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Climate Change

A New Way To Remove CO2 From The Air

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Researchers at MIT have developed a new way of removing carbon dioxide from a stream of air that could be a powerful tool in the battle against climate change.  The new system can pull carbon dioxide out of almost any concentration level of the gas, even including the roughly 400 parts per million level currently found in the atmosphere.

The technique is described in a new paper in the journal Energy and Environmental Science and is based on passing air through a stack of electrochemical plates. The device is essentially a large battery that absorbs carbon dioxide from the air passing over its electrodes as it is being charged up, and then releases the gas as it is being discharged.

To use it, the device would simply alternate between charging and discharging.  Fresh air or some other feed gas would be blown through the system during the charging cycle and then pure, concentrated carbon dioxide would be blown out during discharging.

The specialized battery uses electrodes coated with a compound called polyanthraquinone, which is composited with carbon nanotubes.  These unique electrodes have a binary affinity to carbon dioxide, which means that they either strongly want to capture carbon dioxide or not at all, depending upon whether the device is charging or discharging.

Carbon dioxide is important in many industries such as soft drinks and greenhouse agriculture.  With this device, the stuff could literally be pulled out of the air.  And, of course, in power plants where exhaust gas is dumped into the air, these novel electrochemical cells could be used to prevent the emission of CO2 into the atmosphere.  At the right price, this could be a game changer.

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MIT engineers develop a new way to remove carbon dioxide from air

Photo, posted August 9, 2007, courtesy of William Clifford via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Turning Trash Into Treasure

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Every year, 380 million tons of plastic are created worldwide, and that number continues to grow.  Furthermore, more than 75% of these materials are discarded after one use.  Much of it ends up in oceans and waterways, harming wildlife and spreading toxins.

Recycling most plastics is difficult because while they can be melted and reprocessed, the resultant material is not as structurally strong as the original material.  Thus, plastics are often down-cycled such as turning plastic bottles into molded park benches.

Researchers at Northwestern University, Argonne National Laboratory, and Ames Laboratory have developed a new method for upcycling abundant, seemingly low-value plastics into high-quality liquid products, such as motor oils, lubricants, detergents, and even cosmetics.  The catalytic method  could remove plastic pollution from the environment and contribute to a circular economy.

Plastics don’t degrade when disposed of because they have very strong carbon-carbon bonds.  Instead they just break into smaller bits, known as microplastics.  The researchers viewed these strong bonds as an opportunity rather than a problem.

The new technique actually recoups the high energy that holds these bonds together by catalytically converting polyethylene molecules into value-added commercial products.  The catalyst consists of platinum nanoparticles deposited onto perovskite nanocubes.  Under moderate pressure and temperature, the catalyst cleaves the carbon-carbon bonds in plastic to produce high-quality liquid hydrocarbons. 

The researchers believe these findings could lead to a future in which we can continue to benefit from plastic materials but do so in a way that is sustainable and less harmful to the environment.

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Turning plastic trash into treasure

Photo, posted August 15, 2012, courtesy of Emilian Robert Vicol via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Potential For Offshore Wind

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According to a new report from the International Energy Agency, offshore wind technology has vast potential for meeting our energy needs.  In total, offshore wind has the potential to generate more than 420,000 terawatt-hours of electricity each year, which is more than 18 times the global electricity demand that exists today.

Based on current policy targets and plummeting technology costs, offshore wind could increase 15-fold by 2040, becoming a $1 trillion industry and eliminating 5 to 7 billion tons of carbon dioxide emissions annually.

Offshore wind today generates just 0.3% of the world’s electricity, but its’ use is growing rapidly.  The industry has grown nearly 30% a year since 2010, and 150 new offshore projects are currently in development around the world.  The leading countries are in Europe – especially in the UK, Germany, and Denmark – but China is greatly expanding its offshore capacity and the US, India, Korea, Japan, and Canada are also expected to make large investments in offshore wind going forward.

Offshore wind is in a category of its own because it is considered a variable baseload power generation technology.  This is because the hourly variability of offshore wind is much lower than solar power or onshore wind.  Offshore wind typically fluctuates far less from hour-to-hour than the other variable energy sources.

Technology improvements and industry growth are driving steep cost reductions for offshore wind.  The cost of offshore wind is expected to be cut in half in the next five years, dropping to $60 per megawatt-hour, which is on par with solar and onshore wind and cheaper than new natural gas-fired capacity in Europe.

