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Rising seas are destroying buildings

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

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

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

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

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

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

Earth Wise is a production of WAMC Northeast Public Radio

The human footprint on Earth

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The Earth is a pretty big place, and it is easy to think that humans and their activities occupy very little of it.  But the impact of human activities on our planet continues to grow.  Recent satellite images from NASA’s Earth Observatory show the staggering extent of the human footprint on Earth.

Agriculture is a major part of it.  Farms and pastures take up almost half of the world’s habitable land – land not covered by ice or desert.  Greenhouses have recently proliferated tremendously and now cover 3.2 million acres, an area the size of Connecticut, and they even have effects on local climates.

More than half of the world’s population now lives in cities, which are expanding rapidly.  Enormous cities in Asia are changing the landscape in places like Thailand and Indonesia.  Apart from taking up lots of land, many of the world’s cities are immersed in clouds of air pollution that they generate.

Greenhouse gas emissions continue to grow, and temperatures continue to rise.  The effects of this on the planet are increasingly evident.  Seas are rising, ice is melting, glaciers shrink away, and wildfires continue to burn.  The massive wildfires in and around Los Angeles have made major changes in the local landscape.  Rising seas have flooded coastal wetlands and elsewhere, rivers and lakes have shrunk.

There are also human impacts visible from space that represent positive signs.  Large solar arrays supply the cheapest form of energy in most parts of the world and the number and size of solar installations are at a record high.   These solar installations provide some hope that global warming can be slowed.

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The Growing Human Footprint on Earth, as Seen from Space

Photo, posted July 28, 2012, courtesy of Beth Scupham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Mangrove forests and rising seas

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Mangrove forests play a vital role in the health of our planet.  They protect coastal regions by acting as natural barriers against storms, erosion, and flooding. The intricate root systems of mangrove forests, which allow the trees to handle the daily rise and fall of tides, also serve as biodiversity hotspots, attracting fish and other species seeking food and shelter from predators.

But mangrove forests around the world are under increasing threat from deforestation, coastal development, and climate change.  In fact, according to a new study led by researchers from Northumbria University in England, the mangrove trees in the Maldives are actually drowning. 

The research, which was recently published in the journal Scientific Reports, found that sea levels around the Maldives rose more than 1.18 inches per year from 2017 to 2020.  An unusually intense climate phenomenon, known as the Indian Ocean Dipole, occurred toward the end of this period, causing warmer sea surface temperatures and an increase in sea level in the Western Indian Ocean. 

While mangrove forests can naturally keep pace with gradually rising seas, this rate of sea level rise was too fast.  The rising sea level meant that seawater effectively flooded mangrove forests, causing many trees to lose their resilience and die.  Some islands in the Maldives have lost more than half of their mangrove cover since 2020.

Since mangrove forests also store massive amounts of carbon, the research team fears that the loss of mangrove forests could release large amounts of carbon, further accelerating climate change.

The researchers warn that the findings in the Maldives could have implications for coastal ecosystems around the world.

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“Drowning” mangrove forests in Maldives signal global coastal threat

Photo, posted February 11, 2015, courtesy of Alessandro Caproni via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Carbon levies for shipping

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The global shipping industry is responsible for 90 percent of world trade.  The ships crossing the world’s oceans emit nearly 3% of the global greenhouse gas emissions caused by human activity that are contributing to climate change.  Among the effects of climate change are sea level rise, which is threatening the very existence of small island nations.

One such nation is Tuvalu, which is a group of islands in the South Pacific.  Tuvalu has a total landmass of just 10 square miles, and sea level there is rising 1.5 times faster than the global average.  Predictions are that within 50 to 100 years, low-lying islands like those of Tuvalu could be fully submerged by the ocean.

Representatives from six Pacific Island states and a growing number of Caribbean nations known as the 6Pac+ Alliance are urgently calling upon the International Marine Organization to enact a mandatory universal levy of $150 per ton of shipping emissions from large commercial vessels. 

Most marine vessels typically run on highly polluting heavy fuel oil.  Burning really filthy fuel is the cheapest way to cross the oceans.  There are alternatives including entirely carbon-free technologies, but they will be expensive to implement and utilize.  The cost of shipping would undoubtedly go up and be especially felt by small island nations and in developing countries where most food is imported.

