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Upcycling Plastic Waste | Earth Wise

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People have generated 8 billion tons of plastic waste over time and less than 10% of it has been recycled.  Millions of tons of it escapes into the oceans.  Plastic piles up virtually everywhere on earth.

There are many approaches to dealing with the plastic waste problem and no one of them is a magic bullet.  Engineers at Stanford University have investigated the prospects for upcycling plastic waste for use in infrastructure like buildings and roads.

They used a mix of computer modeling, scientific research, experimental and field data to analyze the potential for using plastic waste in infrastructure.

Among their findings is that recycled glass fiber reinforced polymer composite – which is a tensile plastic commonly used in car, boat, and plane parts – is a promising material for reuse in buildings. 

Roads in which waste plastic is melted down and mixed with conventional paving materials are becoming more common around the world.  India has installed over 60,000 miles of these roads.  Studies show that roads containing waste plastic have the potential to perform better than conventional roads.  They can last longer, are more durable, can tolerate wide temperature swings, and are more resistant to water damage, cracking, and potholes.  Such roads rely less upon virgin fossil resources, which is obviously advantageous.

Upcycling plastic waste in infrastructure is attracting increasing interest because it creates value from something that is strictly a liability and may end up having regulatory advantages as societies move toward more environmentally friendly and sustainable policies.

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Can we use plastic waste to build roads, buildings, and more?

Photo, posted October 7, 2022, courtesy of the Grand Canyon National Park via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Fungus And Carbon Storage | Earth Wise

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

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

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

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

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

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

Earth Wise is a production of WAMC Northeast Public Radio

Rain Gardens And Residential Pollution | Earth Wise

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Stormwater runoff has become the largest source of residential pollution for waterways.  As rainwater runs down roofs, over driveways and patios, and off other hard surfaces, it can pick up pollutants as it flows directly into streams, wetlands, lakes, and groundwater aquifers.  That water is typically routed directly through stormwater pipes and ditches with little filtering or treatment.  The main emphasis is on getting the water off of people‘s property as quickly and efficiently as possible to avoid flooding.

Many municipalities are dealing with the problem by installing rain gardens, which are a type of green infrastructure in commercial spaces that slow down and treat water before it enters streams, wetlands, and other bodies of waters.  When designed and installed properly with appropriate plants, rain gardens are like miniature water treatment facilities   Water gathers in the rain garden, soaks into the soil, and is taken up by plants.  The plants filter nutrients, sediments, and toxic materials from the runoff before excess water ever gets to waterways.

Homeowners are being encouraged to build their own rain gardens.  They need to familiarize themselves with how runoff from their roof, driveway, sidewalk, and roads is currently being routed and treated.  The idea is to try to incorporate that runoff into a rain garden design with sufficient area and infiltration rates.  The runoff would ultimately flow out from a safe, designated location into storm drains at a slower rate than from the previous impervious surfaces.  Homeowners would need to work with their local jurisdictions to find out the requirements for re-routing water in their area and make sure any modifications prevent erosion and protect nearby homes, roads, and other infrastructure.

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Rain gardens help keep pollutants out of waterways

Photo, posted March 3, 2017, courtesy of Jeremy Jeziorski / Oregon Convention Center via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Electric Cars In Norway | Earth Wise

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We are at a relatively early stage of the electric car revolution.  EV sales are increasing rapidly, but they still comprise only a small fraction of the cars on American roads.  So, there is still lots of speculation and argument about how things will actually work when a large fraction of cars are electric.  But there is at least one place where one doesn’t have to speculate:  Norway.

Last year, 80% of new-car sales in Norway were EVs.  That country is essentially an observatory for figuring out what the electrification of vehicles will mean for the environment, workers, and life in general.  In fact, sales of internal combustion cars in Norway will end in 2025.

Based on Norway’s experience, electric vehicles bring benefits and none of the dire consequences that some critics predict.  The transition isn’t problem-free.  There have been unreliable chargers and long waits during periods of high demand.  Auto dealers and retailers have had to adapt to the changes in their businesses.  The pecking order of car brands has changed dramatically making Tesla the best-selling brand and marginalizing long-established carmakers like Renault and Fiat.

