Earlier In Britain | Earth Wise

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The United Kingdom has some of the most detailed records of seasonal changes anywhere in the world.  Since the 18th century, observations of seasonal changes have been recorded by scientists, naturalists, amateur and professional gardeners, and organizations such as the Royal Meteorological Society.  Researchers at two British institutions have collected and collated these records into a database they call Nature’s Calendar, which currently has about 3.5 million records going back to 1736.

By analyzing more than 400,000 observations of 406 plant species in Nature’s Calendar, they found that the average first flowering date from 1987 to 2019 is a full month earlier than the average from 1753 to 1986.  The change correlates very well with rising global temperatures.

The ecological risks associated with earlier flowering times are high.  When plants flower too early, a late frost can kill them – a phenomenon most gardeners have experienced at some point or another.  Beyond that, plants, insects, birds, and other wildlife have co-evolved to be synchronized with plants in their development stages.  A certain plant flowers and attracts a certain kind of insect, which then attracts a particular kind of bird, and so on.  If plants get out of sync with the animals in the ecosystem and the animals can’t change their behavior quickly enough, it can lead to species collapse.

If global temperatures continue to increase at their current rate, spring in the UK could eventually start in February, creating serious problems for many of the species that inhabit forests, gardens, and farms.  The dangers of climate change are not just about extreme weather.

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UK plants flowering a month earlier due to climate change

Photo, posted February 1, 2012, courtesy of Mandy via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Removing Carbon With The Oceans | Earth Wise

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There is increasing concern that reducing carbon emissions alone will not be sufficient to stabilize the climate and that technologies that actively remove carbon dioxide from the air will be needed.  There has been a fair amount of analysis of the efficacy of storing carbon in agricultural soil and in forests, but there has not been comparable studies of the risks, benefits, and trade-offs of ocean-based strategies. 

The oceans currently absorb about a quarter of the world’s carbon dioxide emissions.  There are multiple ways in which oceans could be induced to store much more.  A new report from the National Academies of Sciences, Engineering, and Medicine looks at several ocean carbon dioxide removal strategies in terms of efficacy, potential costs, and potential environmental risks.

One approach involves adding nutrients to the ocean surface to increase photosynthesis by phytoplankton.  The approach has a medium to high chance of being effective and has medium environmental risks.

Another approach is large-scale seaweed farming that transports carbon to the deep ocean or into sediments.   It has medium efficacy chances but higher environmental risks.

Protection and restoration of coastal ecosystems including marine wildlife would have the lowest environmental risk but only low to medium efficacy.

Chemically altering ocean water to increase its alkalinity in order to enhance reactions that take up carbon dioxide would be highly effective but a medium environmental risk.

The report describes some other approaches as well.  It recommends a $125 million research program to better understand the technological challenges as well as the potential economic, social, and environmental impacts of increasing the oceans’ absorption of carbon dioxide.

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Oceans Could Be Harnessed to Remove Carbon From Air, Say U.S. Science Leaders

Photo, posted August 21, 2016, courtesy of Quinn Dombrowski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Direct Air Capture | Earth Wise

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There is a lot of interest in carbon capture and sequestration (or CCS) in the context of trapping the carbon dioxide emissions from power plants and industrial facilities.  The fossil fuel industry is especially enthusiastic about the potential for continuing to burn fuels without harming the environment.  Apart from the technical challenges, there is the looming problem of CCS adding significant costs to power generation that is already losing the economic battle to renewable sources.

Direct air capture is a different matter.   This is the idea of actively taking CO2 out of the atmosphere.  This already happens by natural means such as sequestering it in soil or forests.  But there is considerable work going on aimed at developing technology to capture atmospheric carbon dioxide in massive quantities.

This September marks the opening of a new project called “Orca” in Iceland, which will, for the time being, be the largest direct air capture system in the world.  Once it is running around the clock, Orca will remove up to 4,000 metric tons of CO2 from the atmosphere each year.

Even larger DAC plants – one in the southwestern U.S and another in Scotland – are planned to come online in the next few years.

