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Progress On Perovskite Solar Cells | Earth Wise

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Perovskites are semiconductors with a specific crystal structure.  Their properties make them well suited for making solar cells.  They can be manufactured at room temperature, using much less energy than it takes to make the silicon-based solar cells widely used today.  As a result, perovskite solar panels would be cheaper and more sustainable to produce.  Manufacturing silicon solar cells takes a lot of energy because silicon is forged at around 3000 degrees Fahrenheit. In addition, perovskites can be made flexible and transparent, making it possible to use them in ways unavailable with silicon solar technology.

But unlike silicon, perovskites are very fragile.  The early solar cells made from perovskites in 2009 and 2012 lasted for only minutes.  Lots of potential, but little practicality.

Recently, Princeton Engineering researchers have developed the first perovskite solar cell with a commercially viable lifetime, which is a major breakthrough.  The team projects that the device can perform above industry standards for about 30 years, which is much more than the 20 years designated as a viability threshold for commercial cells.

The research team has developed an ultra-thin capping layer between two of the layers of a perovskite solar cell.  The layer is just few atoms thick but has been demonstrated to dramatically increase the durability of the device. 

There is great potential for the new solar cell technology.  It has efficiency to compete with silicon cells but can be tuned for specific applications and can be manufactured locally with low energy inputs.  If successfully commercialized, the result will be solar panels that are cheaper, more efficient, and more flexible than what are available today.

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Once seen as fleeting, a new solar tech shines on and on

Photo, posted January 8, 2020, courtesy of David Baillot/UC San Diego Jacobs School of Engineering via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Space Tourism And The Climate | Earth Wise

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Space tourism is human space travel for recreational purposes.  A few well-known billionaires have taken rocket rides in recent years and at least a dozen companies are at the vanguard of what they are expecting to be a burgeoning industry.  If space tourism truly takes off – pun intended – it could be a serious threat to the climate and the environment.

Black carbon – essentially soot – is emitted when fossil fuels, including rocket fuels, are burned.  Black carbon absorbs light from the sun and releases thermal energy, making it a powerful climate warming agent.  At lower altitudes, black carbon quickly falls from the sky, remaining in the atmosphere for only a matter of days or weeks.

Rockets are another story entirely.  They dump black carbon into the stratosphere as they blast into space, and up there black carbon is 500 times worse for the climate and sticks around for several years.

A detailed study by researchers at University College London looked at the climate impact of present-day space launches compared with the potential massive expansion of launches from a large space tourism industry.

The overall result is that current space launches are not a significant source of emissions, but space launches would become incredibly significant if projections of tourist space flights proved to be true.  Currently, there are roughly 100 space launches a year world-wide.  If that number becomes thousands, the impact on the climate would be substantial.

The same researchers looked at the ozone impact of rocket launches and reached a similar conclusion.  The current impact of spaceflights is not very significant, but a massive increase in launches could have a major impact on atmospheric ozone concentrations.

Space tourism may be exciting, but it also could be very dangerous for the planet.

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Space Tourism Poses a Significant ‘Risk to the Climate’

Impact of Rocket Launch and Space Debris Air Pollutant Emissions on Stratospheric Ozone and Global Climate

Photo, posted May 30, 2020, courtesy of Daniel Oberhaus (2020) via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Floating Solar | Earth Wise

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The largest floating solar array in Europe, 12,000 panels sitting on top of the Alqueva Reservoir in Portugal – will come online in July.  Installing floating solar arrays, which are sometimes called “floatovoltaics”, produce renewable energy while shielding significant expanses of water from the sun’s heat.  These dual benefits have led to floatovoltaic projects in multiple countries around the world.

The city of Cohoes, in New York’s Albany County, has proposed an 8,000-panel floating solar array on the city reservoir.  Federal funding of $3 million for the project was obtained by local Congressman Paul Tonko and, in May, utility National Grid donated $750,000 towards the project.  Engineering work will shortly be underway on the 3.2 megawatt grid of solar panels.

