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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.

Compressed Air Energy Storage

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The increasing use of solar and wind power has created a growing need for technology to store up the energy they generate for use when it is most needed.

Historically, pumped hydropower has provided the largest amount of storage capacity, but it is limited to only certain geographic locations.   Battery energy storage has been growing rapidly, with the technology becoming better and cheaper over time.  But there are various other ways to store energy that have potential and may well find their place in the changing energy infrastructure.

One of these is compressed air energy storage, which has been around for more than a century.  It has been used as a backup method for restarting power plants.  But to date, the economic viability of using it at a large scale has been lacking.

A Canadian startup company called Hydrostor is developing compressed air energy storage technology that it believes can be used on a utility scale.

The way it works is excess renewable energy is used to run compressors that compress air.  Compressing the air heats it up and the heat is captured and stored in insulated hot water tanks.  The compressed gas is then injected into underground caverns.  When energy is needed, the compressed air is released, the stored heat is added, and the warmed gas is run through turbines to generate electricity.  Additional features improve the system’s efficiency.

Hydrostore has built a 1 MW pilot project in Ontario, Canada and is now commissioning a 2MW system as well.  It is funded to build a 5 MW system in Australia next year and it is bidding for 300 MW and 500 MW systems in North America.  The company has received equity funding from Baker Hughes, a large oil-and-gas services and equipment company.

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Storing energy in compressed air could finally become cheap enough for the big time

Photo courtesy of Hydrostor.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Harsh Winters

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In recent years, there have been some unusually harsh winters in North America and Central Europe. This past January, the Midwestern US experienced extreme cold temperatures. We have all become familiar with the term ‘polar vortex’ and its role in sending cold air to middle latitudes and it is generally agreed that unusual behavior by the jet stream is the primary cause of the extreme winter weather.

For years, climate researchers around the world have been investigating the question as to whether the increasingly common wandering of the jet stream is a product of climate change or is a random phenomenon associated with natural variations in the climate system.

The jet stream is a powerful band of westerly winds over the middle latitudes that push major weather systems from west to east.  These days, the jet stream is increasingly faltering.  Instead of blowing along a straight course parallel to the equator, it sweeps across the Northern Hemisphere in massive waves, producing unusual intrusions of Arctic air into the middle latitudes.

Atmospheric researchers at the Alfred Wegener Institute in Germany have now developed a climate model that can accurately predict the frequently observed winding course of the jet stream.  The breakthrough combines their global climate model with a new machine learning algorithm on ozone chemistry.  Using their new combined model, they can now show that the jet stream’s wavelike course in winter and subsequent extreme weather outbreaks are the direct result of climate change.  The changes in the jet stream are to a great extent caused by the decline in Arctic sea ice, according to the results of the investigations.  The results are not surprising but there is now a detailed model to support the hypothesis.

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A warming Arctic produces weather extremes in our latitudes

Photo, posted January 11, 2011, courtesy of Carl Wycoff via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The American Bumblebee

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Pollinators, such as bees and bats, are vital for global food production.  They provide an ecological service that’s necessary for the reproduction of nearly 75% of the world’s flowering plants, including more than two-thirds of the world’s food crops.

Bumblebees are among the most important plant pollinators.  They pollinate many food crops, including apples, tomatoes, blueberries and legumes, as well as countless types of trees, shrubs, and wildflowers.  But researchers have documented declines in both the abundance and range of many bumblebee species.

The American bumblebee, which is native to North America, is one of them.  The species can currently be found in eastern Canada, throughout much of the Eastern United States, and much of Mexico. 

According to a new study led by York University and recently published in the Journal of Insect Conservation, the American bumblebee is critically endangered, and it faces imminent local extinction from Canada.  This is considered the highest and most at-risk classification before extinction. 

The researchers used data from three sources in their study: the Bumble Bee Watch (which is a citizen science project), the Bumble Bees of North America database (that has records dating back to the late-1800s), and their own field survey work.  They used the IUCN’s Red List assessment criteria to evaluate the status of the American bumblebee within its Canadian range.

The research team found that the species’ area of occurrence has decreased by approximately 70% and its relative abundance dropped by 89% from 2007-2016 when compared to 1907-2006. 

The American bumblebee can still be found throughout its Canadian range.  But immediate conservation action is desperately needed.  

