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The Importance Of Double-Cropping | Earth Wise

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In agriculture, double-cropping is the practice of growing two or more crops or commodities on the same piece of land in the same calendar year.  In Brazil, grain production has increased more than fourfold between 1980 and 2016.  The country now stands as the world’s largest exporter of soybeans and the second largest exporter of corn.  There were two primary drivers of this increase in food production: cropland expansion and double-cropping. 

Cropland expansion has long been recognized as a key driver behind the increase in Brazil’s agricultural output.  But cropland expansion is also a threat to biodiversity by driving habitat loss, deforestation, and an increase in carbon emissions. 

A new study recently published in the journal Nature Food quantified for the first time the impact that double-cropping had on helping Brazil achieve its tremendous growth in grain production.  The international research team examined data from three key agricultural regions in Brazil: the Centre-West, Southeast-South, and Matopiba region.  These three regions accounted for 79% of soybean production and 85% of  corn production in 2016. 

Soybean fields account for more than one third of Brazil’s cropland.  While the increase in soybean production was largely a result of cropland expansion, the increase in corn production was a result of double-cropping. 

Between 2003 and 2016, the study found that double-cropping in Brazil offset the equivalent of approximately 190 million acres of arable land for corn production. (This is more than twice the annual harvested area of corn in the United States).

Double-cropping represents a way to produce more food without clearing more land. 

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The impact of double-cropping

Photo, posted July 15, 2009, courtesy of Daniel Bauer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Greenhouse Gas Emissions From Water Reservoirs | Earth Wise

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A new study by researchers from Washington State University and the University of Quebec at Montreal looked at greenhouse gas emissions from water reservoirs.  It is perhaps surprising to think that water reservoirs are a source of greenhouse gas emissions at all, but that much was already known.  The new study found that those emissions are actually around 29% higher than previously thought.

Overall, the researchers found that the world’s water reservoirs annually produce methane, carbon dioxide, and other greenhouse gases at an amount equivalent to 1.07 billion tons of carbon dioxide.   That is a small fraction of the 36 billion tons produced by fossil fuels and other industrial sources, but it is by no means a negligible amount.   In fact, it is more greenhouse gases than emitted by the entire country of Germany, which is the world’s sixth largest emitter.

Decomposing plant matter near the bottom of reservoirs fuels the production of methane, which is far more potent than carbon dioxide in warming the atmosphere.  This methane degassing accounts for about 40% of emissions from reservoirs.

The study is particularly important because it may be possible to reduce methane emissions from reservoirs by selectively only withdrawing water from near the reservoirs’ surface, which tends to be relatively methane-poor compared to greater depths.  In a related study, reducing withdrawal depth by 10 feet in a Malaysian reservoir reduced methane degassing emissions by 92%.

Human-generated greenhouse gas emissions come from a surprisingly wide range of sources and it is worthwhile studying as many of them as possible in the hope of finding additional ways to reduce the total.

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Greenhouse gas emissions from water reservoirs higher than previously expected

Photo, posted July 22, 2016, courtesy of Iain Merchant via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Pesticide From Beer | Earth Wise

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Researchers from the Neiker Basque Institute for Agricultural Research and Development in Spain have demonstrated that a combination of rapeseed cake and beer bagasse can be used to reduce populations of soil parasites and increase crop yields. 

Beer bagasse is spent brewers’ grain – the stuff that is left over after the beer is made.  Beer brewing generates substantial amounts of by-products, including large amounts of spent grain.  It already has some practical uses, including as a feedstock for biofuel, as a food additive, and it even has some medical uses.  But the new research has shown that the bagasse can be the basis for a biodisinfestation treatment to be used in agriculture.  The aim is to disinfect soils, protect soil microorganisms, and increase crop yields.

The actual material studied was a mixture of beer bagasse, rapeseed cake, and a generous amount of fresh cow manure.  The high nitrogen content of the mixture promotes the activity of beneficial microorganisms in the soil, which helps to break down organic matter and kill off nematodes and other parasites that damage crops.

Nematodes are common parasites that can penetrate plant roots to lay their eggs, which damages the root and prevents the plants from absorbing nutrients effectively.  Application of the bagasse-based mixture over 12 months increased crop yields by 15% and boosted healthy soil microbes.

