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Our cities are sinking

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A new study by the Columbia University Climate School has found that all of the 28 most populous cities in the United States are sinking to some extent.  This phenomenon of subsidence is not just taking place in cities on the coast, where relative sea level is an issue, but also in cities in the interior.

The primary cause of subsidence is large-scale groundwater extraction for human use.  When water is withdrawn from aquifers made up of fine-grained sediments, the pore spaces formerly occupied by water can eventually collapse, leading to compaction below and sinkage at the surface.

The fastest sinking city in the US is Houston, with more than 40% of its area subsiding more than 5 millimeters a year and 12% sinking at twice that rate.  Some local spots are going down as much as 5 centimeters a year.   These seem like very small numbers but the fact that the subsidence is often not uniform across an urban area means that there are stresses to building foundations and other infrastructure.  Parts of Las Vegas, Washington D.C., and San Francisco have particularly fast sinking zones.

There are other causes of subsidence.  In Texas, pumping of oil and gas adds to the phenomenon.  A 2023 study found that New York City’s more than one million buildings are pressing down on the Earth so hard that they may be contributing to the city’s ongoing subsidence.  About 1% of the total area of the country’s 28 largest cities faces some danger from uneven subsidence.

Overall, some 34 million Americans live in cities affected by subsidence.  Global cities facing especially rapid subsidence include Jakarta, Venice, and here in the U.S., New Orleans.

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All of the Biggest U.S. Cities Are Sinking

Photo, posted December 27, 2012, courtesy of Katie Haugland Bowen via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Coexisting birds and solar energy

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Floating photovoltaic systems – known as floatovoltaics – are becoming increasingly popular.  These are arrays of solar panels installed over artificial water bodies such as irrigation ponds, wastewater treatment plants, and reservoirs.  These projects maximize the space for producing clean energy while not taking up natural lands.

Wherever there are bodies of water, there are waterbirds.  A recent study by researchers at the University of California, Davis looked at the potential impact of floating solar projects on birds and other wildlife. 

Birds face many threats from habitat loss, climate change, pollution, and disease.  Many bird populations are in decline.  So, it is important to consider the effects of floating solar projects on birds. 

The researchers have observed birds resting on floating solar structures before dawn, birds jockeying for favorable sites on the structures, and some nesting under the panels.  These are positive interactions.  On the other hand, it is possible that pollutants could be released or leached from floating solar infrastructure.  Such risks must be mitigated.

Floating solar on irrigation ponds and reservoirs can reduce evaporation and reduce algae growth, which benefits both humans and wildlife.

The researchers will continue to monitor bird behavior at floating solar installations using expertise in ecology and energy system science to identify risks and solution pathways so that negative impacts are avoided, and potential ecological benefits are realized.  It is important that as floating solar continues to become more popular, it and waterbirds can coexist.

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Helping Birds and Floating Solar Energy Coexist

Photo, posted February 28, 2019, courtesy of Renee Grayson via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Advantages of vertical farming

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Vertical farming has been increasingly used for leafy greens like lettuce and kale, as well as for herbs and a few fruits like strawberries and tomatoes.  A recent study by the Technical University of Munich has investigated the use of vertical farming for a much broader range of foods.  The study looked at the positive effects of vertical farming on both yield and environmental impact.

Traditional agriculture can reach its limits as a result of extreme weather events or in areas of high population density and resultant high demand.   With vertical farming, food can be grown close to consumers independent of weather and can make very efficient use of space.

The Proteins4Singapore study investigated the potential of a 10-layer vertical farming system cultivating crops, algae, mushrooms, insects, fish, and cultivated meat.  Many of these things are not currently part of many people’s diets.  But these foods can increase the protein yield per cultivation area nearly three hundredfold for crops and 6,000-fold for mushrooms and insects. 

Mushrooms and insects are examples of foods that require little light and cultivating them reduces energy consumption and, therefore, associated costs.

The biggest challenges for controlled environment agriculture – which is what vertical farming is – are the high energy demands for cultivation and the social acceptance.  Some of the foods that are especially well-suited to vertical farming – such as algae and insects – are not generally accepted by many consumers.  Controlled environment agriculture can revolutionize food production, but it will take a combination of technological advances, policy initiatives, and public engagement.

