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Facemask pollution

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During the height of the Covid-19 pandemic, the global usage of disposable facemasks reached a staggering 129 billion per month. Most of these masks are manufactured from petroleum-based non-renewable plastics like polypropylene and the disposal of these masks results in serious pollution problems.  These include the loss of ecological integrity from buried waste in landfills, air pollution from increased waste incineration, and microplastic pollution. 

Recent research by engineers at Washington University in St. Louis investigated the multipronged pollution problem brought about by discarded facemasks.  The study in particular looked at the chemical changes that occur when facemasks are exposed to sunlight, water, and trace metal ions.

Masks littering the environment degrade into nanoplastics and produce reactive oxygen species.  These chemical agents interact with trace metal ions in the environment within hours.  The result is oxides of metals like manganese and iron, which can drive various biogeochemical reactions.

Abandoning and forgetting about plastics like facemasks is an unsustainable practice.  Plastics not only cause physical damage, but also introduce unpredictable and potentially dangerous chemical changes into environmental systems.

Plastic waste is a global problem that has continued to grow and become an increasingly serious threat over decades.  Understanding the nature of the effects of billions of facemasks in the environment is essential to efforts to address the challenges created by them.

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Sun exposure changes chemical fate of littered face masks

Photo, posted August 21, 2021, courtesy of Ivan Radic 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

Sun powered carbon capture

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As the world struggles to implement technologies and find the political will to reduce carbon emissions, there are also ongoing efforts to find ways to capture carbon from emitting sources and from the atmosphere itself.  After capturing carbon dioxide, there is then the need to safely store it or make use of it.

Current methods for capturing and then releasing carbon dioxide are expensive and energy intensive.  In fact, some methods even require the use of fossil fuels.  Recently, researchers at Cornell University have developed a method for capturing carbon dioxide that is powered by sunlight.

The Cornell method mimics the mechanisms that plants use to store carbon which involves using sunlight to make a reactive enol molecule that grabs carbon dioxide.  

Existing chemical-based carbon capture techniques make use of amines, which are organic ammonia-derived compounds that react selectively with carbon dioxide.  But amines are not stable in the presence of oxygen and don’t last, which necessitates the energy-intensive production of more and more amines.

The Cornell method uses the same method that the plant enzyme RuBisCo uses in photosynthesis.  It is based on an inexpensive sorbent material that is capable of a high rate of carbon capture.

The researchers tested the system using flue samples from Cornell’s Combined Heat and Power Building, an on-campus power plant that burns natural gas.  The system was successful in isolating carbon dioxide.

Ultimately, they would like to stage the reaction on what looks like a solar panel, but one that would capture carbon instead of generating electricity.

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In a first, system uses sunlight to power carbon capture

Photo, posted August 8, 2015, courtesy of Holly Victoria Norval via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Self-healing concrete

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Concrete is the most widely used building material on Earth.  It has a dangerous and costly flaw:  it cracks easily.  Cracks in concrete can lead to inconvenient damage or to catastrophic structural failures such as collapses of buildings, bridges, or highways.

Concrete is made by mixing crushed stone and sand with powdered clay and limestone and adding water.  The mixture hardens and once set becomes extremely strong.  However, natural forces like freeze-thaw cycles, drying shrinkage, and heavy loads can cause cracks.  Even very tiny cracks can allow liquids and gases to seep into embedded steel reinforcements causing corrosion and weakness. 

For over 30 years, researchers have investigated microbe-mediated self-healing concrete.  It involves introducing microbial healing agents into cracks and injecting nutrients for the healing agents to produce repair materials.  It is not a very practical solution.

Researchers at Texas A&M University have developed a technique inspired by the behavior of lichen systems. Their system, like lichen, uses a combination of cyanobacteria which turns air and sunlight into food, and filamentous fungi, which produces minerals that seal the cracks. 

In lab tests, the paired microbes were able to grow and produce crack-filling minerals even in challenging environments such as concrete.  If it is possible to produce concrete that can heal itself, it would significantly reduce maintenance costs, extend its longevity, and even protect lives through increased safety.

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Cracking the Code: Deciphering How Concrete Can Heal Itself

Photo, posted May 21, 2009, courtesy of DesignMag via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The oceans are warming faster

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A new study has shown that the rate of ocean warming has more than quadrupled over the past 40 years.  The study, by researchers at the University of Reading in the UK, helps to explain why there have been unprecedented ocean temperatures in 2023 and 2024.