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Offshore Wind Has the Potential to Fulfill Global Electricity Demand 18 Times Over

Photo, posted August 9, 2016, courtesy of Lars Plougmann via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Why Save Endangered Species?

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One often hears the argument that humans need to save the world’s endangered species in order to save ourselves.  Carl Safina, a marine ecologist and award-winning environmental writer, has written a thought-provoking essay that offers the viewpoint that we don’t actually need the wild species of the world but that they need us.

The truth is that human beings have thrived by destroying nature.  We have exploited other species when they were useful to us and simply pushed them aside when they weren’t.  We drove America’s most abundant bird – the passenger pigeon – to extinction.  The most abundant large mammal – the bison – was driven to functional extinction.

In today’s world, people live at high densities in places devoid of wild species and natural beauty.  And while we express concern for elephants, gorillas, sperm whales, tigers, and various other species, how would the lives of most of us be affected at all should they vanish entirely?  The unfortunate truth is that it would make little difference to our lives.

The only species that are really essential to modern living are actually microbes of decay, a few insect pollinators, and the ocean’s photosynthesizing plankton.  Life would go on little changed without most other co-inhabitants of our planet.

Safina argues that our obligation to protect endangered species does not come from our dependence upon them but rather on a moral obligation.  Humans consider ourselves to be the most moral species and, as such, we have moral obligations.  In this case, it is to protect the beauty and wonder of our world, which is not trivial but in fact is the most profound thing on earth.

Safina has much more to say about this and I strongly recommend reading his essay.  You can find the link here.

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The Real Case for Saving Species: We Don’t Need Them, But They Need Us

Photo, posted December 9, 2014, courtesy of Gerry Zambonini via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Should New York Build A Storm Surge Barrier?

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In 2012, Superstorm Sandy’s storm surge combined with a high tide and buried lower Manhattan under 13 feet of water.  Across all five boroughs, subways, highways, and parking garages flooded and homes and businesses were destroyed.  Sandy caused nearly $20 billion in damages in New York City alone and more than 50 people died.

Ever since that disaster took place, there have been discussions about building storm surge barriers to protect the city from future storms.  Columbia University’s Sabin Center recently hosted an event to discuss the feasibility of building such barriers.

A study by the U.S. Army Corps of Engineers called the NY and NJ Harbor and Tributaries Focus Area Feasibility Study (HATS, for short) evaluates five options for coastal protection, which range in scope and price.

The most extensive option would involve constructing six miles of storm surge gates along with 26 miles of floodwalls, levees, and buried seawalls.  This option would cost $62 billion but could theoretically save $131 billion in damages and protect 95% of the study area.

The study also considers the side effects of building storm surge barriers.  These include environmental impacts such as effects on fish and wildlife, water quality, noise and vibrations, and changes in water flow.  While these effects can be quite serious and there is opposition from many quarters related to environmental impacts, others point out that there is really no other credible defense against storm surge.  The debate over whether or not to build storm surge barriers could easily last for many more years.

In the bigger picture, storm surge barriers do nothing to protect against rain-driven flooding, sea level rise, and tidal floods which continue to increase.

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Should New York Build a Storm Surge Barrier?

Photo, posted October 30, 2012, courtesy of Pamela Andrade via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Reducing Emissions From Natural Gas Processing

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Qatar, a small country in the Middle East with a population of about 2.5 million has the highest per capita income of any country in the world.  This is largely a result of being one of the world’s top producers of natural gas.  The upshot of that is that the tiny country has the dubious honor of being the world’s leading emitter of CO2 per capita.

Texas A&M University has a campus in Qatar and researchers there in collaboration with colleagues at the main campus in College Station, Texas have developed a new reactor technology that can help Qatar process its wealth of natural gas while reducing the country’s carbon footprint.

The technology processes natural gas and captured CO2 to produce both syngas – which is a valuable precursor for many products – and high-quality carbon nanotubes, all without releasing CO2 into the atmosphere.

Natural gas reforming is a process by which syngas – a feedstock for liquid hydrocarbons and ultraclean fuels- is produced.  The process requires lots of heat and emits CO2.  The new technology adds a novel CARGEN (or CARbon GENerator) reactor that advances the natural gas reforming process and includes a catalyst that captures the CO2 emissions and produces nanotubes.  The reactor can be driven by either electric or solar power, eliminating the need to burn fuel that ordinarily results in more carbon emissions.