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Disappearing bumblebee species under threat of extinction

Photo, posted August 22, 2011, courtesy of Rachel Elaine via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

China And Plastic Waste

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In January 2018, China enacted its “National Sword” policy which banned the import of most plastics and other materials headed for that country’s recycling processors.  Those processors had handled nearly half of the world’s recyclable waste for the past quarter century.  China took this step because the deluge of soiled and contaminated materials was overwhelming its processing facilities and creating yet another environmental problem for the country, this time not even of its own making.

Prior to China’s ban, 95% of the plastics collected for recycling in the European Union and 70% in the U.S. were sold and shipped to Chinese processors.  A combination of favorable rates for shipping in cargo vessels that carried Chinese goods abroad and low Chinese labor rates made it a very profitable enterprise.

Before China’s ban, only 9% of globally discarded plastics were being recycled and 12% were burned.  The rest ended up in landfills or simply dumped into the environment.  Over the coming decade, as many as 11 million tons of plastic will have to find a new place to be processed or otherwise disposed of.  There is already evidence that plastic waste is accumulating in countries that are dependent on exporting.  In many places, including a number of American cities, there are curtailed collections and new restrictions on what kinds of plastics are accepted.

Some experts are hopeful that China’s ban might actually have an upside if it leads to better solutions for managing the world’s waste.  North America and Europe need to expand processing capabilities and manufacturers need to make their products more easily recyclable.  Mostly, the Chinese ban should be a wake-up call to the world on the need to greatly reduce single-use plastics.

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Piling Up: How China’s Ban on Importing Waste Has Stalled Global Recycling

Photo, posted August 8, 2017, courtesy of Sino-German Urbanisation Partnership via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Crop Diversity

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A study at the University of Toronto suggests that on a global scale, we are growing more of the same kinds of crops, and this diminishing diversity presents major challenges for agricultural sustainability.

In some places, for example here in North America, crop diversity has actually increased.  Back in the 1960s, North Americans grew about 80 crops.  Now there are 93.

But on a global scale, more of the same kinds of crops are being grown on much larger scales.  Just four crops – soybeans, wheat, rice and corn – occupy nearly 50% of the world’s entire agricultural lands.  The remaining 152 crops cover the rest.  Large industrial farms often grow one crop species – usually just a single genotype – across thousands of acres of land.

This decline in global crop diversity is problematic in several ways.  On a cultural level, it threatens regional food sovereignty.  If regional crop diversity is threatened, it makes it more difficult for people to eat or afford foods that are culturally significant to them.

On an ecological level, the dominance by a few genetic lineages of crops makes the agricultural system increasingly susceptible to pests or diseases.  The deadly fungus that is threatening the world’s banana plantations is a prime current example.  The Irish potato famine in the 19th century is a tragic historical example.

As large industrial-sized farms in Asia, Europe and the Americas start to look more and more alike, the dangers of large monocultures of crops that are commercially valuable will only increase.  It will be important for global governments to consider the impact of policies that affect the diversity of the agricultural system and its sustainability in an increasingly hungry world.

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A small number of crops are dominating globally. And that’s bad news for sustainable agriculture

Photo, posted August 13, 2012, courtesy of Alasdair McKenzie via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Fire-Driven Thunderstorms

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In 2016 and 2017, wildfires in western Canada spawned thunderstorms that ignited additional fires, in some cases tens of miles away from the original fire.  These fire-triggered thunderstorms are technically known as pyrocumulonimbus clouds, or “pyroCb’s”.

The physics of pyroCb’s is complex.  When super-heated updrafts from an intense fire suck smoke, ash, burning materials, and water vapor high into the air, these elements cool and form so-called fire clouds that look and act like the cumulonimbus clouds associated with classic thunderstorms.  What is different is that the heat and particulates in the smoke almost always arrest the ability of the cloud to produce rain.  Instead, what remains is a lightning storm that moves across the landscape, triggering more fires.

These PyroCb events appear to be happening far more often, producing more energy, and erupting in places where they have never been seen before.  As the world warms, wildfires themselves are becoming larger and hotter.  In the past decade, wildfires have been burning more than twice as many acres as they did before the turn of the 21st century.  Along with the growth in wildfire activity, there has been an increase in PyroCb events, and there are now an average of 25 per year in western North America.

