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Reducing emissions from ocean shipping

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Ocean shipping is a significant contributor to global carbon emissions, accounting for about 3% of the total.  It is a key part of international trade, moving goods like electronics, automobiles, and oil.  It relies on fossil fuels, and, without significant changes, shipping’s emissions could more than double by 2050.  Ocean shipping is one of the world’s most difficult to decarbonize industrial sectors.

Scientists at the University of Southern California and Caltech, collaborating with a startup company called Calcarea, have developed a shipboard system that could remove up to half of the carbon dioxide emitted by shipping vessels. The system is fairly simple and scalable.

The process mimics a natural chemical reaction that takes place in the ocean.  As a cargo ship moves through seawater, the CO2 from the ship’s exhaust is absorbed into water that is pumped onboard.  This makes the water more acidic.  The treated water is then passed through a bed of limestone, where it reacts with the rock to form bicarbonate, which is a stable compound that already exists naturally in seawater.  The treated seawater, now stripped of the carbon dioxide, is dumped back into the ocean.

Sophisticated ocean modeling examined what would happen when the bicarbonate-rich water is released back into the sea over a hypothetical 10-year period.  The model showed a negligible impact on ocean pH and chemistry.

The researchers estimate that widespread adoption of the technique could reduce shipping-related carbon dioxide emissions by 50%.  The startup company Calcarea is working to bring the technology to market and is in early discussions with commercial shippers.

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USC technology may reduce shipping emissions by half

Photo, posted November 14, 2017, courtesy of Bernard Spragg via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Planting trees to cool the planet

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Planting lots of trees is one of many strategies being pursued to combat climate change. Forests absorb carbon dioxide, provide shade, and help regulate temperatures. They also support biodiversity and improve air and water quality.

According to a new study by researchers from the University of California – Riverside, restoring forests to their pre-industrial extent could reduce global average temperatures by 0.34 degrees Celsius. That’s equivalent to about 25% of the warming the Earth has already experienced.

The study models restoring 4.6 million square miles of forest.  While previous studies have focused on the role trees play in removing carbon, this research adds that trees also alter atmospheric chemistry in ways that boost their cooling impact.

Trees release natural chemicals called BVOCs – biogenic volatile organic compounds – which interact in the atmosphere to form particles that reflect sunlight and promote cloud formation. These effects enhance the cooling impact of forests, especially in climate models that take these chemical reactions into account.

But not all reforestation is created equal. The benefits of reforestation vary by region, with tropical forests offering stronger cooling and fewer drawbacks.  Importantly, the researchers emphasize that meaningful climate benefits don’t require restoring every lost forest. Small, localized efforts can still shift regional climates.

While forest restoration can meaningfully aid climate efforts, the researchers stress that it must complement – not replace – fossil fuel reductions.

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Does planting trees really help cool the planet?

Photo, posted May 20, 2005, courtesy of Ben Britten via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Removing microplastics from water

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Microplastics come from the breakdown of larger plastics in the environment as well as from direct use in various products such as certain cosmetics.  They are found everywhere, from oceans and mountain peaks to the air and water, and alarmingly, in our bodies.  They are ingested by all sorts of organisms, from tiny plankton to fish and marine mammals.  Microplastics just don’t go away.  They don’t biodegrade so they simply accumulate in the environment.

Researchers at North Carolina State University have recently demonstrated proof of concept for a system that actively removes microplastics from water.  Such a system has the potential for helping to cleanse oceans and other bodies of water from the tiny plastic particles.

The system makes use of soft dendritic colloids, which are tiny particles that have the ability to stick to just about any surface.  These sticky particles can attract microplastics and grab them, even in wet and salty conditions.  The colloids are made from chitosan, a harmless and biodegradable polymer made from processed shellfish waste.

The researchers produced small pellets of the colloids that also contain small amounts of magnesium, which makes them bubble up and rise to the surface of water.  The pellets are coated with a gelatin layer, which blocks the magnesium.  As the gelatin gradually dissolves away, the pellets collect microplastics.  Eventually, the result is a microplastic-laden scum that rises to the surface where it can be skimmed away.

The scum itself can be bioprocessed into more chitosan that can create more of these microcleaner pellets to then capture more microplastics.  The researchers are investigating how the process can be scaled up to become a valuable tool in dealing with the microplastics problem.