Global ocean temperatures hit record highs for 450 days straight in 2023 and early 2024.  Some of this unusual warmth came from the El Niño that was taking place at the time, but the rest of the increased temperature came from the sea surface warming up more quickly over the past 10 years than in previous decades.  In the late 1980s, ocean temperatures were rising at a rate of 0.06 degrees Celsius per decade.  According to the recent research, they are now increasing at 0.27 degrees per decade.

The acceleration of ocean warming is driven by growth in the Earth’s energy imbalance, meaning that more energy from the sun is being absorbed by the Earth than is escaping back into space.  This energy imbalance has roughly doubled since 2010 as a result of two factors:  increasing greenhouse gas concentrations in the atmosphere and reductions in the Earth’s albedo.

Earth’s albedo, the measure of how much sunlight is reflected back into space, has been declining since the 1970s, primarily due to the decrease in snow and ice cover, especially in the Arctic. 

The overall rate of ocean warming observed over recent decade is likely to only increase.  This underscores the urgency of reducing fossil fuel burning to avoid even more rapid temperature increases in the future.

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Ocean-surface warming four times faster now than late-1980s

Photo, posted January 18, 2007, courtesy of Alexey Krasavin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Modeling geoengineering

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As the impacts of climate change continue to mount up, there is increasing interest in radical intervention measures designed to keep a lid on rising global temperatures.  Such measures are fraught with potential dangers and unintended consequences but there is no guarantee that one or another of them might still be attempted in the future.  Increasing international interest in geoengineering as a potential strategy for mitigating climate change has created a pressing need to consider its impact before any potentially irreversible actions are taken.

The Natural Environment Research Council in the UK is funding four research projects aimed at understanding the potential consequences of solar radiation modification (SRM) being deployed in the real world.

SRM consists of methods to reflect some of the Sun’s radiation back into space instead of allowing it to reach and warm the earth. 

One approach is stratospheric aerosol intervention in which particles such as sulfates are introduced into the upper atmosphere to reflect sunlight thereby producing a dimming effect.   The idea is to mimic the effects of large volcanic eruptions, which naturally send sulfates into the atmosphere.

A second approach is marine cloud brightening, which increases the reflectivity of clouds over the ocean by spraying very small droplets of sea water into the air.  The fine particles of sea salt enhance cloud condensation nuclei, producing more cloud droplets and making clouds more reflective.

The research aims to deliver independent risk analyses to inform policymakers about the potential environmental impacts of SRM.

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Scientists to model the impact of controlling Earth’s temperature by reflecting solar radiation

Photo, posted May 6, 2009, courtesy of Denys Zadorozhnyi via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Hurricanes and wildfires

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Early March saw more than 200 wildfires break out in the southeastern U.S. – a busy start to the region’s annual fire season.  One fire in the Carolina Forest near Myrtle Beach scorched over 2,000 acres over a two-week period and firefighters were busy containing it and many other blazes.

Strong winds and an unusually long dry period have made fires more likely to ignite and be spread.  Lightning strikes, power line sparking, backyard fire pits and leaf burning all can lead to wildfires under these conditions.

A weather disaster last year may be helping to make this fire season worse than usual.  Hurricane Helene ravaged the Southeast last September, dumping more than a foot of rain in some locations and knocking over hundreds of thousands of acres of trees across the region.

Lots of dead trees lying on the ground allow sunlight to reach the ground and dry out all the biomass, including the trees.  All of this desiccated plant material acts as kindling, providing fuel for wildfires.  Fallen trees can be a fire nuisance for years after a hurricane, especially in the Southeast, where dried out pine needles are highly combustible.  All it takes is an ignition.

In addition, all the fallen trees represent an access issue for firefighters as the logs block roads needed to reach the fires.

Research has shown that climate change is fueling more intense fires in the West.  Whether the changing climate is having a major effect in the Southeast isn’t clear.  But droughts are expected to become more intense and more frequent in the Southeast because of climate change and that isn’t good news for the likelihood of wildfires.

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How Hurricanes Can Fuel Wildfires in the Southeast

Photo, posted March 5, 2025, courtesy of the U.S. Army National Guard / Roberto Di Giovine via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Making hydrogen using bioengineering

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Hydrogen has great potential for helping society to reach net-zero emissions.  The problem is that the most economical and established production methods for hydrogen depend heavily on fossil fuels and result in roughly a dozen kilograms of carbon dioxide emissions for every kilogram of hydrogen produced.

The carbon-free way to produce hydrogen is by splitting water into its component elements.  This process generally requires the use of catalysts and lots of energy.