The city of Cohoes pumps its drinking water supplies from the Mohawk River into the 10-acre, manmade reservoir.  The surface of the water is the largest undeveloped open space in the city.  Such reservoirs constitute prime sites for solar arrays since the space cannot be used for other purposes.  In addition, covering the water’s surface with the solar panels greatly reduces evaporation and helps to inhibit the growth of algae.

There are currently only 14 floating solar arrays in the U.S. and all of those are privately owned.  The Cohoes municipal array will be the first of its kind.  There are nearly 500 reservoirs in New York State and 24,000 nationwide that could be sites for floating arrays.   Drought-stricken Western reservoirs like Lake Mead and Lake Powell could be ideal locations of solar arrays.  Those reservoirs lose huge amounts of water to evaporation.  There are estimates that floating arrays could provide as much as 10% of the nation’s electrical needs.

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National Grid gives Cohoes $750,000 for floating solar array project

Photo, posted August 25, 2010, courtesy of Martin Abegglen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Weaning Off Fossil Fuels | Earth Wise            

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We recently talked about California producing 97% of its electricity from renewables on one sunny afternoon in April.  On May 8th, the state produced enough renewable electricity to meet 103% of consumer demand.  These sorts of records are likely to be increasingly commonplace in the spring when the weather is still fairly mild.

But even while renewables were producing more electricity than California needed, natural gas power plants in the state were still running.

Turning off the gas power plants is not possible.  The reason is that as the sun sets and solar farms stop producing power, California has to quickly replace the power with electricity from other sources.  Natural gas plants are massive industrial facilities that cannot be turned on and off rapidly.  Some take as many as 4 to 8 hours to switch on.  Operators back them down as far as they can go, but even when there is plenty of solar power during the day, natural gas plants are still running.

The state is rapidly building huge battery storage projects as an alternative to gas plants, but so far, they are still only a small fraction of what is needed.   Wind power is another part of the solution along with hydropower.  California imports some power from other states as well and, in fact, also exports power when there is excess.  But keeping the energy system balanced and stable is an ongoing challenge.

California is building huge amounts of solar, huge amounts of wind, and huge amounts of energy storage, which should get the state to at least 90% of the way to a clean grid.  It’s the last 5-10% that is much harder to accomplish before natural gas is no longer part of the energy system.

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California just ran on 100% renewable energy, but fossil fuels aren’t fading away yet

Photo, posted January 10, 2014, courtesy of F.G. via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Storing Sunshine To Make Electricity On Demand | Earth Wise

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Researchers at Chalmers University in Sweden have developed an entirely new way of capturing and storing energy from sunlight.  The system is called the Molecular Thermal Energy Storage System or MOST.  It is based on a specially designed molecule that changes shape when it is exposed to sunshine.

The molecule is composed of carbon, hydrogen, and nitrogen.  When sunlight hits it, it changes into an energy-rich isomer – a molecule made up of the same atoms but arranged together in a different way.  That isomer is stable and can be stored for many years.  When a specially designed catalyst is applied, the stored energy is released in the form of heat and the molecule returns to its original form and can be reused. 

The Chalmers researchers sent some of the energy-laden isomer to researchers in China who used it to operate a micron-thin thermoelectric generator, which used the heat released by the isomer material to generate electricity.  The generator is an ultra-thin chip that could be integrated into electronics such as headphones, smart watches, and telephones.  It is currently only at the proof-of-concept stage, but the results are quite promising.  The integration with the MOST technology provides a way that solar energy can generate electricity regardless of weather, time of day, season, or geographical location.  The results of the study were recently published in the journal Cell Reports Physical Science.

In effect, for this demonstration, Swedish sunshine was sent to the other side of the world and converted into electricity in China. The ultimate goal of this research is to create self-charging electronics that uses stored solar energy on demand.