Ultimately, the question is whether direct air capture is feasible at large enough scale and affordable cost.  The numbers are daunting.  Society releases over 30 billion metric tons of carbon dioxide into the atmosphere each year.  Removing significant amounts of that with DAC technology is an enormous challenge.  Eliminating emissions remains the most practical way to mitigate the effects of climate change.

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The Dream of Carbon Air Capture Edges Toward Reality

Photo, posted November 10, 2017, courtesy of Governor Jay and First Lady Trudi Inslee via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Vanishing Kelp Forests | Earth Wise

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Bull kelp is the dominant species in offshore kelp forests north of Santa Cruz, California along the west coast of North America.  Bull kelp has similar physical structures to terrestrial plants; it anchors to the ocean floor with root-like structures called holdfasts, and has stem-like structures called stipes from which leaf-like blades stretch out through the water, absorbing nutrients and sunshine.

These giant seaweeds form lush underwater forests in northern California’s coastal waters and have long provided critical habitat for many species like salmon, crabs, and jellyfish.  But now, for much of the California coast, only a few patches of bull kelp remain.

A team from University of California Santa Cruz has studied satellite images of about 200 miles of coastline.  They found that starting in 2014, the area covered by kelp has dropped by more than 95%. 

The die-off was driven in part by an underwater heat wave that depleted nutrients in the water and made it harder for the kelp to grow.  Making matters much worse, populations of purple sea urchins, which eat kelp, have exploded in the region because of overfishing and other reductions in urchin predators such as sea otters.  The sea urchins eat kelp holdfasts, creating so-called urchin barrens where their destructive grazing has decimated kelp forests.

Bull kelp is a species at high risk of becoming endangered.  In coming decades, more marine heatwaves are expected.  These events as well as stronger El Niños will become more common and frequent with climate change.  Between these thermal events and the sea urchins, it will be difficult for kelp forests to survive.

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Ninety-five percent of bull kelp forests have vanished from 200-mile stretch of California coast

Photo, posted October 28, 2015, courtesy of Florian Graner/Green Fire Productions via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Forests And Climate Change | Earth Wise

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A carbon sink is anything that absorbs more carbon from the atmosphere than it releases.  Examples of carbon sinks include the ocean, soil, and plants.  In contrast, a carbon source is anything that releases more carbon into the atmosphere than it absorbs.  Volcanic eruptions and burning fossil fuels are two examples.

Forests are among the most important carbon sinks.  Trees remove carbon from the air and store it in their trunks, branches, and leaves, and transfer some of it into the soil.  But in many regions, deforestation, forest degradation, and the impacts of climate change are weakening these carbon sinks. As a result, some climate activists advocate for large-scale tree-planting campaigns as a way to remove heat-trapping CO2 from the atmosphere and help mitigate climate change. 

But according to a new study recently published in the journal Science, planting new trees as a substitute for the direct reduction of greenhouse gas emissions could be a pipe dream.  While planting trees is easy, inexpensive, and can help slow climate warming, the ongoing warming would be simultaneously causing the loss of other trees.  Instead, the research team says it makes more sense to focus on keeping existing forests healthy so they can continue to act as carbon sinks, and to reduce emissions as much as possible and as quickly as possible.        

But keeping forests healthy will require a paradigm shift in forest management.  Instead of trying to maintain forests as they were in the 20th century, the research team says forests need to be managed proactively for the changes that can be anticipated. 

One thing is clear: We cannot plant our way out of the climate crisis.

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Forests and climate change: ‘We can’t plant our way out of the climate crisis’

Photo, posted August 9, 2015, courtesy of Nicholas A. Tonelli via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Blue Carbon Credits | Earth Wise

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Carbon credits have been around since the late 1990s.  The idea is to offset carbon emissions from some carbon emitting activity – anything from a wedding in California to a factory operating in Minnesota – by buying carbon credits earned from a carbon-absorbing activity, such as planting trees in the Amazon.

Blue carbon credits are credits earned by increasing the carbon stored in coastal and marine ecosystems. Coastal ecosystems such as mangroves, tidal marshes, and seagrass meadows in fact sequester and store more carbon per unit area than terrestrial forests and are increasingly being recognized for their important role in mitigating climate change. 