But in the bigger picture, the air in Oslo, the capital of Norway, is measurably cleaner.  The city is quieter as noisy gasoline and diesel vehicles gradually disappear.  Oslo’s greenhouse gas emissions have fallen 30% since 2009.  Meanwhile, there hasn’t been mass unemployment among gas station workers, and the electrical grid has not collapsed.

Norway is perhaps 10 years ahead of us with respect to electric cars.  There are still problems to solve, and difficulties to overcome, but so far, it looks like it will all turn out well.

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In Norway, the Electric Vehicle Future Has Already Arrived

Photo, posted October 15, 2018, courtesy of Mario Duran-Ortiz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Self-Deicing Roads | Earth Wise

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Driving on snowy or icy roads can be pretty dangerous.  That is why roads are salted or coated with sand to provide traction in icy weather.  But excessive use of these substances is bad for the environment and sometimes a storm will blow in before the roads can be coated.

In a paper published in the American Chemical Society Journal ACS Omega, researchers in China describe a method of adding microcapsules filled with a chloride-free salt mixture to the asphalt with which roads are paved.  The idea is to provide the road itself with long-term snow melting capabilities.

The researchers prepared a sodium-acetate salt and combined it with a surfactant, silicon dioxide, sodium bicarbonate, and blast furnace slag, which is a waste product from power plants.  The substances were reduced to a fine powder and then coated with a polymer solution to form tiny microcapsules.  The microcapsules were then used to replace some of the standard mineral filler in asphalt.

Lab experiments showed that the special additive lowered the freezing point of water on the asphalt to -6 degrees Fahrenheit.   The researchers estimated that a 2-inch-thick layer of the anti-icing asphalt would be effective at melting snow for seven or eight years.  A real-world pilot test of the coating on a highway offramp showed that it melted snow that fell on the road whereas an uncoated road required snow removal operations.

According to the researchers, given the cost of materials used for the coating and its potential useful lifetime, it could be a practical and economic enhancement for wintertime snow and ice removal.  Maybe we’ll someday have roads that can fairly often deice themselves. 

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Keeping drivers safe with a road that can melt snow, ice on its own

Photo, posted April 8, 2007, courtesy of the Oregon Department of Transportation via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Keeping The Keeling Curve Going | Earth Wise

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The world’s longest-running record of direct readings of carbon dioxide levels in the atmosphere is the Keeling Curve, measurements taken at the summit of Mauna Loa in Hawaii.  The readings have been going on with almost no interruption since Charles Keeling began taking them in the 1950s.  But the eruption of Mauna Loa last November toppled power lines at the mountaintop observatory and buried a mile of the main road up the mountain in lava.

Scientists have been scrambling to resume measurements and the near-term solution has been to take them, for the first time, on Mauna Kea, the neighboring large volcano about 25 miles away.  The National Oceanic and Atmospheric Administration flew in and installed instruments at the Mauna Kea observatory so that only about a week went by without measurements.   It happened so quickly because months earlier, NOAA had already started looking into installing a backup site on Mauna Kea where there is an observatory run by the University of Hawaii.

NOAA used helicopters to install solar panels and batteries on Mauna Loa to restore power in the short term since it will be months before a new road can be built on the still-cooling lava. The plan is to collect parallel measurements for a year to see if Mauna Kea, which hasn’t erupted for thousands of years, might become a long-term backup for Mauna Loa.

The Hawaiian volcanoes are uniquely suited for the measurements because they are surrounded by thousands of miles of empty ocean and are very high up, away from towns, cars, and forests.  Scientists are now monitoring measurements from the two sites to see how they compare.

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Battling Lava and Snowstorms, 2.5 Miles Above the Pacific

Photo, posted November 2, 2015, courtesy of Neal Simpson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

California Flooding | Earth Wise

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Starting in December, a series of “atmospheric rivers” brought record storms to California producing as much rain in three weeks in some areas as they normally have in an entire year.  The historic levels of rain (and snow in the mountains) have swollen rivers, flooded roads and homes, forced evacuations, knocked out electric power for millions of people, and resulted in more than 20 deaths.

Atmospheric rivers are air currents that carry large amounts of water vapor through the sky.  They are not unusual for California but recurrent waves of them like those that have happened recently are very infrequent.  Studies by the U.S. Geological Survey have shown that such a phenomenon recurs in California every 250 years.  There were a series of storms causing disastrous floods in California in 1861-62.