The result is that Qatar’s CO2 emissions would be converted into two products that are important to its economy.  In particular, carbon nanotubes are very expensive and extremely versatile, and can be used to manufacture products such as computers and other high-quality materials.

The next step for the researchers is to partner with industry collaborators to further scale up the technology.

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Qatar Researchers Develop Natural Gas Processing Technology That Could Reduce Qatar’s Carbon Footprint

Photo, posted September 30, 2012, courtesy of Jimmy Baikovicius via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Keeping Plants Plump

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The leading cause of crop failures worldwide is drought.  Ironically, the very close runner-up is flooding.  Facing a changing and increasingly erratic climate, farmers need all the help they can get in protecting their crops.

Researchers at the University of California, Riverside, have created a chemical to help plants hold onto water, which could stem the tide of massive annual crop losses from drought.  Details of the team’s work is described in a paper published in Science.

The chemical is called Opabactin, but is also known as “OP.” OP is gamer slang for overpowered, referring to the best character or weapon in a game.

OP mimics abscisic acid, or ABA, which is the natural hormone produced by plants in response to drought stress.  ABA slows a plant’s growth, so it doesn’t consume more water than is available and doesn’t wilt.  OP is 10-times stronger than ABA, which makes it a super hormone.  It works fast.  Within hours, there is a measurable improvement in the amount of water plants release.  Because it works so quickly, OP could give farmers more flexibility in how they deal with drought.   Plants can’t predict the future, but if, for example, farmers think there is a reasonable chance of drought, they could make decisions such as to apply OP to improve crop yields.

The research team is now trying to find a second chemical tool.  Whereas OP slows down plant growth, the team wants to find a molecule that will accelerate it.  Such a molecule could be useful in controlled environments such as indoor greenhouses.  There are times when you want to speed up growth and times when you want to slow it down.

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Game changer: New chemical keeps plants plump

Photo, posted June 7, 2013, courtesy of Bayer CropScience UK via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And El Niño

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The term El Niño refers to a large-scale ocean-atmosphere climate interaction linked to a periodic warming in sea surface temperature across the central and east-central equatorial Pacific Ocean.  Amazingly, the phenomenon was originally recognized by fishermen off the coast of South America in the 1600s, with the appearance of unusually warm water in the Pacific Ocean.

According to a new study published in the Proceedings of the National Academy of Sciences, climate change is increasing the frequency of extreme El Niño events, leading to intensifying droughts, worsening floods, and shifting hurricane patterns.

The study, led by scientists in China and the US, looked at data from 33 El Niños dating back to 1901.  Since the 1970s, El Niños have been forming farther to the west in the Pacific Ocean, where temperatures are warmer.  Strong El Niños can cause severe drought in dry climates such as Australia and India, intense flooding in wetter climates such as the US Pacific Northwest and Peru, and more hurricanes to form in the Pacific and fewer in the Atlantic.

Before 1978, 12 out of 14 El Niños formed east of the International Dateline.  Since 1978, all 11 have formed in the central or western Pacific Ocean a shift of hundreds of miles.  There have been three so-called super El Niños since the shift – in 1982, 1997, and 2015.  These have set new average temperature records and triggered catastrophic natural disasters.

With rising global temperatures, El Niños are likely to continue to intensify, with major impacts on human societies around the world.

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Climate Change is Making El Niños More Intense, Study Finds

Photo, posted January 20, 2016, courtesy of Los Angeles District via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Safe And Simple Hydrogen Peroxide

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We don’t think about hydrogen peroxide very often.  Perhaps we have a bottle of it under our bathroom sink that we haven’t touched in a few years.   But it is an important product manufactured in the millions of tons each year and the basis of a $6 billion global business.

Hydrogen peroxide is widely used as an antiseptic, a detergent, in cosmetics, as a bleaching agent, in water purification, and in many other applications.  It is produced in industrial concentrations of up to 60% in solution with water in order to maximize the economics of transportation.  This makes transportation hazardous and costly because the concentrated form is unstable.  Most applications use a far more diluted form.

Researchers at Rice University have developed a new method for producing hydrogen peroxide that is much simpler and safer than the current technology, which actually dates back to the 1930s.  The Rice technique requires only air, water and electricity to produce the chemical.  The electrosynthesis process, which is detailed in the journal Science, uses an oxidized carbon nanoparticle-based catalyst.