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Converting solar energy to electricity on demand

Photo, posted March 11, 2013, courtesy of Steve Slater via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Record Renewable Use In California | Earth Wise

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California, the most populous state, is the second largest electricity user.  Only Texas, the second most populous state, uses more energy, in part because it consumes large amounts in refining fossil fuels. Overall, California uses about 8% of the electricity generated in the U.S.

Thus, it was a significant milestone when briefly, on April 3, a record 97.6% of the energy on California’s statewide grid came from renewable energy resources.  (The previous record of 96.4% was set just a few days earlier).

Renewable energy’s share of the power typically peaks in the spring when mild temperatures keep demand relatively low and higher sun angles drive greater solar energy production.

On April 8, a record peak solar power production was set at 13,628 megawatts just after noon.  On March 4, the state set an all-time wind generation record of 6,265 megawatts. 

California now has over 15,000 MW of grid-connected solar power and 8,000 MW of wind.  Another 600 MW of solar and 200 MW of wind are coming online by June.  The state also has about 2,700 MW of energy storage online and that will climb to 4,000 MW by June.

In 2020, 34.5% of the state’s retail electricity sales came from wind and solar sources.  Adding in hydropower and nuclear power, nearly 60% of the state’s electricity came from non-fossil fuel.  Despite the effects of drought on hydropower generation and the impact of the pandemic on the pace of renewable energy projects, California continues its dramatic transition to sustainable energy.

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Solar and wind notched records as renewables met California’s energy demand

Photo, posted September 20, 2016, courtesy of Tom Brewster Photography / BLM via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

River Of Dust | Earth Wise               

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Every year, more than 100 million tons of dust blow out of North Africa.  Strong seasonal winds lift the dust from the Sahara Desert northward.  A few times a year, the winds from the south are strong and persistent enough to drive the dust all the way to Europe.

On March 15, a large plume of Saharan dust blew out of North Africa and crossed the Mediterranean into Western Europe.  European cities were blanketed with the dust, degrading their air quality, and turning skies orange.  Alpine ski slopes were stained with the dust.

These dust events are associated with so-called atmospheric rivers that arise from storms.  Such rivers usually bring extreme moisture but can also carry dust.  Over the past 40 years, nearly 80% of atmospheric rivers over northwestern Africa have led to extreme dust events over Europe.  The March 15 event was associated with Storm Celia, a powerful system that brought strong winds, rain, sleet, hail, and snow to the Canary Islands.

Atmospheric dust plays a major role in climate and biological systems.  The dust absorbs and reflects solar energy and also fertilizes ocean ecosystems with iron and other minerals.

The climate effects of dust are complicated.  Dust can decrease the amount of sunlight reaching the surface, affect cloud formation, and decrease temperatures.  But dust also darkens the snowpack, leading to more rapid snowmelt.  A 2021 dust event resulted in a rapid melt of Alpine snow, reducing its depth by half in less than a month.

The effects of this year’s dust event are not yet known, but this atmospheric river associated with Storm Celia appeared to carry less water and more dust compared with the 2021 event.

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An Atmospheric River of Dust

Photo, posted December 2, 2019, courtesy of Catherine Poh Huay Tan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Large Mammals And Climate Change | Earth Wise         

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The natural world has an important part to play in mitigating the effects of climate change.  We mostly think about the role of plant life which absorbs carbon in trees, grasses, and other flora.  However, a new study published by Oxford University looks at the role of large wild animals in restoring ecosystems and reducing the effects of climate change.

According to the study, there are three important ways in which large animals such as elephants, rhinos, giraffes, whales, bison, and moose can potentially mitigate the effects of climate change:  carbon stocks, albedo, and fire regimes.

When large herbivores graze, they disperse seeds, clear vegetation, and fertilize soil.  All of these things build more complex and resilient ecosystems which helps to maintain and increase carbon stocks in the soil and in plant tissues thereby helping to reduce CO2 in the atmosphere.