The atmospheric rivers are born in the warm waters of the tropical Pacific.  During La Nina phases, the atmospheric rivers typically make landfall on the northern West Coast. During El Nino phases, atmospheric rivers are more likely to end up in Southern and Central California. During transitions between the phases, as is happening now, the storms can cover large parts of the state.

Modern forecasting is pretty good at predicting the forthcoming occurrence of these storms and has led to some helpful actions, such as reservoir operators preventing dams from overflowing or bursting.  But there is a gap between science and decision-making.  It is pretty clear what needs to be done when tornados or hurricanes are on the way.  It is less clear what actions are appropriate when there are going to be repeated heavy rainstorms.

These storms will have an effect on California’s megadrought, but just how much of an effect remains to be seen.

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Flooding in California: What Went Wrong, and What Comes Next

Photo, posted January 5, 2023, courtesy of Sarah Stierch via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Mauna Loa Eruption And Climate Tracking | Earth Wise

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Mauna Loa, the largest active volcano in the world, erupted for the first time in nearly 40 years in late November.  A 124-foot aluminum tower at the top of the volcano has been the site of carbon dioxide measurements for over 60 years but the eruption cut off power to the site, stopping the monitoring.

Carbon dioxide measurements on Mauna Loa began in 1958.  The project was started by geochemist Charles Keeling and eventually taken over by his son Ralph Keeling upon his father’s death in 2005.  It is the longest continuous record of the rising levels of carbon dioxide in the world.

Mauna Loa is an ideal location for carbon dioxide monitoring because it is a remote location away from both carbon dioxide sources like dense population centers and roads, and carbon sinks like areas of heavy vegetation.

There are hundreds of carbon dioxide monitoring stations around the world, including more than 70 operated by the National Oceanic and Atmospheric Administration, so the interruption will not stop global recordkeeping.  But Mauna Loa holds significant symbolism as the first and most frequently sited source of carbon dioxide data.

There have been other interruptions in the measurements.  Federal budget cuts in 1964 paused them for about 3 months.  A 1984 eruption also cut off power to the facility and shut it down for about a month.

When the facility first started operating, the average carbon dioxide concentration was measured at 313 parts per million.   Most recently, levels have peaked at around 421 parts per million, the greatest concentration in at least 4 million years. 

Power will be restored to the Mauna Loa facility and its measurements will resume.

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Mauna Loa Eruption Threatens a Famous Climate Record

Photo, posted November 29, 2022, courtesy of L. Gallant / USGS via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Electric Cars And The Remote Road Test | Earth Wise

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One reason many people are hesitant about switching to an electric car is range anxiety, the fear that their car’s battery will die on them in the middle of a trip.  It is pretty much the same thing as running out of gas, but somehow it seems like more of a danger.

Perhaps this was true when charging stations were few and far between and electric cars couldn’t go very far on a charge, but these days, the average electric car can drive about 200 miles on a charge and there are charging stations all over the place.

A big difference between gas cars and electric cars is that many people can charge their cars at home and start every day with the equivalent of a full tank.  With an electric car, there is little reason to use up all nearly all the charge before filling up the tank again.

The truth is that most people don’t drive all that much on the average day anyway.  In the US, the average driver goes about 39 miles a day.  In Europe, is it considerably less.  Yes, there are some people who drive 200 miles a day, but they are few and far between.

Remote and regional Australia is a place where distances between essential services can be very large.  But a new study from the Australian National University found that even under those trying conditions, the vast majority of residents, about 93%, can go about their business even with the lower-range electric vehicles available on the market without having to recharge en route.

Electric cars may not be practical for some drivers, but for most, they are already a great choice.

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Electric vehicles pass the remote road test

Electric car range and 5 reasons why your range anxiety is unwarranted

Photo, posted May 21, 2022, courtesy of Ivan Radic via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Scourge Of Salt | Earth Wise

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Rising seas are increasing saltwater intrusion on land and rising temperatures are causing greater evaporation.   The result is mounting levels of salt in waters and in soils.