Researchers at the University of Oxford are developing a synthetic biology approach to the production of so-called green hydrogen.  The idea is to replace expensive, exotic metal-based catalysts with a highly-efficient, stable, and cost-effective catalyst based on genetically-engineered bacteria.

There are specific microorganisms that can naturally induce the chemical reaction that reduces protons to hydrogen by the use of hydrogenase enzymes.  While these reactions do occur naturally, they are limited to low hydrogen yields.

The Oxford researchers genetically engineered the bacterium Shewanella oneidensis by inserting a light activated electron pump called Gloeobacter rhodopsin as well as adding nanoparticles of graphene oxide and ferric sulfate.  All of this tinkering with the bacterium resulted in a ten-fold increase in hydrogen yield.

The researchers believe that their system, based entirely on biological methods rather than traditional chemical approaches, could be scaled up to produce ‘artificial leaves’ that, when exposed to sunlight, would immediately begin producing hydrogen.  The Oxford work was published last summer in the Proceedings of the National Academy of Science.

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A green fuels breakthrough: bio-engineering bacteria to become ‘hydrogen nanoreactors’

Photo, posted July 27, 2016, courtesy of Blondinrikard Froberg via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Growing safer potatoes

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We are often advised to avoid eating green areas on potatoes.  The green comes from chlorophyll that occurs naturally when potatoes are exposed to light.  It is harmless but when it is there, it can be accompanied by a natural toxin – a substance called solanine, which is a steroidal glycoalkaloid or SGA.  Sunlight can produce solanine as well as chlorophyll.  Solanine is produced by plants to protect them from insects. 

Solanine is bitter tasting so one is unlikely to consume much of it.  But consuming enough of it can lead to gastrointestinal complications like diarrhea, abdominal pain, vomiting, and sweating. 

Researchers at the University of California Riverside have discovered a way to eliminate toxic compounds from potatoes, making them safer to eat and easier to store.  They have identified a key genetic mechanism in the production of SGAs.  They found a specific protein that controls the production and believe it will be possible to control where and when SGAs are produced.  Thus, it may be possible to have SGAs present in the leaves of potato plants, thereby protecting them from insects, while having none in the potatoes themselves.  By limiting SGAs to non-edible parts of plants, they can be safer and more versatile plants.  For example, modified potatoes could be stored in sunny places without worry and would always be safe to eat.

Plants have evolved ingenious ways to balance growth, reproduction, and defense.  Our growing understanding of these mechanisms can allow people to redesign crops to meet modern needs, increase food safety, and reduce food waste.

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Growing safer spuds: Removing toxins from potatoes

Photo, posted October 14, 2013, courtesy of Elton Morris via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Solar-powered desalination

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People in remote, low-income regions far from the ocean often need to meet their water needs from groundwater and groundwater is becoming increasingly saline due to climate change.  Desalination of brackish groundwater is a huge and largely untapped source of drinking water, but there are challenges in making the process efficient and reliable.

Engineers at MIT have developed a solar-powered desalination system that requires no batteries or external power sources and is capable of producing large quantities of clean water despite the variations of sunshine throughout the day.

The system is based on the process of electrodialysis and consists of water pumps, an ion-exchange membrane stack, and a solar panel array.  What is unique about it is that it makes use of sensors and a control system that predicts the optimal rate at which to pump water through the system based on the output of the solar panels.  As a result, it uses nearly all of the electricity generated to produce clean water and does not need stored or grid-based energy.

The MIT engineers tested a community-scale prototype on groundwater wells in New Mexico over a six-month period.  The system harnessed on average over 94% of the electricity generated by its solar panels and produced as much as 5,000 liters of water per day despite large variations in weather and sunlight.

The new renewable-powered, battery-free system could provide much-needed drinking water at low cost, especially for communities where access to seawater and to grid power are limited.  The team plans to further test and scale up the system so it can supply larger communities and even whole municipalities with low-cost drinking water.

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Solar-powered desalination system requires no extra batteries

Photo courtesy of Shane Pratt.

Earth Wise is a production of WAMC Northeast Public Radio

A better way to produce green hydrogen

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Hydrogen has great potential as a fuel and an energy carrier for many applications.  Burning it or consuming it in fuel cells does not produce carbon emissions.  As a result, there has long been the vision for a future hydrogen economy.  Whether the hydrogen economy would ever come about given how various other technologies have evolved over time is questionable.  But regardless, hydrogen is valuable for many industrial and commercial applications including the manufacture of ammonia and the refining of metals.