Grazing large animals trample vegetation which opens up areas of dense vegetation to create open mixes of grass and shrubs and can reveal snow-covered ground in cold regions.  Such open habitats are lighter in color (higher in albedo) and reflect more solar radiation into the atmosphere, cooling the Earth’s surface rather than heating it up.

Large grazing animals can lessen wildfire risk by browsing on woody vegetation that would otherwise fuel the fires and also by creating paths that act as firebreaks.

In marine ecosystems, whales and other large animals fertilize phytoplankton, which capture some 37 billion tons of CO2 each year.

Overall, large animals are an important part of the natural world’s ability to reduce the effects of the changing climate by helping with localized adaptation to the changes taking place in ecosystems.

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Large mammals can help climate change mitigation and adaptation

Photo, posted August 20, 2017, courtesy of Jon Niola via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Smart Window | Earth Wise

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Researchers at Oxford University have developed a new adaptable smart window technology that has the potential of reducing the energy usage of the average home by a third.

The technology uses a spectrally tunable low-emissivity coating that can control the amount of heat that comes into a room without affecting the quality of the light that enters.

The thermal energy from the sun’s infrared rays is absorbed by the glass and then is re-emitted as heat.  That heat can either be used to warm the room using transparent electrical heaters embedded in the glass or can be reflected away to cool the room.  The windows can change according to seasonal needs.

The researchers built a prototype using a material called an active chalcogenide-based phase change material.  When it is cold, the infrared rays from the sunlight are harvested and used to heat the building.  When it is warm, the new glass can switch state to reflect the heat and reduce the need for air conditioning.  The active phase change material is adjustable so that the amount of heat absorbed or reflected can be tuned for precise temperature control.  There is essentially no effect on visible light passing through the window.  Current low-emissivity glass for windows can reduce heat transfer, but its properties cannot be altered according to seasonal needs.

The researchers estimate that using windows fitted with the new prototype glass – including the energy required to control the film – would save 20 to 34% in energy usage annually compared to double-glazed windows found in many modern homes.

A spinout company from Oxford called Bodle Technologies is collaborating with two existing industrial partners to develop the technology further.

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New adaptable smart window coating could help heat or cool a home and save energy

Photo, posted April 26, 2008, courtesy of Lima Andruska via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change On Mount Everest | Earth Wise

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Climate change has shown up in the highest place on Earth.  The highest glacier on Mount Everest is rapidly retreating with rising temperatures.

New research by an international team led by the University of Maine and published in the journal Climate and Atmospheric Science has determined that the South Col Glacier atop Mount Everest has shrunk by half since the 1990s.   Its ice mass has thinned by an estimated 180 feet.

The glacier used to be covered by snow, which reflected the sun’s light and insulated the mass of ice under the snow.  But warmer temperatures, lower humidity, and more severe winds have eliminated the snow cover, fueling the decline of the glacier.

The study of the South Col Glacier highlights the critical balance created by snow-covered surfaces and exposes the potential for loss throughout high mountain glacier systems as snow cover is depleted by warming temperatures.  When even the highest glacier on Mount Everest is impacted, it is clear that no place is safe from the warming climate.

The human significance of this development is substantial.  More than 200 million people in Asia depend on meltwater from glaciers in the high mountains of the continent for their freshwater needs.  But now glaciers in the mountains are melting faster than they can be replenished by snowfall.

As for Mount Everest itself, future expeditions on the mountain will face new challenges as glacier melting causes more avalanches and climbers accustomed to digging into ice and snow will need to scale more exposed bedrock.  Climate predictions for the Himalaya in general all anticipate continued warming and continued loss of glacier mass.

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Climate Change Has Reached the Top of Mount Everest, Thinning Its Highest Glacier

Photo, posted October 27, 2011, courtesy of Goran Hogland via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A New “Wonder Material” | Earth Wise

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Graphene is a form of carbon made of single-atom-thick layers. It has many remarkable properties and researchers around the world continue to investigate its use in multiple applications.

