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California Flooding | Earth Wise

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

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

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

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

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

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

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

Earth Wise is a production of WAMC Northeast Public Radio

Polar Bears and Tires | Earth Wise

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There is lots of interest in traction.  People want to find better ways to move across wet and frozen surfaces safely.   This applies to both the shoes on our feet and the tires on our cars. 

Researchers at the University of Akron along with colleagues at Syracuse University and at Bridgestone, the tire company, have been studying how many arctic animals can walk and run across the ice without slipping and falling.  Their research focused on the paws of polar bears.

Previous studies discovered that polar bears have papillae – little bumps on the pads of their feet – that provide improved traction on snow.  The new research also looked at the paws of other species of bear – brown bears and black bears – and found that these others also have papillae on their paw pads, but that those of polar bears are as much as 50% taller.  These taller bumps give the pads a 30-50% increase in frictional shear stress.

The research may lead to various applications. For example, snow tires typically have deeper treads, but the polar bear study may lead to some new designs that would improve traction.  People who do high-altitude climbing are interested in the research as are companies that deliver goods in bad weather.  Anyone who has to be out and about in bad weather would like to get a better grip.

There are various other animals with traction-improving adaptations that are probably worth studying.  These include dogs, wolves, foxes, and mountain goats.  The same researchers at Akron have also studied other animals with unique abilities to deal with challenging surfaces including geckos, spiders, and mussels.  The natural world is filled with examples of creatures who can easily function in environments that we humans find very challenging.

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UA researchers’ focus on tire traction leads to investigation of polar bear paws

Photo, posted March 2, 2008, courtesy of Sam Weng via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Glacial Loss In The Swiss Alps | Earth Wise

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In 2022, glaciers in the Swiss Alps melted more than in any year on record.   This is the latest piece of bad news for the country’s glaciers, which have lost more than half of their volume of ice since the 1930s.

The melting season for Switzerland’s snow and ice typically starts in May and ends in early October.  This year’s melting season caused glaciers in the Diablerets mountain group to thin by an average of 13 feet, which is 3 times the amount of thinning observed over the past decade.   The Tsanfleuron pass between two of the glaciers is now exposed as bare rock for the first time in several thousand years. Across Switzerland, glaciers lost about 6% of their remaining volume just this year.  The previous worst year for glaciers was 2003, when losses were nearly 4%. 

There was significant melting this year in part because of the small amount of snowfall over the winter.  That snow melted quickly, being sped up by the warming effect of dust from the Sahara Desert falling on the snow.  By early summer, there was no longer a protective blanket of snow on the glaciers, exposing them to summer heat.

The loss of glaciers is far more serious than the disappearance of aesthetically pleasing landscape features.   Glaciers act as reservoirs of water that persist through the summer months.  Melt from glaciers provides water to ecosystems and creates habitats for plants and animals.  Cold runoff from glaciers affects downstream water temperatures which have a major impact on insects, fish, and other creatures.  Globally, melting glaciers contribute more than 20% of the observed ongoing sea-level rise.

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Rocky Road for Swiss Glaciers

Photo, posted June 22, 2015, courtesy of Dennis Jarvis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

River Of Dust | Earth Wise               

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Every year, more than 100 million tons of dust blow out of North Africa.  Strong seasonal winds lift the dust from the Sahara Desert northward.  A few times a year, the winds from the south are strong and persistent enough to drive the dust all the way to Europe.

On March 15, a large plume of Saharan dust blew out of North Africa and crossed the Mediterranean into Western Europe.  European cities were blanketed with the dust, degrading their air quality, and turning skies orange.  Alpine ski slopes were stained with the dust.

These dust events are associated with so-called atmospheric rivers that arise from storms.  Such rivers usually bring extreme moisture but can also carry dust.  Over the past 40 years, nearly 80% of atmospheric rivers over northwestern Africa have led to extreme dust events over Europe.  The March 15 event was associated with Storm Celia, a powerful system that brought strong winds, rain, sleet, hail, and snow to the Canary Islands.

Atmospheric dust plays a major role in climate and biological systems.  The dust absorbs and reflects solar energy and also fertilizes ocean ecosystems with iron and other minerals.

The climate effects of dust are complicated.  Dust can decrease the amount of sunlight reaching the surface, affect cloud formation, and decrease temperatures.  But dust also darkens the snowpack, leading to more rapid snowmelt.  A 2021 dust event resulted in a rapid melt of Alpine snow, reducing its depth by half in less than a month.

