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Harvesting Water From The Air | Earth Wise

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Engineers at MIT have created a superabsorbent material that can soak up significant amounts of moisture from the air, even in desert-like conditions.

The material is a transparent, rubbery substance made from hydrogel, which is a naturally absorbent material that is already widely used in disposable diapers.  The MIT researchers enhanced the absorbency of hydrogel by infusing it with lithium chloride, which is a type of salt that is a powerful desiccant.

They found that they could infuse hydrogel with more salt than was possible in previous studies.  Earlier studies soaked hydrogels in salty water and waited 24 to 48 hours for the salt to infuse into the gels.  Not much salt ended up in the gels and the material’s ability to absorb water vapor didn’t change much.  In contrast, the MIT researchers let the hydrogels soak up the salt for 30 days and found that far more salt was absorbed into the gel.  The result was that the salt-laden gel could then absorb and retain unprecedented amounts of moisture, even under very dry conditions.

Under very dry conditions of 30% relative humidity, the gels captured 1.79 grams of water per gram of material.  Deserts at night have those levels of relative humidity, so the material is capable of generating water in the desert.

The new material can be made quickly and at large scale.  It could be used as a passive water harvester, particularly in desert and drought-prone regions.  It could continuously absorb water vapor from the air which could then be condensed into drinking water.  The material could also be used in air conditioners as an energy-saving, dehumidifying element.

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This salty gel could harvest water from desert air

Photo, posted July 26, 2021, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cutting Deforestation | Earth Wise

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Deforestation is a major contributor to climate change because the destruction of tropical rainforests worldwide eliminates a crucial natural sink for carbon.  Between 2015 and 2020, roughly 39,000 square miles of forest were cut down, an area about 70% the size of the entire state of New York.  In many places, such as the Amazon and Congo Basins, deforestation continues to accelerate.  In Bolivia, deforestation rose 59% over the past five years; in Ghana, the rise was 71%.

A new report from the World Resources Institute revealed one bright spot in the deforestation story:  both Indonesia and Malaysia have cut deforestation by more than half in recent years.  The two countries have managed to keep rates of primary forest loss to near record-low levels.

Over the past five years, Indonesia saw a 64% decline and Malaysia a 57% decline in deforestation.  Indonesia is the second largest source of deforestation with only Brazil removing more trees.

Indonesia has a national goal of having its forests absorb more carbon than they release by 2030.  They have moved to curb logging and limit the clearing of land for palm oil plantations.  They have also ramped up efforts to suppress forest fires.

It is good that Indonesia and Malaysia and some other countries have shown progress in reducing forest loss.  However, too many other countries have seen continued activities and policies that are causing acceleration of deforestation in critical areas.  Protecting forests is an important part of the effort to mitigate the effects of climate change.  Preserving forests also is essential for protecting the people and the biodiversity that depend on them.

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Indonesia, Malaysia Have Cut Deforestation in Half in Last Half-Decade

Photo, posted March 22, 2021, courtesy EPJT Tours via of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Global Aquaculture And Environmental Change | Earth Wise

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Blue foods are fish, invertebrates, algae, and aquatic plants that are captured or cultured in freshwater and marine ecosystems.  They include approximately 2,200 species of fish, shellfish, plants and algae as well as more than 500 species farmed in freshwater.  Blue foods play a central role in food and nutrition security for billions of people, and are a cornerstone of the livelihoods, economies, and cultures of many communities around the world.

But many of the world’s largest aquatic food producers are highly vulnerable to human-induced environmental change.  According to a new paper recently published in the journal Nature Sustainability, more than 90% of global blue food production is at risk from environmental changes, with top producers like the United States, Norway, and China facing the biggest threat.  Alarmingly, the research also found that some of the highest-risk countries in Asia, Latin America and Africa demonstrate the lowest capacity for adaptation. 

The paper is the first-ever global analysis of environmental stressors impacting the production quantity and safety of blue foods. A total of 17 anthropogenic stressors were surveyed, including rising seas and temperatures, ocean acidification, changes in rainfall, algal blooms, pollution, and pesticides. 