In 2019, a new material composed of single-atom-thick layers was produced for the first time.  It is phosphorene nanoribbons or PNRs, which are ribbon-like strands of two-dimensional phosphorous.  These materials are tiny ribbons that can be a single atomic layer thick and less than 100 atoms wide but millions of atoms long.  They are comparable in aspect ratio to the cables that span the Golden Gate Bridge.   Theoretical studies have predicted how PNR properties could benefit all sorts of devices, including batteries, biomedical sensors, thermoelectric devices, nanoelectronics, and quantum computers. 

As an example, nanoribbons have great potential to create faster-charging batteries because they can hold more ions than can be stored in conventional battery materials.

Recently, for the first time, a team of researchers led by Imperial College London and University College London researchers has used PNRs to significantly improve the efficiency of a device.  The device is a new kind of solar cell, and it represents the first demonstration that this new wonder material might actually live up to its hype.

The researchers incorporated PNRs into solar cells made from perovskites.  The resultant devices had an efficiency above 21%, which is comparable to traditional silicon solar cells.  Apart from the measured results, the team was able to experimentally verify the mechanism by which the PNRs enhanced the improved efficiency.

Further studies using PNRs in devices will allow researchers to discover more mechanisms for how they can improve performance.

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‘Wonder material’ phosphorene nanoribbons live up to hype in first demonstration

Photo, posted October 6, 2010, courtesy of Alexander AlUS / CORE-Materials via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Big Year For European Solar Power | Earth Wise

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The installed solar capacity in the European Union grew by 34% in 2021.  This means that Europe is on pace to quadruple its solar energy generation by 2030.

During 2021, the 27 countries of the European Union installed 25.9 gigawatts of new solar capacity, compared with 19.3 gigawatts in 2020.  This was the biggest year yet for solar growth, beating out the previous record of 21.4 gigawatts set in 2011.  A gigawatt of solar electricity is enough to power about 300,000 homes, so the 2021 installations can produce enough electricity for about 8 million households.  The European Union is home to about 450 million people.

SolarPower Europe, an industry trade organization, projects that solar energy capacity in the EU will increase from the current 165 gigawatts to 328 gigawatts in 2025 and as much as 672 gigawatts by 2030.

The EU has the goal of generating 45% of its electricity from renewable sources by 2030, which is an important milestone in achieving climate neutrality by 2050. 

Challenges still facing the EU include obstacles to permitting, electricity grid bottlenecks, and assurance of solar panel supplies.  Much of Europe’s supply of solar panels comes from China.  The EU wants to boost its own production of solar panels to 20 gigawatts per year by 2025.

The US currently has about 113 GW of installed solar capacity and is projected to install about 300 gigawatts of new capacity over the next 10 years.

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For the European Union, 2021 Was a Banner Year for Solar Power

Photo, posted May 3, 2007, courtesy of Bernd Sieker via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Importance Of City Trees | Earth Wise

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It is well known that green spaces can improve the quality of life and create a better climate in cities.  City trees and vegetation can help reduce urban heat island effects by shading buildings and roads, deflecting radiation from the sun, and releasing moisture into the atmosphere.  City trees and green spaces have also been proven to increase property values, promote wildlife and plant diversity, reduce noise pollution, and improve human health.  But how important are trees and vegetation for producing cleaner air in cities?

According to a new study led by researchers at the University of Gothenburg in Sweden, trees do contribute to cleaner air in cities, but the degree to which they do so varies greatly between different locations. 

The research team measured air pollutants across seven urban settings in the city of Gothenburg, and compared them with pollutants on the leaves of deciduous trees.  The researchers chose to focus on polycyclic aromatic hydrocarbons (PAHs), which are pollutants generated primarily during the incomplete combustion of organic materials, like coal, oil, and wood.