Rising sea levels cause salty ocean water to push further into river deltas.  There is already a surge in saltiness across all inhabited continents.   Seawater works its way further upstream when dams hold back water.  Pumps that remove fresh water from underground sources for irrigation and drinking supplies add to the problem.  In dry regions, irrigation systems delivering water to crops increasingly bring salt onto fields.

People add to the problem by pouring saline drainage water from mines into rivers and by using salt to de-ice roads in the winter.

A modeling study pinpointed hotspots for climate change-induced salinization in numerous locations including the U.S. Southwest, wide areas of Australia, Mexico, South Africa, Brazil, central India, northern China, and more.

Some ecosystems are adapted to saline environments but major alterations in the balance between saline and fresh water is creating growing problems for ecosystems, lake fisheries, crop growing, and even human health.

The damage caused by salt is likely to be so severe that salinization will become a major cause of environmental refugees when the land they live on can no longer sustain them. 

Salt will be a growing threat to the world’s food supplies, especially where farmers depend on artificial irrigation.  About a third of the world’s food is grown in irrigated fields, and a fifth of those fields are deemed to already be salt-contaminated.  Ultimately, only a halt to climate change will be capable of combatting the scourge of salt.

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Salt Scourge: The Dual Threat of Warming and Rising Salinity

Photo, posted June 3, 2017, courtesy of Jason Jacobs via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Houseplants And Indoor Air Quality | Earth Wise

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Many of us have houseplants in our homes and offices.  The foliage and flowers add beauty and comfort to our indoor spaces.  But it turns out that there are health advantages as well.

Many studies have demonstrated that indoor houseplants can help keep you happier and healthier by improving your mood, reducing fatigue, lowering stress and anxiety, and improving focus.  Houseplants can also improve indoor air quality.

According to a new study by researchers from the University of Birmingham in the U.K. in partnership with the Royal Horticultural Society, ordinary houseplants can potentially make a significant contribution to reducing indoor air pollution.

The researchers tested three types of houseplants commonly found in homes in the U.K: Peace lily, corn plant, and fern arum.  These plants are easy to maintain and not overly expensive. 

In the study, the research team exposed these houseplants to nitrogen dioxide, which is a common indoor pollutant.  The plants were isolated in a test chamber containing levels of nitrogen dioxide comparable to what might be in an office situated next to a busy road.  The researchers found that all the plants were able to remove about half of the nitrogen dioxide in the chamber in just one hour.    

In a poorly ventilated small office with high levels of air pollution, the researchers calculated that five houseplants would remove up to 20% of the nitrogen dioxide.  In a larger space, the effect would be smaller – around 3.5% – although this figure could be increased by adding more plants.

Bringing nature indoors is one way to breathe cleaner air.

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Common houseplants can improve air quality indoors

Reducing air pollution with plants

Photo, posted September 21, 2014, courtesy of Olin Gilbert via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Electric Pickup Trucks | Earth Wise

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There are more and more electric cars on the market as auto manufacturers move toward fleet-wide electrification.  In the United States, pickup trucks are massively popular.  The top three selling vehicles in the country are all trucks, led by the Ford F-Series.  Thus, it is no surprise that automakers are now turning their attention to electric pickup trucks.

Some of the trucks are from established manufacturers like Ford and Chevy and others from new companies like Rivian.  The Ford F-150 Lightning is bound to be a big seller.  There are hundreds of thousands of pre-orders for Tesla’s exotic Cybertruck, now expected to enter the market next year.

A recent study looked at the environmental impact of pickup truck electrification.  The central question is what does the transition to electric trucks mean for the overall decarbonization of the transportation industry?

Researchers from the University of Michigan and the Ford Motor Company conducted a cradle-to-grave assessment of the life cycle of pickup trucks and compared the implications of truck electrification to those of sedans and SUVs.

The study found that replacing an internal combustion-powered vehicle with a battery-powered vehicle results in greater total greenhouse gas emission reductions as the size of the vehicle increases, which is no real surprise considering how much more gas larger vehicles use.

The study also found that manufacturing electric vehicles produces more emissions than gas-powered vehicles, but the impact is offset by savings in their operation.  Breakeven time is little more than a year.

Basically, the results are that replacing gas-powered trucks with electric trucks is even a bigger win for the planet than replacing gas cars with electric cars.  Let’s hope we see plenty of electric trucks on the roads in the near future.