The research is one of seven scientific papers published by the Blue Food Assessment as part of a global effort to inform future aquatic food sustainability. 

The report calls for more transboundary collaboration and for a diversification of blue food production in high-risk countries to cope with the impact of environmental change. 

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Vulnerability of blue foods to human-induced environmental change

New research finds that more than 90% of global aquaculture faces substantial risk from environmental change

Photo, posted December 30, 2014, courtesy of NOAA’s National Ocean Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar Power And Water | Earth Wise

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Solar power is a prime example of clean energy, but it does not come without complications and potential problems.  One problem that has arisen in the Californian desert is the effect on scarce water supplies.  Solar farms don’t use up water when they are operating but they consume it when they are being built.

One of the densest areas of solar development in North America is in a corridor along Interstate 10 near Palm Springs, California.  Multiple utility-scale solar projects are underway near the small town of Desert Center.  The projects are being built on public land overseen by the Department of Interior’s Bureau of Land Management.  The location is ideal for solar power projects:  endless sunshine, nearby transmission lines to distribute power, and a major highway for easy transportation of construction materials.

The problem is that during construction of the solar farms, the law requires developers to reduce the amount of dust being generated that can otherwise spread health problems like Valley Fever.  Preventing dust from flying requires water and lots of it.

The water comes from groundwater and building the solar farms is drying up local wells and emptying the aquifer that is part of the Chuckwalla Valley Groundwater Basin.  For the people who live in Desert Center and adjacent areas, this is a serious problem. It is also a problem for the desert ecosystem that supports palo verde and ironwood trees as well as endangered desert tortoises.

This isn’t an easy problem to solve. Seven approved new utility-scale solar projects in the area will provide enough electricity to power 2 million homes. But having enough water to build those projects won’t be easy.

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Solar Is Booming in the California Desert, if Water Issues Don’t Get in the Way

Photo, posted October 16, 2017, courtesy of UC Davis College of Engineering via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

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

How To Support Pollinators | Earth Wise

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Pollinators of all sorts have been in decline for a while.  This is especially true of bees, bats, and monarch butterflies.  Without pollinators, fruits, vegetables, and other plants cannot provide their contributions to our food supply.  According to experts, about 30% of the food that ends up on our tables gets there because of pollinators.

Bees are the most efficient pollinators, but plenty of other insects do their share as well.  Butterflies and months, flies, beetles, and wasps all are good pollinators.  In addition to insects, birds and bats can also be pollinators. 

Entomologists at Texas A&M University have offered some science-based advice for homeowners who want to keep pollinators around and thriving during the summer months.

Pollinators need flowers that bloom at different times of the year.  So, home gardens should overlap blooms.  Native and drought-tolerant species are good additions to a garden or landscape.

Colorful gardens attract more pollinators because different pollinators are attracted to different colors.  Bumblebees like blues and purples; other bees are attracted to yellows and whites.  Butterflies like bright colors like oranges and pinks.

Plant flowers with different shapes and sizes because pollinators flower preferences come in all shapes and sizes.

Provide shelter for pollinators.  Houses for bees and other pollinators are available for purchase. Or people can make their own using plastic tubes.

And probably most importantly, go easy on pesticides.  If it is really necessary to apply pesticides, do it in the evening when most pollinators have called it a day.

Having a colorful garden with lots of variety is a fine addition to one’s home.  Beyond that, it is a valuable contribution to helping preserve essential pollinators.

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Top Five Tips For Supporting Pollinators This Summer

Photo, posted August 14, 2017, courtesy of USFWS Midwest Region via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wind And Solar Pass Coal | Earth Wise

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For the first five months of this year, wind and solar generated more electricity than coal in the United States.  This is a first.  Total renewable energy generation exceeded coal-fired power in both 2020 and 2022, but that counted hydroelectric power as one of the renewable sources.

This year, wind and solar alone generated a total of 252 terawatt-hours of energy through May compared with coal’s output of 249 terawatt-hours.  Hydropower generated an additional 117 terawatt-hours during that period.

While solar and wind power have been expanding at a rapid rate, the biggest change this year has been a precipitous drop in coal-fired generation due to a combination of low natural gas prices, a mild winter, and a series of coal plant retirements.