The study demonstrated that agricultural byproducts can be an effective treatment for root-knot nematodes and other soil parasites, increase crop yields, and help promote sustainable food systems to reduce waste from the agricultural industry.  The researchers hope to identify other potential organic treatments for tackling soil parasite problems.

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Beer byproduct mixed with manure proves an excellent organic pesticide

Photo, posted July 1, 2011, courtesy of Quinn Dombrowski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Butterflies And Moths In A Changing World | Earth Wise

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Extinction is a part of life.  Plant and animal species disappear all the time.  In fact, approximately 98% of all the organisms that have ever existed on planet earth are now extinct. Earth’s so-called ‘normal’ rate of extinction is thought to be somewhere between 0.1 and 1 species per 10,000 species per 100 years. 

But anthropogenic climate change is bringing about rapid change in nature. Put more simply, human activity is killing nature at an unprecedented rate.  According to many scientists, the earth’s sixth mass extinction has already begun. Mass extinctions are defined as times when the Earth loses more than 75% of its species in a geologically short interval.

The changing climate puts immense pressure on species for change.  According to a new study by researchers from the University of Helsinki and the Finnish Environment Institute, the few butterfly and moth species capable of adjusting to the changing climate by moving up their flight period and moving further north have fared the best.

In Finland, researchers compared temporal shifts in the flight period and spatial shifts in the northern range boundary of 289 moth and butterfly species, as well as changes in abundance over a roughly 20-year period.

They found that about 45% of species that either moved northward or advanced their flight period fared much better than the roughly 40% of species that did not respond in either way.  On average, the populations of these poorly responding species declined.  But the 15% of species that did both had the largest increase in abundance. 

The ability to adapt to a changing climate is going to be vital for species survival. 

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Butterflies and moths have difficulty adjusting to a rapidly changing climate

What is mass extinction and are we facing a sixth one?

Photo, posted August 16, 2017, courtesy of Tero Laakso via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wind Farms Slowing Each Other Down | Earth Wise

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Offshore wind is booming in Europe.  The expansion of wind energy in the German Bight and Baltic Sea has been especially dramatic.  At this point, there are about 8 gigawatts of wind turbines in German waters, the equivalent of about 8 nuclear power plants.  But space in this region is limited so that wind farms are sometimes built very close to one another.

A team of researchers from the Helmholtz Center Hereon, a major German research institute, has found that wind speeds downstream from large windfarms are significantly slowed down.  In a study published in the journal Nature Scientific Reports, they found that this braking effect can result in astonishingly large-scale lowering of wind speeds.

On average, the regions of lowered wind can extend 20-30 miles and, under certain weather conditions, can even extend up to 60 miles.  As a result, the output of a neighboring wind farm located within this distance can be reduced by 20 to 25 percent.

These wake effects are weather dependent.  During stable weather conditions, which are typically the case in the spring in German waters, the effects can be especially large.  During stormy times, such as in November and December, the atmosphere is so mixed that the wind farm wake effects are relatively small.

Based on their modeling, it is clear that if wind farms are planned to be located close together, these wake effects need to be taken into account.  The researchers next want to investigate the effects that reduced wind speeds have on life in the sea.  Ocean winds affect salt and oxygen content, temperatures, and nutrients in the water.  It is important to find out how reduced winds might affect marine ecosystems.

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Are wind farms slowing each other down?

Photo, posted November 23, 2011, courtesy of David J Laporte via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Greenland Becoming Darker | Earth Wise

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According to research published by Dartmouth University, a weather pattern that pushes snowfall away from parts of Greenland’s ice sheet is causing the continent to become darker and warmer.

Reducing the amount of fresh, lighter-colored snow exposes older, darker snow on the surface of Greenland’s ice sheets.  Fresh snow is the brightest and whitest. The reflectivity of snow decreases fairly quickly as it ages. This decrease in albedo – or reflectivity – allows the ice sheet to absorb more heat and therefore melt more quickly. 

The research attributes the decrease in snowfall in Greenland to a phenomenon called atmospheric blocking in which persistent high-pressure systems hover over the ice sheet for up to weeks at a time.  Such systems have increased over Greenland since the mid-1990s.  They push snowstorms to the north, hold warmer air over Western Greenland, and reduce light-blocking cloud cover.

All of this contributes to Greenland melting faster and faster.  According to research cited in the study, the Greenland ice sheet has warmed by nearly 5 degrees Fahrenheit since 1982.  Overall, Greenland is experiencing the greatest melt and runoff rates in the last 450 years, at the minimum, and quite likely the greatest rates in the last 7,000 years.