The idea behind putting a price on ships’ carbon emissions is to both provide a financial incentive for the shipping industry to reduce its emissions and provide revenue for countries that incur costs from dealing with rising seas.

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Pacific and Caribbean Island Nations Call for the First Universal Carbon Levy on International Shipping Emissions

Photo, posted November 23, 2006, courtesy of Stefan Lins via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

2023: A year of extreme climate

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There have already been all sorts of extreme weather this year in many parts of the world and undoubtedly there will be more to talk about in the coming months.  But the American Meteorological Society has recently published its State of the Climate report for 2023 and it was a year for the record books.

In 2023, the Earth’s layers of heat-reflecting clouds had the lowest extent ever measured.  That means that skies were clearer around the world than on average, a situation that amplifies the warming of the planet.  Since 1980, clouds have decreased by more than half a percent per decade. 

The most dramatic climate effect last year occurred in the world’s oceans.  About 94% of all ocean surfaces experienced a marine heatwave during the year.  The global average annual sea surface temperature anomaly was 0.13 degrees Celsius above the previous record set in 2016.  This is a huge variation for the ocean.  Ocean heatwave conditions stayed in place for at least 10 months in 2023 in vast reaches of the world’s oceans.  Ocean heat was so remarkable that climate scientists are now using the term “super-marine heatwaves” to describe what is going on. 

There were many other ways in which 2023 experienced weather extremes.  July experienced a record-high 7.9% of the world’s land areas in severe drought conditions.  During the year, most of the world experienced much warmer-than-average conditions, especially in the higher northern latitudes.  These unprecedented changes to the climate are unlikely to be one-time occurrences; 2024 is likely to be another one for the record books.  

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New Federal Report Details More of 2023’s Extreme Climate Conditions

Photo, posted May 27, 2021, courtesy of Wendy Cover/NOAA via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Natural solutions for coastal defense

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Protecting coastal cities and towns from the dangers of tsunamis, storm surges, and sea-level rise has become an ever-increasing challenge.  There are so-called hard coastal defenses as well as nature-based solutions.  A new study by the University of Tokyo has found that combining the two types of defenses may be the most effective way to protect, support, and enrich coastal communities.

Sea walls, dikes, dams, and breakwaters are the traditional hard measures.  They are popular and have proven track records but are facing challenges to keep pace with increasing climate risks.  They are expensive to build and require continuous upgrades and repairs.  While they do provide protection from many disaster risks, they also can cause significant disruption to coastal ecosystems as well as to coastal communities.

Nature-based coastal defenses include such things as mangroves and coral reefs.  So-called soft measures involve restoring, rehabilitating, reforesting, and nourishing natural ecosystems that protect coastal areas.

The Tokyo researchers analyzed the defense strategies in terms of risk reduction, climate change mitigation, and cost-effectiveness over a 20-year period. The results of the study were that among all coastal defense options in lower-risk areas, hybrid measures provide the highest risk reduction and can harness the advantages of both hard and soft measures. 

The findings provide strong evidence for integrating nature-based components into coastal defenses, but these approaches have not yet been adequately tested in circumstances of extreme events and high-risk urgency.  Research in this area has important implications for policy makers, coastal planners, and communities looking to make evidence-based decisions.

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A natural touch for coastal defense

Photo, posted October 22, 2021, courtesy of Kevin Dooley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Global coral bleaching

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The world’s coral reefs are in the midst of a global bleaching event being driven by extraordinarily high ocean temperatures.  This is the fourth such global event on record and is predicted to be the largest one ever.  Coral bleaching occurs when corals are stressed by heat and eject the symbiotic algae within them that they need to survive.  Bleached corals can recover if water temperatures cool soon enough.  Otherwise, they die.

Each of the three previous coral bleaching events has been worse than the last.  The first, in 1998, affected 20% of the world’s reefs.  The second, in 2010, affected 35%.  The third, from 2014 to 2017, affected 56% of reefs.

The current bleaching event was confirmed by satellite observations early in April and was already seen to be affecting more than half of the world’s coral areas across the Pacific, Indian, and Atlantic Oceans.  The ongoing event is expected to be the worst bleaching ever experienced by Australia’s Great Barrier Reef.  A small saving grace is that the current bleaching event is not expected to be of extremely long duration because the El Niño in the Pacific has abated.

Coral bleaching events are becoming more severe and frequent due to increased marine heat waves driven by climate change.  Last year was particularly difficult for corals as global sea temperatures reached record high levels for several months.

