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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.

Carbon Dioxide Levels Higher Again | Earth Wise

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The National Oceanic and Atmospheric Administration reported that carbon dioxide levels measured in May at the Mauna Loa Observatory reached a value of 421 parts per million.  This is 50% greater than pre-industrial levels and is in a range not seen on earth for millions of years.

Before the Industrial Revolution, CO2 levels fairly steadily measured around 280 parts per million, pretty much for all 6,000 years of human civilization.  Since the Industrial Revolution began in the 18th century, humans have generated an estimated 1.5 trillion tons of CO2 pollution, much of which will continue to warm the atmosphere for thousands of years.

The present levels of carbon dioxide are comparable to those of an era known as the Pliocene Climatic Optimum, which took place over 4 million years ago. 

The bulk of the human-generated carbon dioxide comes from burning fossil fuels for transportation and electrical generation, from cement and steel manufacturing, and from the depletion of natural carbon sinks caused by deforestation, agriculture, and other human impacts on the natural environment.

Humans are altering the climate in ways that are dramatically affecting the economy, infrastructure, and ecosystems across the planet.  By trapping heat that would otherwise escape into space, greenhouse gases are causing the atmosphere to warm steadily, leading to increasingly erratic weather episodes ranging from extreme heat, droughts, and wildfires, to heavier precipitation, flooding, and tropical storm activity.

The relentless increase of carbon dioxide measured at Mauna Loa is a sober reminder that we need to take serious steps to try to mitigate the effects of climate change.

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Carbon dioxide now more than 50% higher than pre-industrial levels

Photo, posted December 20, 2016, courtesy of Kevin Casey Fleming 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.

Climate Change And The Next Pandemic | Earth Wise

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As the planet continues to heat up, animals big and small are moving towards the poles to escape the heat.  According to researchers, these animals are likely to come into contact with other animals that they normally wouldn’t, and are likely to relocate to regions with large human populations.  These factors create opportunities for pathogens to get into new hosts, which dramatically increases the risk of a viral jump to humans.  Climate change could lead to the next pandemic.      

An international research team led by scientists at Georgetown University recently made this connection between climate change and viral transmission.  In the study, which was recently published in the journal Nature, researchers conducted the first comprehensive assessment of how climate change will restructure the global mammalian virome.  Their work focused on geographic range shifts. 

As animals eccounter other animals for the first time, the study projects that they will share thousands of viruses.  And as animals increasingly move into the same areas as humans, there will be greater opportunities for these viruses to jump to humans.  The research team says that the impact on conservation and human health could be alarming as viruses jump between species at unprecedented rates. 

In our warming world, much of this process may unfortunately already be underway.  And efforts to reduce greenhouse gas emissions may not be enough to stop these events from unfolding. 

According to the study, climate change will become the biggest upstream risk factor for disease emergence, eclipsing deforestation, industrial agriculture, and the wildlife trade.  Pairing wildlife disease surveillance with real-time studies of environmental change may be part of the solution to predicting and preventing the next pandemic. 

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Climate change could spark the next pandemic, new study finds

Coronavirus and Climate Change

Photo, posted October 16, 2014, courtesy of Shawn Thomas / NPS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Forest Loss | Earth Wise

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India is one of the most biodiverse countries in the world.  An estimated 47,000 plant species and 89,000 animal species can be found in India, with more than 10% of each thought to be on the list of threatened species. 

India is also among the top ten countries in the world in terms of total forest coverage.  According to Indian government data, the total forest and tree cover in India is 312,000 square miles, which is 24.62% of the geographical area of the country.

However, forest loss in India has been a problem for many decades driven largely (researchers thought) by land use change.  But it turns out that climate change may also have been contributing to forest loss, and its impact is projected to become an even bigger problem in the coming years. 

In the first ever national-scale study of the relationship between forest loss and rainfall and temperature trends in India, researchers from the University of Reading in the U.K. found that climate change may have contributed to large declines in forest since the turn of the century.

The study, which was recently published in the journal Global Change Biology, found far greater forest losses were observed where and when the climate was changing most rapidly.  Decreases in rainfall had the strongest impact on forest loss. 

These findings exacerbate concerns about the already-worrying levels of deforestation in the country, and contradict official reports that have shown relatively small decreases in forest coverage in recent years. 