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New Water Microcleaners Self-Disperse, Capture Microplastics and Float Up for Removal

Photo, posted January 17, 2018, courtesy of Bo Eide via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The dangers of deep sea mining

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The White House is considering an executive order that would fast-track permitting for deep-sea mining in international waters and allow mining companies to bypass a United Nations-backed review process.

Deep sea mining is the extraction of minerals from the seabed in the deep ocean.  Most of the interest is in what are known as polymetallic nodules, which are potato-sized mineral deposits that have built up in layers over thousands of years. They are located several miles below the surface, primarily in what is called the Clarion-Clipperton zone, which is an environmental management area of the Pacific Ocean about halfway between Mexico and Hawaii.

A new multiyear study led by UK’s National Oceanography Center and published in the journal Nature found that the site of a deep-sea mining test in 1979 still showed lower levels of biodiversity than in neighboring undisturbed sites 44 years later.

Much is not known about the undersea nodules.  We know that they produce oxygen.  If the nodules are removed, will that reduce the amount of oxygen in the deep sea and affect the organisms that live there?  If mining occurs, what effect will the metal-containing sediment plumes churned up by the mining process have? 

The nodule fields sustain highly specialized animal and microbial communities.  More than 20 billion tons of nodules are estimated to lie on the seabed of the Clarion-Clipperton Zone.  If large-scale mining takes place, and there is much interest in that happening, it is important to find out what the impact will be on the ocean and its ecosystems because it is likely to be largely irreversible.

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Deep sea mining for rare metals impacts marine life for decades, scientists say

Photo, posted September 4, 2014, courtesy of James St. John via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Trapping carbon with rocks

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Many experts say that combating global warming will require both drastically reducing the use of fossil fuels and permanently removing billions of tons of CO2 already in the atmosphere.  Developing practical, large-scale technologies for carbon removal is a significant challenge.

There is a nearly inexhaustible supply of minerals that are capable of removing carbon dioxide from the atmosphere, but they don’t do it quickly enough to make a significant dent in the ever-growing supply in the atmosphere.  In nature, silicate minerals react with water and atmospheric CO2 to form minerals in the process called weathering.  But this chemical reaction can take hundreds or even thousands of years.

Researchers at Stanford University have developed a new process for converting slow-weathering silicates into much more reactive minerals that capture and store carbon quickly.  The new approach resembles a centuries-old technique for making cement.  They combine calcium oxide and another common mineral containing magnesium and silicate ions in a furnace.   The result are new materials that, when exposed to water, quickly trap carbon from the atmosphere.

In their experiments, the carbonation process took weeks to months to occur, thousands of times faster than natural weathering.

The idea would be to spread these materials over large land areas to remove CO2 from the air.  Meaningful use for trapping carbon would require annual production of millions of tons.  But the same kiln designs used to make cement could produce the needed materials using abundant minerals found in many places.  In fact, the required minerals are often common leftover materials – or tailings – from mining.

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Scientists discover low-cost way to trap carbon using common rocks

Photo courtesy of Renhour48 via Wikimedia.

Earth Wise is a production of WAMC Northeast Public Radio

Tigers in India

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The Anthropocene is the term that describes the current era in Earth’s history when human activities are having a significant impact on the planet.  It is an epoch filled with species extinction and species attrition in both numbers and range.  The population of large carnivores are among the most affected species and recovering these animals that play important roles in ecosystems is a formidable challenge.

Tigers in Asia are a prime example of extirpation – removal of a species from a specific area.  They have been eliminated in more than 90% of their historic Asian range over the past century.  A new study, published in Science has found that tigers in India are making a comeback.

India’s National Tiger Conservation Authority estimates that between 2010 and 2022, India’s tiger population grew from 1,706 to 3,682.  Tigers are thriving not only on protected lands but also near some human communities.

Tigers are gone from poorer areas where poaching was prevalent and from areas affected by the violent conflict associated with India’s Maoist rebellion.  On the other hand, the big cats can be found near some prosperous communities where poaching is rare.  Farmers keep cattle in enclosures to protect them from tigers.  

The success in protecting tigers in India could provide some insights for Europe where wolves are making a comeback, and perhaps even in the American West where the resurgence of wolf populations is triggering a violent backlash.

