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A hidden global water crisis

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A major crisis is unfolding beneath our feet: Earth’s continents are losing freshwater at unprecedented rates.  Recent satellite data has uncovered a hidden global water crisis, suggesting the problem is more urgent than previously thought. 

The study, which was led by researchers from Arizona State University, found that since 2002, climate change, unsustainable groundwater use, and extreme droughts have driven dramatic declines in the planet’s freshwater reserves.

The research team found that drying areas on land are expanding at a rate roughly twice the size of California every year.  Additionally, the rate at which dry areas are getting drier now outpaces the rate at which wet areas are getting wetter, reversing long-standing hydrological patterns.   

Approximately 75% of the world’s population lives in countries that have been losing freshwater for more than two decades.  As the availability of freshwater dramatically shrinks, the global population continues to expand. 

The study, which was recently published in the journal Science Advances, identifies four continental-scale “mega-drying” regions, all located in the northern hemisphere, and warns of severe consequences for water security, agriculture, sea level rise, and global stability. 

The researchers identified the type of water loss on land, and for the first time, found that 68% came from groundwater.  Groundwater loss alone now contributes more to sea level rise than melting ice sheets. 

The findings stress the urgent need for sustainable water management, international cooperation, and global policies to slow groundwater loss.

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Satellites just revealed a hidden global water crisis—and it’s worse than melting ice

Unprecedented continental drying, shrinking freshwater availability, and increasing land contributions to sea level rise

Photo, posted January 16, 2012, courtesy of Kecko via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Record forest loss

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The world lost a record amount of forests last year.  The biggest factor for the unprecedented losses were wildfires that raged around the world.

According to the annual update by the University of Maryland and the World Resources Institute, pristine rainforests alone lost 17 million acres, which was nearly twice as much as in the previous year.  Overall, the world lost the equivalent of 18 soccer fields of forested land every minute last year.

Over time, agriculture has been the primary cause of forest losses, but last year, for the first time since record-keeping began, fires were the leading cause, accounting for nearly half of all the destruction.

With respect to the climate, wildfires emitted over 4 billion tons of greenhouse gasses, which is more than four times the amount generated by air travel in 2023.

Land clearing for agriculture, cattle farming, and other purposes was by no means in decline last year.  In fact, it rose by 14%, which was the sharpest increase in almost a decade.  This trend could permanently transform critical natural areas, unleashing large amounts of carbon, intensifying climate change, and fueling even more extreme fires.

Forests are a major contributor to the natural storing of carbon dioxide.  Intact tropical forests are especially effective at storing carbon.

Brazil has the largest area of tropical forest and it accounted for 42% of all tropical primary forest loss in 2024.  Fires fueled by the worst drought on record caused two thirds of that loss, more than a sixfold increase over the previous year.

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Global Forest Loss Hit a Record Last Year as Fires Raged

Photo, posted September 12, 2024, courtesy of the USDA Forest Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Polar bear population decline

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Researchers from the University of Toronto have directly linked the population decline in polar bears living in Canada’s Western Hudson Bay to climate change.  Between 1979 and 2021, the polar bear population in this region has declined by nearly 50%.

The monitoring data over this period shows that the average size of polar bears has declined, the size of cub litters has dropped, and cub survival rates are reduced.

The primary factor is the declining amount and duration of sea ice.  When there is less ice, bears have less feeding time and less energy overall.  The loss of sea ice means that bears spend less time hunting seals and more time fasting on land.  The lack of food leads to reduced reproduction, cub survival, and, ultimately, population decline. 

The average body mass of adult females has dropped by 86 pounds and of cubs by 47 pounds.  With shorter hunting periods and less food, mothers produce less milk.  Not only have cub litter sizes dropped over the monitoring period, but mothers are keeping their cubs longer because they are not strong enough to live on their own.  The bottom line is that the survival of cubs directly impacts the survival of the population.

Western Hudson Bay is considered to be a bellwether for polar bear populations globally.  It is one of the southernmost populations of polar bears and it has been monitored for a long time.  With the Arctic warming at a rate four times faster than the global average, polar bear populations in other Arctic regions are likely to be experiencing similar declines. 

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Polar bear population decline the direct result of extended ‘energy deficit’ due to lack of food

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

Earth Wise is a production of WAMC Northeast Public Radio

Shrinking polar ice

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Arctic sea ice has shrunk to near-historic lows during this Northern Hemisphere summer.  The minimum extent for the year occurred on September 11th.  Ice cover in the Arctic Ocean has been shrinking and thinning for more than 40 years.  The amount of frozen seawater in the Arctic goes up and down during the year as sea ice thaws and regrows between seasons.