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Vertical Farming to increase yields and reduce environmental impact

Photo, posted October 21, 2022, courtesy of Fred Miller / University of Arkansas System Division of Agriculture via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Bees and urban wildflowers

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Post-industrial cities often have large numbers of vacant lots, left behind as people have moved out of the area.  Local residents are often tempted to plant wildflowers to make these deserted spaces more attractive. 

Wildflowers are an important food source for bees.  Pollinators like bees play a vital role in food production and attracting them with food sources is a good idea.  However, a study by researchers at the University of Cambridge in the UK found that there are dangers associated with planting wildflowers in some urban settings.

Wildflowers growing on land previously used for buildings and factories can accumulate lead, arsenic, and other metal contaminants from the soil.  These metals have previously been shown to damage the health of pollinators that ingest the metals in the nectar as they feed.

The Cambridge study was carried out in Cleveland, Ohio, which has nearly 34,000 vacant lots.  Cleveland was previously the site of iron and steel production, oil refining, and car manufacturing.  The researchers tested the nectar from flowering plants growing on disused land throughout the city.  Lead was the contaminant found in the highest concentrations.  They also found that different species of plants accumulate different amounts and different types of metals.

The goal of the study was not to discourage the planting of wildflowers in towns and cities.  It is to highlight the importance of growing the right species of wildflowers as well as to encourage testing soils for metals before planting wildflowers and to clean up pollution.  Wildflowers are important for pollinators, but it is also important that they don’t contribute to the decline of pollinator populations that has already been happening for a number of reasons.

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Growing wildflowers on disused urban land can damage bee health

Photo, posted August 26, 2012, courtesy of RJP via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The oceans are warming faster

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A new study has shown that the rate of ocean warming has more than quadrupled over the past 40 years.  The study, by researchers at the University of Reading in the UK, helps to explain why there have been unprecedented ocean temperatures in 2023 and 2024.

Global ocean temperatures hit record highs for 450 days straight in 2023 and early 2024.  Some of this unusual warmth came from the El Niño that was taking place at the time, but the rest of the increased temperature came from the sea surface warming up more quickly over the past 10 years than in previous decades.  In the late 1980s, ocean temperatures were rising at a rate of 0.06 degrees Celsius per decade.  According to the recent research, they are now increasing at 0.27 degrees per decade.

The acceleration of ocean warming is driven by growth in the Earth’s energy imbalance, meaning that more energy from the sun is being absorbed by the Earth than is escaping back into space.  This energy imbalance has roughly doubled since 2010 as a result of two factors:  increasing greenhouse gas concentrations in the atmosphere and reductions in the Earth’s albedo.

Earth’s albedo, the measure of how much sunlight is reflected back into space, has been declining since the 1970s, primarily due to the decrease in snow and ice cover, especially in the Arctic. 

The overall rate of ocean warming observed over recent decade is likely to only increase.  This underscores the urgency of reducing fossil fuel burning to avoid even more rapid temperature increases in the future.

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Ocean-surface warming four times faster now than late-1980s

Photo, posted January 18, 2007, courtesy of Alexey Krasavin via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Tracking atmospheric mercury

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Atmospheric mercury is a toxic pollutant released into the air from natural sources—such as volcanoes and wildfires—and from human activities like coal burning and gold mining.  Once in the atmosphere, mercury can travel long distances before settling onto land or into water, transforming into toxic forms that threaten ecosystems and human health.

But tracking atmospheric mercury is a costly and challenging endeavor, requiring specialized equipment and trained personnel. Active monitors, which pump air to collect mercury, are expensive and need electricity, while passive samplers, using activated charcoal for remote areas, cost up to $100 each.

Researchers from Cornell University have found a cheap method for tracking toxic atmospheric mercury near gold mining sites throughout the Global South: wild fig trees.  In the study, which was conducted in the Peruvian Amazon and recently published in the journal Frontiers in Environmental Science, the research team found that the rings in wild fig trees can serve as natural archives of atmospheric mercury, capturing and preserving historical pollution levels over time.