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Study: Greater greenhouse gas reductions for pickup truck electrification than for other light-duty vehicles

Photo, posted September 22, 2020, courtesy of Steve Jurvetson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Cheaper Electric Cars | Earth Wise

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The price of the batteries that power electric cars has fallen by about 90% since 2010.  This continuing trend will eventually make EVs less expensive than gas cars.

For many years, researchers have estimated that when battery packs reach the price of $100 per kilowatt-hour of energy storage, electric cars will cost about the same as gasoline-powered vehicles.  In 2021, the average price of lithium-ion battery packs fell to $132 per kilowatt-hour, down 6% from the previous year.  According to analysts, batteries should hit the average of $100 as soon as 2024.

It is not the case that as soon as the $100 level is reached, EVs will abruptly reach cost parity.  Across different manufacturers and vehicle types, the price shift will occur at different rates.  However, by the time batteries reach $60 a kilowatt-hour, EVs will be cheaper than equivalent gasoline models across every vehicle segment.

It is not known exactly when EVs will cost less than gasoline models, but there is little doubt that this point is coming.  We have only been talking about the purchase price of a new vehicle.  When one looks at the total cost of ownership of a vehicle, including fuel, insurance, maintenance, and depreciation, it is a different story.

Because of savings on fuel and maintenance, EVs are already in many if not most cases cheaper to own than gas-powered cars.  The Department of Energy provides an online calculator to help consumers estimate the cost differences between gasoline and electricity.

In any case, the number of electric cars on the market is increasing and the number of gas-powered cars will be shrinking.  Sooner or later, we will all drive electric.

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Inside Clean Energy: Batteries Got Cheaper in 2021. So How Close Are We to EVs That Cost Less than Gasoline Vehicles?

Photo, posted July 29, 2017, courtesy of Steve Jurvetson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Roads And Chimpanzees | Earth Wise

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The chimpanzee is a species of great ape native to tropical regions of Central and West Africa.  Chimpanzees are highly social animals and can live to be over 50 years old.  In fact, chimpanzees are our closest cousins.  We share about 98% of our genes with chimpanzees. 

According to the African Wildlife Federation, it’s estimated that at most only 300,000 chimpanzees remain in the wild today.  They face a myriad of challenges, including habitat degradation and hunting. 

According to new research from the University of Exeter in the U.K., roads have a negative impact on chimpanzee populations that can extend for several miles.  In the study, which was recently published in the journal Conservation Letters, the researchers analyzed the impact of major and minor roads on wild western chimpanzee numbers in the eight African countries in which they live.  They found that negative impacts extended an average of 10.7 miles from major roads, and 3.4 miles from minor roads.  The researchers found that the density of chimpanzee populations dropped steadily from the edges of these areas to the lowest value alongside the roads.  Only 4.3% of the chimpanzees’ range remains unaffected by roads. 

While the study did not investigate why roads affect chimpanzee numbers, the research team did offer some clues.  In addition to noise and roadkill, roads provide access to unexploited areas for industries that often reduce or remove chimpanzee habitats.  Roads can also restrict chimpanzee movements, and provide easier access for hunters. 

The researchers hope their findings will bring about more effective guidelines to mitigate the impact of roads on wildlife.   

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Roads have far-reaching impact on chimpanzees

Photo, posted August 12, 2014, courtesy of Rod Waddington via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Is Peak Oil Here? | Earth Wise

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For many years there has been talk of “peak oil”, the point at which rising world oil consumption would peak and then start declining.  Some analysts have been predicting that this could happen by the 2030s.   But the coronavirus pandemic drove a 9% slump in oil demand in 2020 that some economists are saying might never be entirely reversed.

There are three major forces driving down the world’s appetite for oil:  decarbonization of economies to meet the goals of the Paris climate agreement, declining demand for oil as renewable energy sources and electric vehicles are increasingly adopted, and detoxification as cities act to curb particulates and emissions from burning petroleum.

The largest single factor is electric vehicles.  Automobiles currently consume almost half of the world’s oil.  As of the end of 2020, there were an estimated 10 million electric cars as well as more than 600,000 electric buses and trucks.  This is still less than 1% of all vehicles, but 5% of all new cars being bought are now electric and the number is growing rapidly.  Experts estimate that nearly a quarter of global car sales will be electric vehicles by 2025 and many car manufacturers are promising to sell only electric cars within the next 10 years.