Widespread coral bleaching impacts economies, livelihoods, food security, and more.  Coral reefs provide ecosystem services essential to marine life and human populations as well.  Global action will be needed for coral interventions and restorations.

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Satellites watch as 4th global coral bleaching event unfolds

Photo, posted March 23, 2012, courtesy of Oregon State University via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Artificial reefs

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The coral reefs that surround tropical islands are a refuge for a wide variety of marine life and also form a natural buffer against stormy seas.  The changing climate is bleaching coral reefs and breaking them down.  Extreme weather events are becoming more common and are threatening coastal communities with flooding and erosion.

Researchers at MIT are designing architected reefs – sustainable offshore structures that mimic the wave-buffering effects of natural reefs and can also provide habitats for fish and other marine life.

There are already artificial reefs in a number of places used to protect coastlines.  These are typically made from sunken ships, retired oil and gas platforms, and even assemblies of concrete, metal, car tires, and stones.  Generally, it takes quite a lot of material to form an effective barrier to waves.

The MIT group has developed a cylindrical structure surrounded by four rudder-like slats.  Their experiments have shown that when this structure stands in the way of a wave, it efficiently breaks the wave and creates turbulent jets that dissipate the energy in the wave.  The engineers calculated that the new design could reduce as much wave energy as existing artificial reefs but use 10 times less material.

Based on the initial experiments with lab-scale prototypes, these artificial reefs would reduce the energy of incoming waves by more than 95%.

Coral reefs are only found in tropical waters, whereas these artificial reefs don’t depend on temperature and could be placed along any coastline for protection.  In a time of rising seas and increasingly frequent storms, these artificial reefs may be just what coastlines need.

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Artificial reef designed by MIT engineers could protect marine life, reduce storm damage

Photo, posted December 9, 2010, courtesy of Phoenix Wolf-Ray via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Seabirds rescuing coral reefs

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A new study by researchers at Lancaster University in the UK has found that the presence of seabirds on islands adjacent to tropical coral reefs can more than double the coral growth rates on those reefs.

The study found that when coral reefs grow faster, they can bounce back more quickly from bleaching events that occur when the seas become too warm.  The focus of the study was a type of coral called Acropora, which provides complex structures supporting fish populations and reef growth. 

The researchers found that Acropora around islands populated by seabirds recovered from bleaching events about 10 months faster than reefs located away from seabird colonies.  Speeding up coral recovery times could prove the difference between continuing to bounce back from bleaching events and dying off.

The seabirds are helping the coral reefs with their droppings.  The birds feed on fish in the open ocean far from islands and then return to the islands to roost.  They deposit nitrogen- and phosphorus-rich nutrients in the form of guano, some of which is washed off of the islands by rain and into the surrounding seas.  The nutrients fertilize corals and other marine species.

To determine whether the faster growth rates were really due to the bird-supplied nutrients, the researchers studied rat-infested islands that had no bird populations.  The study confirmed that it was the presence of seabirds that provided enhanced nutrients for the coral reefs.  In fact, a primary outcome of the study was to add further weight to the growing body of evidence of the ecological damage across ecosystems on land and sea from invasive rats on tropical islands.

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Feathered friends can become unlikely helpers for tropical coral reefs facing climate change threat

Photo, posted September 15, 2019, courtesy of Rickard Zerpe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Disappearing snow crabs

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Alaska snow crabs are a cold-water species found off the coast of Alaska in the Bering, Beaufort, and Chukchi Seas. They are one of ten commercially-fished species in Alaskan waters. The perils of crab fishing in this region have been well documented for many years in the reality TV series Deadliest Catch.

Last year, officials in Alaska canceled the winter snow crab season for the first time ever due to a sharp population decline. While the number of juvenile snow crabs was at record highs just a few years earlier, approximately 90% of snow crabs mysteriously disappeared ahead of the 2021 season. 

This year, officials in Alaska have once again canceled the snow crab harvest season for the second year in a row, citing the overwhelming numbers of crabs – in the billions – missing from Alaskan waters. 

Scientists have suspected that the warming ocean temperatures triggered this snow crab population collapse.  But did the crabs move someplace else or die off?  According to a new study recently published by scientists at the National Oceanic and Atmospheric Administration, warmer ocean temperatures likely caused the snow crabs to starve to death.  The research team found a significant link between recent marine heat waves in the eastern Bering Sea and the sudden disappearance of the snow crabs that began showing up in surveys in 2021.