This year, the minimal extent of sea ice shrank to 1.65 million square miles.  That’s about 750,000 square miles less than the average for late summer over the years between 1981 and 2010, representing a decrease of more than 30%.  The all-time low of 1.31 million square miles was actually set in 2012.  Sea ice coverage can fluctuate from year to year, but it has trended downward since it has started being tracked in the late 1970s.  The loss of sea ice has averaged about 30,000 square miles per year.

Sea ice extent has not only been shrinking; the ice has been getting younger and thinner.  Presently, the overwhelming majority of ice in the Arctic Ocean is first-year ice, which is thinner and less able to survive the warmer months.  There is far less ice that is three years or older.

Meanwhile, sea ice in the southern polar regions was also low this year.  In the sea around Antarctica, scientists are tracking near record-low sea ice at a time when it should have been growing extensively during the darkest and coldest months in the Southern Hemisphere.

Polar ice loss compounds polar ice loss.  The loss of sea ice increases heat in the polar regions, where temperatures have risen about four times more than the global average.

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Arctic Sea Ice Near Historic Low; Antarctic Ice Continues Decline

Photo, posted September 15, 2016, courtesy of Mario Hoppmann via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Satellites discovering penguins

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The loss of sea ice in Antarctica has forced emperor penguins to seek out new breeding grounds.  Some colonies have traveled more than 20 miles in search of stable ice.  Emperor females lay a single egg on a stretch of sea ice at the start of winter and males keep the eggs warm while the females go hunting for up to two months to bring back food for their hatchlings.

Emperor penguins are the tallest and heaviest of all living penguin species.  The loss of sea ice has led to unprecedented breeding failure in some emperor penguin colonies.  Emperor penguins are not threatened by hunting, habitat loss, or other human-caused problems, but the changing climate could be their undoing.

Emperor colonies are easy to spot from above.  The penguins are up to four feet tall and the droppings from large colonies stand out vividly against white snow.  A careful study of satellite imagery has revealed four previously unknown colonies of emperor penguins along the edges of Antarctica.  This is the first bit of good news about the penguins in quite a while.  The new discoveries, reported in the journal Antarctic Science, brings the total number of known colonies to 66.

The new discoveries are encouraging, but emperor penguins remain at risk from the warming climate.  Three of the four new colonies are small, with fewer than 1,000 birds.  So, the discovery does not have a big impact on the overall emperor penguin population.  The addition of the new colonies is overshadowed by the recently reported colony breeding failures resulting from early and rapid ice losses.

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Thousands of Emperor Penguins Discovered by Satellite

Photo, posted January 19, 2014, courtesy of Christopher Michel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Pesticides and beeswax

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Honey bee colonies in the United States have experienced annual population declines since 2006.  Commercial beekeepers have reported honey bee colony loss rates averaging 30% each winter, which is startling when compared to historical loss rates of just 10-15%.  According to the USDA, there are many factors contributing to this decline, including parasites, pests, diseases, pesticides, and a phenomenon called Colony Collapse Disorder, in which worker bees abandon a hive and leave behind the queen.

According to a new study by researchers from Cornell University, beeswax in managed honey bee hives contains a variety of pesticide, herbicide, and fungicide residues.  Because bees reuse wax over years, these harmful chemicals can accumulate inside hives, exposing current and future generations of bees to long-term toxicity. 

The study, which was recently published in the Journal of Veterinary Diagnostic Investigation, adds that humans may also be exposed to these pesticides through contaminated honey, pollen, and beeswax (which is used in certain soaps, lotions, and cosmetics).  However, the amounts in these products are unlikely to pose a major threat to human health.

Pesticides get into the beeswax when bees feast on the nectar and pollen of plants that have been treated with the chemicals. According to the researchers, understanding which contaminants are impacting domestic honey bee populations could help better protect them and other pollinators, including birds, bats, wild bees, and other insects.

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Pesticides detected in beeswax

Photo, posted November 22, 2008, courtesy of Andrew Rivett via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Groundwater loss

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Groundwater is the water found underground in the cracks and spaces in soil, sand, and rock.  It is held in aquifers and bubbles up naturally into springs, streams, and rivers, but also is pumped out for use by people.  Groundwater provides almost half the drinking water in the U.S. and is a main source of water for agriculture.