Large predators can survive in the modern world with creative thinking and willingness to find a balance between protection and coexistence.

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India Doubled its Tiger Population in a Little More Than a Decade

Photo, posted January 8, 2014, courtesy of Roderick Eime via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Tearing down small dams to restore rivers

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There are more than 31,000 dams in the northeastern United States.  More than 4,000 of them are in the Hudson River watershed.  Most of these dams are quite small and were built in the 19th century to form ponds and to power grist, textile, paper, saw, and other kinds of mills as the region developed its industrial infrastructure.  The nonprofit organization American Rivers estimates that 85% of U.S. dams are unnecessary at best and pose risks to public safety at worst. 

Dam removals have been occurring for over 100 years, but the vast majority have taken place since the mid-2010s and have increased dramatically since the 2021 Bipartisan Infrastructure Law, which provided funding for such projects.

So far, 806 Northeastern dams have come down and hundreds more are in the pipeline.

Dam removals improve aquatic fish passage, water quality, watershed resilience, and habitat for all the organisms in river ecosystem food chains, ranging from insects to fish to otters to eagles.  Small dams have degraded habitat and altered downstream hydrology and sediment flows.  They have created warm, stagnant, low-oxygen pools that trigger algal blooms and favor invasive species.

But removing even small dams is not an easy matter.  Projects range in cost from $100,000 to $3 million and qualifying for funding – whether federal or state – requires projects to meet a variety of requirements including community support.  Not all dams can be removed, but many more should.

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How Tearing Down Small Dams Is Helping Restore Northeast Rivers

Photo, posted September 20, 2010, courtesy of Doug Kerr via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fighting harmful algal blooms with harmful algal blooms

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Harmful algal blooms – HABs – occur when colonies of algae grow out of control and produce toxic or harmful effects on people, marine life, and birds.  HABs occur naturally but their frequency and intensity are often associated with increased nutrient loading (mainly phosphorous and nitrogen) in bodies of water that is the result of runoff from sources like lawncare and agriculture.

Researchers at Florida Atlantic University have developed a technique for transforming cyanobacteria – also known as blue-green algae and a prime HAB material – into an effective material for removing phosphorous from water.

Their process converts blue-green algal biomass – essentially hazardous waste – into a custom-made adsorbent material that can pull harmful phosphorous from water.  The algae is first quickly heated up using microwaves and then it is modified by adding lanthanum chloride. 

The study took blue-green algae from Florida’s Lake Okeechobee, synthesized the adsorbent material in minutes, and using only small amounts of it could remove 90% of the phosphorous present in only half an hour.  It worked perfectly well in the presence of natural organic matter.  Using the harmful algae itself to prevent algal growth in bodies of water is an innovative way to reduce its further occurrence.

Phosphorous is a major contributor to the occurrence of harmful algal blooms, which can lead to toxic water conditions, loss of aquatic life, and significant economic losses for the fishing and tourism industries.  This technique could prove to be an essential tool for managing the growing problem of nutrient pollution.

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FAU Engineering Develops New Weapon Against Harmful Algal Blooms

Photo, posted October 27, 2010, courtesy of Jennifer L. Graham / U.S. Geological Survey via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Investing in carbon capture

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The interests of billionaires seldom seem to coincide with our own.  In fact, they often seem to be quite the opposite.  But there are a number of billionaires who are trying to help the world combat climate change.  Yes, they want to make money doing it, but doing it is nevertheless in everyone’s interest.

A group headed by Bill Gates that included some of the wealthiest people from around the world met last summer in London to evaluate companies working to mitigate the effects of climate change.  These included companies developing carbon dioxide removal technologies.  Stripping carbon dioxide out of the atmosphere is an obvious way to deal with the fact that we continue to dump too much of it into the atmosphere –   obvious, but extremely difficult to do at any scale that makes a difference.

Companies working on carbon capture have raised more than $5 billion since 2018.  There are hundreds of companies working on it and investors include billionaires, venture capitalists, private equity firms, and major corporations.  Companies like Microsoft, Google, and United Airlines have committed billions of dollars to purchase removal credits:  payments to companies for removing carbon dioxide.

There are only a few dozen carbon removal facilities operational today and together they only capture a tiny fraction of the carbon dioxide humans release into the atmosphere.  The hope is that such facilities will scale up in size and number so that they will make a real dent in the problem.  But it will take many years at best, and the planet doesn’t have that much time.  To make a difference, carbon emissions must be reduced as quickly as possible.