Hydrogen is produced in industrial quantities from natural gas by a carbon-dioxide-producing process known as methane-steam reforming.  To take its place as a green energy source, hydrogen needs to be produced by splitting water into its constituent oxygen and hydrogen components by the process of electrolysis. 

The problem is economic.  Methane-steam reforming produces hydrogen at a cost of about $1.50 per kilogram.  Green hydrogen costs about $5 a kilogram.

Researchers at Oregon State University have developed a new photocatalyst that enables the high-speed, high-efficiency production of hydrogen.  The material, called RTTA, is a metal organic framework containing ruthenium oxide and titanium oxide.  Ruthenium oxide is expensive, but very little is needed.  For industrial applications, if the catalyst shows good stability and reproducibility, the cost of the small amount of this exotic material becomes less important.

The photocatalyst, when exposed to sunlight, quickly and efficiently splits water yielding hydrogen.  The Oregon State discovery has real potential.

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Oregon State University research uncovers better way to produce green hydrogen

Photo, posted July 7, 2023, courtesy of Bill Abbott via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A dangerous invasive species

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Weeds are the bane of every gardener’s existence.  They pop up, uncontrolled and unwelcome, and must be tediously managed time and time again.  But in some cases, weeds are more than just a nuisance.  Some are a public health hazard. 

Meet giant hogweed.  Native to Europe’s Caucasus Mountains, giant hogweed belongs to the carrot family. The plant resembles Queen Anne’s Lace – on steroids. Giant hogweed can grow up to 15 feet tall with three inch stems, five-foot-wide leaves, and an umbrella-like canopy of white flowers.

Botanists brought giant hogweed to England as an ornamental plant in the 1890s.  It made its way to the U.S. via horticultural channels.  In fact, one of the first specimens was planted in a Victorian garden near Rochester, NY.  

As with most invasive plants, it quietly escaped cultivation. In the U.S., giant hogweed can be found in New England, the Mid-Atlantic Region, and the Northwest, with plants preferring moist habitat near roadside ditches and stream banks.   

While a seemingly innocent flowering plant, giant hogweed is actually one of the most hazardous plants in the U.S.  Brushing against or breaking the plant releases sap that, when combined with sunlight and moisture, can cause severe burn-like lesions, blistering sores, and purplish or blackened scars.  Getting sap in your eyes can result in temporary or even permanent blindness.

With each plant dropping up to 120,000 seeds, it’s no surprise that giant hogweed is proving difficult to eradicate.

If you suspect giant hogweed is growing near you, photograph the plant from a safe distance and report the sighting to local environmental authorities. 

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Plant Pest Risk Assessment for Giant Hogweed

Giant Hogweed

Photo, posted March 22, 2021, courtesy of Scottish Invasive Species Initiative via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Industrial heat and solar power

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Many industrial processes require extremely high temperatures, typically more than 1,800 degrees Fahrenheit.  This heat is generally produced by burning fossil fuels – either coal or natural gas – which emits large amounts of greenhouse gases. This level of heat cannot be economically produced using renewable electricity.  As a consequence, decarbonizing these industrial processes is very difficult.

Researchers at ETH Zurich in Switzerland have recently demonstrated a new method of obtaining high-temperature heat based on solar radiation.  They have engineered a device called a thermal trap.  It consists of a quartz rod coupled to a ceramic absorber that can efficiently absorb sunlight and convert it to heat.

In laboratory-scale experiments, they exposed a foot-long quartz rod to artificial light 135 times more intensive than sunlight and were able to produce temperatures as high as 1,900 degrees.  The artificial light source was needed to mimic the effects of concentrated solar energy plants that typically make use of large numbers of mirrors to direct intense solar energy onto a small area.

There are already concentrated solar power plants that operate at temperatures as high as 1,100 degrees and use the heat to operate turbines to generate electricity.  These plants lose efficiency at higher temperatures because of radiative heat losses.  The Zurich thermal trap minimizes these losses and permits higher temperature operation.

The hope is that at a large scale, the new approach may make it possible to use solar energy to decarbonize energy-intensive industrial processes.

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Using solar energy to generate heat at high temperatures

Photo courtesy of ETH Zurich / Emiliano Casati.

Earth Wise is a production of WAMC Northeast Public Radio

Cloud brightening

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Solar geoengineering is a type of climate intervention:  deliberate actions designed to affect the climate.  There are several ways to try to reduce the amount of sunlight reaching the surface of the earth and all of them are controversial.  Perhaps the least controversial approach is cloud brightening.