The world’s supply of groundwater is steadily declining.  The combination of climate change and human population growth is increasingly diminishing groundwater.

A study by the Desert Research Institute published in the journal Nature Communications has mapped the global permanent loss of aquifer storage capacity for the first time.  Computer modeling with advanced machine learning techniques has provided a detailed picture of the world’s groundwater situation.

The study found that global aquifer storage capacity is disappearing at a rate of 10 miles a year, about the size of 7,000 Great Pyramids of Giza.  The loss of groundwater storage is permanent, forever reducing the amount of water that can be captured and stored because the pumping of groundwater can cause the ground surface above to sink, collapsing the space where water can be stored.

About 75% of this subsidence is occurring over cropland and urban regions.  The United States, China, and Iran account for most of the global groundwater storage loss but many other places in the Middle East and Asia are experiencing significant groundwater withdrawal as well.

Most regions of the world do not have monitoring programs for groundwater pumping.  The study underscores the need to better understand this issue on a global scale and take appropriate action before it is too late.

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Scientists Map Loss of Groundwater Storage Around the World

Photo, posted August 7, 2015, courtesy of NRCS Oregon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Glacier Loss Day | Earth Wise

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Glaciers are sensitive indicators of climate change that respond to changes in both temperature and precipitation.  But they are not only affected by climate change, they also affect climate change.  As glaciers melt, they contribute to sea level rise, alter regional hydrology, and influence the global energy balance.

A group of glacier experts from the University of Innsbruck in Austria introduced a concept called “Glacier Loss Day” or GLD as a way to measure the annual mass balance of glaciers.  Mass balance is the difference between the amount of snow and ice that accumulates on a glacier and the amount that melts or sublimates.  If the mass balance is positive, the glacier is growing.  If the mass balance is negative, the glacier is shrinking.

GLD is the day during the year when the glacier has lost all the mass it gained during previous winter.  This is a similar concept to Earth Overshoot Day, which marks the date when humankind’s demand for ecological resources exceeds the amount the planet can regenerate during the year.

The Hintereisferner, a glacier in the Tyrolean Alps, has been monitored for more than 100 years and there are continuous records of its mass balance since 1952.  In 2022, the GLD on the Hintereisferner was measured on the 23rd of June.  In the two previous years, it was reached in the middle of August.  Even in years with large negative balances, such as 2003 and 2018, GLD did not occur until the end of July.

Every summer in the future may not be like 2022, but the trend is clear.  Climate change is taking its toll on glaciers.  Experts project that the Hintereisferner will lose half of its volume in the next 10 to 20 years.

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Glacier Loss Day indi­cates record break­ing glacier melt

Photo, posted July 20, 2023, courtesy of Pedro Szekely via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Record Polar Ice Melting | Earth Wise

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Sea levels are rising and ocean warming is responsible for the bulk of that rise.  As water heats up, it expands, which drives up sea levels.  But on top of that, global warming is melting the polar ice sheets, and that is leading to about a quarter of the world’s sea level rise. So far, polar melting has fueled about an inch of sea level rise, two-thirds from Greenland and one third from Antarctica.   According to scientists, by the end of this century, melting polar ice caps could raise sea levels between 6 and 10 inches.

The seven worst years for polar ice sheet melting have occurred during the past decade.  The worst year on record was 2019.  The loss in 2019 was driven by an Arctic summer heatwave, which resulted in record melting from Greenland, amounting to nearly 500 billion tons melted that year.  Antarctica lost 180 billion tons of ice that year, mostly due to melting glaciers and record melting from the Antarctic Peninsula.

Ice losses from Greenland and Antarctica can now be reliably measured by satellites in space.  A team of researchers led by Northumbria University in the UK has combined 50 satellite surveys taken between 1992 and 2020.

They have found that the Earth’s polar ice sheets have lost over 8,000 billion tons of ice over that time period.  That much ice corresponds to an ice cube roughly 12 miles high.

The satellite technology is now at the stage where the ice sheet status can be continuously updated.  Such monitoring is critical to predict the future behavior of the ice sheets and provide risk warnings of the dangers that coastal communities around the world will face.

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Polar ice sheet melting records have toppled during the past decade

Photo, posted December 19, 2017, courtesy of Jasmine Nears via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

An Accelerating Rate Of Mountain Forest Loss | Earth Wise

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Mountains contribute disproportionately to the Earth’s diversity of life.  While mountains account for about 25% of the land area on Earth, they are home to more than 85% of the mammal, bird, and amphibian species.  But alarmingly, forested mountain habitats in which these species live are disappearing, and they appear to be disappearing at an accelerating rate.