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The New Climate Gold Rush: Scrubbing Carbon From the Sky

Photo, posted April 19, 2020, courtesy of Greg Rubenstein via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Reducing farm nutrient pollution

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When farmers add nutrients to their fields in excess of their crops’ ability to utilize them, these excess nutrients can enter the surrounding environments and create environmental problems.  The primary culprits are nitrogen and phosphorous.  These fertilizer components emerge from fields and enter local waterways in surface runoff.

Researchers at the University of Illinois Urbana-Champaign have developed a form of designer biochar that can provide phosphorous in a time-released fashion and reduce the amount that escapes into the environment.

The researchers used sawdust and lime sludge, which are byproducts from milling and water treatment plants, respectively.  They mixed the two ingredients and formed pellets which were then slow-burned in low-oxygen conditions to create phosphorous-laden designer biochar.  Once the pellets bind all the phosphorous they can hold, they can be spread onto fields where the nutrient is slowly released over time.

They tested the pellets in working field conditions.  The pellets are used to remove phosphorous from drainage water and then can be reused in the field to provide the nutrient to the plants.   

The results were very encouraging.  The biochar proved to be a very effective way to provide phosphorous to crops and then reduce how much phosphorous enters the environment.  The cost of producing the biochar pellets was less than half that of alternative substances for phosphorous removal. 

There is currently no regulation that requires farmers to remove phosphorous from drainage water but there are a growing number of conservation-minded farmers who want to reduce nitrogen and phosphorous losses from their fields.  The idea that the recyclable pellets can both provide and control phosphorous is an attractive one.

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Scientists tackle farm nutrient pollution with sustainable, affordable designer biochar pellets

Photo, posted July 16, 2016, courtesy of Rick Obst via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Limiting global warming

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A pressing question from the recently concluded 29th annual United Nations Climate Change Conference in Azerbaijan is how to transition away from fossil fuels and speed up climate mitigation in line with the 1.5 °C global warming target.

Keeping global average temperatures below 1.5 °C above pre-industrial levels is crucial to avoid the most severe impacts of climate change, including extreme weather, rising seas, biodiversity loss, and disruptions to food and water security. 

According to a new study by researchers from Stockholm University, Chalmers University of Technology, and Uppsala University in Sweden, it is still possible to limit global warming to 1.5 °C.  But the study found that the United States, the European Union, and 16 other countries will have to exceed their own current targets in order to achieve this global goal.  

The study, which was recently published in the journal Nature Communications, introduced an “additional carbon accountability” indicator, which quantifies countries’ responsibility for mitigation and carbon dioxide removal in addition to achieving their own targets.

The study identified 18 countries that should be accountable for increasing their ambitions to stay within their equal per capita share of the global carbon budget for 1.5 °C.  Additional carbon accountability is highest for the United States and China, and highest per capita for the United Arab Emirates, Russia, Saudi Arabia, and the U.S.

Failure to limit global warming risks catastrophic impacts of climate change.

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COP29: Possible to limit climate change to 1.5°C – if EU and 17 other countries go beyond their own targets

Photo, posted December 27, 2015, courtesy of Gerry Machen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Removing nanoplastics from water

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Plastic pollution is a growing problem for people and for the environment in multiple ways.  When plastics break down over time, they can form small particles called microplastics – bits smaller than sesame seeds – and these, in turn, can break down into even smaller pieces called nanoplastics.  They are too small to be seen with the naked eye and can enter the body’s cells and tissues.

Recent studies have shown that nanoplastics are increasingly showing up in bottled water.  In fact, measurements on several popular brands of bottled water found an average of nearly a quarter million tiny pieces of plastic in a single liter of bottled water.

The health effects of ingesting all of this plastic are not really known, but they are unlikely to be anything good.  Finding a way of avoiding this contamination of the beverages we drink is a pressing need.

Researchers at the University of Missouri have created a new liquid-based solution that eliminates more than 98% of microscopic plastic particles from water.  The method makes use of water-repelling solvents made from safe, non-toxic natural ingredients. A small amount of this designer solvent absorbs plastic particles from a large volume of water.