The results revealed that the pollutants in leaves did increase over time.  The researchers were able to show a clear correlation between the level of air pollutants and the concentration of pollutants in leaves. 

But at the same time, the researchers discovered that pollution levels varied greatly between measurement sites.  For example, the levels of PAHs were seven times higher at the most polluted site (the city’s main bus station) than they were at a location on the periphery of the city.

The research team hopes its findings will be used to help guide the planning of future urban landscapes.

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Trees are important for cleaner air in cities

Photo, posted November 5, 2021, courtesy of Maria Eklind via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Large Solar Projects In The U.S. | Earth Wise

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The United States now has over 108 gigawatts of total solar generating capacity, which is enough to power about 19 million homes.  There are more than 3 million solar installations across the country, the majority of which are residential systems.

The growth in solar power has been enormous over the past 13 years.  In 2008, the total solar capacity in the U.S. was 0.34 gigawatts.

In recent times, utility-scale solar installations have been on the rise.  At least 10 systems in excess of 100 megawatts have come online just in 2021.  These systems have been built in Georgia, Ohio, California, Texas, and Nevada.  Other large installations have come online in Virginia, Utah, Indiana, and Florida.  Overall, Texas has had the most new installations, followed by California and Florida.

The largest utility-scale solar project completed this year is the Eunice Solar Project in Andrew, Texas.  The 420-megawatt project is part of the Permian Energy Center which also features 40 megawatts of battery energy storage.

The pipeline for new utility-scale solar projects under construction includes more than 17 gigawatts, so there is strong continuing growth in the industry.

The Biden administration has proposed a blueprint for the nation to produce 45% of its electricity from solar power by 2050.  Currently, solar energy contributes about 4% of the country’s power.  Being able to produce almost half the country’s electricity from the sun by 2050 would require a vast transformation in technology and the energy industry.  Whether there is the political will and the wherewithal to achieve this remains to be seen.

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U.S. Solar Market Insight

Photo, posted March 7, 2019, courtesy of Hedgerow Inc via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Reducing COVID-19 Spread With UV Light | Earth Wise

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New research published by the University of Colorado Boulder analyzes the effects of different wavelengths of ultraviolet light on the SARS-CoV-2 virus.   The research found that a specific wavelength of UV light is not only extremely effective at killing the virus that causes COVID-19, but also that this wavelength is safer for use in public spaces.

UV light is naturally emitted by the sun and most forms of it are harmful to living things – including microorganisms and viruses.   The most harmful UV radiation from the sun is filtered out by the atmosphere’s ozone layer.   Human-engineered UV light sources screen out harmful UV rays with a phosphorus coating on the inside of the tube lamps.  Hospitals and some other public spaces already use UV light technology to disinfect surfaces when people are not present.

The new research found that a specific wavelength of far-ultraviolet-C, at 222 nanometers, was particularly effective at killing SARS-CoV-2, but that wavelength is blocked by the very top layers of human skin and eyes.  In other words, that light has essentially no detrimental health effects for people while it is very capable of killing off viruses.

The researchers argue that this safe wavelength of Far UV-C light could serve as a key mitigation measure against the COVID-19 pandemic.  They imagine systems that could cycle on and off in indoor spaces to routinely clean the air and surfaces or perhaps create an ongoing, invisible barrier between teachers and students, customers and service workers, and other places where social distancing is not practical.  Installing these specialized UV lights would be much cheaper than upgrading entire HVAC systems in buildings.

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Specific UV light wavelength could offer low-cost, safe way to curb COVID-19 spread

Photo, posted January 18, 2008, courtesy of Phil Whitehouse via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wastewater And Ammonia | Earth Wise

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Ammonia is the second most produced chemical in the world.  More than half of it is used in agriculture to produce various kinds of fertilizer, to produce cotton defoliants that make cotton easier to pick, and to make antifungal agents for fruits.  Globally, ammonia represents more than a $50 billion a year market.