The Greenland ice sheet is the second largest ice body in the world, after the Antarctic ice sheet.  It is 1,800 miles long and about 700 miles wide at its greatest width.  Its thickness is between 1.2 and 1.9 miles.  If the entire sheet were to melt, it would lead to a global sea level rise of 24 feet.  So, the darkening of Greenland is a source of great concern.

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Greenland Becoming Darker, Warmer as Snow Changes

Photo, posted April 3, 2012, courtesy of Francesco Paroni Sterbini via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Vanishing Kelp Forests | Earth Wise

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Bull kelp is the dominant species in offshore kelp forests north of Santa Cruz, California along the west coast of North America.  Bull kelp has similar physical structures to terrestrial plants; it anchors to the ocean floor with root-like structures called holdfasts, and has stem-like structures called stipes from which leaf-like blades stretch out through the water, absorbing nutrients and sunshine.

These giant seaweeds form lush underwater forests in northern California’s coastal waters and have long provided critical habitat for many species like salmon, crabs, and jellyfish.  But now, for much of the California coast, only a few patches of bull kelp remain.

A team from University of California Santa Cruz has studied satellite images of about 200 miles of coastline.  They found that starting in 2014, the area covered by kelp has dropped by more than 95%. 

The die-off was driven in part by an underwater heat wave that depleted nutrients in the water and made it harder for the kelp to grow.  Making matters much worse, populations of purple sea urchins, which eat kelp, have exploded in the region because of overfishing and other reductions in urchin predators such as sea otters.  The sea urchins eat kelp holdfasts, creating so-called urchin barrens where their destructive grazing has decimated kelp forests.

Bull kelp is a species at high risk of becoming endangered.  In coming decades, more marine heatwaves are expected.  These events as well as stronger El Niños will become more common and frequent with climate change.  Between these thermal events and the sea urchins, it will be difficult for kelp forests to survive.

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Ninety-five percent of bull kelp forests have vanished from 200-mile stretch of California coast

Photo, posted October 28, 2015, courtesy of Florian Graner/Green Fire Productions via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Transparent Wood | Earth Wise

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In recent years, there have been efforts to change the nature of wood to give it new properties.  People have demonstrated so-called augmented wood with integrated electronics, energy storage capabilities, and other properties.  Several different groups of researchers have developed wood that is actually transparent.

In 2016, researchers at KTH Royal Institute of Technology in Stockholm demonstrated transparent wood made by selectively extracting lignin – the substance that makes up the cell walls of wood -and replacing it with a polymer.  The result is a new material that is weatherproof, fairly fire resistant, stronger than wood, lighter than wood, and transparent.

When the lignin is removed from wood, the empty pores left behind need to be filled with something that restores the wood’s strength.  The early versions of transparent wood used polymethyl methacrylate – essentially acrylic plastic – for this purpose.  But that material is made from petroleum, so it is not an environmentally desirable approach.

Recently, the KTH researchers have successfully tested an eco-friendly alternative:  limonene acrylate, which is a monomer made from renewable citrus, such as peel waste that can be recycled from the orange juice industry.

There are many potential applications for transparent wood as a structural material.  These include load-bearing windows, skylights, and semi-transparent facades that are strong and thermally insulating and yet permit light to enter. 

Transparent wood would be a very attractive material for many applications in that it comes from renewable sources and offers excellent mechanical properties including strength, toughness, low density, and low thermal conductivity.

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Citrus derivative makes transparent wood 100 percent renewable

Photo, posted October 12, 2018, courtesy of Mussi Katz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Insanely Cheap Energy | Earth Wise

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The International Energy Agency, founded in 1974, keeps track of the world’s energy systems and anticipates how they are likely to change over time.  Policymakers around the world look to the agency’s annual World Energy Outlook publication for guidance.

In 2000, the agency made the prediction that by the year 2020, there would be a total of 18 gigawatts of photovoltaic solar power installed.  Within seven years, that number was already too small.

The IEA was not the only source to miss the mark on solar power.  The head of solar analysis at BloombergNEF in 2005 expected solar to eventually supply 1% of the world’s electricity.  It is already 3% and Bloomberg now predicts that it will be 23% by 2050 and expects that to be an underestimate. 