Coal generated almost half of the country’s electricity as recently as 2008.  Since then, coal has steadily declined as older coal plants shut down and were replaced by natural gas plants and renewable energy sources.  The coal industry had a bit of a reprieve last year when natural gas prices spiked in response to the disruptions in gas supplies in Europe due to the war in Ukraine.  The benchmark for natural gas prices – known as Henry Hub – was $8.81 in August 2022.  In May of this year, it was $2.15.  Given this trend, the demand for coal has steadily declined. 

The US has retired another 7% of the coal fleet – 14 gigawatts of capacity – since the start of 2022.  Meanwhile, power companies have added 22.5 GW of wind and solar capacity in just the past 12 months.

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In a First, Wind and Solar Generated More Power Than Coal in U.S.

Photo, posted September 20, 2016, courtesy of Bureau of Land Management via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cryo Conservation | Earth Wise

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Recent studies have shown that there has been a 69% decline in global animal populations since 1970.  There is a biodiversity crisis in the world.  In the face of this situation, there is a growing interest in using cold storage to preserve genetic samples taken from animals threatened with extinction.

Just as egg-freezing is used to preserve human fertility for a later date, the cryogenic freezing of genetic material from animals could be important in reducing species extinctions.  Living cell banks – also known as cryobanks – could preserve genetic materials from animals that include skin cells, embryos, semen, and live tissues.  These materials could be cultured and used for various applications including DNA extraction, assisted reproduction, ensuring genetic diversity in animal populations, and potentially reintroducing species back into their natural habitats.

There is a facility called the Frozen Zoo at the San Diego Wildlife Alliance which has genetic material from 965 different species, including 5% of the vertebrates currently listed as threatened on the IUCN Red List.  Further sampling from zoos and aquariums could increase that representation to almost 17%.

Genetic samples of 50% of the species currently listed as extinct in the wild are already represented in the Frozen Zoo.  Further sampling from the zoological community could increase this number to 91%.  This could provide a critical lifeline for these species that are on the brink of extinction.  As wildlife populations continue to decline around the world, it is more critical than ever to collect and preserve genetic samples from threatened species.

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Cryo conservation – a cool solution to saving species from extinction

Photo, posted September 30, 2018, courtesy of Andy Morffew via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Shrinking Glaciers And Methane | Earth Wise

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The Arctic region is warming much faster than the rest of the planet.  In fact, according to a study published last year in the journal Nature, the Arctic has been warming nearly four times faster than the rest of the globe during the last 43 years.  This rapid warming is leading to substantial reductions in sea ice, thawing of permafrost, shifts in wildlife populations, and changes in ocean circulation patterns, among other changes. 

According to new research recently published in the journal Nature Geoscience, shrinking glaciers in the warming Arctic are exposing bubbling groundwater springs, which could provide an underestimated source of methane, a potent greenhouse gas.  Methane is more than 25 times as potent as carbon dioxide at trapping heat in the atmosphere.

The study, which was led by researchers from the University of Cambridge and the University Centre in Svalbard, Norway, found large sources of methane gas leaking from groundwater springs unveiled by melting glaciers. 

As glaciers retreat in the Norwegian archipelago of Svalbard and leave behind newly exposed land, groundwater beneath the Earth seeps upward and forms springs. In 122 out of the 123 springs studied, the research team found that the water was highly concentrated with dissolved methane.  When the spring water reaches the surface, the excess methane can escape to the atmosphere. 

Researchers are concerned that additional methane emissions released by the Arctic thaw could dramatically increase human-induced global warming.  If this phenomenon in the Svalbard archipelago is found to be more widespread across the Arctic — where temperatures are quickly rising and glaciers melting — the methane emissions could have global implications. 

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The Arctic has warmed nearly four times faster than the globe since 1979

Shrinking Arctic glaciers are unearthing a new source of methane

Photo, posted October 22, 2022, courtesy of David Stanley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

An Electric Cruise Ship | Earth Wise

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The shipping industry accounts for about 3% of global manmade greenhouse gas emissions.  In 2018, the International Maritime Organization, the UN body that regulates global shipping, set a target to cut the industry’s greenhouse gas emissions by at least half by 2050.