The effects of this year’s dust event are not yet known, but this atmospheric river associated with Storm Celia appeared to carry less water and more dust compared with the 2021 event.

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An Atmospheric River of Dust

Photo, posted December 2, 2019, courtesy of Catherine Poh Huay Tan via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Large Mammals And Climate Change | Earth Wise         

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The natural world has an important part to play in mitigating the effects of climate change.  We mostly think about the role of plant life which absorbs carbon in trees, grasses, and other flora.  However, a new study published by Oxford University looks at the role of large wild animals in restoring ecosystems and reducing the effects of climate change.

According to the study, there are three important ways in which large animals such as elephants, rhinos, giraffes, whales, bison, and moose can potentially mitigate the effects of climate change:  carbon stocks, albedo, and fire regimes.

When large herbivores graze, they disperse seeds, clear vegetation, and fertilize soil.  All of these things build more complex and resilient ecosystems which helps to maintain and increase carbon stocks in the soil and in plant tissues thereby helping to reduce CO2 in the atmosphere.

Grazing large animals trample vegetation which opens up areas of dense vegetation to create open mixes of grass and shrubs and can reveal snow-covered ground in cold regions.  Such open habitats are lighter in color (higher in albedo) and reflect more solar radiation into the atmosphere, cooling the Earth’s surface rather than heating it up.

Large grazing animals can lessen wildfire risk by browsing on woody vegetation that would otherwise fuel the fires and also by creating paths that act as firebreaks.

In marine ecosystems, whales and other large animals fertilize phytoplankton, which capture some 37 billion tons of CO2 each year.

Overall, large animals are an important part of the natural world’s ability to reduce the effects of the changing climate by helping with localized adaptation to the changes taking place in ecosystems.

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Large mammals can help climate change mitigation and adaptation

Photo, posted August 20, 2017, courtesy of Jon Niola via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Spring is Sooner And Warmer In The United States | Earth Wise

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Despite some March snowstorms in the Northeast, the record shows that spring is getting warmer and coming sooner in the United States.

The independent research organization Climate Central analyzed 52 years of spring data across the United States.  Half of the 234 locations studied had an increase in their average spring temperatures of at least 2 degrees.  About 70% of the locations had at least 7 extra days above their normal spring temperatures.  About the only part of the country where spring hasn’t gotten much warmer is in the upper Midwest.

Over that time period, the average spring temperature in Albany, NY has increased by 2.1 degrees.  And compared with 1970, there are now 11 more warm spring days in New York’s Capital Region.

Spring warming has been greatest in the Southwest.  The three cities with the largest temperature increases were Reno, Nevada at 6.8 degrees, Las Vegas, Nevada with 6.2 degrees, and El Paso, Texas with 5.9 degrees.

Spring has been arriving early as a result of the warming conditions, cutting into the cold winter months.  While an early spring sounds like nothing but good news, the shift can cause problems.  An early spring and early last freeze can lengthen the growing season.  With it comes the arrival of mosquitoes and pollen and its associated allergy season.

A greater problem is that spring warming can disrupt the timing of ecosystem events.  For example, migratory birds could show up at the wrong time, impacting their food availability and breeding success.

As the overall climate changes, so does the spring.

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2022 Spring Package

Photo, posted March 20, 2011, courtesy of Suzie Tremmel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change On Mount Everest | Earth Wise

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Climate change has shown up in the highest place on Earth.  The highest glacier on Mount Everest is rapidly retreating with rising temperatures.

New research by an international team led by the University of Maine and published in the journal Climate and Atmospheric Science has determined that the South Col Glacier atop Mount Everest has shrunk by half since the 1990s.   Its ice mass has thinned by an estimated 180 feet.

The glacier used to be covered by snow, which reflected the sun’s light and insulated the mass of ice under the snow.  But warmer temperatures, lower humidity, and more severe winds have eliminated the snow cover, fueling the decline of the glacier.

The study of the South Col Glacier highlights the critical balance created by snow-covered surfaces and exposes the potential for loss throughout high mountain glacier systems as snow cover is depleted by warming temperatures.  When even the highest glacier on Mount Everest is impacted, it is clear that no place is safe from the warming climate.

The human significance of this development is substantial.  More than 200 million people in Asia depend on meltwater from glaciers in the high mountains of the continent for their freshwater needs.  But now glaciers in the mountains are melting faster than they can be replenished by snowfall.