Current methods to make ammonia require enormous amounts of heat – generated by burning fossil fuels – to break apart nitrogen molecules so that they can bind to hydrogen to form the compound. Ammonia production accounts for about 2% of worldwide fossil energy use and generates over 400 million tons of CO2 annually.

Engineers at the University of Illinois Chicago have created a solar-powered electrochemical reaction that uses wastewater to make ammonia and does it with a solar-to-fuel efficiency that is 10 times better than previous comparable technologies.

The process uses nitrate – which is one of the most common groundwater contaminates – to supply nitrogen and uses sunlight to power the reaction.  The system produces nearly 100% ammonia with almost no hydrogen side reactions.  No fossil fuels are needed, and no carbon dioxide or other greenhouse gases are produced.  The new method makes use of a cobalt catalyst that selectively converts nitrate molecules into ammonia.

Not only is the reaction itself carbon-neutral, which is good for the environment, but if it is scaled up for industrial use, it will consume wastewater, thereby actually being good for the environment.  The new process is the subject of a patent filing and the researchers are already collaborating with municipal corporations, wastewater treatment centers, and others in industry to further develop the system.

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Combining sunlight and wastewater nitrate to make the world’s No. 2 chemical

Photo, posted August 29, 2018, courtesy of Montgomery County Planning Commission via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

People And The Earth’s Increasing Heat | Earth Wise

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A new study by Princeton University and the National Oceanic and Atmospheric Administration had found clear evidence that human activity is the primary cause of the significant increase in heat stored in our planet.  In fact, the study found that there is less than a 1% chance that natural variability is the sole cause of the increase.

The researchers looked at data from satellite observations to determine the amount of energy received by the earth and the amount reflected and emitted by the Earth.  In a balanced physical system, the amount of incoming energy should equal the amount of outgoing energy.  But the earth’s system is not balanced at this point.  More energy is coming in than going out, which is driving changes in the climate system.  There have been other studies looking at the human influence on the climate, but this new study is the first to examine a 20-year continuous satellite energy balance record to see if natural fluctuations in the climate system or human activities is the primary driver for the significant change in the planet’s energy balance.

The study examined 50 different climate models to look at this energy balance under scenarios where there was no human influence.  These include changes in the sun’s output, volcanic eruptions, variations in pollution aerosols, and more.

The results, to no great surprise, are that increasing greenhouse gases over the last twenty years is by far the most important driver for the energy imbalance.  This imbalance is what is driving rising temperatures, increasing sea levels, and causing other climate changes.

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Human activities responsible for rapid increase in Earth’s heat

Photo, posted May 6, 2021, courtesy of Marlis Borger via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Understanding Geoengineering | Earth Wise

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The most recent report from the UN Intergovernmental Panel on Climate change includes discussion of a number of extreme and untested solutions to the climate crisis.  Among these are solar geoengineering – modifying clouds or spraying tiny reflective particles into the upper atmosphere in order to block some of the sun’s light and thereby cool the planet.  The underlying principles are relatively straightforward.

There have been various models that predict the extent to which solar geoengineering would lower the earth’s average temperature.  What hasn’t been modeled to any real extent is what other effects it would have.

The new report discusses the results of models that predict how temperatures would vary at different latitudes and how geoengineering would affect rainfall and snowfall.  According to the models, releasing sulfate aerosols into the upper atmosphere to block sunlight would lower average precipitation.  But every region would be affected differently.  Some regions would gain in an artificially cooler world, but others might, for example, suffer by no longer having suitable conditions to grow crops.

The drop in temperature would allow the planet’s carbon sinks (plants, soils, and oceans) to take up more carbon dioxide from the atmosphere.  However, as long as people continue to pollute, carbon dioxide would continue to make the oceans more acidic, causing significant harm to marine ecosystems.  Furthermore, solar geoengineering would have to be an ongoing process that would go on indefinitely and if it were to suddenly stop, it would lead to rapid warming.