The idea is based on something called the Twomey effect, which is that large numbers of small droplets in the atmosphere reflect more sunlight than small numbers of large droplets.  Spraying vast quantities of minuscule aerosols into the sky, thereby forming many small droplets, could change the reflective properties of clouds.  If clouds are more reflective, then less sunlight reaches the surface, and the temperature goes down.

This form of geoengineering is thought to be less risky because it can be performed on a localized basis and can use relatively benign materials such as sea salt. 

In early April, scientists from the University of Washington started testing a device that sprays tiny sea-salt particles into the air from the deck of a decommissioned aircraft carrier in Alameda, California.  The test was simply to see whether the machine propelled a mist of suitable size.

Within two weeks, Alameda officials ordered a stop to the experiment, citing potential health and environmental risks.  After a month-long investigation, Alameda ruled that the experiment does not generate a measurable risk to health, wildlife, or the environment.

But before more ambitious experiments take place, there are potential side effects of cloud brightening that need to be studied.  It may turn out to be a useful tool in fighting global warming, but in any case, such technology should not be viewed as a substitute for moving away from fossil fuels.

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A Test of Cloud-Brightening Machines Poses No Health Risk, Officials Say

Photo, posted September 8, 2011, courtesy of Justin Ladia via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Carbon dioxide and wildfires

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Climate change is a key factor in the increasing risk and extent of wildfires.  Wildfires require the alignment of several factors, including humidity, temperature, and the lack of moisture in fuels, such as trees, shrubs, and grasses.  All of these factors have strong ties to climate variability and climate change.

While the global surge in wildfires is often attributed to hotter and drier conditions, a new study by researchers from the University of California – Riverside has found that increasing levels of a greenhouse gas may be an even bigger factor. 

According to the study, which was recently published in the journal Communications Earth & Environment, carbon dioxide is driving an increase in the severity and frequency of wildfires by fueling the growth of plants that become kindling.

Centuries of burning fossil fuels to produce heat, electricity and to power engines has added alarming amounts of carbon dioxide to the atmosphere.  In fact, atmospheric CO2 levels are measuring more than 420 parts per million, which is a level not seen on earth for 14-16 million years. 

Plants require carbon dioxide, along with sunlight and water, for photosynthesis.  But rising levels of CO2 in the atmosphere are driving an increase in plant photosynthesis – an effect known as the carbon fertilization effect.  This effect can make plants grow bigger and faster. 

Warming and drying are important fire factors.  These are the conditions that make the extra plant mass more flammable.  But the study found that the increase in fires during hotter seasons is driven by the CO2-fueled growth of plants.   

The researchers hope their findings will urge policymakers to focus on reducing carbon dioxide levels in the atmosphere.

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CO2 worsens wildfires by helping plants grow

Current carbon dioxide levels last seen 14 million years ago

Photo, posted January 17, 2024, courtesy of Jennifer Myslivy, BLM Fire/NIFC via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Where not to plant trees

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Planting huge numbers of trees is often proposed as a way to reduce the severity of climate change.  Studies have looked at the potential for Earth‘s ecosystems to support large additional areas of forest and have found that it would be possible to have at least 25% more forested area than we do now.  This in turn could capture large amounts of carbon and substantially reduce the amount in the atmosphere.

A recent study by researchers at Clark University in Massachusetts and The Nature Conservancy mapped the climate impact of tree planting across the globe, identifying where it would be most and also least beneficial.  The study, published in Nature Communications, found that trees planted in arid, desert regions or in snowy places like the Arctic would, on balance, worsen warming rather than reduce it.

Trees take up carbon dioxide from the atmosphere, which helps to keep warming in check.  But trees with dark, green leaves also absorb heat from sunlight.   Snow and desert sand, on the other hand, are light-colored and reflect more sunlight back into space.  For this reason, trees planted in snowy areas or in the desert will absorb more sunlight than their surroundings.  This can negate the climate benefits of soaking up carbon dioxide.

Previous studies only looked at how much carbon dioxide would be removed by planting trees in order to determine how much warming would be prevented.  The new study finds that it matters where the trees are planted.

Fortunately, the new study also shows that tree planting projects that are currently underway or that are in the pipeline are largely concentrated in regions where they will indeed help slow global warming.

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This Map Shows Where Planting Trees Would Make Climate Change Worse

Photo, posted April 5, 2022, courtesy of UC Davis Arboretum and Public Garden via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Why was 2023 so hot?