According to a new study recently published in the journal One Earth, more than 300,000 square miles of mountain forest has been lost globally since 2000, which is an area larger than the state of Texas. 

A research team led by scientists from Leeds University in the United Kingdom and the Southern University of Science and Technology in China tracked changes in mountain forests on an annual basis from 2001 to 2018.  The researchers found logging to be the biggest driver of mountain forest loss, responsible for 42% of the overall decline.  This is followed by wildfires at 29%, so-called “slash-and-burn” cultivation at 15%, and permanent or semi-permanent agriculture at 10%.  Significant losses occurred in Asia, Africa, Europe, Australia, and South America, but not in Oceania or North America.

The research team also found that the rate of mountain forest loss seems to be accelerating: in fact, the annual rate of loss increased 50% from 2010-2018 when compared with 2001-2009.

While developing additional forest protection strategies and interventions is critical, the researchers emphasize the importance of also considering food production, livelihoods, and human wellbeing in any new measures.

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Mountain forests are being lost at an accelerating rate, putting biodiversity at risk

Photo, posted December 6, 2018, courtesy of Lance Cheung / USDA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

An Agreement To Protect Biodiversity | Earth Wise

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The UN Biodiversity Conference in Montreal in December concluded with a historic deal aimed at stemming the rising tide of extinctions.  Nearly 200 countries signed on to the agreement to protect 30% of the Earth’s land and sea by the end of this decade.

Part of the agreement also pledges that countries will reduce fertilizer runoff from farms by 50%, reduce the use of harmful pesticides by 50%, and stem the flow of invasive species. 

Of course, all of these promises are only words unless they are backed up by actions and actions cost money.  The agreement promises to direct $200 billion a year towards biodiversity by the end of this decade.  Wealthy countries were urged to provide $100 billion a year to fund the actions of poorer countries, but they resisted the pressure.  Eventually, they did agree to send $30 billion a year to developing countries by 2030.

It is a significant step forward to establish clear targets for stopping biodiversity loss.  However, the ultimate success of the pact will depend on the willingness of countries to cooperate and compromise.

According to UN estimates, about a million species across the globe face extinction as a result of rising temperatures, air and water pollution, invasive species, and habitat loss due to development.   At present, only 16% of land and 8% of the oceans are within protected areas. 

The UN Environment Program stated that “for far too long humanity has paved over, fragmented, over-extracted, and destroyed the natural world on which we all depend.  Now is our chance to shore up and strengthen the web of life, so it can carry the full weight of generations to come.”

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In Historic Deal, Countries Agree to Protect 30 Percent of Earth to Halt Biodiversity Loss

Photo, posted August 13, 2015, courtesy of Andrew H via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Oxygen Loss In Lakes | Earth Wise

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Researchers from Cornell University and Rensselaer Polytechnic Institute have found that the continual warming in the world over the past 25 years has been reducing the amount of oxygen in many lakes.

Data from more than 400 lakes – mostly in the United States – shows that lakes with dissolved oxygen losses strongly outnumber those with gains.  Overall, the researchers found that the amount of low oxygen water is increasing by 0.9% to 1.7% per decade on average  and the volume of lake water lacking oxygen has increased by more than 50% from 25 years ago.

In the summer, lake surfaces may be about 70 degrees while the lake bottom may be about 40 degrees.  The colder water is denser than the warmer water which causes resistance to the layers mixing.  It is akin to having oil and vinegar in a cruet.  This is known as stratification.   The result is that oxygen from the atmosphere is prevented from replenishing dissolved oxygen in deep waters.  This is a normal seasonal phenomenon.

However, with winter ending sooner than it used to, seasonal stratification is starting earlier and ending later. As warming continues, it is likely that there will be an increasing number of oxygen-depleted lakes in the future.

Oxygen deprivation in water can lead to hypoxia (low oxygen) and even anoxia (no oxygen), which have negative consequences for fish and other species.  Reducing oxygen in lake water can lead to buildup of methane.   Nutrients from agricultural runoff, released from unsettled lake sediment, increase the likelihood of harmful algal blooms.

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Warming climate prompts harmful oxygen loss in lakes

Photo, posted June 23, 2010, courtesy of Alexander Acker via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Glacial Loss In The Swiss Alps | Earth Wise

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In 2022, glaciers in the Swiss Alps melted more than in any year on record.   This is the latest piece of bad news for the country’s glaciers, which have lost more than half of their volume of ice since the 1930s.