The more we learn about geoengineering, the more it becomes clear that there would be many side effects as well as serious moral, political, and practical issues.  Society has to consider if all these things represent too much danger to allow us to seriously consider such a strategy.

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In the New UN Climate Report, a Better Understanding of Solar Geoengineering

Photo, posted September 9, 2012, courtesy of Kelly Nighan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Sunscreen For Corals | Earth Wise

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Sunscreen from beachgoers entering ocean waters is one of the greatest threats to coral reefs and there are global efforts to reduce or eliminate the use of many of the most harmful chemicals people use to protect themselves from the sun’s rays.  However, scientists at the Smithsonian Conservation Biology Institute have found that some corals have a natural sunscreen of their own that helps protect them from the effects of climate change.

Hawaiian blue rice corals feature a deep blue pigment that is created by chromoprotein that filters out harmful ultraviolet radiation from the sun.  UV damage has harmful impacts to reproduction in many coral species, but it appears not to have the same effect on blue rice coral.

In a study published in Scientific Reports, Smithsonian researchers studied the devastating effects that bleaching had on brown rice coral in the Hawaiian bleaching events of 2014 and 2015.  During the same events, blue rice coral either recovered quickly or was not affected by the elevated ocean temperature at all.

The blue-pigmented corals had dramatically greater reproductive vigor than the brown-pigmented version.  The key factor appears to be the sun-screening ability of the blue pigment in the particular symbiotic algae that lives inside the coral tissue known as zooxanthellae.  The coral protects the algae and in turn the algae provide the coral with food in the form of sugars produced as a waste product from photosynthesis.  In the case of the blue version, the algae also produce sunscreen for the coral.

By better understanding the role UV-protective pigments play in mitigating the adverse effects of climate change and warming oceans, scientists can learn why some species are better equipped to survive in a changing environment.

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Smithsonian Conservation Biology Institute Scientists Find Corals’ Natural “Sunscreen” May Help Them Weather Climate Change

Photo, posted September 28, 2009, courtesy of Matt Kieffer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Potential Of Artificial Photosynthesis | Earth Wise

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The sun is the primary source of energy on the earth.  Enough solar energy hits the earth in one hour to meet all of human civilization’s energy needs for an entire year.  The two leading forms of renewable energy – photovoltaic solar power and wind power – are ways of making use of the sun’s energy.  Wind power is indirectly provided by the sun; photovoltaic power uses sunlight to generate electricity.

The most efficient use of solar energy on the planet is one perfected by plants millions of years ago:  photosynthesis.  Photosynthesis is a complex sequence of processes by which plants convert sunlight and water into usable energy in the form of glucose.  Plants utilize a combination of pigments, proteins, enzymes, and metals to perform their magic.  If we can develop artificial photosynthesis, it would be a dramatic improvement of humans’ ability to power society cleanly and efficiently.  Whereas photovoltaics capture about 20% of the sun’s energy, photosynthesis stores 60% of the sun’s energy as chemical energy.

Researchers across the globe are working to develop artificial photosynthesis.  A group at Purdue university has been making progress in trying to mimic the ability of leaves to collect light and split water molecules to generate hydrogen. This is a critical step in photosynthesis that is accomplished by protein and pigment complexes known as “photosystems II”.  The Purdue group is experimenting with these proteins and various synthetic catalysts in order to try to develop artificial leaves based on abundant, nontoxic materials. 

It is likely to take a decade or more for artificial photosynthesis technology to become part of our energy system, but its ultimate potential is enormous.

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Soaking up the sun: Artificial photosynthesis promises a clean, sustainable source of energy

Photo, posted June 14, 2007, courtesy of Alex Holyoake via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

WAMC Northeast Public Radio

WAMC/Northeast Public Radio is a regional public radio network serving parts of seven northeastern states (more...)