Apart from starting new fires, pyroCb’s also have similar effects as moderate-sized volcanic eruptions.  Smoke and aerosols from wildfires can rise high into the stratosphere, where they can linger for months.  Eventually, the particles carried aloft in the atmosphere do come down, dumping dangerous chemicals on far flung regions of the earth.  But unlike volcanic eruptions, which are relatively rare events, pyroCb’s are happening more and more each year.

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Fire-Induced Storms: A New Danger from the Rise in Wildfires

Photo, posted July 31, 2013, courtesy of Loren Kerns via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And The Polar Vortex

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This winter has seen some brutally-cold weather in many places, some of it record-breaking.  Predictably, some climate-change deniers point to this as evidence that the climate is not warming at all.  They are quite wrong.

For starters, it is essential to understand the difference between climate and weather.  Climate is the average weather patterns in a region over extended periods of time.  Weather is the short-term fluctuations in temperature, precipitation, barometric pressure, wind, and so forth.  There can be extremes in weather of many types in a given climate region including very cold weather in a warming climate.

The recent cold weather events in the U.S. stem from the flow of Arctic air into southern regions.  Such flows are impacted dramatically by the behavior of the jet stream.  These high-altitude east-to-west winds are driven by temperature differences between cold arctic air and warm tropical air and play a huge role in our weather. 

The Arctic has seen extremely unusual warming due to the changing climate, weakening and fracturing the polar vortex, which is a persistent low-pressure area near the pole.   The changing air flow from the Arctic causes the jet stream to take wild swings.  When it swings further south, it causes cold air to reach farther south.  These swings tend to hang around for a while, leading to extended periods of cold weather in the winter and, actually, extended periods of warm weather or even droughts in the summer.  Studies have predicted that extreme, deadly weather events could increase by as much as fifty percent by 2100.

As more Arctic air flows into southern regions, North America can expect to see harsher winters.  The warming climate doesn’t always lead to warmer weather.

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Why cold weather doesn’t mean climate change is fake

Photo, posted January 30, 2019, courtesy of Kyle via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Wildfires And The Water Supply

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Hotter and dryer conditions are leading to an increasing number of wildfires in North America and elsewhere around the world.  The damage they cause is well-known.  But one aspect of that damage that tends to be overlooked is the impact on aquatic environments and drinking water supplies.

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The Return Of The Bison

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At one time there were 20 to 30 million bison in North America, dominating the landscape from the Appalachians to the Rockies, and from the Gulf Coast to Alaska.   A combination of habitat loss and totally unregulated hunting of the huge animals reduced the population to just over 1,000 in 1889.  

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Renewable Energy Jobs

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According to a new report by the International Renewable Energy Agency, more than half a million new jobs were generated by the renewable energy industry last year, an increase of 5.3% when compared with 2016.  The total number of people working in the renewables sector – which includes large hydropower facilities – has now exceeded 10 million people worldwide.

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An Internal Price On Carbon

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As the world looks to reduce carbon emissions, many companies are dealing with paying for their carbon emissions as part of the cost of doing business.  But apart from the situations in which companies already are required to pay for their carbon emissions, a growing number of companies now build carbon pricing into their business plans even if they are not yet directly paying for their emissions.  This practice is known as putting an internal price of carbon into their business plan.

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The Monarch Highway

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We have talked about the monarch butterfly on a number of occasions.  The population of these iconic orange and black butterflies in North America has plummeted from 1 billion to 33 million over the past 20 years.  People have undertaken a variety of efforts to try to save the species but now a major project to restore the dwindling habitat of the monarch is underway.

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A Helpful Invader

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Invasive species are a great concern for the health and stability of ecosystems.  They are defined as plants, animals or pathogens that are non-native to the ecosystem under consideration and whose introduction causes or is likely to cause harm.  It is that latter consideration that isn’t always obvious.

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Australia On The Run

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We’ve all come to take for granted the ability of GPS systems to help us find our way around our cities, the countryside and, for that matter, the world in general.  Software interacting with Global Positioning Satellites allows us to pinpoint our location on the Earth with remarkable accuracy.  At least, as long as places on Earth stay put.  But the problem is that they actually don’t.

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Wilderness Lost

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Wilderness areas are strongholds for biodiversity.  They buffer and regulate local climates, and they support many of the world’s most politically and economically marginalized communities.  While there is a great deal of attention being paid to the loss of species around the world, there is relatively little focus on the loss of entire ecosystems.  Simply put, wilderness is on the decline, and it has been ever since human civilization began its inexorable expansion.

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WAMC Northeast Public Radio

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