As for Mount Everest itself, future expeditions on the mountain will face new challenges as glacier melting causes more avalanches and climbers accustomed to digging into ice and snow will need to scale more exposed bedrock.  Climate predictions for the Himalaya in general all anticipate continued warming and continued loss of glacier mass.

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Climate Change Has Reached the Top of Mount Everest, Thinning Its Highest Glacier

Photo, posted October 27, 2011, courtesy of Goran Hogland via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

An Arctic Bus | Earth Wise

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People have built vehicles for all sorts of extreme environments.  There are deep-sea exploration vessels and there have been lunar and Mars rovers.  But one thing that hasn’t existed so far are buses to transport groups of people around in extreme conditions in the Arctic.  Engineers at two Russian Universities are developing a passenger bus for riding in the Far North.   The project is being funded by the Russian Federation Ministry of Science and Higher Education and the URAL Automobile Manufacturing Plant.

The requirements for the vehicle are daunting.  The bus must be operable at extreme temperatures – 60 below zero Fahrenheit and lower – and have no difficulties even in challenging off-road conditions.

Current Arctic crew buses are not capable of getting through snow blockages and the all-terrain tracked vehicles that can get through them do not have sufficient passenger capacity. In addition to being able to go through snowbanks, the bus should be able to float on water for an hour.

Apart from its ability to withstand harsh Arctic conditions, the bus will also have a quarters module.  This means that it will have an autonomous life-support system for passengers in case of emergency.  The quarters module will be designed to sustain up to 20 people for up to 24 hours.  The module might also be used to hold medical equipment, thereby enabling practitioners to reach remote settlements and treat patients. 

The first tests of prototypes for the bus will be conducted in the near future.  The project aims to have the new Arctic Bus design complete and ready for manufacture by the end of 2023 and it will go into production in 2024.

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“Arctic Bus” Being Readied to Be Tested in the Far North

Photo, posted April 21, 2017, courtesy of Markus Trienke via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Melting Himalayan Glaciers | Earth Wise

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The great mountain ranges of central Asia, including the Himalayas, contain the third-largest deposit of ice and snow in the world, trailing only Antarctica and the Arctic.  The Himalayan range contains about 15,000 glaciers, and is part of a region widely referred to as the Third Pole due to its extraordinary reserves of freshwater.

But in recent years, scientists have observed an increase in the rate of Himalayan glacier loss.  According to a new study led by researchers from the University of Leeds in the UK, the accelerating melting of the Himalayan glaciers threatens the water supply of millions of people in Asia. 

In the study, researchers reconstructed the reach of the Himalayan glaciers during the Little Ice Age, which was the last major glacier expansion 400-700 years ago. They found that these glaciers began losing ice 10 times faster during the modern era.  In fact, the glaciers have shrunk from a peak of nearly 11,000 square miles to around 7,500 square miles today.   

This exceptional acceleration of melting of the Himalayan glaciers could have significant implications.  Hundreds of millions of people rely on Asia’s major river systems for food and energy, and depend on these glaciers to feed rivers during the dry seasons.  These rivers include the Brahmaputra, Ganges, and Indus.  The changing global climate could disastrously impact water resources and livelihoods of the Greater Himalayan region.

According to the research team, people living in these regions have already seen changes that are unlike anything witnessed for centuries.  This study is the latest to confirm that these changes are accelerating and pose a significant threat to entire nations and regions. 

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Himalayan glaciers melting at ‘exceptional rate’

Photo, posted March 13, 2018, courtesy of Sarunas Burdulis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Nanoplastics In The Air | Earth Wise

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The world is awash in plastic.  Discarded plastic litters our roadways, woodlands, and beaches.  It piles up in landfills.  Plastic enters the oceans by the millions of tons.  And plastic is finding its way even to remote and supposedly pristine parts of the world.

A team of researchers has found nanoplastics at the isolated high-altitude Sonnblick Observatory in the Austrian Alps.  This is the first time the particles were found in the area.  The researchers were looking for certain organic particles and only found the nanoplastics by chance.

The detected plastic particles were less than 200 nanometers in size, about one hundredth the width of a human hair.  It is highly unlikely that such particles originated in remote Alpine areas.

The researchers were looking for organic particles by taking samples of snow or ice, evaporating them, and then burning the residue to detect and analyze the vapors.  They described the detection method as essentially like a mechanical nose.  In this case, the nose smelled burning plastics in the form of polypropylene and polyethylene terephthalate.