The decline in oil demand is pretty much inevitable at this point.  The main question is how quickly it will happen.  Road transport makes up 48% of global oil demand, petrochemicals account for 14%, aviation 7%, and shipping 6%.  Ultimately all these things are likely to diminish over time. 

Only time will tell, but the long-awaited arrival of peak oil may already have happened.

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Amid Troubles for Fossil Fuels, Has the Era of ‘Peak Oil’ Arrived?

Photo, posted April 14, 2019, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Paving With Plastic | Earth Wise

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The country of Ghana has an ambitious plan to recycle and reuse as much plastic waste as it produces each year (which is over a million tons) by 2030.  As part of this plan, they have started to pave roads in Accra, the capital city, with asphalt containing a slurry of used plastics – shredded and melted bags, bottles, and snack wraps.  Only a quarter of Ghana’s roads are currently paved, so waste plastic has many opportunities for use in paving.

Plastic roads first appeared in India two decades ago.  There are now over 60,000 miles of them in that country.  Several countries have only recently built their first plastic roads including South Africa, Vietnam, Mexico, the Philippines, and the United States.

Studies have shown that roads containing waste plastic have the potential to perform as well or better than traditional roads.  They can last longer, can tolerate wide temperature swings better, are stronger and more durable, and are more resistant to water damage, cracking, and potholes.

Ordinarily, asphalt for roads consists of 90 to 95% aggregate – typically some mixture of gravel, sand, and limestone – and 5 to 10% bitumen, which is a black gooey substance extracted from crude oil that binds the aggregate together.  Plastic-enhanced roads replace varying amounts of the bitumen (often as little as 4-10%, but sometimes much more), with plastic that is actually a stronger binding agent.

Plastic roads reduce the amount of bitumen in roads, thereby reducing carbon emissions.  The plastics are not heated enough to release gases and the roads do not appear to shed microplastics.  Plastic roads will not solve the world’s plastic waste problem, but they can help by diverting lots of plastic from landfills.

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How Paving with Plastic Could Make a Dent in the Global Waste Problem

Photo, posted June 4, 2010, courtesy of Sustainable Initiatives Fund Trust via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Improved Radar For Cars | Earth Wise

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Self-driving cars require a variety of sensor systems in order for the cars to safely navigate roads and deal with the wide range of objects and conditions that they encounter.  Two competing technologies that cars use to identify and locate objects on the scene are radar and LiDAR. 

Radar uses transmitted radio waves to locate objects and LiDAR bounces laser beams off of objects.   Each has its shortcomings.   Radar has the problem that only a small fraction of the transmitted signals gets reflected back to the sensor, so that there is frequently insufficient data to fully characterize a scene.  LiDAR has the problem that it is an optical system that does not work well in fog, dust, rain, or snow.  It is also much more expensive than radar.

Researchers at the University of California San Diego have developed a new system that they describe as a LiDAR-like radar. The system consists of two radar sensors placed on a car’s hood and spaced about 1.5 meters apart.  This configuration enables the system to see more space and detail than a single radar sensor.

Having two radars at different vantage points with an overlapping field of view creates a region of high-resolution with a high probability of detecting the objects that are present.  The system also overcomes noise problems of conventional radar systems.

The researchers developed new algorithms that can fuse the information from two different radar sensors and produce a new image free of noise.

Self-driving cars have to combine detection technologies like radar with cameras and ultrasonic sensors.  Duplicating the capabilities that people use in order to safely drive a car is a complex problem requiring a combination of multiple sensors and sophisticated software.

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Upgraded radar can enable self-driving cars to see clearly no matter the weather

Photo, posted January 2, 2014, courtesy of Bradley Gordon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Shutting Down Pollution | Earth Wise

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With much of the country shut down as the coronavirus forces people to stay at home, there has naturally been a drastic reduction of traffic on roads and highways.   And with that decrease, there has been a dramatic reduction in pollution as well.

A satellite that detects emissions in the atmosphere linked to cars and trucks has observed huge declines in pollution in major metropolitan areas such as Los Angeles, Seattle, New York, Chicago, and Atlanta.