The research team warns that rapid changes to the climate in some regions will require targeted preservation action to reduce the risk to biodiversity in India. 

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Indian forest loss ‘worse than feared’ due to climate change

Photo, posted January 20, 2013, courtesy of Dicky Broadhurst / Frontier Official via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Record Levels Of Deforestation In The Amazon | Earth Wise

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The Amazon rainforest is the largest rainforest in the world, covering more than 2.5 million square miles.  It’s home to 10% of all known species in the world.  The Amazon rainforest’s biodiversity is so rich that scientists are still discovering new plant and animal species today.  

The Amazon rainforest absorbs huge amounts of carbon dioxide from Earth’s atmosphere, making it a key part of mitigating climate change.  The vast rainforest acts as what’s known as a carbon sink.  Simply put, a carbon sink is anything that absorbs more carbon from the atmosphere than it releases.  But as trees in the Amazon disappear, so does the ability of the rainforest to absorb carbon dioxide.

Deforestation of the Amazon rainforest remains a major problem.  According to satellite data from the Brazilian government, the number of trees cut down in the Brazilian Amazon in January far exceeded deforestation figures for the same month last year.  Approximately 166 square miles of land was deforested in January alone, which is five times greater than what was lost in January, 2021.

Cattle ranching – both for beef and for leather – remains the leading cause of deforestation in the Amazon rainforest.  Trees in the Amazon are also cut down for their wood, as well as to clear the land in order to grow food crops, such as soy, sugar, and oil palm. 

Many companies have pledged to achieve “net zero” deforestation in their supply chains over the years, but most have not lived up to the commitment. 

Deforestation is not only a major driver of climate change, but it’s also the leading cause of species extinction.  Preserving the Amazon rainforest is vital. 

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Amazon deforestation: Record high destruction of trees in January

Greenpeace calls on fast food giants to take a stand against Bolsonaro’s Amazon destruction

Hundreds of Companies Promised to Help Save Forests. Did They?

Photo, posted July 14, 2018, courtesy of Alexander Gerst via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Synthetic Palm Oil | Earth Wise

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Palm oil is the world’s cheapest and most widely used vegetable oil.  Producing it is a primary driver of deforestation and biodiversity loss in the tropics.  In Borneo, for example, oil palm cultivation has accounted for more than half of all deforestation over the past two decades.   More than one million square miles of biodiversity hotspots could be threatened by oil palm cultivation, which could potentially affect more than 40% of all threatened bird, mammal, and amphibian species.

Today, the world consumes over 70 million tons of palm oil each year, used in products ranging from toothpaste and oat milk to biodiesel and laundry detergent.

Given this situation, there are now multiple companies developing microbial oils that might offer an alternative to palm oil while avoiding its most destructive impacts.

A company called C16 Biosciences is working on the problem in Manhattan, backed by $20 million from a Bill Gates’ climate solutions investment fund.  A California-based startup called Kiverdi is working to manufacture yeast oil using carbon captured from the atmosphere. 

Xylome, a Wisconsin-based startup is working to produce a palm oil alternative that they call “Yoil”, produced by a proprietary strain of yeast.  The oil from the yeast strain is remarkably similar to palm oil. 

The challenge is to be able to produce microbial oils at large scale and at a competitive price.  Unless valuable co-products could be manufactured along with the oil, it may be difficult to compete with palm oil.  Without regulatory pressures and willingness of consumers to pay more, it may be difficult to replace palm oil in many of its applications.

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Can Synthetic Palm Oil Help Save the World’s Tropical Forests?

Photo, posted December 9, 2008, courtesy of Fitri Agung via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Kenya’s Tana River Basin | Earth Wise

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The Tana River is the longest river and most important waterway in Kenya.  It flows 620 miles from its headwaters in the Abderdare mountain range and Mount Kenya to the Indian Ocean.  The Tana River produces approximately half of the country’s electricity, and supplies Nairobi, the capital of Kenya, with 80% of its water.   

According to the United Nations Environment Programme, eight million people live along the Tana River, where coffee, tea, corn and other crops are grown for export, and fishing and cattle grazing help produce food for large portions of the country’s population. 

But the long-term ability of the river to provide these and other essential services is increasingly under threat due to many factors, including pollution, soil erosion, deforestation, and poor land use practices.   