The technique itself is not actually new.  Previous studies have used tree rings to track mercury pollution from coal combustion, particularly in Canada. But the research team wanted to test this method in regions of the Global South, where mercury emissions from gold mining are widespread.

According to the research team, wild fig trees might soon serve as an important biomonitoring tool, helping scientists better understand how mercury disperses across landscapes and through time.

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Tree rings track atmospheric mercury cheaply

Photo, posted November 13, 2012, courtesy of Steve Kessler via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Repurposing used tires

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Every year, millions of tires from cars and trucks end up in landfills.  Just in the U.S., more than 270 million tires were scrapped in 2021 and more than 50 million of them ended up in landfills.  Discarded tires take up huge amounts of space but, more importantly, create environmental hazards.  They leach chemicals into the environment and are a serious fire hazard.

Some tires are chemically recycled via pyrolysis, which is a high-temperature process to decompose the materials in the tire.  But that process introduces harmful byproducts like benzene and dioxins. 

Researchers at the University of North Carolina Chapel Hill have introduced a new chemical method for breaking down rubber waste.  The process transforms discarded rubber into valuable precursors for epoxy resins.

Rubber – either natural rubber or the synthetic kind used in tires – is made of polymers cross-linked together to form a tough, flexible, and durable material.  These very desirable properties make it difficult to break down rubber.

The new research has led to a two-step chemical process that breaks down the rubber into functional materials that be used to produce epoxy resins.  The method does not require extremely high temperatures, uses aqueous media, and takes only six hours.   It represents an efficient, scalable solution for repurposing rubber waste which, even as many other aspects of motor vehicle are changing for the better, remains a continuing environmental problem associated with driving.

This new research marks a significant step towards greener recycling technologies.

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A Cleaner Future for Tires: Scientists Pioneer Chemical Process to Repurpose Rubber Waste

Photo, posted May 5, 2011, courtesy of TireZoo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The human footprint on Earth

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The Earth is a pretty big place, and it is easy to think that humans and their activities occupy very little of it.  But the impact of human activities on our planet continues to grow.  Recent satellite images from NASA’s Earth Observatory show the staggering extent of the human footprint on Earth.

Agriculture is a major part of it.  Farms and pastures take up almost half of the world’s habitable land – land not covered by ice or desert.  Greenhouses have recently proliferated tremendously and now cover 3.2 million acres, an area the size of Connecticut, and they even have effects on local climates.

More than half of the world’s population now lives in cities, which are expanding rapidly.  Enormous cities in Asia are changing the landscape in places like Thailand and Indonesia.  Apart from taking up lots of land, many of the world’s cities are immersed in clouds of air pollution that they generate.

Greenhouse gas emissions continue to grow, and temperatures continue to rise.  The effects of this on the planet are increasingly evident.  Seas are rising, ice is melting, glaciers shrink away, and wildfires continue to burn.  The massive wildfires in and around Los Angeles have made major changes in the local landscape.  Rising seas have flooded coastal wetlands and elsewhere, rivers and lakes have shrunk.

There are also human impacts visible from space that represent positive signs.  Large solar arrays supply the cheapest form of energy in most parts of the world and the number and size of solar installations are at a record high.   These solar installations provide some hope that global warming can be slowed.

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The Growing Human Footprint on Earth, as Seen from Space

Photo, posted July 28, 2012, courtesy of Beth Scupham via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cooling cities

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As the climate warms, city dwellers tend to suffer from extreme heat more than people in rural areas because of the urban heat island effect. Extensive surfaces of man-made materials like concrete, asphalt, and brick absorb the sun’s energy and lead to temperatures well above those in the surrounding countryside.

Cities can take countermeasures that include creating urban green spaces full of plants that cool the surrounding air and the use of cool roofs that reflect the sun’s energy back into space.  Local governments in many cities provide incentives for planting more trees.  But more could be accomplished by encouraging the use of cool roofs.

The heat island effect has been well-known for a long time, but scientists are only recently learning what interventions are most effective. A recent study modeled two days of extreme heat in London in 2018 and compared the potential effects of cool roofs, green roofs, roof-top solar panels, and ground level vegetation. They found that cool roofs are the most effective way to lower temperatures and would have reduced London temperatures by 2 degrees on average and as much as 3.6 degrees in some places.