Los Angeles is infamous for its rush-hour traffic but that has pretty much ceased to exist. Similar changes can be seen in the San Francisco Bay Area, where nearly 7 million residents have been ordered to shelter in place.  New York City is less dependent on car travel than in other metro areas, but the shutdown of office buildings, schools, and restaurants has nonetheless resulted in a substantial reduction of traffic on the streets of the city.

While this sudden decline in air pollution over U.S. cities has some near-term health benefits, those benefits are likely to be fairly minor in the big picture.  When the coronavirus outbreak subsides and people are allowed to leave their homes and go back to their normal lives, air pollution will most certainly rebound to previous levels.  In any event, studies have shown that long-term exposure to air pollution has a larger impact on public health than any transient events.

Having much cleaner air for a while is certainly a good thing, but this shutdown is not a sustainable way to reduce air pollution and the long-term effects of the coronavirus crisis will certainly not be positive.

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Traffic and Pollution Plummet as U.S. Cities Shut Down for Coronavirus

Photo, posted March 15, 2020, courtesy of Tom Collins via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Falling U.S. Carbon Emissions

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Reducing carbon emissions is a goal embraced by nearly every country in the world, but actually accomplishing it isn’t easy. It is true that renewable energy sources are playing a growing role in energy systems, but counterbalancing that trend is growing energy demand, especially in developing countries.

Here in the US, energy-related CO2 emissions actually went up nearly 3% in 2018 compared with 2017.  But the US Energy Information Administration is now forecasting a 2% drop in emissions this year.

The main reason energy-related emissions are headed lower at this point is coal-fired power plant retirements.  More than 90% of the coal used in the US goes toward electric power and utilities are increasingly turning away from coal.

The rapid shift away from coal has mostly been due to the increasing use of natural gas.  Natural gas is not actually a clean and green fuel, but it is definitely less carbon-intensive than coal.  Overall, the total installed capacity of renewable sources – hydropower, wind, solar, geothermal, and biomass – has now actually surpassed the capacity of coal plants.  Given that renewables have in many places become the cheapest power option, there is little chance that coal has much of a future, despite efforts by the current administration.

The electric power sector is gradually moving away from all carbon-emitting sources – a trend that is being reinforced by legislation in many states.  The real CO2 emissions leader is petroleum, which accounts for nearly half of the total.  We have a long way to go to reduce emissions from the use of petroleum.  There are over 250 million cars and trucks on US roads and only a little over a million of them don’t burn fossil fuels.

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US energy-related CO2 emissions expected to fall this year, almost solely due to a drop in coal use

Photo, posted November 6, 2017, courtesy of Cindy Shebley via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Making Roads From Ocean Plastic

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Like many other places around the world, India has a big problem with plastic waste.  Its 1.3 billion people each use an average of 24 pounds of plastic per year and much of it ends up in the Arabian Sea and Indian Ocean.

Fishermen in India’s southern state of Kerala have taken on the battle against plastic waste in the ocean by launching a campaign called Suchitwa Sagaram, or Clean Sea, in which they are collecting the plastic and bringing it back to shore.

In the first 10 months of the program, fisherman have removed 25 tons of plastic from the Arabian Sea.  Once the plastic waste reaches shore, it is fed into a plastic shredding machine.  As is the case for many of India’s plastic recycling schemes, the shredded plastic from the sea is converted into material that is used for road surfacing.

There are more than 20,000 miles of plastic roads in India, mostly in rural areas.  In fact, more than half the roads in the southern state of Tamil Nadu are plastic.  Such roads have become popular because they are more resilient to India’s searing heat.  The melting point of plastic roads is around 150 degrees Fahrenheit as compared to 122 degrees for conventional roads.

Roads made from recycled plastic are also cheaper than ones using conventional plastic additives.  A mile of plastic road uses the equivalent of a million and a half plastic bags and saves about a ton and a half of asphalt.  Overall, plastic roads are about 8% cheaper than conventional roads and create jobs for people in the fishing communities.

India’s plastic roads are a promising way to fight the problem of ocean plastic pollution.

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These Indian fishermen take plastic out of the sea and use it to build roads

Photo, posted April 25, 2016, courtesy of Bo Eide 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...)