The solvent sits on the water’s surface.  When mixed with the water, it absorbs the plastic and eventually comes back to the surface carrying the plastic leaving behind clean, plastic -free water.

Ultimately, the hope is to scale up the process so it can be applied to increasingly large amounts of water – even lakes and, eventually, oceans.  There is work to be done, but it is a potential way to address an increasingly worrisome and pervasive form of pollution.

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Mizzou scientists achieve more than 98% efficiency removing nanoplastics from water

Photo, posted August 9, 2012, courtesy of Enid Martindale via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The largest carbon removal plant

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Direct air capture (DAC) is process that removes carbon dioxide out of the air and stores it away where it can no longer trap heat in the atmosphere.  It is intended to be a way of getting rid of the greenhouse gases that have built up in the atmosphere.  In principle, it’s a great idea.  In practice, it is a huge challenge.

In 2017, a company called Climeworks became the first company to take carbon dioxide out of the air and sell it as a product for use in carbonated drinks and in greenhouses.  In 2021, the company opened a DAC plant called Orca in Iceland that captures CO2 and permanently stores it underground.  Clients like Microsoft pay Climeworks for doing this as a way of offsetting their own emissions.

Recently, Climeworks has started operating a new plant called Mammoth – also in Iceland – that will be able to capture about 10 times more carbon dioxide than Orca.  Iceland is a prime location for DAC technology because its abundant geothermal energy makes powering it cheap and environmentally friendly.

Mammoth, when fully operational, will remove about 36,000 tons of carbon dioxide a year, the largest DAC system in the world.  But there is a long, long way to go.  Microsoft alone emits nearly 13 million tons of carbon dioxide a year.

There are multiple DAC projects in development including several in the United States being funded by the Bipartisan Infrastructure Law.  The four DAC hubs being developed under the program are each supposed to have the capacity to capture at least a million metric tons of CO2 a year.

Whether DAC can make a real difference remains to be seen.

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The world’s largest carbon removal plant is here, and bigger ones are on the way

Photo credit: Climeworks

Earth Wise is a production of WAMC Northeast Public Radio

Marine carbon dioxide removal

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About 30% of the carbon dioxide emitted by human activity is absorbed by the oceans.  As a result, they are getting warmer and more acidic, and the currents that help shape global weather are shifting.  To try to reduce global warming, people want to be able to store even more carbon dioxide in the oceans without the negative effects of doing so.

There are multiple efforts across the globe to achieve effective marine carbon dioxide removal.  Some are based on sinking carbon-rich materials to the bottom of the sea.  This is the marine equivalent of capturing CO2 from the air and storing it underground.  Other efforts involve increasing the alkalinity of the ocean, which increases its ability to chemically react with carbon dioxide as well as lowers its acidity, which is desirable in many ways.

Running Tide, a U.S.-based company, has been dumping thousands of tons of wood-industry waste 190 miles off the coast of Iceland.  The company has also been experimenting with dumping algae and kelp and sinking it deep below the ocean.  Such materials on land either get burned or decay, in both cases releasing CO2 into the atmosphere.  On the deep-sea bottom, the carbon is trapped.

Other efforts involve pumping seawater through electrodialysis filter systems to remove excess acidity or adding alkaline rocks to increase water alkalinity.

All of these efforts are a form of geoengineering, and like proposed ideas to cool the atmosphere, pose potential risks.  There is no silver bullet to solve the climate crisis.  It will take a combination of many solutions to address the issue of excess carbon dioxide in the atmosphere.  Marine carbon dioxide removal is one of the solutions that may play a role.

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Scientists Are Trying to Coax the Ocean to Absorb More CO2

Photo, posted February 22, 2018, courtesy of Bobbie Halchishak/USFWS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Biochar and carbon

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Biochar is a charcoal-like substance that is made by burning organic materials like crop and forestry wastes in a controlled process called pyrolysis, which is burning in an oxygen-deprived environment.  Pyrolysis produces little or no contaminating fumes and results in a stable form of carbon that can’t easily escape into the atmosphere.  Biochar is a very efficient way to convert carbon into a stable form.

Adding charred biomass to improve soil quality has been done for thousands of years.  Indigenous people in the Amazon added charcoal, food residue, and other waste to their soil.  When mixed with soil, biochar creates favorable conditions for root growth and microbial activities, which reduces greenhouse gas emissions. 