What has happened is that the world has unexpectedly gotten to the point where solar is the cheapest source of energy in most places.  Over the past decade, every time solar production capacity has doubled, its cost has dropped by 28%.

Historically, a combination of groundbreaking research in Australia and intense Chinese industrial development led to the creation of a massive new industry.  When Germany passed laws encouraging the use of solar power, suddenly there was massive global demand and a struggle to keep up with supply.

The industry had its fits and starts, and many players fell by the wayside.    But at this point, solar technology continues to get better and cheaper.  Market forces are pretty hard to beat and when solar technology can supply insanely cheap energy, it is going to be used in more and more places.

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‘Insanely cheap energy’: how solar power continues to shock the world

Photo, posted January 10, 2020, courtesy of Tony Webster via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Accelerating Global Glacier Loss | Earth Wise

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Glaciers represent the snows of centuries compressed over time to form flowing rivers of ice.  Glaciers always change, accumulating snow in the winter and losing ice to melting in the summer.  But in recent times, the melting has been outpacing the accumulation.

Glaciers are a sensitive indicator of climate change.  They have been melting at a high rate since the mid-20th century – regardless of altitude or latitude. But up until recently, the full extent of glacial ice loss has only been partially measured and understood.

Now, according to new research led by scientists from ETH Zurich in Switzerland and the University of Toulouse in France, nearly all the world’s glaciers are becoming thinner and losing mass.  And the changes are accelerating.  The study, which is the most comprehensive and accurate of its kind to date, is the first to include all the world’s glaciers – around 220,000 in total – excluding the Greenland and Antarctic ice sheets. The research team’s findings were recently published in the journal Nature.

Between 2000 and 2019, the world’s glaciers lost an average of more than 294 billion tons of ice per year.  Between 2000 and 2004, glaciers lost an average of about 250 billion tons of ice each year.  But between 2015 and 2019, ice mass loss jumped up to an average of approximately 328 billion tons annually.    

Glacial melt is responsible for 21% of the observed sea level rise during this two decade time period studied.

This research is just another reminder of how we need to act urgently if we want to prevent the worst-case climate change scenario from becoming a reality. 

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Global glacier retreat has accelerated

Photo, posted September 17, 2015, courtesy of Richard Whitaker via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Improving Solar Cells With Human Hair | Earth Wise

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Researchers at the Queensland University of Technology in Australia have been able to improve the performance of perovskite solar cells using material made from human hair.

Perovskite solar cells are an up-and-coming technology that offers the possibility of making solar cells less expensive, more efficient, and flexible so that there could be solar-powered clothing, backpacks, or even tents for camping.  While the technology has been shown to be as effective in converting sunlight to electricity as currently available silicon technology, it faces problems with stability and durability.

The Australian research centered on the use of carbon nanodots to improve perovskite solar cell performance.  The nanodots were created in a rather unique way.  The carbon came from hair scraps from a Brisbane barbershop that were first broken down and then burned at nearly 500 degrees Fahrenheit. 

By adding a solution of the carbon nanodots into the process of making the perovskites, the dots formed a wave-like layer in which the perovskite crystals in the cells are surrounded by the carbon dots.  It serves as a protective layer, essentially a kind of armor, for the active portions of the material.

The result was solar cells with a higher power conversion efficiency and greater stability.  The researchers did not explain why they chose human hair as the source of carbon, but it does make for an interesting sidelight to the promising research.

Perovskite solar cells could be very important for spacecraft applications where reducing weight is paramount.  But in order to be able to use them for this purpose, perovskite solar cells will need to be able to cope with the extreme radiation and temperature variations in space.

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Carbon dots from human hair boost solar cells

Photo, posted October 3, 2009, courtesy of Arktoi via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Radar Satellites And Hazard Mitigation | Earth Wise

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Scientists have concluded that the changing climate is primarily the result of increased human-caused greenhouse gas emissions.  Some of the effects of global climate change include melting glaciers, warming oceans, intensifying storms, and rising seas.

Another consequence of global climate change is natural disasters like floods and wildfires.  Climate change is increasing the frequency and severity of wildfires and increasing the odds of record-breaking floods in many parts of the United States and all around the world.

As a result, scientists in Australia have turned to technology for better assistance in keeping tabs on these climate change-driven natural disasters.  Researchers from Curtin University in Perth, Australia have found that satellites can improve the ability to detect, monitor, prepare for, and withstand natural disasters, including floods, wildfires, and earthquakes.