This goal has led to a variety of designs for eco-friendly ships, including car carriers, superyachts, and cargo ships with retractable sails.  But most of the designs still rely to at least some extent on engines that run on fossil fuels.

The Norwegian cruise ship company Hurtigruten has announced that it will build a zero-emissions electric cruise ship with retractable sails covered in solar panels.  The ship is expected to set sail in 2030.  Hurtigruten is a relatively small company, with a fleet of eight ships, each with a capacity of 500 passengers.  But the company hopes that its innovative plan will inspire the entire maritime industry.

The ship will predominantly run off of electric motors powered by 60 megawatt batteries that can be charged in port with renewable energy.  To reduce reliance on the battery, when it is windy, three retractable sails will rise out of the deck, reaching a maximum height of 164 feet.  The sails will be covered in solar panels that will generate energy to top off the batteries while sailing.

The ship will have 270 cabins to hold 500 passengers and 99 crew members.  The streamlined shape of the ship will result in less air resistance to further reduce energy use.

Hurtigruten already has a hybrid, battery-supported cruise ship and is currently in the process of converting its entire fleet to hybrid battery power.

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An electric cruise ship with gigantic solar sails is set to launch in 2030

Photo, posted January 15, 2023, courtesy of Bernard Spragg via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Renewables In China | Earth Wise

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A couple of years ago, China set an ambitious goal for renewable energy capacity – which includes wind, solar, hydroelectric, and nuclear power – for it to exceed fossil fuel capacity by 2025.  According to a recent report by Reuters, China has hit this goal two years ahead of schedule.  Renewables now make up 50.9% of the country’s power capacity.

The rapid growth in renewable capacity has largely been driven by investments in wind and solar megaprojects in the sparsely populated west of the country that export power to the manufacturing centers in the east.  China’s most recent 5-year plan calls for 570 gigawatts of wind and solar power to be installed over that period, which more than doubles its installed capacity.  The plan makes use of what it called “clean energy bases”, which utilize sandy and rocky deserts, other types of barren lands, and wastelands left behind by coal mining.  The largest clean energy bases make use of vast deserts in Inner Mongolia and Gansu.

One cautionary note is that power capacity refers to the maximum amount of electricity that a power plant can produce under ideal conditions.  Thus, for example, it refers to how much electricity a solar farm can generate at noon on a cloudless day.  So, the new figures from China don’t necessarily reveal how much electricity China is actually drawing from renewables.  In reality, China still gets a great deal of its power from coal.

China is the world’s largest emitter of carbon dioxide – more than twice as much as the United States, albeit from nearly 4 times the population.  The rapid growth of renewables is at least moving that country in the right direction.

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Fossil Fuels Now Account for Less Than Half of China’s Power Capacity

Photo, posted December 2, 2015, courtesy of IBM via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The World’s Hottest Day | Earth Wise

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Early in July – for four days in a row – the average global temperature was the highest ever recorded.  As many places around the world endured dangerous heatwaves, the average global temperature on the fourth of July reached 62.92 degrees Fahrenheit, the highest ever recorded by human-made instruments.  On July 6th, the global temperature climbed even further to 63.01 degrees.

The average global temperature on an annual basis was about 56.7 degrees from the 1880s through the 1910s.  Temperatures rose a bit after that but ended up about 57.2 degrees until the 1980s.  After that, temperatures have risen fairly steadily as heat-trapping gases have accumulated in the atmosphere driving the current average above 58 degrees.

Global temperatures have only been directly measured since the mid-20th century.  There are proxy measurements from sources like tree rings, ice core samples, glacier measurements, and more that indicate that the recent readings may be the warmest days the earth has seen in millennia.

Average global temperature is determined using temperature readings at thousands of locations on both land and sea across the entire planet.  Those readings are compared with average temperatures at those locations for the date and the difference (known as the temperature anomaly) used to calculate a global average.

With the recent arrival of the El Niño in the Pacific Ocean, it is likely that the warming already being driven by greenhouse gas accumulation will intensify further. 