According to the study, warmer ocean water dramatically increases snow crabs’ caloric needs. But with the warmer water also disrupting much of the region’s food web, snow crabs had a hard time foraging for food and weren’t able to keep up.

Researchers expect the population may eventually find refuge in colder waters further north.

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Climate Change And Crabs

Billions of crabs went missing around Alaska

Photo, posted August 28, 2013, courtesy of Boris Kasimov via Flickr.

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The Value Of Seagrass | Earth Wise

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Seagrasses are found in shallow salty and brackish waters in many places around the world, from the tropics to the Arctic Circle.  They get their name from their long green, grass-like leaves.  They are not seaweeds at all but are more closely related to flowering plants on land. 

We hear a lot about threatened ocean ecosystems and most of the attention is on coral reefs and coastal mangrove forests.  Seagrass meadows get much less press, but they in fact provide wide-ranging services to society and store a great deal of carbon.

A new study by the University of Michigan demonstrates that seagrass ecosystems should be high up on the global conservation agenda.  The study puts a dollar value on the many services – which include storm protection, fish habitat, and carbon storage – provided by seagrasses in the Caribbean.  The numbers are enormous.

The researchers estimate that the Caribbean holds up to half of the world’s seagrass meadows by surface area, and it contains about a third of the global carbon storage by seagrasses.  They calculated that the Caribbean seagrasses provide about $255 billion in services to society each year, which includes $88 billion in carbon storage.

In the Bahamas alone, ecosystems services provided by seagrasses are valued at more than 15 times the country’s 2020 gross domestic product.

Blue carbon is the name used to describe carbon stored in coastal and open-ocean ecosystems.  The idea of selling blue carbon offset credits, which monetize the carbon stored in this way, is gaining traction.  For many Caribbean nations, this is likely to provide impetus for protecting seagrass ecosystems from human impacts, including nutrient pollution and overfishing.

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Caribbean seagrasses provide services worth $255B annually, including vast carbon storage, study shows

Photo, posted June 27, 2023, courtesy of Daniel Eidsmoe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Airplane Turbulence And Climate Change | Earth Wise

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If you’ve ever been on an airplane, chances are pretty good that you’ve experienced turbulence.  As the busy summer travel season kicks off, travelers are being encouraged to brace themselves for a bumpier-than-usual ride. 

There has been a major increase in the number of severe turbulence cases on both domestic and international flights.  According to a new study by researchers from the University of Reading in the U.K., climate change is leading to this increase in turbulence, driving up costs (via wear and tear on aircrafts), and increasing the risks for passengers and flight attendants.  In the United States alone, turbulence costs the airline industry $150-$500 million annually. 

The study, which was recently published in the journal Geophysical Research Letters, found that warmer air, caused by carbon emissions, is creating bumpier flights around the world.  In fact, the study found that severe turbulence in the North Atlantic is up by 55% since 1979. 

The changing climate is affecting air travel in other ways as well.  A faster jet stream across the Atlantic is altering travel times.  Rising temperatures are reducing the weight that aircraft can carry.  Rising seas are threatening low-lying coastal airports around the world. 

But carbon emissions from aviation are also a significant driver of the climate crisis.  Air travel accounts for approximately 3% of global greenhouse gas emissions, and is one of the fastest growing sources of emissions. According to the International Civil Aviation Organization, emissions from international air travel are expected to triple by 2050.

The future is shaping up to be a bumpy ride.

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Climate crisis leading to more turbulence during flights, says study

Evidence for Large Increases in Clear-Air Turbulence Over the Past Four Decades

Climate Scientist Explains Increase In Airplane Turbulence

Airports and Rising Seas

Photo, posted May 9, 2018, courtesy of Steve Lynes 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

Sea Level Rise And Global Security | Earth Wise

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Recently, United Nations General Secretary Antonio Guterres addressed the U.N. Security Council on the issue of the security threats created by rising sea levels. In the past, some members of the Security Council – notably Brazil, China, Russia, and at times, India – have argued that the U.N.’s climate program should address such issues and that the Security Council doesn’t have a mandate or the expertise to consider the issue.   The underlying problem is that by addressing the security issues created by rising seas, other sensitive geopolitical issues might come to the forefront.