The process could enable point-of-use production of pure hydrogen peroxide solutions, which would eliminate the need to transport the hazardous concentrated chemical.  The use of a solid electrolyte instead of the traditional liquid electrolyte eliminates the need for product separation or purification that is part of the current technology.

In the future, instead of storing containers of hydrogen peroxide, hospitals that use it as a disinfectant could turn on a spigot and get, for example a 3% solution on demand.  Instead of storing chemicals to disinfect swimming pool water, future homeowners could flick a switch and turn on their peroxide reactor to clean their pools.

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Water + air + electricity = hydrogen peroxide

Photo, posted April 19, 2009, courtesy of Robert Taylor via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The March Of The Penguins Toward Extinction

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According to a new study from the Woods Hole Oceanographic Institution, the warming climate may render emperor penguins extinct by the end of this century.  The study, which was part of an international collaboration between scientists, finds that emperor penguins will likely experience an 86% decline by 2100 if the global climate continues to warm at the current rate.  At that point, it would be very unlikely for them to recover, according to the study’s lead author.       

The research was funded by the National Science Foundation and recently published in the journal Global Change Biology.

The fate of emperor penguins is largely tied to the fate of sea ice.  The penguins use sea ice as a place for breeding, feeding, and molting.  They look for very specific conditions of sea ice – it must be locked in to the Antarctic shoreline but also close enough to open seawater to give them access to food. The study predicts that this sea ice will gradually disappear, depriving the birds of their habitat, food sources, and ability to raise their young.     

The researchers combined two existing computer models to study three different climate change scenarios.  If the average global temperature increases by only 1.5 degrees Celsius, the study found that only 5% of sea ice would be lost by 2100, resulting in a 19% drop in penguin colonies.  If the planet warms by 2 degrees Celsius, the sea ice loss nearly triples and more than a third of penguin colonies disappear.  The ‘business as usual’ scenario where the planet continues to warm at the current rate will ensure a near complete loss of emperor penguin colonies by 2100. 

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Unless warming is slowed, emperor penguins will be marching towards extinction

Photo, posted January 15, 2011, courtesy of Eli Duke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Clean Gas From An Artificial Leaf

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Photosynthesis is the process used by plants, algae and certain bacteria to harness energy from sunlight and turn it into chemical energy.  It is often described as the green engine of life on earth.

For quite some time, there have been extensive research efforts around the world in the area of artificial photosynthesis.  The goal is to somehow mimic the behavior of plants in order to generate clean-burning fuels using nothing more than sunlight and the carbon dioxide in the air.

Researchers at the University of Cambridge have recently demonstrated a so-called artificial leaf that can directly produce syngas using sunlight.   Syngas is a fuel gas mixture consisting primarily of hydrogen and carbon monoxide.  Most people haven’t heard of syngas, but many products are created using it.  Being able to produce it sustainably would be a critical step to a far greener chemical and fuel industry.

The artificial leaf contains two light absorbers, similar to the molecules in plants that harvest sunlight, which are combined with a catalyst made from the naturally abundant element cobalt.  When the device is immersed in water, one light absorber uses the catalyst to produce oxygen.  The other carries out the chemical reaction that reduces carbon dioxide and water into carbon monoxide and hydrogen.  The result is the syngas mixture.

It turns out that even a rainy or overcast day provides enough light to drive the process.

Previous artificial leaf devices have mostly just produced hydrogen.  The Cambridge device produces syngas thanks to the novel combination of materials and catalysts it uses.

The researchers are now focused on finding ways to use the technology to produce a sustainable gasoline substitute.

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‘Artificial leaf’ successfully produces clean gas

Photo, posted August 15, 2014, courtesy of Mike Mozart via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Stranded Coal Assets In Japan

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Japan is facing a looming financial problem as a result of heavy investments in coal technology that may quickly become stranded assets as renewable energy sources become increasingly inexpensive.

Japan is gradually adding more ambitious policies with regard to climate change including goals to reduce emissions and to have renewables become the main source of power over the next three decades.  But despite these policy efforts, Japan is still investing heavily in coal power.  Japan currently has 21 new coal projects with over 11 GW of under-construction, permitted or pre-permitted coal capacity.  But these tens of billions of dollars in assets would have to be closed prematurely in order to remain consistent with the goals of the Paris Climate Agreement.