The melting season for Switzerland’s snow and ice typically starts in May and ends in early October.  This year’s melting season caused glaciers in the Diablerets mountain group to thin by an average of 13 feet, which is 3 times the amount of thinning observed over the past decade.   The Tsanfleuron pass between two of the glaciers is now exposed as bare rock for the first time in several thousand years. Across Switzerland, glaciers lost about 6% of their remaining volume just this year.  The previous worst year for glaciers was 2003, when losses were nearly 4%. 

There was significant melting this year in part because of the small amount of snowfall over the winter.  That snow melted quickly, being sped up by the warming effect of dust from the Sahara Desert falling on the snow.  By early summer, there was no longer a protective blanket of snow on the glaciers, exposing them to summer heat.

The loss of glaciers is far more serious than the disappearance of aesthetically pleasing landscape features.   Glaciers act as reservoirs of water that persist through the summer months.  Melt from glaciers provides water to ecosystems and creates habitats for plants and animals.  Cold runoff from glaciers affects downstream water temperatures which have a major impact on insects, fish, and other creatures.  Globally, melting glaciers contribute more than 20% of the observed ongoing sea-level rise.

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Rocky Road for Swiss Glaciers

Photo, posted June 22, 2015, courtesy of Dennis Jarvis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Decreasing Forest Area Per Capita | Earth Wise

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Over the past 60 years, global forest area has decreased by 315,000 square miles, an area about twice the size of California. Combined with global population growth over that period, this has resulted in more than a 60% decline in global forest area per capita.

The continuous loss as well as degradation of forest affects the integrity of forest ecosystems and reduces their ability to generate and provide essential services and sustain biodiversity.  It impacts the lives of at least 1.6 billion people worldwide – primarily in developing countries – who depend upon forests in multiple ways.

According to the new study published in the journal Environmental Research Letters, forest losses have been occurring primarily in lower-income countries in the tropics while forest gains have occurred in higher-income countries in the mid-latitudes or extratropics. 

More than half of the world’s forest losses were in Brazil, home to the Amazon rainforest.  In the past 60 years, that country has had a net loss of 170,000 square miles of forest.  While most high-income countries had net forest gains, Canada actually had a net loss of about 11,000 square miles of forest.

Economic growth has a stronger association with net forest gain than with net forest loss.  Therefore, the study highlights the need to strengthen the support given to lower income countries, especially in the tropics, to help improve their capacity to minimize or curtail their forest losses.  To help address this ongoing displacement of forest losses to lower income countries, higher-income nations need to reduce their dependence on imported tropic forest products.

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New study finds global forest area per capita has decreased by over 60%

Photo, posted April 19, 2011, courtesy of ©2011CIAT/NeilPalmer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Declining Bird Populations | Earth Wise

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A study by scientists from multiple institutions around the world including Cornell University has found that significant declines in bird populations are taking place across the planet.  Loss and degradation of natural habitats, direct overexploitation of many species, and climate change are driving the bird population declines.

According to the study, approximately 48% of existing bird species worldwide are known or suspected to be undergoing population declines.  The populations of 39% of bird species appear to be stable.  Only 6% of birds have increasing populations.

A study in 2019 determined that nearly 3 billion breeding birds have been lost in the U.S. and Canada over the past 50 years.  The new study shows that the same patterns of population decline and extinction are happening globally.  According to the study, there are now the first signs of a new wave of extinctions of continentally distributed bird species.

The ultimate fate of bird populations is strongly dependent on stopping the loss and degradation of habitats.   Habitat loss is generally driven by human demand for resources.  Reducing the human footprint on the natural world is what is needed.  Birds are a highly visible indicator of environmental health, and their declining populations signal a much wide loss of biodiversity and threats to human health and wellbeing.

There is a global network of bird conservation organizations trying to prevent further loss of bird species and bird abundance.  Keeping track of the situation is essential and there is growing participation by the public in bird monitoring.  But ultimately, it depends on governments and society in general to support sustainable resource use and learn how to share the planet with nature.

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Global Bird Populations Steadily Declining

Photo, posted January 9, 2022, courtesy of Martien Brand 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.

Marine Heatwaves And Fish | Earth Wise

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Marine heatwaves are periods of abnormally high temperatures in the ocean that can trigger devastating impacts on ecosystems, including coral bleaching, toxic algal blooms, and mass mortality events.  Marine heatwaves can occur in any ocean and in any season.  They are defined based on the differences between actual and expected temperatures for the location and time of year.     