The research team used Synthetic Aperture Radar (SAR) data, which was acquired by the European Space Agency Sentinel-1 satellite.  The researchers also used data acquired by other satellites to evaluate these Australia-specific case studies.

According to the researchers, SAR data provides remote monitoring capabilities of Earth’s surface around the clock and in all weather, which is something that traditional optical Earth Observation (EO) imagery cannot do. The ability to function through fog, clouds, rainfall, and smoke is what makes SAR so valuable.

The research team says that the data can be used to improve how people track and respond to natural disasters, by precisely mapping topography, tracking movements of the ground, and mapping damage to infrastructure. 

As the climate continues to change, the ability to mitigate hazards like floods and wildfires will be increasingly important. 

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Radar satellites can better protect against bushfires and floods

Photo, posted May 11, 2007, courtesy of Bert Knottenbeld via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Should We Block The Sun? | Earth Wise

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There is growing concern that greenhouse gas emissions are not falling quickly enough to avoid dangerous levels of global warming.  As a result, there is the impetus to examine other options.  Among these are geoengineering, which is one of the most contentious issues in climate policy.  Geoengineering embodies many risks that make even seriously considering it seem risky in itself.

Despite this, the National Academies of Science, Engineering, and Medicine has issued a report saying that governments urgently need to know whether solar geoengineering could work and what its side effects might be.

Solar geoengineering is also called solar radiation modification, which entails reflecting more of the sun’s energy back into space.  This would likely be accomplished by injecting aerosols into the atmosphere, much like what happens after large volcanic eruptions.

Schemes for solar geoengineering raise numerous issues.  Although solar geoengineering might cool the earth’s surface to a global temperature target, the cooling may not be evenly distributed, affecting many ecosystem functions and biodiversity.   It would likely upset regional weather patterns in potentially devastating ways, for example by changing the behavior of the monsoon in South Asia.  It might dangerously relax public commitments to reduce greenhouse emissions. 

Despite these concerns, or perhaps because of them, the committee that produced the report believes that technology to reflect sunlight deserves substantial funding and should be researched as rapidly and effectively as possible.  Once any geoengineering projects get into the hands of policymakers, they may gather momentum that bypasses the advice of scientists.  So, it important to make progress on the science while geoengineering is still only theoretical.

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Should We Block the Sun? Scientists Say the Time Has Come to Study It.

To intervene or not to intervene? That is the future climate question

Photo, posted August 3, 2018, courtesy of Tomasz Baranowski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Increasing Palm Oil Production Without Harming The Environment | Earth Wise

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Palm oil is the most important source of vegetable oil in the world.  The oil itself and ingredients based on it are found in approximately 50% of the products on supermarket shelves, including both food and non-food items.  Many of the mysterious chemicals that show up on ingredient lists such as sodium lauryl sulfate are actually derived from palm oil.

Dozens of countries produce palm oil, but about 2/3 of the world’s supply comes from Indonesia and the demand for its oil keeps growing.  To keep up with that demand, Indonesia continues to convert valuable ecosystems that contribute greatly to biodiversity to palm production.

A four-year research project at the University of Nebraska- Lincoln has found that keeping up with palm oil demand may not necessarily mean converting valuable, fragile ecosystems into agricultural land.  According to the study published in Nature Sustainability, palm oil yields on existing farms and plantations could be greatly increased with improved management practices.

The researchers identified key practices that could lead to larger yield.  These include improved harvest methods, better weed control, improved pruning, and better plant nutrition.  With such practices, Indonesia could produce 68% more palm oil on existing plantation areas.

The results were surprising to the researchers and are significant from both environmental and economic standpoints.  In particular, it could have a great impact on the millions of individual farmers who draw their livelihood from small palm farms often containing just a few acres.  In Indonesia, about 42% of land used for palm oil production is owned by smallholder farms.

The researchers are now working with various stakeholders in Indonesia to put these management techniques into practice.

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Husker research shows palm oil production can grow while protecting ecosystems

Photo, posted August 15, 2006, courtesy of Lian Pin Koh via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Farming Productivity | Earth Wise

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The future potential impacts of anthropogenic climate change on global agricultural systems has been well studied, but how human-caused climate change has already affected the agricultural sector is not as well understood.  But a new study led by researchers at Cornell University and supported by the USDA National Institute of Food and Agriculture and the National Science Foundation examined this issue. 