According to a new report by the Carbon Tracker Initiative, a financial think tank, and the University of Tokyo, offshore wind power will be cheaper than coal in Japan by 2022, new solar cheaper by 2023, and onshore wind less expensive by 2025.  The price of offshore wind is already comparable to existing coal power in Japan.  Japan had a total of 55.5 GW of solar capacity last year and has the potential to reach 150 GW by 2030.

The report notes that 42% of the global coal fleet likely became unprofitable last year and this could rise to 72% by 2040.  The authors contend that building coal power today equals high-cost power and financial liabilities tomorrow.  The planned and operating coal capacity in Japan is partially protected by regulations that give coal generators an unfair advantage in the marketplace.  Ultimately, the stranded coal assets are likely to be passed down to consumers through higher power prices.

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Land of the Rising Sun and Offshore Wind

Photo, posted April 25, 2019, courtesy of Jen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Roofs Going Green

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Green roofs are roofs on buildings that are partially or completely covered with vegetation and a growing medium, generally planted over a waterproofing membrane.  The modern version of these roofs began in Germany in the 1960s and spread to many other European countries over time.  With concerns about climate change and shrinking natural resources rising, green roofs are becoming increasingly popular across North America.  The Toronto-based organization Green Roofs for Healthy Cities estimates that the number in North America has increased by about 15% since 2013.

Replacing black asphalt and shingles with plants can lower the surrounding air temperature, filter dirty storm water, and reduce building energy use.  The National Research Council of Canada estimates that a green roof can reduce air conditioning use in a building by as much as 75%.  The roofs also help to reduce air pollution and greenhouse gas emissions according to the EPA.

As the benefits of green roofs become more widely known, cities around the world are passing green roof legislation.  Copenhagen passed a law in 2010 requiring all new commercial buildings to have green roofs if their roofs are not sloped too much.  Toronto was the first city in North America to pass a green roof law in 2009.  Over 640 green roofs covering more than five million square feet have since been constructed in Toronto.

Apart from the environmental benefits, green roofs are providing pleasant spaces in the urban environment that may include flower beds, trees, herb gardens, gazebos and picnic tables.  As for the economics, studies show that over the course of a roof’s lifetime, green roofs are actually considerably cheaper than conventional roofs taking into account energy savings.

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The Green Revolution Spreading Across Our Rooftops

Photo, posted July 15, 2014, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Protecting Canola Crops From Frost

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Canola is one of Canada’s most valuable crops.  In fact, Canada is the world’s largest exporter of canola oil.  The international market for canola oil is $27 billion a year.  The oil is very popular because it has a relatively low amount of saturated fat, a substantial amount of monosaturated fat, and is very neutral tasting.

Canadian canola farmers worry a great deal about late season, non-lethal frosts because the frosts prevent chlorophyll – a photosynthetic pigment in the seeds – from breaking down, a process they call “degreening”.  The farmers seek to have high-quality yellow embryos at seed maturity.  When the harvest contains more than 2% of green seeds, it can no longer produce Grade No. 1 quality oil.  When green seeds are processed to extract canola oil, the chlorophyll in the seeds reduces the oil’s storability and quality.  As a result, farmers receive a lower price for frost-damaged green seed canola.  This costs Canadian farmers and estimated $150 million annually.

Researchers at the University of Calgary have developed gene-based technology to produce canola plants that can withstand late-season frost and still produce high-quality seed.  They identified a specific protein that controls chlorophyll breakdown and seed maturity.  Genetic manipulation is able to enhance the seed degreening system.  They were able to reduce the amount of chlorophyll in the genetically modified canola lines by 60% after the plants were exposed to non-lethal frost. 

Ultimately, the researchers plan to develop a method to incorporate the modification into canola hybrid lines in such a way that it will be readily accepted by consumers concerned about genetically modified organisms.

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New technology helps protect valuable canola crops from frost

Photo, posted August 29, 2018, courtesy of Tinker and Rove via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Smarter Prospecting

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The global demand for copper and gold continues to grow.  Copper is widely used in building materials, plumbing, and electronics.  Gold is still highly valued for jewelry and coinage, but nearly a third of the world’s gold is now used in electronics. 

Both of these metals are getting increasingly difficult to find as many of the known sources have been exhausted.  Companies spend millions of dollars drilling deeper and deeper in search of new deposits.