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Five separate weather-tracking organizations have proclaimed 2023 as the hottest year on record. They all agreed that 2023 beat the previous record-holder – 2016 – by a wide margin.  Organizations that use a pre-industrial baseline of 1850-1900 found that 2023 was 1.45 to 1.48 degrees Celsius above the baseline.  But what caused 2023 – especially the second half of it – to be so hot?

Scientists believe that there were multiple factors that contributed to the record-breaking heat.

First and foremost is the long-term rise in greenhouse gases.  Over 100 years of burning fossil fuels along with major changes in land use (particularly deforestation) have led to a significant rise in the heat-trapping blanket of the gases in the atmosphere.

On top of this long-term trend, the return of the El Niño condition in the Pacific in May helped temperatures rise further.

At the same time, the tropical Pacific was not the only ocean that was hotter than normal.  The global sea surface temperature set new records in 2023 and there were multiple marine heat waves.  Heat trapped by the atmosphere is absorbed by the oceans, raising their temperatures.

Another factor is the quantity of aerosols in the atmosphere.  Many of these aerosols actually cool the atmosphere by reflecting the sun’s light back into space.  Society’s efforts to reduce air pollution and improve air quality have led to decreasing levels of aerosols.

2024 started with some seriously cold weather in some places but predictions are that this year will be roughly as warm as 2023 and possibly warmer given that the dynamics driving last year’s weather are all still in place.

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Five Factors to Explain the Record Heat in 2023

Photo, posted February 22, 2016, courtesy of Jasmin Toubi 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

Liquid Fuel From Sunshine | Earth Wise

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A key goal of artificial photosynthesis research is to be able to produce a useful liquid fuel using only carbon dioxide, water, and sunlight in a single step.  Such a so-called solar fuel would produce net zero carbon emissions and would be completely renewable.

Bioethanol has long been touted as a green alternative to fossil fuels, since it is made from plants rather than petroleum.  But producing it takes up agricultural land that could be used to grow food instead and there are emissions associated with many aspects of the process by which plant mass becomes fuel.

Researchers from the University of Cambridge in the UK have developed a so-called artificial leaf that produces ethanol or propanol – usable liquid fuels – in a single step.  They developed a copper and palladium-based catalyst that allows the artificial leaf to directly produce multicarbon complex chemicals.  Earlier versions of artificial leaves could make simple chemicals, such as syngas, which would then require additional processing to turn into high-density fuels.

The new device produces liquid fuel from carbon dioxide and water simply by shining sunlight on it.

At present, the artificial leaf is a proof-of-concept device that exhibits only modest efficiency.  The researchers are working to optimize the device’s light absorbers so that they can better make use of sunlight and to optimize the catalyst so that it can convert more of the sunlight into fuel.  In addition, the device needs to be scaled up so that it can produce large volumes of fuel.

All that being said, it is an important step towards people being able to do what plants have been doing for millions of years.

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Driving on sunshine: clean, usable liquid fuels made from solar power

Photo, posted March 23, 2015, courtesy of Astro via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Wildfire Smoke And Global Weather | Earth Wise

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In 2019 and 2020, wildfires burned 72,000 square miles in Australia, roughly the same area as the entire country of Syria. During the nine months when the fires raged, persistent and widespread plumes of smoke filled the atmosphere.

These aerosols brightened a vast area of clouds above the subtropical Pacific Ocean.  Beneath these clouds, the surface of the ocean and the atmosphere cooled.  The effect of this was an unexpected and long-lasting cool phase of the Pacific’s La Niña-El Niño cycle.

A new modeling study by the National Center for Atmospheric Research in Boulder, Colorado quantified the extent to which aerosols from the Australian wildfires made clouds over the tropical Pacific reflect more sunlight back towards space.  The resultant cooling shifted the cloud and rain belt known as the Intertropical Convergence Zone northward.  These effects may have helped trigger the unusual three-year-long La Niña, which lasted from late 2019 through 2022.

The impacts of that La Niña included intensifying drought and famine in Eastern Africa and priming the Atlantic Ocean for hurricanes.  2020 was the most active tropical storm season on record, with 31 storm systems, including 11 that made landfall in the U.S.

The study highlights widespread multi-year climate impacts caused by an unprecedented wildfire season.  The wildfires set off a chain of events that influenced weather far from where the fires occurred.  In the future, climate experts will need to include the potential effects of wildfires in their forecasts.

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How Wildfire Smoke from Australia Affected Climate Events Around the World

Photo, posted December 19, 2019, courtesy of Simon Rumi via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

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