Climate change is also complicating matters.  According to new research from the University of East Anglia, many species within the Tana River Basin will be unable to survive if global temperatures continue to rise at the current pace.  However, the study, which was recently published in the journal PLOS ONE, also found that many of these species could be saved if the world could meet the climate goals of the Paris Agreement. 

Globally, climate and land use changes are the two biggest threats to biodiversity.  According to researchers, 36% of the Tana River Basin has already been converted to agriculture. 

The research team says stronger commitments on climate change are needed from global leaders.  The climate and biodiversity crises can only be solved with urgent action to reduce global greenhouse gas emissions. 

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The impact of climate change on Kenya’s Tana river basin

Economics of Ecosystem Services of the Tana River Basin

Photo, posted August 19, 2010, courtesy of Luigi Guarino via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Importance Of Double-Cropping | Earth Wise

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In agriculture, double-cropping is the practice of growing two or more crops or commodities on the same piece of land in the same calendar year.  In Brazil, grain production has increased more than fourfold between 1980 and 2016.  The country now stands as the world’s largest exporter of soybeans and the second largest exporter of corn.  There were two primary drivers of this increase in food production: cropland expansion and double-cropping. 

Cropland expansion has long been recognized as a key driver behind the increase in Brazil’s agricultural output.  But cropland expansion is also a threat to biodiversity by driving habitat loss, deforestation, and an increase in carbon emissions. 

A new study recently published in the journal Nature Food quantified for the first time the impact that double-cropping had on helping Brazil achieve its tremendous growth in grain production.  The international research team examined data from three key agricultural regions in Brazil: the Centre-West, Southeast-South, and Matopiba region.  These three regions accounted for 79% of soybean production and 85% of  corn production in 2016. 

Soybean fields account for more than one third of Brazil’s cropland.  While the increase in soybean production was largely a result of cropland expansion, the increase in corn production was a result of double-cropping. 

Between 2003 and 2016, the study found that double-cropping in Brazil offset the equivalent of approximately 190 million acres of arable land for corn production. (This is more than twice the annual harvested area of corn in the United States).

Double-cropping represents a way to produce more food without clearing more land. 

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The impact of double-cropping

Photo, posted July 15, 2009, courtesy of Daniel Bauer 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.

Not All Trees Cool The Planet | Earth Wise

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A new study from Clark University has found that deforestation does not always contribute to planetary warming, as is generally assumed.  The researchers have found that there can be places where removing trees actually cools the planet.

Forests soak up carbon dioxide from the air and store it in the trees themselves and in the soil.   This process is important for slowing the accumulation of greenhouse gases in the atmosphere.

The new research focuses on a different effect that forests have on climate.  They are darker than other surfaces, which causes them to absorb more sunlight and retain heat.  This is known as the albedo effect.

In most places, the absorption of carbon outweighs the albedo effect and forests help cool the planet.  But there are some locations, including the Intermountain and Rocky Mountain West, where more forest actually leads to a hotter planet when both processes are taken into account.  State-of-the-art satellite remote sensing allowed the researchers to quantify the effects of forest loss in the United States.

The upshot of this research is that large-scale tree-planting initiatives, such as Canada’s 2Billion Trees Initiative and the Nature Conservancy’s Plant a Billion Trees campaign need to make sure to put the right trees in the right places.

Every year, about a million acres of forest are being converted to non-forest across the lower 48 states as a result of suburban and exurban expansion and development.   It is important to take into account the albedo effect in trying to replace the climate-cooling capabilities of these disappearing forests by planting more trees.

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Clark geographer Christopher Williams: More trees do not always create a cooler planet

Photo, posted June 5, 2017, courtesy of Todd Petrie via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Non-Native Plants And Insect Decline | Earth Wise

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Global insect populations have been in decline since the beginning of the 20th century.  The decline accelerated during the 1950s and 1960s, and it has reached alarming levels during the past 20 years.

The causes of plummeting insect populations include habitat destruction, deforestation, climate change, light pollution, and the rise of industrial agriculture.  This so-called insect apocalypse is being mirrored by a bird Armageddon because so many bird species depend on insects for their diets.

A still controversial, but increasingly likely factor in the decline of insect populations is the spread of non-native plants in agriculture, agroforestry, and horticulture.  A recent study published in the journal Ecological Entomology presents recent data supporting the proposition that the widespread displacement of native plants is a key cause of insect declines. 