Looking into the issue, the researchers found a strong correlation between high concentrations of nanoplastics and winds coming from the direction of major European cities – especially Frankfurt and the industrial Ruhr area of Germany, but also the Netherlands, Paris, and even London.

Modeling supports the idea that nanoplastics are transported by air from distant urban places.  This is particularly worrisome because it means that there are likely hotspots of nanoplastics in our cities and in the air that we are breathing.  Plastics appear to be everywhere.

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Nanoplastics found in the Alps, transported by air from Frankfurt, Paris and London

Photo, posted July 1, 2013, courtesy of Robert J. Heath via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Metals In Western Water Supplies | Earth Wise

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A new study published by the University of Colorado Boulder looked at the problem of rivers being contaminated by acid rock drainage.  Rocks that include sulfide-based minerals, such as pyrite, oxidize when exposed to air and water.  The resulting chemical reaction produces sulfuric acid which, when present in water, dissolves metals like lead, cadmium, and zinc.  The recent study found that rare earth elements are also leached out of rock by this process.

Rock drainage occurs naturally throughout the western United States, but historic mines that disturbed large amounts of rocks and soil have dramatically increased this process and have led to growing downstream water pollution.  Upwards of forty percent of the headwaters of major rivers in the West are contaminated by some form of acid mine or rock drainage.

The warming climate has brought longer summers and less snow in winters.  Longer, lower stream flows make it easier for metals to leach into watersheds and concentrate the metals that would otherwise be diluted by snowmelt.

Rare earth elements are essential components of many high-tech devices such as computers, hard drives, and cell phones.  There is not a long history of studying the hazards they might represent when they enter the environment.

The study looked at the Snake River watershed in Colorado and found that increasing amounts of rare earth elements are entering Colorado water supplies.  Concentrations of rare earth elements are not ordinarily monitored and there are no water quality standards set for them.

According to the researchers, once rare earth elements get into water, they tend to stay there.  Traditional treatment processes don’t remove them.  It is a growing problem that needs to be addressed.

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Rare earth elements and old mines spell trouble for Western water supplies

Photo, posted October 27, 2007, courtesy of Dion Gillard via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Disappearing Mountaintop Glacier Ice | Earth Wise

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A newly released study has found that mountaintop glacier ice in the tropics of all four hemispheres has diminished dramatically over the past 50 years.  Among the findings of the study, published in the journal Global and Planetary Change, are that a glacier near Puncak Jaya, in Papua New Guinea, lost about 93% of its ice between 1980 and 2018.  Between 1986 and 2019, the area covered by glaciers on top of Mt. Kilimanjaro in Africa decreased by nearly 75%.

The study combined NASA satellite imagery with data from ice cores drilled during field expeditions on tropical glaciers around the world.  The combination of measurements demonstrated that climate change is causing these glaciers to disappear and that the ice loss has accelerated in recent years.

The study looked at glacier ice in Kilimanjaro in Tanzania, the Andes in Peru and Bolivia, the Tibetan Plateau and the Himalayas, and ice fields in Papua, New Guinea.  Collecting ice cores from these places provides information on the climate in these regions over the centuries and millennia.  As snow falls on a glacier each year, it is buried and compressed to form layers that preserve the chemistry of snow, pollutants from the atmosphere, and biological material such as plants and pollen.

Glaciers in the tropics respond more quickly to climate change because they exist in the warmest areas of the world and survive only at very high altitudes. For many of these tropical glaciers, it is too late to prevent their demise.  It is not too late to attempt the slow down the buildup of greenhouse gases in the atmosphere that is causing the planet to warm, but we don’t have unlimited time to act.

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Mountaintop glacier ice disappearing in tropics around the world

Photo, posted February 12, 2009, courtesy of Christoph Strassler via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Overwintering Fires | Earth Wise

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Fires that go on for long periods of time, surviving the snow and rain of winter to reemerge in the spring, are becoming more common in high northern latitudes as the climate warms.  Such fires are called holdover fires, hibernating fires, overwintering fires, or even zombie fires.  Whatever people choose to call them, this type of wildfire is occurring more often.

These smoldering fires start out as flaming fires but then enter an energy-saver mode.  They start above ground but then smolder in the soil or under tree roots through the winter.  They barely survive based on the oxygen and fuel resources that they have but can transition back into flaming fires once conditions are more favorable.

Dutch researchers used ground-based data with fire detection data from NASA’s Moderate Resolution Imaging Spectroradiometer instruments on the Terra and Aqua satellites to study fires in the boreal forests of Alaska and Canada’s Northwest Territories.  They found a way to identify overwintering fires based on their unique characteristics.  