Cool roofs are created by swapping out dark, heat-absorbing roofing materials with reflective materials or simply by painting roofs white. Los Angeles is the first major city to require that all new residential construction includes a cool roof. 

Apart from the effectiveness of passive cooling techniques, using them also reduces the reliance upon air conditioning to protect people from heat.  Air conditioners themselves contribute considerable amounts of heat to urban environments.

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The surprisingly simple way cities could save people from extreme heat

Photo, posted February 21, 2024, courtesy of Warren LeMay via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Potential for floating solar

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As installations of utility-scale solar power continue to expand around the world, there is the issue of where to put them.  They do take up considerable amounts of space and, in many places, available land is at a premium.

An alternative to taking up available land with solar panels is to deploy them on the surfaces of lakes and reservoirs.  A study by researchers at Bangor and Lancaster Universities in the UK calculated the potential electrical output for floating photovoltaic installation on nearly 68,000 lakes and reservoirs around the world.  The lakes and reservoirs selected were no more than 6 miles from a population center, were not in a protected area, and didn’t dry up and didn’t freeze for more than six months each year.  The calculations were based on covering just 10% of the surface area of the bodies of water.

The calculations were evaluated country-by-country.  Five countries could meet their entire electricity needs by floating installations including Papua New Guinea, Ethiopia, and Rwanda.  Many countries, mostly in Africa, South America, and Central Asia, could get between 40% and 70% of their electricity this way.  Most European countries could only meet a few percent of their electricity needs from floating solar, but even that could be significant. 

There are other benefits to floating solar apart from freeing up land.  The panels stay cooler, making them more efficient, and reservoirs lose less water through evaporation and the growth of algal blooms is reduced because there is less light reaching the water.

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Some countries could meet their total electricity needs from floating solar panels, research shows

Photo, posted November 25, 2015, courtesy of Smabs Sputzer via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Declining pollinator populations

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Scientists have been sounding the alarm on the global struggle of pollinators for decades.  Many recent studies have highlighted alarming declines in pollinator populations, sparking concern about the potential negative impacts on ecosystems and agriculture.  Habitat loss, invasive species, and climate change are some of the factors linked to the population declines. But most pollinator research has focused on well-studied species in easily-accessible regions.

In a new study recently published in the journal PLOS One, a research team led by Northern Arizona University compiled data on four major families of bees and butterflies to create species distribution models, allowing them to assess changes over time and space across North America.

The researchers confirmed that bee and butterfly populations are declining in major regions of North America due to ongoing environmental changes, and found that significant gaps in pollinator research limit the ability to protect these species. 

The highest species richness was found along North America’s West Coast –  especially in California. But the models showed a decline in species richness over the past century in western North America.  In contrast, the research team found disproportionate increases in eastern North America.

Comparisons with climate data indicate that the pollinator population changes are at least partly due to the impacts of climate change, including prolonged drought and habitat degradation. 

The study identifies regions of declining populations where officials can prioritize conservation efforts, and highlights how improved monitoring methods could address the knowledge gaps on pollinator populations.

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Bee and butterfly records indicate diversity losses in western and southern North America, but extensive knowledge gaps remain

Bees and butterflies on the decline in western and southern North America

Photo, posted April 3, 2017, courtesy of Tracie Hall via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Good owls and bad owls

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In the forests of the Pacific Northwest, spotted owls have been the subject of environmental concern for more than 30 years.  Over the past 20 years, northern spotted owl populations have declined by up to 80% as the birds have faced marginalized territories and increasing numbers of wildfires.  Only about 3,000 of them remain on federal lands.  Spotted owls are picky eaters and are not very adaptable.

The barred owl, a larger and more ornery species, has been moving in on spotted owl turf for 50 years, competing for food and space, and out-reproducing them and chasing them out of their nesting spots.

A last-ditch effort to rescue the northern spotted owl from possible extinction has been proposed by the U.S. Fish and Wildlife Service.  The plan would be to eradicate up to half a million barred owls over the next 30 years in Washington, Oregon, and Northern California.  The owls would be dispatched using cheap and efficient methods, such as shotguns.