Blue carbon credit awards have to date been relatively few and far between and have mostly been granted for mangrove restoration efforts.  But mangrove projects are now ramping up dramatically in scope.  Scientists are working hard to analyze the amount of carbon in other ecosystem types – seagrasses, salt marshes, seaweeds, and seafloor sediments – so that these systems can also enter the carbon credit market.

Over the past 20 years, conservation scientists have spread over 70 million seeds in the bays of Virginia to restore over 9,000 acres of seagrass meadows that were devastated by disease in the 1930s.  The restored meadows are absorbing nearly half a ton of CO2 per acre. 

The rules to allow for blue carbon credits are recent and evolving, which is a big deal. The market may currently be small, but it is growing exponentially.  But as important as carbon credits are, it is still paramount to decarbonize before turning to offsets for existing emissions.

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Why the Market for ‘Blue Carbon’ Credits May Be Poised to Take Off

Photo, posted July 2, 2009, courtesy of Nicolas Raymond via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Turning Wood Into Plastic | Earth Wise

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Plastic pollution is particularly pernicious because plastics can take hundreds of years to degrade in the environment.  For this reason, researchers across the globe search for ways to shift from petrochemical plastics to ones that are biodegradable.

Producing biodegradable plastics is challenging both from the standpoint of the methods needed and from the results obtained.  Producing them often requires toxic chemicals and can be very expensive.  The materials that emerge often do not have the durability and strength of conventional plastics and can be unstable when exposed to moisture.

Researchers at the Yale School of the Environment have developed a process of decomposing the porous matrix of natural wood into a slurry that can be formed into a biodegradable plastic.  The material shows high mechanical strength, stability when holding liquids, and is resistant to the effects of ultraviolet light.  Along with all these favorable properties, the material can be recycled or safely biodegraded in the natural environment.

The slurry mixture is created by taking wood powder – a processing residue usually discarded in lumber mills – and deconstructing it with a biodegradable and recyclable solvent.  The resulting mixture has a high solid content and high viscosity and can be casted and rolled without breaking.

The researchers conducted a comprehensive life cycle assessment to test the environmental impacts of the bioplastic compared with conventional plastics.  Sheets of it were buried in soil and observed to fracture after two weeks and completely degrade after three months.  The material can also be broken back down into the slurry by mechanical stirring.

The remaining topic to investigate is the potential impact on forests if the manufacturing of this bioplastic is scaled up.

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Turning wood into plastic

Photo, posted October 12, 2016, courtesy of the US Forest Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Collapse of Northern California Kelp Forests | Earth Wise

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For thousands of years, thick canopies of kelp formed an underwater forest spanning the coast of Northern California.  Kelp is the cornerstone of a rich subtidal community, providing food and habitat for all sorts of marine creatures.  But in recent years, a shocking transformation has occurred.  Satellite imagery reveals that the area covered by kelp forests off the coast of Northern California has declined by more than 95%.  Only a few small, isolated patches remain.  

In a new study, researchers at the University of California Santa Cruz found that the kelp forest decline was an abrupt collapse as opposed to a gradual decline. 

According to the study, which was recently published in the journal Communications Biology, kelp forests north of San Francisco were resilient to warming events in the past, like El Niños and marine heatwaves. But the decline of a key sea urchin predator – the sunflower sea star – from sea star wasting disease caused the kelp forests’ resiliency to plummet.  Sea urchins are voracious consumers of kelp.     

But it was a series of events – not just the sea urchins – that combined to decimate the Northern California kelp forest.   A marine heatwave that became known as “the blob” developed in 2014 and moved down the West Coast in 2015.  Around the same time, a strong El Niño event developed and brought warmer water up the coast from the south.  The warming ocean waters combined with the ravenous sea urchin population resulted in the dramatic decline of kelp. 

According to researchers, the prospects for a Northern California kelp forest recovery remain poor unless sea urchin predators return to the ecosystem. 

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The collapse of Northern California kelp forests will be hard to reverse

Photo, posted August 13, 2019, courtesy of Sara Hamilton of OSU College of Science via Flickr.

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