Despite important agricultural breakthroughs in technology, fertilizer use and global trade during the past 60 years, it turns out that the climate crisis is already eroding farm productivity.  According to the study, which was recently published in the journal Nature Climate Change, global farming productivity is 21% lower than it could have been without climate change.  This is the equivalent of losing approximately seven years of farm productivity increases since the 1960s. 

The researchers developed a model linking annual changes in weather and productivity with output from the latest climate models over six decades to quantify the effect of anthropogenic climate change on what economists call “total factor productivity.” This measure captures the overall productivity of the agricultural sector. 

The research team reviewed 200 variations of the model, but the results remained largely consistent:  anthropogenic climate change is already slowing down global food production.  The researchers say the historical impacts of climate change have been larger in naturally warmer climates, like in parts of Africa, Asia, and Latin America.   

Climate change is not some distant problem to solve in the future.  It is already having an impact on the planet and it needs to be addressed now.

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Climate change cut global farming productivity 21% since 1960s

Photo, posted October 2, 2013, courtesy of the United Soybean Board via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Silent Killer | Earth Wise

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Air pollution is deadly.  Studies have found that particles from air pollution can enter our lungs and bloodstream, contributing to major health conditions including heart disease, stroke, cancer, and kidney disease.  Globally, air pollution is responsible for the premature deaths of millions of people every year. 

The first line of defense against air pollution is ambient air quality standards.  But according to researchers from McGill University, more than half of the world’s population lives without the protection of adequate air quality standards.

The research team focused on a specific type of air pollution called particulate matter 2.5 (more commonly called PM2.5).  PM2.5 refers to tiny particles or droplets in the air that are two and one half microns or less in width.  These tiny particles are responsible for an estimated 4.2 million premature deaths every year globally, including more than one million deaths in China, nearly 200,000 in Europe, and more than 50,000 in the United States.

In the study, which was recently published in the Bulletin of the World Health Organization, the researchers found that where there are air quality protections, the standards are often worse than what the WHO considers safe.  Some regions with high air pollution levels, like the Middle East, don’t even measure PM2.5 air pollution.  The researchers found that the weakest air quality standards are often violated, while the strictest standards are often met. 

More than half of the world’s population is in urgent need of adequate air quality standards.   

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Air pollution: The silent killer called PM 2.5

Photo, posted November 17, 2019, courtesy of Kristoffer Trolle via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Solar Cell Greenhouses | Earth Wise

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A recent study at North Carolina State University has shown that it can be feasible to use see-through solar panels in greenhouses to generate electricity.  The idea is to use semi-transparent solar panels on greenhouses that allow some of the light to get in for the plants to grow while making the greenhouses energy neutral or even allowing them to generate more power than they use.

The question is how the semi-transparent solar panels might affect greenhouse crops.  To investigate this issue, researchers grew crops of red leaf lettuce from seed to full maturity under a standard set of growing conditions – temperature, water, fertilizer, and CO2 concentration – but varied the light they get. 

A control group was exposed to the full spectrum of white light while three experimental groups were exposed to light through different types of filters that absorbed the particular wavelengths of light that would be absorbed by different types of semitransparent solar cells.

The researchers paid close attention to characteristics of the lettuce that are important to growers, grocers, and consumers:  general appearance, leaf number, leaf size, and weight.  The results were that the lettuce produced using all three kinds of filtered light was essentially identical to that produced in the control group.    Further research is underway looking at how harvesting various wavelengths of light affects biological processes for lettuces, tomatoes, and other crops.

Getting growers to use solar-powered greenhouses would be very difficult if doing so would result in a loss of productivity.  But given these experimental results, it appears as though the decision will boil down to a simple economic argument about whether the investment in new greenhouse technology would be offset by energy production and its resultant savings.

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Study Finds Plants Would Grow Well in Solar Cell Greenhouses

Photo, posted April 8, 2008, courtesy of Brian Boucheron via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Breaking Down Polystyrene | Earth Wise

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The proliferation of global plastic waste continues to be a growing problem for the world.  Hundreds of millions of tons of plastics are produced each year and most of it is used once and then discarded.  The properties that make plastics so attractive – durability and chemical stability – make it difficult to do anything with discarded plastics other than deposit them in landfills – where they don’t easily degrade over time – or burn them, which dumps carbon dioxide and various hazardous gases into the atmosphere.