The concept of killing off vast numbers of barred owls is awful, and nobody likes the idea.  However, other strategies have failed, and time is running out.  The only way to preserve the northern spotted owl is to protect and increase its habitat and have fewer barred owls.

To say that the proposed plan is controversial is a massive understatement.  A coalition of 75 wildlife and animal welfare organizations described it as a “colossally reckless action.”

A central issue in the debate is whether humans are responsible for this situation and should try to rectify it or, despite our desire to protect the spotted owl, we should just let nature take its course.

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They Shoot Owls in California, Don’t They?

Photo, posted April 4, 2022, courtesy of Kyle Sullivan / BLM via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Where not to plant trees

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Planting huge numbers of trees is often proposed as a way to reduce the severity of climate change.  Studies have looked at the potential for Earth‘s ecosystems to support large additional areas of forest and have found that it would be possible to have at least 25% more forested area than we do now.  This in turn could capture large amounts of carbon and substantially reduce the amount in the atmosphere.

A recent study by researchers at Clark University in Massachusetts and The Nature Conservancy mapped the climate impact of tree planting across the globe, identifying where it would be most and also least beneficial.  The study, published in Nature Communications, found that trees planted in arid, desert regions or in snowy places like the Arctic would, on balance, worsen warming rather than reduce it.

Trees take up carbon dioxide from the atmosphere, which helps to keep warming in check.  But trees with dark, green leaves also absorb heat from sunlight.   Snow and desert sand, on the other hand, are light-colored and reflect more sunlight back into space.  For this reason, trees planted in snowy areas or in the desert will absorb more sunlight than their surroundings.  This can negate the climate benefits of soaking up carbon dioxide.

Previous studies only looked at how much carbon dioxide would be removed by planting trees in order to determine how much warming would be prevented.  The new study finds that it matters where the trees are planted.

Fortunately, the new study also shows that tree planting projects that are currently underway or that are in the pipeline are largely concentrated in regions where they will indeed help slow global warming.

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This Map Shows Where Planting Trees Would Make Climate Change Worse

Photo, posted April 5, 2022, courtesy of UC Davis Arboretum and Public Garden via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Who wins: Wind or solar?

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A new study by the University of Exeter in the UK suggests that the world may have crossed a tipping point that will inevitably make solar power our main source of energy.  This data-driven model of technology seems to fly in the face of the current situation in which wind power contributes considerably more generation than solar power – by a factor of 3 in the U.S. and nearly double worldwide.

Wind and solar power both have advantages and disadvantages.  Solar power is quiet, requires little maintenance, and presents little danger to wildlife.  It is also practical for individual homes.  Residential wind power is not really a viable option for most people in most places.  But on the other hand, wind energy can produce more power than solar, can work both day and night, and can be located offshore far away from people.  On land, both wind and solar power take up lots of space and compete with other land use needs as well as countering people’s aesthetic preferences.

Both technologies continue to get cheaper over time, although solar has especially seen significant cost reductions.  The cost of solar power, which is already the cheapest form of electricity production, is estimated to fall to as low as $20 per megawatt hour over time from the current level of $40 per megawatt hour.

Wind and solar energy are on track to account for more than a third of the world’s electricity by 2030, according to the Rocky Mountain Institute.  Despite the predictions of various studies and the ambitions of specific technologies, it seems likely that wind and solar power will both play an expanding role in our energy systems for a long time to come.

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World may have crossed solar power ‘tipping point’

Photo, posted November 22, 2008, courtesy of Oregon Department of Transportation via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Record low Antarctic sea ice

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Antarctica’s winter came to a close in September and during that month, the continent reaches its maximum amount of sea ice that grows during the darkest and coldest months.  This year, that maximum occurred on September 10th and turned out to be the lowest on record.

The sea ice around Antarctica reached a maximum extent of 6.5 million square miles according to NASA researchers.  That was nearly 400,000 square miles below the previous record low set in 1986. 

There are several possible causes for the meager growth of Antarctic sea ice this year.  It may be a combination of several factors including El Niño, wind patterns, and warming ocean temperatures.  Recent research indicates that ocean heat is most likely playing an important role in slowing ice growth in the cold season and enhancing ice melting in the warm season.