Many insects depend on a limited number of plants for survival.  In many cases, insects’ diets are restricted to a single plant family.  When native host plants dwindle or disappear from an area, the population of insects that depend on those plants shrinks.

There are examples of insects that adopt introduced plants as food sources, such as silver-spotted skipper butterfly larvae feeding on invasive kudzu in the eastern U.S.  But generally, the widespread incursion of non-native plants is harmful to native insect populations.

Non-native plants are especially popular for horticulture.  Millions of acres of potential insect habitat have been transformed into food deserts for native insects.  The authors of the recent study recommend that Americans should extensively include native plants in their yards to help preserve insect diversity.

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How Non-Native Plants Are Contributing to a Global Insect Decline

Photo, posted May 2, 2004, courtesy of Bernard Spragg via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Restoring Tropical Forests | Earth Wise

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Tropical forests store more than half of the world’s above-ground carbon.  For this reason, deforestation is one of the greatest threats to global climate regulation.   Once forests are degraded through partial clearing and agricultural conversion, they are often perceived as no longer having much ecological value even though degraded forests still provide important ecosystem services despite no longer storing as much carbon.

As a result, once forests have been degraded, they tend to be seen as prime candidates for full conversion to agricultural plantations.   But this is not actually the case.

An international team of scientists, including researchers from Arizona State University’s Center for Global Discovery and Conservation Science, has provided the first long-term comparison of above-ground carbon recovery rates between naturally regenerating and actively restored forests in Southeast Asia.

First of all, the research shows that allowing forests to regenerate naturally results in significant amounts of restored above-ground carbon storage.  It is definitely worthwhile to allow forests to recover rather than giving up on them and putting the land to other uses.

But more importantly, the researchers found that forest areas that undergo active restoration recover their carbon-storing ability 50% faster than naturally recovering forests.

Restoration methods include planting native tree species and thinning vegetation around saplings to improve their chances of survival.   

These findings suggest that restoring tropical forests is a viable and highly scalable solution to regaining lost carbon stocks on land.  What is needed is sufficient incentive to engage in active forest restoration.  The current price of carbon is not sufficient to pay for restoration, but as the climate crisis intensifies, this is likely to change.

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Tempe to Hawaii: ASU professors teach Hawaiian youth about coral reef conservation

Photo, posted May 22, 2008, courtesy of Eric Chan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Increasing Air Pollution | Earth Wise

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According to researchers from the University of Exeter, half of the world’s population is exposed to increasing air pollution despite global efforts to improve air quality.  The study, which was completed in conjunction with the World Health Organization, suggests that air pollution represents a major and growing threat to human health. 

For the study, which was recently published in the journal Climate and Atmospheric Science, the researchers reviewed global air quality trends between 2010 and 2016.  The research team examined those findings against a backdrop of global policies to reduce air pollution.  The researchers used ground monitoring data and satellite data to develop yearly air quality profiles for individual countries and regions. 

The scientists focused on fine particulate matter, which is a mixture of solid particles and liquid droplets found in the air.  Some of the particles, like dust, soot, or smoke, are large enough to be seen by the naked eye.  Others are so small that they can only be seen using a microscope.  Inhaling fine particulate matter can cause all sorts of health issues, including asthma, respiratory inflammation, and even promote cancer. 

For much of the world’s population, the consequences of polluted air are more deadly than war, violence, and many diseases.  According to the World Health Organization, more than four million deaths every year can be attributed to outdoor air pollution.  Some of the major sources of air pollution include coal-fired power plants, agriculture, transportation, and deforestation. 

The study found that low and middle income countries experience the highest burden of air pollution around the world, with the largest concentrations found in central and southeastern Asia.

More long term policies are needed to curb this growing threat to public health. 

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Half of the world’s population exposed to increasing air pollution

Photo, posted August 2, 2019, courtesy of Ron Reiring via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Disappearing Rainforests | Earth Wise

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Forest loss is a major contributor to climate change, and it is continuing at a rapid pace.  The tropics lost about 30 million acres of tree cover in 2019, a third of which was within humid tropical primary forests, which are especially important for biodiversity and carbon storage.  To put that loss in a human-scale perspective, it is the equivalent of losing a football field of primary forest every six seconds for the entire year.

The losses last year were 2.8% higher than in the previous year, and these losses have continued over the past 20 years despite worldwide efforts to halt deforestation.  