It costs about $400 to drill one meter into rock and it is not uncommon to drill to depths of one to two kilometers.  So, it can cost nearly a million dollars to drill a hole that has no guarantee of success.  Given that ore deposits are tiny compared with the totality of the search space, prospecting for these metals is very much like looking for a needle in a haystack.

A researcher at the University of South Australia has developed a suite of geochemical tools to more accurately target valuable mineral deposits and thereby save drilling companies millions of dollars.  The goal is to have drilling for valuable minerals be faster, cheaper and more environmentally friendly.

By mapping out where key chemical elements are found in greater concentrations, the new suite of tools greatly increases the chances of finding an ore deposit at a target site and thereby greatly improve the return on investment for exploration companies.  The tools have been successfully tested at an iron oxide-copper-gold deposit in the north of South Australia, leading to a four-fold increase in the known footprint of their ore body.  Finding economically viable enriched ore sites can generate both revenues and jobs.

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Prospecting for gold just got a lot easier (and cheaper)

Photo, posted April 21, 2005, courtesy of Adam via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Geoengineering And Volcanoes

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Solar geoengineering is a theoretical strategy for curbing the effects of climate change by introducing aerosol particles in the upper atmosphere to reflect some of the Sun’s radiation back into space and thereby cool the planet.  It would basically be intentionally tinkering with the climate system on a global scale.

The concept is fraught with the danger of unintended consequences and most experts consider the idea almost unthinkable.  But there are those who see it as a last resort if all our other efforts to mitigate the effects of climate change are unsuccessful.

Proponents of the idea like to describe the technique as being like a human-made volcano.  Major volcanic eruptions spew ash particles into the atmosphere which can linger for as long as a few years.  The result is cooler temperatures, sometimes across much of the globe.  The Krakatoa eruption of 1883 lowered average Northern Hemisphere temperatures by more than 2 degrees and created chaotic weather patterns until about 1888.

Researchers at the Carnegie Institution and two Chinese research institutions used sophisticated modeling techniques to compare the effects on the climate of a volcanic eruption with long-term geoengineering deployment.

They found that the volcanic eruption created a greater temperature difference between the land and sea than the geoengineering and resulted in very different precipitation scenarios.  In both cases, there would be less available water for people on land.

Overall, the study demonstrated that volcanic eruptions are imperfect analogs for geoengineering and that scientists should be very cautious about extrapolating too much from them.  It is important to evaluate geoengineering from an informed position, but the truth is that it represents a great and perilous unknown.

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Geoengineering Versus A Volcano

Photo, posted November 1, 2002, courtesy of the NASA Goddard Space Flight Center via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Urban Agriculture And Sustainability Goals

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In 2016, the City Council of Phoenix, Arizona adopted eight Environmental Sustainability goals for 2050 that lay out the desired long term requirements in order to become a Sustainable Desert City.  Recently, a group of researchers from Arizona State University assessed how urban agriculture can help Phoenix, a desert city of 1.6 million people, meet those sustainability goals.  

Using public records and high-resolution satellite imagery, researchers analyzed the potential benefits of growing crops in three types of urban areas in Phoenix: vacant lots, rooftops, and building facades.  The study, which was supported by the National Science Foundation and the USDA, estimated that there are 28 square miles (or 5.4% of city space) available for urban agriculture.  The data-driven analysis found that 71% of the available areas for urban agriculture would come from existing buildings as opposed to vacant lots. 

All this available space for urban agriculture in Phoenix could supply the city with nearly 183,000 tons of fresh produce annually, which would allow for the delivery of fresh fruits and vegetables to all of the city’s existing food deserts. In fact, the city’s own urban-agriculture output could meet 90% of the fresh produce demand that currently exists in Phoenix. 

In addition to producing food, rooftop agriculture could also reduce the energy use in buildings by 3% per building per year, and displace more than 55,000 tons of CO2 annually.  The use of vacant lots could increase the total Phoenix green space by 17%, and reduce the number of areas lacking green space by 60%.   

This study demonstrates the many different ways that urban agriculture can benefit a city. 

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Urban agriculture can push the sustainability

Photo, posted May 10, 2011, courtesy of Stephen Zank via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Pesticides In The Great Barrier Reef

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Australia’s Great Barrier Reef is one of the greatest natural wonders in the world and it has been under siege by warming waters and ocean acidification.  Widespread coral bleaching has damaged or destroyed large portions of the 1,400-mile long coral reef system.  But the effects of climate change are not the only threat to the reef.  Pesticides found in waterways that flow into the Great Barrier Reef are another serious problem.