The record-low ice extent so far this year is a continuation of a downward trend in Antarctic sea ice that has gone on since the ice reached a record high in 2014.  Prior to that year, the ice surrounding the southern continent was actually increasing slightly by about 1% every decade.

Meanwhile, Arctic sea ice reached its minimum extent in September and it was the sixth-lowest level in the satellite record.  Scientists track the seasonal and annual fluctuations of polar sea ice because they shape polar ecosystems and play a significant role in global climate.  Sea ice melting at both poles reinforces global warming because bright sea ice reflects most of the Sun’s energy back to space while open ocean water absorbs 90% of it.

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Antarctic Sea Ice Sees Record Low Growth  

Photo, posted June 30, 2023, courtesy of Pedro Szekely via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Missing Antarctic Sea Ice | Earth Wise

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It is summer here in the United States, but it is winter in Antarctica.  Antarctic sea ice is water that forms and melts entirely in the ocean and it has a pattern of growth and reduction that has been monitored by satellites for the past 44 years.  The area of sea ice that surrounds the continent of Antarctica is known as the sea ice ‘extent’ and it had been quite stable for much of those years.

In 2016, the sea ice extent began to decline.  Since then, there have been several record summer lows with both the summers of 2021/22 and 2022/23 setting new minimum records.

This August, the deviation from all previous records intensified.  This winter’s sea ice extent is over 900,000 square miles below the long-term average, an area about the size of Greenland or, for example, Texas and Alaska combined.

Climate models have long predicted that Antarctic sea ice would reduce as a result of global warming but the current change to sea-ice extent is so dramatic that it is difficult to explain.  Sea ice extent is affected by multiple factors including the El Niño Southern Oscillation, the strength of the southern hemisphere jet stream, and regional low-pressure systems.  The warming climate is certainly the overall force that is changing Antarctic sea ice extent over time.

Antarctic sea ice extent is important because it covers a vast area of the dark Southern Sea with a bright white surface that reflects the sun’s energy back into space, helping to reduce temperatures at the pole and protecting glaciers and polar ice sheets. 

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The mystery of the missing Antarctic sea ice

Photo, posted November 7, 2016, courtesy of Rob Oo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Upper Atmosphere Is Cooling | Earth Wise

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The part of the atmosphere closest to the Earth’s surface has been warming since the Industrial Revolution.  This warming is associated with increasing amounts of carbon dioxide as well as other human-made chemicals that have been changing the makeup of the atmosphere. Climate change is generally thought about in terms of the lowest regions of the atmosphere – known as the troposphere – where our weather happens.

But climate models also predict that another result of the changes to the makeup of the atmosphere is that most of the atmosphere up higher will get dramatically colder.  The same gases that are warming the bottom few miles of air are cooling the much greater expanses above that extend to the edge of space.

Recent satellite data has confirmed the accuracy of these models and provide further confirmation of the human fingerprint of climate change. The natural variability of weather that complicates climate models does not play a role in the upper atmosphere.

In the higher levels of the atmosphere, the effects of increasing levels of carbon dioxide are quite different.  In the thinner air up there, the heat trapped and re-emitted by CO2 does not bump into other molecules creating warming.  Instead, it escapes to space.  Combined with the trapping of heat at lower levels, the result is a rapid cooling of the upper atmosphere.

There are potential problems associated with the cooling upper atmosphere including that it is contracting.  The result is that the crowd of manmade objects in low orbit remains there longer, and there is a potential increased degradation of the ozone layer. 

The changes we are making to the atmosphere are having significant effects from the surface of the earth to the edge of space.

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The Upper Atmosphere Is Cooling, Prompting New Climate Concerns

Photo, posted August 18, 2021, courtesy of Arek Socha via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Record Polar Ice Melting | Earth Wise

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Sea levels are rising and ocean warming is responsible for the bulk of that rise.  As water heats up, it expands, which drives up sea levels.  But on top of that, global warming is melting the polar ice sheets, and that is leading to about a quarter of the world’s sea level rise. So far, polar melting has fueled about an inch of sea level rise, two-thirds from Greenland and one third from Antarctica.   According to scientists, by the end of this century, melting polar ice caps could raise sea levels between 6 and 10 inches.