In a summer already marked by extreme heatwaves in many locations, having the entire planet 4 or 5 degrees hotter than normal is a very big deal and most certainly not a record to celebrate.

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Earth reaches hottest day ever recorded 4 days in a row

Photo, posted October 29, 2008, courtesy of Darek via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fungus And Carbon Storage | Earth Wise

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It is well-known that plants and trees store enormous amounts of carbon.  What has not been common knowledge is that the vast underground network of fungi across the world’s lands stores billions of tons carbon, roughly equivalent to 36% of yearly global fossil fuel emissions.

These mycorrhizal fungi form symbiotic relationships with almost all land plants.  The fungi transport carbon, converted by sugars and fats by plants, into soil.  They have been supporting life on land for at least 450 million years and form sprawling underground networks everywhere – even beneath roads, gardens, and houses – on every continent on earth.

An international team of scientists analyzed hundreds of studies looking at plant-soil processes to understand how much carbon is being stored by fungi on a global scale.  The findings, published in the journal Current Biology, revealed that over 13 billion tons of CO2 is transferred from plants to fungi each year, more than China emits annually.  This process transforms the soil beneath our feet to a massive carbon pool and constitutes the most effective carbon storage activity in the world.

Given that fungi have such a crucial role in mitigating carbon emissions, the researchers are recommending that fungi should be considered in biodiversity and conservation policies. More needs to be done in protecting the underground networks of mycorrhizal fungi. The UN has warned that human activities are degrading soils and that 90% of the world’s soils could be degraded by 2050.  Not only would this obviously be very bad for the productivity of crops and plants, but we now know this could be catastrophic for curbing climate change and rising temperatures.

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Fungi stores a third of carbon from fossil fuel emissions and could be essential to reaching net zero

Photo, posted May 28, 2023, courtesy of Geoff McKay via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Electric Motors For Aviation | Earth Wise

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Aviation contributes about 3% of global greenhouse gas emissions.  Its carbon footprint is one of the more difficult ones to reduce.  Electrifying planes would shrink that footprint considerably, but it represents a significant technical challenge.  To date, only small all-electric planes have gotten off the ground.  The electric motors in those planes generate hundreds of kilowatts of power.  To power large planes, like commercial airliners, megawatt-scale motors are required.

A team of MIT engineers is developing a 1-megawatt motor that could be a key step towards electrifying commercial aircraft.  They have designed and tested major components of the motor and have calculated how the completed design could generate one megawatt of power at a weight and size competitive with existing small aircraft engines.

To be suitable for aircraft use, motors have to be compact and lightweight.  The more power electric motors generate, the bigger they are and the more heat they produce.  Cooling motors requires additional components that take up space and add significant weight.  The MIT motor design and associated power electronics are each about the size of a typical checked suitcase and weigh less than an adult passenger.

Once the MIT team can demonstrate an entire functional motor, the design could be used to power regional aircraft and could be the enabling element of hybrid-electric propulsion systems for jet aircraft.  Possible future configurations could make use of multiple one-megawatt motors powering multiple fans distributed along aircraft wings.

Electrification of aircraft is a slow but steady area of development and technologies such as that being developed at MIT could end up meeting the practical needs of the aircraft of the future.

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Megawatt electrical motor designed by MIT engineers could help electrify aviation

Photo, posted September 14, 2019, courtesy of Dylan Agbagni via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Decontaminating Drinking Water | Earth Wise

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At least two billion people around the world often drink water that is contaminated with disease-causing microbes.  Waterborne diseases are responsible for two million deaths each year, mostly among children under the age of five.

There are various ways to decontaminate water, including chemicals that can themselves produce toxic byproducts as well as using ultraviolet light, which takes fairly long to disinfect the water and requires a source of electricity. 

Scientists at Stanford University and the SLAC National Accelerator Laboratory have recently invented a low-cost, recyclable powder that kills thousands of waterborne bacteria every second when the water containing it is exposed to ordinary sunlight.  The discovery of this ultrafast disinfectant could be a tremendous benefit to the nearly 30% of the world’s population with no reliable access to safe drinking water.