Their data indicates that overwintering fires tend to be linked to high summer temperatures and large fire seasons.  Between 2002 and 2018, overwintering fires generally accounted for a small amount of the total burned area in the region but in individual years with hot and severe fire seasons, the number can escalate.  In 2008 in Alaska, for example, overwintering fires accounted for nearly 40% of the burned area.

Early detection of these overwintering fires could help with fire management and reduce the amount of carbon – which is stored in large amounts in the region’s organic soils – that gets released to the atmosphere during fires.

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Overwintering Fires on the Rise

Photo, posted September 14, 2017, courtesy of Andrew R. Mitchell/USDA 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.

Saving The Giant Sequoia | Earth Wise

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Giant sequoia trees are some of the most remarkable living things on earth.  They can live up to 3,000 years.  The tallest specimens tower over 300 feet, but it is their girth that really sets them apart.  They are usually 20 feet in diameter, and some are up to 35 feet across at the widest.  The largest tree in the world by volume is the General Sherman tree, which has a volume of 52,508 cubic feet. At 2,100 years old, it weighs 2.7 million pounds and is not only the largest living tree, but also the largest living organism by volume on the planet.

Giant sequoias are incredibly hardy.  To have survived thousands of years, the oldest of these trees have endured hungry animals, diseases, fires, snowstorms, El Niño events, years-long droughts, and the efforts of loggers during the 19th and 20th centuries.

In February, unusually high winds knocked down 15 giant sequoias in Yosemite National Park.  While sequoias are amazingly adapted to their narrow range in California’s Western Sierras, it appears as though climate change is altering their habitat faster than the species can migrate or adapt.  Shorter cold seasons have meant more rain instead of snow, leading to floods and mudslides in the winter.  Fires are more likely with less snowpack.  Hotter, drier summers put sequoias under greater stress.

Forest managers work to preserve existing groves through fire mitigation, supplementary water, and careful stewardship of young trees in existing groves.  If these efforts are successful through the ensuing decades, climate change may be just one more thing the sequoias outlasted.  But at least some conservationists are now considering planting a new generation of sequoias in colder, nearby habitats. 

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To Save Giant Sequoia Trees, Maybe It’s Time to Plant Backups

Photo, posted June 8, 2008, courtesy of Joi Ito via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Record Heat In The Arctic | Earth Wise

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By mid-November, the Arctic stays dark around the clock and twilight does not return until the end of January.  But even as winter darkness descended upon the Arctic this year, record-breaking high temperatures in the region continued.  In late November, temperatures across the entire Arctic basin were 12 degrees Fahrenheit above normal and some locations saw temperatures as high as 30 degrees above normal.

The entire summer and fall in the Arctic were characterized by exceptionally warm temperatures.  In June, the Siberian town of Verkhoyansk – located north of the Arctic Circle – registered a high temperature of 100.4 degrees.  The refreezing of the Arctic Ocean was greatly delayed this year.  The Northeast Passage along the Siberian Coast remained navigable for a record 112 days before freezing in November, breaking the previous record by more than a month.  The extent of sea ice covering the Arctic Ocean in October was the lowest ever recorded for that month.

The strongest warming occurring in the Arctic is during the fall.  That is because rapidly disappearing sea ice is enabling the dark waters of the Arctic Ocean to absorb heat in the summer and then radiate it back into the atmosphere until late in the fall.  The Arctic region is heating up three times faster than the rest of the planet, which has led to the volume of sea ice decreasing by 2/3 in the past 40 years.

According to researchers, the extreme heat in Siberia this year would have been virtually impossible without human-caused climate change and became 600 times more likely because of human emissions of greenhouse gases.

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Record-shattering Warmth Pushes Arctic Temperatures to 12 Degrees F Above Normal

Photo, posted September 1, 2009, courtesy of the U.S. Geological Survey via Flickr. Photo Credit: Patrick Kelley, U.S. Coast Guard.

Earth Wise is a production of WAMC Northeast Public Radio.

Improved Radar For Cars | Earth Wise

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

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

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

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

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

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

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

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

Earth Wise is a production of WAMC Northeast Public Radio.