The seven worst years for polar ice sheet melting have occurred during the past decade.  The worst year on record was 2019.  The loss in 2019 was driven by an Arctic summer heatwave, which resulted in record melting from Greenland, amounting to nearly 500 billion tons melted that year.  Antarctica lost 180 billion tons of ice that year, mostly due to melting glaciers and record melting from the Antarctic Peninsula.

Ice losses from Greenland and Antarctica can now be reliably measured by satellites in space.  A team of researchers led by Northumbria University in the UK has combined 50 satellite surveys taken between 1992 and 2020.

They have found that the Earth’s polar ice sheets have lost over 8,000 billion tons of ice over that time period.  That much ice corresponds to an ice cube roughly 12 miles high.

The satellite technology is now at the stage where the ice sheet status can be continuously updated.  Such monitoring is critical to predict the future behavior of the ice sheets and provide risk warnings of the dangers that coastal communities around the world will face.

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Polar ice sheet melting records have toppled during the past decade

Photo, posted December 19, 2017, courtesy of Jasmine Nears via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

It Really Is Greenhouse Gases | Earth Wise

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The scientific consensus that human-generated carbon dioxide is changing the climate began to form in the 1980s. 

For a long time, the changes to the climate were simply denied.  After a while, as those changes became increasingly hard to ignore, the argument shifted to the changes being real but not caused by anything people are doing.  The multi-trillion-dollar fossil fuel industry was strongly motivated to focus attention away from the association between carbon dioxide and climate change.

The greenhouse gas effect has been known since the 19th century.  It isn’t just real; it is essential to life on earth.  Without sufficient levels of carbon dioxide in the atmosphere to trap some of the sun’s heat, the earth would be an ice planet incapable of supporting much in the way of life.  But there can be too much of a good thing.

Naysayers continue to grasp at alternative explanations for the warming planet rather than the inconvenient truth.  Some people try to claim that it is the release of heat from all our energy-generating activities -power plants, heaters and air conditioners, vehicles, and so on – that is warming the planet.

That issue has been studied in detail.  Human activity does generate a lot of heat and, technically speaking, that heat does help warm the planet.  However, the sun dumps 10,000 times more heat on the earth than all of human energy production added together.  Just the normal fluctuations in solar energy are 10 times larger than everything we do put together.

What is increasingly warming the planet is not the continuing energy striking the earth; it is primarily the fact that growing levels of greenhouse gases in the atmosphere are trapping more and more of that heat and preventing it from escaping into space.

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Integrating anthropogenic heat flux with global climate models

Photo, posted August 25, 2009, courtesy of Gerald Simmons via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A Bad Year For California Rice | Earth Wise

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Rice production is the third largest cereal crop in the United States after corn and wheat.  Four regions in the country produce almost the entire U.S. rice crop:  the Arkansas Grand Prairie, the Mississippi Delta, the Gulf Coast, and the Sacramento Valley in California.  Arkansas is the largest producer of rice in the country by far, but California ranks second.

A combination of drought and water shortages in the Sacramento Valley has taken a major toll on the California rice crop.  This year, rice growers have only planted half as much grain as usual.  The changes in rice plantings in California are so substantial that they are easily visible from space.

In Colusa and Glenn counties, rice acreage this year dropped by 84 and 75 percent respectively, compared to 2021.  Farther to the east, in Butte Country, rice acreage was down by 17%.  The change was smaller there because farmers in that county had more groundwater to tap into.

According to the USDA, the California rice crop will be reduced by 38% this year, making it the smallest rice crop in the state since 1977.  California mostly grows short- and medium-grained rice, which is used in dishes like sushi, paella, and risotto.  Arkansas and other states produce most of the long-grain rice such as basmati and jasmine rice.

In late September, there was a burst of rain, which offered some short-term relief for farmers.  However, it will take much more wet weather to ease the ongoing drought conditions.  As of the end of September, over 40% of California remained in extreme drought and 17% was in exceptional drought.

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A Rough Year for Rice in California

Photo, posted March 21, 2020, courtesy of Ajay Suresh via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

WAMC Northeast Public Radio

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