Polystyrene is one of the most widely used plastics.  It is found in foam packaging materials, disposable food containers, plastic cutlery, storage containers, and many other places. 

Recycling plastics like polystyrene is generally not economically feasible.  Sorting plastics by type is time and labor intensive and the chemical processes required to break down plastics into usable precursor materials require significant energy input and the use of toxic solvents.

Recently, a team of scientists at Ames Laboratory in Iowa has developed a process based on ball-milling that deconstructs commercial polystyrene in a single step, at room temperature, in ambient atmosphere, and in the absence of harmful solvents.

Ball-milling is a technique that places materials in a milling vial with metal ball bearings which is then agitated to initiate a chemical reaction.  This approach is known as mechanochemistry.

The method represents an important breakthrough that enables dismantling of a polymer that includes its chemical breakdown without requiring solvents or the high temperatures generally needed to thermally decompose it.  This discovery opens up new avenues for low-temperature recovery of monomers from polymer-based systems that include composites and laminates.  It could be a very useful weapon in the battle against plastic waste.

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Polystyrene waste is everywhere, and it’s not biodegradable. Scientists just found a way to break it down.

Photo, posted December 11, 2010, courtesy of Warrenski via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Red Hot Chili Solar Panels | Earth Wise

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The majority of solar panels in use today are made from either single-crystal or polycrystalline silicon, the same stuff used to make the ubiquitous chips in computers, cell phones, and countless other devices.  In addition, a growing fraction of solar panels utilize thin-film technology, which offers cost and flexibility advantages.

Monocrystal silicon still provides the highest efficiency and longest lifespan in commercially available panels, but the lower costs and some other features of thin-film solar panels are growing that market over time.

More recently, perovskite solar cell technology has been a source of great interest in the research community.  Perovskites are a class of minerals with a specific crystalline structure that already have uses in various applications.  As a solar cell material, perovskites offer the potential for converting more sunlight to electricity, being manufactured far more cheaply using no exotic or expensive materials, being more defect-tolerant, as well as a having number of other advantages.  They also have the potential for having very high efficiency. 

Recently, a group of researchers in China and Sweden published results of studies demonstrating that the addition of a novel ingredient has increased the efficiency of perovskite solar cells to nearly 22%, which is better than most commercial silicon solar cells.  The ingredient is capsaicin, the chemical that gives chili peppers their spicy sting.  Adding capsaicin expands the grains that make up the active material of the solar cell, allowing the more effective transport of electricity. 

Why did the researchers think of adding the active ingredient of hot peppers to a solar cell in the first place?  So far, they aren’t saying.

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Solar panels capture more sunlight with capsaicin – the chemical that makes chili peppers spicy

Photo, posted August 16, 2019, courtesy of Pedro via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Oil Platforms And Biodiversity | Earth Wise

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We have previously reported on the important role that offshore oil platforms seem to play for fish.  In short, the support structures of offshore oil platforms that often rise hundreds of feet through the water column create essentially a prefabricated reef for marine life.

According to a new study recently published in the British journal Ecological Solutions and Evidence, the large gatherings of fish around oil and gas platforms attract harbour porpoises searching for food – despite the fact that noise from industrial activities normally scares porpoises away.    

Harbour porpoises are one of the smallest whale species and the only whale species that’s known to breed in Danish waters.  The species has been protected in Danish waters since 1967.  Previous studies have demonstrated that underwater noises from sources like shipping and industry typically scare porpoises away. 

But according to new research from scientists at Aarhus University in Denmark, there are actually more porpoises around the largest Danish oil platform – Dan F – in the North Sea than there are within the three to ten kilometers surrounding the platform.  The research team found that the platform acts as a natural reef where porpoises can find favorable habitat and food. 

Currently, the international OSPAR convention requires that all decommissioned oil and gas platforms be removed from the ocean.  But according to researchers, leaving the old platforms in the ocean to serve as artificial reefs is actually more beneficial to the marine environment. 

In the Gulf of Mexico, the United States program Rigs to Reefs has converted 558 oil and gas platforms into artificial reefs.

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Harbor porpoises attracted to oil platforms when searching for food

Photo, posted March 26, 2008, courtesy of Dave Herholz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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