Dust And Himalayan Glaciers | Earth Wise

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Glaciers in the Himalayas have been melting and retreating, as have glaciers around the world.  As is the case elsewhere, human-driven climate change is a major factor.  But at the lofty heights of the Himalayas, warming temperatures are not the biggest culprit.  Black carbon – released into the air by burning fossil fuels or biomass such as plants, trees, and shrubs – darkens the snow and causes it to absorb more of the sun’s heat.  A recent study by an international team of scientist has identified another important factor:  dust.

An estimated 5 billion tons of desert dust enters the Earth’s atmosphere every year.  Dust from places like Saudi Arabia gets picked up by spring winds and gets deposited on the western sides of mountains, where it can make the air 10 times more polluted than most European cities.  Dust blows across industrial and desert areas in the Indian subcontinent and the Middle East and lands in the Himalayas.  According to the new study, this dust is often the dominant cause of snow melt in those areas.

Desert dust causes snow melt in the same way that black carbon does.   Dirty snow absorbs sunlight more easily than clean snow.

Desert dust is a natural part of Earth’s systems, but the amount of it in the atmosphere has steadily increased since the Industrial Revolution, when humans greatly expanded into desert areas and broke through surface crust that held large amounts of dust in place.

There is not much we can do about desert dust, short of eliminating deserts.  But the disappearance of the Himalayan ice pack – which sustains over a billion people – can be mitigated by reducing greenhouse gas emissions to address climate change .

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Himalayan glaciers melting because of high-altitude dust

Photo, posted March 13, 2018, courtesy of Sarunas Burdulis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Fall Safety Tips | Earth Wise

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The fall season has its own weather-related hazards, such as raging wildfires across the West and a busy hurricane season in the Atlantic.  There might even be snow in some places.  The National Weather Service issued a set of four broad safety tips for being prepared for the dangers of fall weather.

With regard to wildfires, it is important for smokers to properly discard cigarettes, for people to avoid activities with open flames or sparks, and to use fire-resistant landscaping around our homes. The Weather Service issues Red Flag Warnings when conditions are ripe for wildfires.

In this busy hurricane season, even people who don’t live in hurricane surge evacuation areas need to know their home’s vulnerability to damage from high winds and inland flooding.  People should have a plan that includes an emergency kit and a safe place to shelter should they need to evacuate.

It is important to have a plan in case strong winds pose a threat.  When preparing for an extreme wind event, secure objects that can be tossed or rolled, trim trees near homes, and have a plan in case of an extended power failure.  Strong winds can even happen on a clear day.

The key advice in case you encounter flood waters is “turn around, don’t drown.”  It is never safe to walk or drive into a flooded roadway.  It is best to delay travel until roads are clear.

Fall can be the most beautiful season of the year, but it also has its dangers.  Following advice such as that provided by the Weather Service is prudent and potentially life-saving.

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Four safety tips for fall hazards: Small actions can have big impacts

Photo, posted October 30, 2014, courtesy of Virginia State Parks via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

More Carbon Dioxide From Thawing Permafrost | Earth Wise

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The Arctic is warming much faster than the rest of the planet.  Stories about the loss of polar ice and hundred-degree temperatures in Siberia have become commonplace.  One of the most troubling aspects of the warming Arctic is the thawing of permafrost.  Permafrost is ground that remains frozen for at least two years; some of it has been frozen for tens or hundreds or even thousands of years.  Found under a layer of soil, permafrost is composed of rock, soil, sediments, and varying amounts of ice.  It stores the carbon-based remains of plants and animals that froze before they could decompose.  Permafrost covers almost a quarter of North America, but it is starting to thaw.

Scientists estimate that there are more than 16,000 billion tons of carbon locked away in Arctic permafrost, which is almost double the amount of carbon that is currently in the atmosphere.  Climate models predict that the warming of the Arctic could lead to 5 to 15% of that carbon to be emitted as carbon dioxide by the year 2,100, which would be enough to raise global temperatures by 0.3 to 0.4 degrees Celsius.

New research has increased this estimate because it includes a key pathway for CO2 to enter the atmosphere that earlier models ignored.   When carbon from thawing permafrost escapes into Arctic lakes and rivers, it is oxidized by ultraviolet and visible light and it then escapes into the atmosphere as CO2.  This process is known as photomineralization and is estimated to raise permafrost-related CO2 emissions by 14%.

Recent studies project that with every 1-degree Celsius increase in temperature, 1.5 million square miles of permafrost could be lost through thawing.

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Climate Models Underestimate CO2 Emissions from Permafrost by 14 Percent, Study Finds

Photo, posted July 7, 2014, courtesy of NPS Climate Change 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...)