The new disinfectant is a harmless metallic powder that works by absorbing both ultraviolet and high-energy visible light from the sun.  It consists of nano-sized flakes of aluminum oxide, molybdenum sulfide, copper, and iron oxide.  The key innovation is that when these four metallic ingredients are immersed in water, they all function together by reacting with the surrounding water and generating chemicals that quickly kill bacteria. The chemicals themselves don’t last long.  They quickly break down in the water leaving completely safe drinking water.

The nontoxic powder is recyclable.  It can be removed from water with a magnet.  It can also be reused at least 30 times.  Apart from its uses in less developed parts of the world, it could be valuable for hikers and backpackers who want to drink water from natural sources of unknown quality.

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New nontoxic powder uses sunlight to quickly disinfect contaminated drinking water

Photo, posted February 27, 2013, courtesy of Petras Gagilas via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Greenhouse Gas Emissions Are Still Increasing | Earth Wise

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Recent research has found that the level of greenhouse gases emitted by human activity has reached an all-time high level of nearly 60 billion tons a year.  Despite increasing public attention, policy measures, and adoption of green technologies, the pace at which these changes have been taking place has simply not kept up with the ongoing burning of fossil fuels by increasingly industrialized societies.  The rate at which greenhouse gas emissions has increased over time has indeed slowed, but emissions need to start decreasing and as soon and as much as possible.

Human-induced warming has reached a ten-year average from 2013-2022 of 1.14 degrees Celsius above pre-industrial levels, up from a 1.07 degrees average between 2010-2019. 

Scientists have calculated a carbon budget that describes how much more carbon dioxide can be emitted before global warming exceeds the threshold of 1.5 degrees Celsius that is widely predicted to lead to potentially catastrophic changes to the climate.  In 2020, the Intergovernmental Panel on Climate Change calculated that the remaining carbon budget was about 500 billion tons of carbon dioxide.  Over the past three years, nearly half of that carbon budget has already been exhausted by the continuing onslaught of carbon emissions.

Researchers describe their study as a timely wake-up call that the pace and scale of climate action to date has been insufficient and that we need to change policy and approaches in light of the latest evidence about the state of the climate system.  Time is no longer on our side in trying to stave off the worst effects of climate change.

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Greenhouse gas emissions at ‘an all-time high’, warn scientists

Photo, posted September 18, 2015, courtesy of In Hiatus via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Below-Average Dead Zone In The Gulf of Mexico | Earth Wise

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The Gulf of Mexico dead zone, or hypoxic area, is an area of low oxygen content that can kill fish and other marine life.  It occurs every summer and is mostly a result of excess nutrient pollution from human activities in cities and farms throughout the Mississippi River watershed.  The nutrients carried by the river into the gulf stimulate an overgrowth of algae, which eventually die and decompose, which depletes oxygen in the water as the algae sink to the bottom.

The resultant low oxygen levels near the bottom of the gulf cannot support most marine life.  Fish and shrimp often leave the area seeking better places to be.  Animals that can’t swim away – like mussels and crabs – can be stressed by the low oxygen level or even killed.

The National Oceanic and Atmospheric Administration produces a dead zone forecast each year based on a suite of models developed by NOAA and partners at multiple universities. 

The latest forecast, completed in May, found that the discharge of nutrients in the rivers was about one-third below the long-term average between 1980 and 2022.  Nitrate loads were down 42% and phosphorous levels down 5%.

Based on these measurements, the scientists forecast a summer dead zone that will cover an estimated 4,155 square miles, which is 22% lower than the 36-year average of 5,364 square miles.  Ongoing efforts by the Interagency Mississippi River and Gulf of Mexico Hypoxia Task Force to reduce nutrient levels seem to be paying off.

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NOAA forecasts below-average summer ‘dead zone’ in Gulf of Mexico

Photo, posted September 6, 2013, courtesy of NOAA Photo Library via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Big Year For Rooftop Solar | Earth Wise

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The global capacity of rooftop solar power grew by 49% in 2022.  Overall, the installed amount of rooftop solar grew from 79 gigawatts to 118 gigawatts last year and it is projected to reach 159 gigawatts by the end of this year.  By comparison, a typical nuclear power plant can produce 1 gigawatt; a gas-powered power plant is typically half a gigawatt.