Last year, 125,000 tons of carbon dioxide were removed worldwide in the durable carbon market, which is a carbon credit marketplace for carbon removal.  About 93% of that was in the form of biochar. 

Biochar represents a value-added way to deal with agricultural waste and also to make use of dead trees in forests that should be removed to lower the risk of wildfires caused by the presence of all that dry tinder material. 

A bill to fund biochar research is pending before the Senate Agricultural Committee.  It is a rare example of bipartisan legislation.

Biochar is currently expensive to make in the US because large amounts of biomass must be shipped to one of the fewer than 50 small-scale production facilities in the country.   But with appropriate infrastructure, biochar could play an important role in efforts to sequester carbon and combat climate change.

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Biochar Is ‘Low-Hanging Fruit’ for Sequestering Carbon and Combating Climate Change

Photo, posted September 3, 2019, courtesy of Tracy Robillard / NRCS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Self-heating concrete

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States in the colder parts of the country spend an estimated $2.3 billion a year on snow and ice removal as well as untold millions on repairing roadways damaged by winter weather.  Researchers at Drexel University have been researching a way to extend the service life of concrete surfaces like roadways and to help them maintain a surface temperature above freezing during the winter.

Preventing freezing and thawing as temperatures go up and down and reducing the amount of plowing and salting is a desirable goal.  The Drexel team has developed a cold-weather-resilient concrete mix that is capable of melting snow on its own using only the thermal energy in the environment and not requiring salt, shoveling, or heating systems.

The system uses low-temperature liquid paraffin that turns from its room-temperature liquid state into a solid when temperatures go down.  Incorporating the liquid paraffin into concrete triggers heating when temperatures drop due to the energy released by the phase change.

Tests on slabs of the concrete on the Drexel campus over the past two years recorded 32 freeze-thaw events.  The special slabs maintained a surface temperature between 42 and 55 degrees for up to 10 hours when air temperatures dipped below freezing.

The heating is enough to melt a couple of inches of snow at a rate of a quarter inch an hour.  It’s not enough to melt a heavy snow event before plows are needed, but it can help deice road surfaces and increase transportation safety.  And simply preventing the surface from freezing, thawing, and refreezing can go a long way towards preventing deterioration.  It is promising research toward reducing an ongoing problem in colder climates.

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Drexel’s Self-Heating Concrete Is One Step Closer to Clearing Sidewalks Without Shoveling or Salting

Photo, posted March 16, 2024, courtesy of Ajay Suresh via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Forever chemicals in water

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So-called forever chemicals are pervasive in a wide range of products.  These are man-made substances called per- and polyfluoroalkyls or PFAS.  They get their unfortunate nickname because the chemical bonds in them are so strong that the compounds don’t break down for hundreds or even thousands of years.

PFAS compounds are used in makeup, dental floss, nonstick pans, food wrappers, pesticides, stain-resistant fabrics and carpets, firefighting foams, and more.  High level exposure to some of these chemicals has been linked to a variety of health problems include high cholesterol, liver and immune system damage, pregnancy problems, and kidney and testicular cancer.

A recent study published in the journal Nature Geoscience has found that PFAS chemicals are showing up in water around the world.  The study looked at more than 45,000 water samples and found that about 31% of ground water tested that wasn’t even near any obvious source of PFAS contamination had levels of the chemicals that are considered harmful to human health by the EPA.  About 16% of surface water samples – streams, rivers, ponds, and lakes – also not near any known source, had similar hazardous PFAS levels.

The EPA has now imposed strict new drinking water limits for six types of PFAS.  Going forward, water systems are required to monitor for these chemicals and remove them if they are found above allowable levels.  The new rules make the United States one of the strictest countries in the world in terms of regulating PFAS in water.

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EPA puts limits on ‘forever chemicals’ in drinking water

Photo, posted May 5, 2020, courtesy of Brandon Shaw via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Planting Rocks To Capture Carbon | Earth Wise

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Getting humanity to stop dumping carbon dioxide into the atmosphere continues to be very challenging regardless of how increasingly apparent the need to do so becomes.  For this reason, climate change mitigation strategies increasingly include interventions in the form of removing carbon dioxide that is already there.  There are a variety of ways to draw carbon dioxide out of the atmosphere, but they face a host of technological, economic, and even environmental difficulties.