According to several studies, even under moderate climate warming scenarios, oceans will experience more frequent and longer-lasting marine heatwaves in the years to come.

Researchers from the University of British Columbia’s Institute for the Oceans and Fisheries in Canada have found that extremely hot years will wipe out hundreds of thousands of tons of fish globally this century.  These losses are in addition to the projected decreases to fish stocks from long-term climate change. 

Under a worst-case scenario where no action is taken to curb greenhouse gas emissions, the research team’s model predicts a 6% drop in the amount of potential catches per year.  In addition, the biomass (or amount of fish by weight) is projected to decrease in 77% of exploited species due to the extreme temperatures.

As a result of climate change and these extreme heat events, the research team projected that fisheries’ revenues would decrease by an average of 3% globally, and employment would fall by 2% globally – a loss of likely millions of jobs.

The research team says active fisheries management is critical.  Catch quotas, for example, need to be adjusted in years when fish stocks are suffering from marine heat events.  In severe cases, the fisheries may need to be shuttered in order to allow fish stocks to rebuild.  

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Fevers are plaguing the oceans — and climate change is making them worse

Marine heatwaves could wipe out an extra six per cent of a country’s fish catches, costing millions their jobs

Photo, posted October 11, 2016, courtesy of Kahunapule Michael Johnson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Coral Reefs And Ecosystem Services

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A new study led by the University of British Columbia provides the first comprehensive look at what climate change, overfishing, and habitat destruction of coral reefs mean for their ecosystem services.  For humans, this means how the global decline in coral reefs has affected their ability to provide essential benefits including food, livelihoods, and protection from storms.

The study found that global coverage of living corals has declined by about half since the 1950s and the diversity of reef species has declined by more than 60%.  So, it is no surprise that there has been a significant loss in the ability of reefs to provide ecosystem services.

The study analyzed data from coral reef surveys around the world, fisheries catches, indigenous consumption, and more.  Apart from the declines in reef coverage and biodiversity, the study found that fish catches on coral reefs peaked in 2002 and has steadily declined since then, despite increased fishing efforts.

The findings of the study led the researchers to conclude that continued degradation of coral reefs in the years to come threaten the well-being and sustainable development of millions of people in communities on the coast that depend on coral reefs.  Fish and fisheries provide essential nutrients in places with few alternative sources of nutrition.  Coral reef biodiversity and fisheries have added importance for indigenous communities, where important cultural relationships exist with reefs.

The study’s authors say that the results are a call to action.  The level of destruction happening all over the world’s coral reefs is threatening people’s culture, their daily food, and their history.  It is not just an environmental issue; it is a human rights issue.

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Photo, posted September 22, 2010, courtesy of David Burdick / NOAA Photo Library via Flickr.

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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.

Tree-Planting Is Not Necessarily A Good Thing | Earth Wise

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There is no question that forests have a major role in efforts to combat climate change as well as to slow biodiversity loss.   As a result, tree-planting on a massive scale has gained traction as a strategy and there have been major commitments made to plant billions of trees around the world.

A new study at Stanford University has rigorously analyzed the potential effects of these efforts and has found some significant problems.  For example, the Bonn Challenge, which seeks to restore an area of forest more than eight times the size of California over the next 10 years, has 80% of its commitments in the form of  planting monoculture tree plantations or a limited mix of trees that produce fruit and rubber, rather than restoring natural forests.   The problem is that plantations have significantly less potential for carbon sequestration, habitat creation, and erosion control than natural forests.  The potential benefits of the planting dwindle further if planted trees replace natural flora – forests, grasslands, or savannahs – which are ecosystems that have evolved to support local biodiversity.

The study looked at previous policies that created subsidies for planting trees.  Chile’s Decree Law, in effect from 1974 to 2012, has served as a model for similar policies in a number of countries.  Those subsidies further reduced native forest cover by encouraging the establishment of plantations in places where forests might have naturally regenerated.  The subsidies expanded the area covered by trees, but decreased the area of native forests.

The study recommends that nations should design and enforce their forest subsidy policies to avoid undesirable ecological impacts and actually promote the recovery of carbon- and biodiversity-rich ecosystems.

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Poorly designed tree-planting campaigns could do more harm than good, according to Stanford researcher and others

Photo, posted April 28, 2016, courtesy of the U.S. Department of State via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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