Rooftop solar constitutes a relatively small fraction of the total global installed solar capacity, which is dominated by utility-scale solar arrays.  Total installed solar capacity rose from 950 gigawatts to 1,177 gigawatts last year and is projected to reach 1,518 gigawatts this year.  That is enough power to meet more than half the electricity demand of the European Union.

The rapid growth of solar power can only continue if there is more energy storage put in place to manage the peaks and troughs in solar output.  Countries will also need to upgrade their power grids to be able to transport excess solar power from where it is generated to where it is needed.   Bottlenecks in the grids of most of the leading solar-producing nations are already interfering with further solar development.

The overall potential for rooftop solar is based on the number of rooftops that would be suitable for solar power, which depends on the size, shading, orientation, and location of the roofs.  According to the National Renewable Energy Laboratory, rooftops in the United States have the potential for more than 1,000 gigawatts of solar capacity. Currently, only about 4% of US homes have rooftop solar. 

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Rooftop Solar Grew Nearly 50 Percent Globally Last Year

Photo, posted November 16, 2022, courtesy of Oliver Knight via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Moss And Carbon Storage | Earth Wise

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All plants, including algae and cyanobacteria, carry out photosynthesis. During the process of photosynthesis, plants remove carbon dioxide from the air and release oxygen to the air.  As a result, plants play a crucial role in the fight against climate change. 

According to a new study recently published in the journal Nature Geoscience, mosses – those tiny plants often found on the ground or rocks – might be important antidotes to climate change.  The study, which was led by scientists from the University of New South Wales in Australia and the Institute of Natural Resources and Agrobiology in Spain, uncovered evidence that mosses have the potential to store a massive amount of carbon in the soil beneath them.

The researchers found that mosses sequester around seven billion tons more carbon in the soil than is stored in the bare patches of soil typically found near them.  To put that figure in perspective, that is six times the annual global carbon emissions caused by global land use change, which includes things like deforestation, urbanization, and mining.  The researchers also found that moss-covered soil possessed heightened levels of vital nutrients and fewer instances of soil-borne plant pathogens on average compared to moss-less soil.

Mosses cover an area of more than 3.6 million square miles, which is similar in size to Canada, and can thrive in challenging environments.  The widespread presence and hardiness of mosses is why they can have such a significant impact on soil biodiversity and carbon sequestration. 

The research team hopes future work will focus on understanding the role of all types of vegetation, not just mosses and trees, in capturing carbon.

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Study: Modest moss supports billions of tons of carbon storage

Photo, posted August 23, 2017, courtesy of Peter Handke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Water For Arizona | Earth Wise

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The Phoenix area is the fastest growing region in the country.  Arizona’s two major sources of water – groundwater and the Colorado River – are dwindling from drought, climate change, and overuse.  Officials in the state are considering a radical plan to construct a desalination plant off the Mexican coast that will take the salt out of seawater, and then pipe that water hundreds of miles, much of it uphill, to Phoenix.

The project is the brainchild of the Israeli company, IDE, which is one of the world’s largest desalination companies.  IDE has asked Arizona to sign a 100-year contract to buy water from the project. 

There are multiple complications surrounding the plan.  Desalination plants are common in California, Texas, and Florida, and in more than 100 other countries.  But the Arizona project is unusual because of the distance involved and because the state is landlocked.  The water would have to travel 200 miles and climb 2,000 feet along the way.

There is also the issue of waste brine, which is a major output of desalination plants.  In this case, the brine would flood the northern Gulf of California, potentially threatening a productive fishery.  In addition, the pipeline, as well as electrical transmission lines, would have to go through the Organ Pipe Cactus National Monument, a UNESCO biosphere reserve.

The plant would be located in Puerto Peñasco, a struggling town with its own water problems.

With booming home construction going on in the Phoenix area, the need for more water continues to grow.  Whether this plan will be approved by Arizona and by Mexico remains to be seen.

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Arizona, Low on Water, Weighs Taking It From the Sea. In Mexico.

Photo, posted September 26, 2008, courtesy of Dan via Flickr.

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