A new study at Yale University evaluated a type of climate intervention called enhanced rock weathering.  Rock weathering is a natural chemical process by which certain minerals absorb carbon dioxide over time.  Enhanced rock weathering is simply speeding up weathering such so it can have beneficial results soon enough to make a difference.

The study explored the potential of applying crushed basalt, which is a fast-weathering rock that forms when lava cools, to agricultural fields around the world.  Basically, the idea is for farmers to mix the crushed rocks into their fields. There is no real downside to doing this.  In fact, adding crushed basalt to fields rejuvenates depleted soils and helps counter ocean acidification.

The study simulated the results of enhanced rock weathering on 1,000 agricultural sites around the world.  Over a 75-year period, these sites would remove 64 billion tons of carbon dioxide from the atmosphere.  This is roughly the amount climate scientists believe is needed to take out of the atmosphere. 

Enhanced rock weathering has been used on a small scale on farms around the world.  Perhaps it is time to ramp up its use.

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‘Planting’ rocks in farms, along with emissions reductions, could help meet key IPCC carbon removal goal

Photo, posted January 14, 2023, courtesy of Ron Reiring via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Removing Carbon Dioxide Won’t Get the Job Done | Earth Wise

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Limiting global warming to no more than 1.5-2 degrees Celsius above pre-industrial levels is a crucial goal for humankind.  Countries, companies, and other organizations around the world have committed to achieving ‘net zero’ emissions.  This is distinct from zero emissions in that it includes removing carbon dioxide from the atmosphere to offset the amounts we are putting into it.  Carbon dioxide removal is increasingly touted as the way to achieve emission goals.  But it is a realistic strategy?  According to a recent paper by a leading climate scientist in the journal Nature, the answer in the short term is decidedly no.

In 2022, the world emitted 45 billion tons of carbon dioxide into the atmosphere.  Last year’s bipartisan Infrastructure Law earmarked $3.5 billion for developing four direct air capture hubs in the US.  Each of these is expected to eventually be able to extract a little over a million tons of CO2 from the air each year. These hubs combined would therefore remove about 52 minutes’ worth of the year’s emissions over the course of the year. 

The bottom line is that unless we drastically reduce emissions, all the carbon dioxide removal strategies combined will scarcely make a dent in the problem.

We will never be able to eliminate all sources of emissions, particularly from certain industries, and carbon dioxide removal will be a very important technology to address those emissions, but in the big picture, it is essential that the world decarbonizes as much as possible and as soon as possible.

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Carbon dioxide removal is not a current climate solution — we need to change the narrative

Photo, posted January 19, 2009, courtesy of Wladimir Labeikovsky via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Ocean-based Climate Intervention And Deep-sea Ecosystems | Earth Wise

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Deep-sea ecosystems cover more than 40% of the Earth.  These regions are some of the least well-known and understood areas of our planet but are home to numerous ecosystems.  The deep seas are already directly exposed to the effects of human-induced climate change but could potentially be greatly threatened by efforts to artificially counteract climate change.

A class of geoengineering solutions called ocean-based climate interventions are increasingly being claimed as promising ways to mitigate climate change.  Such interventions would remove carbon dioxide from the atmosphere and sequester it in the deep sea.  There is very little known about the impact of such efforts on ocean biogeochemistry and the biodiversity of ocean ecosystems.

One approach is direct CO2 injection into the deep ocean, which would sequester large amounts of it and reduce the concentration in the atmosphere.  However, too much carbon dioxide in the water is called hypercapnia, which can have serious consequences on marine life.

Other approaches include ocean fertilization – which is enhancing phytoplankton production at the surface, leading to their eventual deposition on the deep-sea floor – and crop waste deposition – which is deep-sea disposal of terrestrial crop waste. 

A multinational study led by the Scripps Institution of Oceanography warns that there needs to be much more research and governance before any such interventions ever take place.  The deep sea faces unprecedented threats from industrial fisheries, pollution, warming, deoxygenation, acidification, and other climate-related problems.  Ocean-based climate intervention represents yet another serious threat to the functioning of these essential ecosystems.

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Web Links

HKU Marine Scientist contributes to research assessing the potential risks of ocean-based climate intervention technologies on deep-sea ecosystems

Photo, posted January 6, 2010, courtesy of Emrys Roberts via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

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