Brazil single-handedly accounted for over a third of all global loss of humid tropical primary forests. Bolivia experienced record-breaking tree cover loss due to fires.  The losses in its forests were 80% greater than in any previous year.  The fires were often started by people who were trying to clear land for agriculture but had the fires go out of control. Several countries in Africa’s Congo Basin also experienced sustained or worsening forest loss. 

Indonesia, often the focus of the world’s attention for its deforestation activities, actually saw a 5% reduction in primary forest loss in 2019.  It was the third year in a row for lower losses.  The now-permanent moratorium on clearing forests for oil palm plantations and logging seems to be working.

Going forward, the coronavirus pandemic poses additional threats to the world’s forests in the near future.  There may be a tendency to sacrifice forests in pursuit of economic recovery, which will only lead to future complications for the health and livelihoods of millions of people around the world.

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We Lost a Football Pitch of Primary Rainforest Every 6 Seconds in 2019

Photo, posted February 7, 2011, courtesy of Chad Skeers via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Planting Trees and Climate Change | Earth Wise

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Forests are among the most important natural carbon sinks.  Trees remove carbon from the air and store it in their trunks, branches, and leaves, and transfer part of it into the soil.  But in some regions, these natural carbon sinks are starting to weaken due to deforestation, forest degradation, and the impacts of climate change.  This problem has led some climate mitigation projects to focus on increasing the overall number of trees on the planet. 

But, according to a paper recently published in the journal Science, “we can’t plant our way out of climate change.”  That’s the simple message from Restoration Ecologist Karen Holl and University of São Paulo Professor Pedro Brancalion to anyone who thinks planting one trillion trees will reverse the effects of climate change.  They say planting more trees is only one piece of the puzzle.  Any initiatives like 1t.org or the Trillion Tree Campaign must be done carefully and be accompanied by commitments to long-term management.

Tree plantings can provide many environmental benefits, including improving water quality, biodiversity, and increasing shade.  But trees can sometimes have undesirable impacts, such as harming native species and ecosystems or reducing water availability, depending on where and how the trees are planted.

The authors suggest four principles that should guide forest enhancement initiatives: reduce forest clearing and degradation, balance ecological and social goals, view tree plantings as one part of a multifaceted solution, and plan, coordinate and monitor the work. 

While tree plantings can clearly be part of the solution, slowing the pace of climate change requires a comprehensive approach that must start with burning less fossil fuels.

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Challenges in tree-planting programs

Planting trees is no panacea for climate change

Photo, posted December 1, 2019, courtesy of Akuppa John Wigham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Tropical Forests As Carbon Sinks | Earth Wise

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Tropical forests are an important part of the global carbon cycle because they take up and store large amounts of carbon dioxide.  Because of this, deforestation in the Amazon and other tropical forests is a major contributor to the growing CO2 levels in the atmosphere.

Therefore, climate models need to accurately take into account the ability of tropical forests to sequester carbon.  It turns out that this is not such a simple matter.  A new study by the International Institute for Applied Systems Analysis sought to determine how much detail about tropical forests is needed in order to make valid assumptions about the strength of forest carbon sinks.

They looked at the role of both biotic factors – differences between plant species that are responsible for capturing more or less carbon from the atmosphere – and abiotic factors – local environmental factors like soil properties that also influence carbon sink strength.

It is generally assumed that more diverse forest communities capture available resources more efficiently as a result of complementary characteristics and preferences of certain species to specific conditions.  Factors like soil texture and chemistry are also important.  In general, the results show that abiotic and biotic factors interact with one another to determine how much carbon can be stored by the ecosystem.

Traditional projections of the role of tropical forests in storing carbon mostly rely on remote sensing techniques that integrate over large spatial areas.  The new study shows that there can be large differences in the carbon storing ability of tropical forests and that more detailed models are needed to produce more accurate projections.

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Shedding light on how much carbon tropical forests can absorb

Photo, posted July 17, 2014, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Forest Regrowth In The Amazon | Earth Wise

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The Amazon is the largest tropical rainforest in the world.  It covers an area approximately equal in size to the lower 48 states, and is home to an estimated 10% of the world’s biodiversity and 15% of its freshwater.  These so-called “lungs of the planet” provide many important global ecological services, including carbon storage, and regulating air quality and climate.