According to a new study by the University of Queensland, the combined toxicity of 22 of the most common pesticides that flow into the Reef are not meeting pollution reduction targets.

Different pesticides affect different organisms.  Herbicides affect organisms that photosynthesize such as seagrass, corals, mangroves, and algae.  Insecticides affect insect larvae in freshwater, and crustaceans such as crabs, prawns, and lobsters.  Previous assessments have only examined individual pesticides and only for limited times.  The new study has utilized a methodology that estimates the combined toxicity of multiple pesticides found in the waterways that discharge into the Reef and does it for the entire wet season.

The research revealed that the pesticide reduction target set in the Australian Government’s Reef 2050 Water Quality Improvement Plan is not being met.  Only one natural resource management region – the Cape York region – was found to be meeting its target.

By having estimates of the risk posed by pesticides in the various regions and individual waterways, governments, farmers, and conservationists can see which areas pose the greatest risk and where to maximize efforts.  Stakeholders have to come together to reduce pesticide concentrations through better management practices and by using less toxic pesticides.

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High pesticide concentrations continue to enter Great Barrier Reef

Photo, posted July 29, 2010, courtesy of Kyle Taylor via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Bad News For The Aletsch Glacier

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The Aletsch Glacier in Switzerland is the largest glacier in the Alps.  Every year, it attracts thousands of visitors from around the world.  The huge ice flow in the Upper Valais region of Switzerland is an Alpine tourist attraction second only to the Matterhorn.  In the summer, meltwater from the glacier is an important water source in the dry Rhone Valley.

As the climate continues to warm, the massive glacier continues to shrink.  The tongue of the glacier has receded by about a kilometer since the year 2000 and scientists predict that this trend will continue over the coming years.

Detailed simulations by researchers at ETH Zurich assessed the future of the Aletsch Glacier under different scenarios related to the concentration of CO2 in the atmosphere and the resulting warming.

The best-case scenario in which global warming is limited to less than 2 degrees Celsius would result in the glacier being half the size it is today by the end of the century.  If the global community does not pull together quickly to take effective measures against global warming, Switzerland could warm by as much as 4 to 8 degrees and by 2100, what was once the largest glacier in the Alps will be a couple of measly patches of ice.

To understand how much global warming has already impacted the glacier to date, even if somehow the climate remains the same as it has been for the past 10 years going forward, the ice volume of the Aletsch glacier will still decrease by nearly half its volume by the end of the century.  The glacier is no longer in equilibrium with the climate.

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Gloomy forecast for the Aletsch Glacier

Photo, posted April 7, 2007, courtesy of Jessica Gardner via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Out-Migration And Reforestation

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A challenging global trend is that of deforestation in developing countries.  But there are places where the opposite trend is happening.  Nepal is one such place.

According to satellite imaging, in 1992 forest covered 26% of Nepal.  As of 2016, that number was 45%. 

To some extent, the forest regrowth was a result of policy changes from about three decades ago, when the government began removing management authority from bureaucrats and shifting it to local communities across the country.  This local management helped to reduce illegal logging and many local villages undertook tree-planting campaigns.

But perhaps a bigger factor at play is human migration.  In recent decades, millions of Nepalis have left the country to work in the Persian Gulf, Southeast Asia, and elsewhere.  The out-migrants wire money home and meanwhile, families left behind rely less on forest products or abandon farmland, aiding reforestation.  A 2018 study showed that the areas with the highest out-migration experience, on average, had the most forest recovery.

Globally, migration has important impacts on forests, but not always positive ones.  In many countries, forests seem to recover as people leave rural areas to work elsewhere.  El Salvador, for example, has seen a rebound of its forests as many of its rural residents move to cities or even to the United States. But in Guatemala and Nicaragua, the return of migrants bringing money they have earned overseas has led to an expansion of cattle ranching that has harmed forests.

The global relationship between migration and forests is a complicated one that depends on whether the migration is one-way or “circular” (meaning that the migrants eventually return) and how returning migrants make use of their earnings from abroad.

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In Nepal, Out-Migration Is Helping Fuel a Forest Resurgence

Photo, posted September 30, 2018, courtesy of Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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