Guterres’ speech focused on the real possibility that rising seas could disrupt and destabilize global societies unless there is an organized international effort to get ahead of the problem.  Major cities facing serious impacts from rising seas include Cairo, Lagos, Bangkok, Jakarta, Mumbai, Shanghai, Copenhagen, London, Los Angeles, New York, and Buenos Aires, among others.

In all, Guterres said that the danger is most acute for about 900 million people living in low-lying coastal areas.  Some countries, particularly small island developing countries, could disappear entirely.

The world is already facing refugee crises related to politics, warfare, and extreme weather.  The flood of refugees created by rising seas could be biblical in magnitude.

The confluence of climate change and global security is growing steadily.  As the global body primarily responsible for maintaining international peace and security, the U.N. Security Council cannot duck this issue much longer.  It has a critical role to play in building the political will required to address the security challenges looming from rising seas.

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Sea Level Rise Could Drive 1 in 10 People from Their Homes, with Dangerous Implications for International Peace, UN Secretary General Warns

Photo, posted July 19, 2021, courtesy of Face of the World via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Turning Plastic Into Protein | Earth Wise

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Our planet is choking on plastic.  According to the United Nations, 79% of the 6.3 billion tons of plastic produced every year accumulates in landfills.  Half of all plastic produced is actually designed to be used just once and thrown away.  But plastic is not only accumulating on land.  In fact, the world’s oceans are projected to contain more plastic by weight than fish by the year 2050.     

According to new research, solving the plastic waste issue could help address another prominent global issue: hunger.  A multidisciplinary team of engineers, chemists, and biologists led by researchers from Michigan Tech University has developed a process to break plastics down to be recycled into useful products, including edible protein powder.

The research team’s process converts plastic into compounds using heat and a reactor that deconstructs the material’s polymer chains. The oil-like substance is then fed to a community of oil-eating bacteria.  The bacteria grow rapidly on the oily diet, producing more bacterial cells composed of roughly 55% protein.  This majority-protein byproduct is then dried out and turned into an edible powder.   The end result doesn’t look like plastic at all.  In fact, it resembles a yeast byproduct that comes from brewing beer. 

This research is funded by an award from the US Department of Defense.  The DoD often deploys soldiers in areas where access to food is challenging.  Converting plastic to protein could be part of a solution to that problem. 

While eating something that began as plastic might take some getting used to, it could be part of the solution to both plastic pollution and global hunger.

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Turning Trash Into Treasure: The Plastic to Protein Powder Solution

Beat Plastic Pollution

Photo, posted February 2, 2022, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Better Marine Protected Areas | Earth Wise

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Marine protected areas are regions of seas, oceans, estuaries, and in the US, the Great Lakes, that are afforded special protections.  MPAs restrict human activity for conservation purposes, generally in order to protect natural or possibly cultural resources.   MPAs may limit such things as development, fishing practices, fishing seasons, catch limits, moorings, and removal or disruption of marine life.

A new study by the University of Plymouth in the UK looked at the effectiveness of MPAs in increasing the total abundance of reef species.  It looked at the MPAs in Lyme Bay, off the south coast of England, where two of them are co-located but governed by different constraints.

The study found that whole-site management of an MPA can increase the total abundance of reef species within its borders by up to 95%.  This is in contrast to the MPA where only known features are conserved and human activity is otherwise allowed to continue unchecked.  In that place, species abundance increased by only 15%.

The whole-site MPAs were observed to have other benefits as well.   They show higher levels of functional redundancy, meaning that when there are species losses, they are compensated by other species.  Whole-site MPAs also exhibit higher levels of species diversity.

MPAs are increasingly being recognized as a sustainable way to enhance the marine environment even while supporting coastal communities.  The Global Ocean Alliance, a 72-country alliance led by the UK, has set a target of protecting 30% of all marine areas by 2030.  The new study shows that even more important than simply establishing marine protected areas, it is essential that they are effectively implemented.

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Whole-site management of Marine Protected Areas can lead to a 95% increase in reef species

Photo, posted October 28, 2011, courtesy of Benjamin Evans via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Marine Predation And Climate Change | Earth Wise

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Climate change is taking a toll on forests, farms, freshwater resources, and economies all around the world.  But ocean ecosystems remain the center of global warming.