Deforestation in the Amazon exploded in the 1970s and remains one of its biggest threats today.  Since the 1970s, more than 20% of the Amazon rainforest has been cleared.  Cattle ranching, soy and palm plantations, logging, and climate change are some of the biggest drivers of deforestation.  

Now, according to a new study recently published in the journal Ecology, the regrowth of Amazonian forests following deforestation may happen more slowly than previously thought.  These findings could have significant impacts on climate change predictions as the ability of forest regrowth in the Amazon – so-called secondary forests – may have been overestimated.  The research, which was conducted in Bragança, Brazil and includes two decades of forest monitoring, reveals that climate change and the wider loss of forests could be hampering regrowth.    

After 60 years of regrowth, the research team found that secondary forests only held 40% of the carbon when compared with forests undisturbed by humans.  Secondary forests also take less carbon from the atmosphere during periods of drought, and climate change is increasing the number of drought-years in the Amazon.  (During their 20 years of monitoring, the researchers also found biodiversity levels in secondary forests were only 56% of those seen in undisturbed forests). 

More long-term studies are needed to better understand the impacts of reforestation efforts.  

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Amazon forest regrowth much slower than previously thought

Photo, posted September 6, 2009, courtesy of Nao Lizuka via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Out-Migration And Reforestation

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A challenging global trend is that of deforestation in developing countries.  But there are places where the opposite trend is happening.  Nepal is one such place.

According to satellite imaging, in 1992 forest covered 26% of Nepal.  As of 2016, that number was 45%. 

To some extent, the forest regrowth was a result of policy changes from about three decades ago, when the government began removing management authority from bureaucrats and shifting it to local communities across the country.  This local management helped to reduce illegal logging and many local villages undertook tree-planting campaigns.

But perhaps a bigger factor at play is human migration.  In recent decades, millions of Nepalis have left the country to work in the Persian Gulf, Southeast Asia, and elsewhere.  The out-migrants wire money home and meanwhile, families left behind rely less on forest products or abandon farmland, aiding reforestation.  A 2018 study showed that the areas with the highest out-migration experience, on average, had the most forest recovery.

Globally, migration has important impacts on forests, but not always positive ones.  In many countries, forests seem to recover as people leave rural areas to work elsewhere.  El Salvador, for example, has seen a rebound of its forests as many of its rural residents move to cities or even to the United States. But in Guatemala and Nicaragua, the return of migrants bringing money they have earned overseas has led to an expansion of cattle ranching that has harmed forests.

The global relationship between migration and forests is a complicated one that depends on whether the migration is one-way or “circular” (meaning that the migrants eventually return) and how returning migrants make use of their earnings from abroad.

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In Nepal, Out-Migration Is Helping Fuel a Forest Resurgence

Photo, posted September 30, 2018, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Importance Of The Amazon Rainforest Fires

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The Amazon rainforest covers extensive parts of Brazil, Peru, Colombia, and small parts of six other countries.  It is the largest rainforest in the world and is instrumental in driving the weather and climate in South America.

The raging wildfires in the Amazon rainforest are a source of great concern.  The Amazon is always prone to wildfires during the dry season in South America, but the extent and number of fires this year cannot be attributed simply to drought.  The surge in fires has come from illegal deforestation by loggers and farmers, who are using the cleared-out land for cattle ranching.

Rainforests produce consistently high amounts of rainfall throughout the year by pulling water from the soil and then releasing it into the atmosphere.  The Amazon rainforest essentially makes it rain in South America. 

Over time, the forest plays a crucial role in cycling carbon out of the atmosphere by turning it into biomass.  The Amazon jungle sucks up as much as a quarter of the planet’s atmospheric carbon dioxide.

Pristine rainforest burns less frequently and less intensely than cleared and recovering forest.  As more and more of the Amazon rainforest is deforested, it becomes more likely to burn each year.

The major disruption of the water dynamics in South America has the potential to not only drive the weather in South American countries but even potentially influence natural resources like snow packs in the Northern Hemisphere.

The skies of Sāo Paulo, Brazil’s financial hub have been dark at midday because of the Amazon fires.  This is like having a fire in California and seeing the smoke in Boston.  The Amazon rainforest fires are a big problem for the whole world.

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The Amazon Rainforest has been burning for weeks. Here’s why that matters.

Photo, posted August 21, 2019, courtesy of NASA Goddard Space Flight Center 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...)