Despite their vast ability to absorb heat and carbon dioxide, oceans are warming.  In fact, according to scientists, the oceans have absorbed 90% of all the warming that has occurred during the past 50 years. 

The ocean’s surface layer, which is home to most marine life, takes most of this heat.  As a result, the top 2,300 feet of global ocean water has warmed approximately 1.5°F since 1901.

Well it turns out that a hotter ocean is also a hungrier ocean.  According to a new study recently published in the journal Science, researchers discovered that predator impacts in the Atlantic and Pacific oceans peak at higher temperatures.  The effects of more intense marine predation could disrupt ecosystem balances that have existed for millennia. 

An international research team led by the Smithsonian Institution and Temple University analyzed predator and prey data collected from 36 sites, running along the Atlantic and Pacific coasts from Alaska in the north to Tierra de Fuego at the tip of South America.  The research team found that, in warmer waters, predators’ more voracious appetites left outsized marks on the prey community.  Total prey biomass plunged in warmer waters when prey were left unprotected.  However, in the coldest zones, leaving prey exposed or protected made nearly no difference at all.  

As the oceans continue to warm, more intense predation will create winners and losers and could jeopardize the overall health of marine ecosystems.  

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As the ocean heats up hungrier predators take control

Photo, posted July 14, 2017, courtesy of Jonathan Chen 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.

Keeping Venice From Flooding | Earth Wise

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Since 2003, Venice Italy has been building a system of mobile gates at three inlets to its famous lagoon.  The project is called MOSE, the Italian word for Moses, but is actually an acronym for the Italian words meaning Experimental Electromechanical Module.  

The 78 mobile gates are metal box structures that sit at the bottom of inlet channels.  When a high tide is predicted, compressed air is pumped into the structures.  The air causes the barriers to rise up to the surface and block the flow of the tide, thereby preventing water from flowing into the lagoon.

The system had an important test on November 3 when water levels were predicted to rise four-and-a-half feet above normal at high tide and strong winds were blowing.  Water at that level is enough to flood 60% of the city, including the famous St. Mark’s Square, which is unfortunately the lowest part of the city.

Activating the flood gates proved to be successful.  Even though high tide water levels in fact rose 4.3 feet in the surrounding Adriatic Sea, they only reached 2.7 feet in Venice, which was enough to prevent significant flooding.

Rising sea levels have led to increasingly frequent floods in Venice.  In 2019, before the MOSE system was available for use, there were more than 25 high-water events swamping Venice, including one in November of that year that was the second worst on record.

Some researchers have calculated that the system will need to be closed for as much as 3 weeks a year by the end of the century even if emission reductions are reasonably effective.  If they aren’t, the gates may be closed for at least two months a year by 2080.

After many years of delays, setbacks and controversies, the system is finally operational.

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Venice Holds Back the Adriatic Sea

Photo, posted October 25, 2014, courtesy of Pedro Szekely via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Most Powerful Tidal Turbine Is Generating Power | Earth Wise

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The movement of waves, tides, and currents in the ocean carry enormous amounts of energy that in principle could be harnessed and converted into electricity to help power our homes, buildings, and cities.  Oceans cover nearly three-quarters of our planet, and the most populated areas of the world are located near oceans.

Ocean energy technologies lag far behind solar and wind power and remain mostly undeveloped.  This is a result of the unique challenges standing in the way of widespread deployment.  There are the considerable expenses of early-stage development, the wide variety of technical approaches from which winning strategies have yet to emerge, and the substantial challenges of operating in the ocean environment that include the physical impact of waves and tides, powerful and unpredictable weather, and corrosion and bio-fouling from the ocean and its inhabitants.

Despite these challenges, there is ongoing progress on ocean energy.   The world’s most powerful tidal turbine has come online this past April.  Known as the Orbital O2, the floating turbine is anchored in Scotland’s Fall of Warness, where a subsea cable connects it to the European Marine Energy Center.

The turbine produces enough electricity to meet the demand of about 2,000 homes in the UK.  It is expected to operate for the next 15 years.

Built by the Scottish engineering company Orbital Marine, the O2 was financed by the ethical investment platform Abundance Investment as well as being supported by the Scottish government and the European Union.   Orbital Marine’s goal is to commercialize this technology to play a role in tackling climate change using this new green energy technology.

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The world’s most powerful tidal turbine is now generating power

Photo, posted June 12, 2015, courtesy of David Stanley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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