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Hurricanes and wildfires

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Early March saw more than 200 wildfires break out in the southeastern U.S. – a busy start to the region’s annual fire season.  One fire in the Carolina Forest near Myrtle Beach scorched over 2,000 acres over a two-week period and firefighters were busy containing it and many other blazes.

Strong winds and an unusually long dry period have made fires more likely to ignite and be spread.  Lightning strikes, power line sparking, backyard fire pits and leaf burning all can lead to wildfires under these conditions.

A weather disaster last year may be helping to make this fire season worse than usual.  Hurricane Helene ravaged the Southeast last September, dumping more than a foot of rain in some locations and knocking over hundreds of thousands of acres of trees across the region.

Lots of dead trees lying on the ground allow sunlight to reach the ground and dry out all the biomass, including the trees.  All of this desiccated plant material acts as kindling, providing fuel for wildfires.  Fallen trees can be a fire nuisance for years after a hurricane, especially in the Southeast, where dried out pine needles are highly combustible.  All it takes is an ignition.

In addition, all the fallen trees represent an access issue for firefighters as the logs block roads needed to reach the fires.

Research has shown that climate change is fueling more intense fires in the West.  Whether the changing climate is having a major effect in the Southeast isn’t clear.  But droughts are expected to become more intense and more frequent in the Southeast because of climate change and that isn’t good news for the likelihood of wildfires.

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How Hurricanes Can Fuel Wildfires in the Southeast

Photo, posted March 5, 2025, courtesy of the U.S. Army National Guard / Roberto Di Giovine via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

National drought

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Climate change brings with it many kinds of extreme weather.  It isn’t just higher temperatures.  It is changing patterns of weather and weather events that are rare or even unprecedented.

Late October saw drought conditions throughout almost the entire United States.   Only Alaska and Kentucky did not have at least moderate drought conditions.

The previous four months were consistently warmer than normal over a large area of the country.  When that period started, about a quarter of the country was at least somewhat dry, but in late October, 87% of the country was dry.

Droughts in many parts of the U.S. and in places around the world are becoming more frequent, longer in duration, and more severe. 

Residents of New York City were urged to start conserving water.  This October was the driest October since record keeping began in 1869.  The upstate reservoirs that supply New York’s water were below two-thirds full.  They are normally more than three-quarters full in the fall.

Even the Southeast, which received huge amounts of rain from Hurricane Helene, is experiencing drought.  Not much rain had fallen since that storm and warmer temperatures mean more evaporation and drier soils.

Drought is not just a lack of precipitation.  Drought conditions are driven by abnormally high temperatures that remove moisture from the atmosphere and the ground.

Whether widespread drought conditions will persist is unknown.  If a predicted La Niña condition develops in the tropical Pacific, drought conditions in the southern half of the country could get worse, but the Northeast could see lots of rain and snow.

To have nearly the entire country experiencing drought conditions is pretty rare.  But unusual weather is becoming the new normal.

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In a Record, All but Two U.S. States Are in Drought

Photo, posted May 21, 2024, courtesy of Adam Bartlett via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Cities and rainwater

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Cities across the country are grappling with the problem that bigger, more frequent rainstorms occurring as a result of climate change are overtaxing the systems put in place to handle stormwater.  Cities use a combination of so-called green infrastructure – such as rain gardens and porous pavements – and traditional gray infrastructure, such as pipes, tunnels, and pump stations.

In 2011, Philadelphia drew national attention for its Green City, Clean Waters program that was designed to manage the increasing amount of storm water using mostly green infrastructure.  Thirteen years later, the city is experiencing billions of gallons of polluted stormwater overflowing its sewage outfall pipes each year.  Green infrastructure is cheaper and faster to build, but it is not coping with increasing rainfall.

About 700 U.S. municipalities, mostly in the Northeast and around the Great Lakes, rely on these combined sewer systems.  Based on updated climate projections, many are having to greatly increase gray infrastructure projects that include concrete holding tanks, tunnels, and pipes that can divert and hold onto flows until the rain stops, and water treatment plants can recover.  These projects can take decades to implement and cost billions of dollars.

All across the country, cities are going to need to bite the bullet and make large-scale investments in conventional sewage infrastructure and repairs to stop billions of gallons of raw sewage from running into rivers.  The increased storms present a daunting challenge for America’s cities.

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Faced With Heavier Rains, Cities Scramble to Control Polluted Runoff

Photo, posted August 29, 2011, courtesy of Reggie via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Sponging up a river

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During the first week of February, an atmospheric river dumped enormous amounts of rain on Southern California.  Over the course of four days, Los Angeles received 9 inches of rain.  The average annual rainfall in the city is only 14 inches.

But Los Angeles was not the site of a flooding disaster because the city has spent years preparing for this type of deluge by becoming a “sponge city.”   By installing lots of green spaces and shallow basins with porous soil, Los Angeles was able to soak up 8.6 billion gallons of water during the storm, enough to meet the water needs of 100,000 people for a year.

Cities covered with impermeable concrete sidewalks and paved areas make storm-related flooding worse because they are unable to absorb water.  Instead, the water flows into drains and overwhelms infrastructure.

Natural materials like dirt and plants take in water from storms and can filter it into underground aquifer that cities can then tap into, especially during droughts.  Adding green spaces to cities has many other benefits beyond the ability to absorb large amounts of rainwater.

The so-called sponge-city movement is catching on in many other places.  Philadelphia is revamping its water systems in a 25-year project that includes green spaces to absorb stormwater runoff.  In China, the government has spent more than a decade adding spongy elements to dozens of cities around the country.

Sponge cities are part of a broader effort to combine modern engineering techniques with natural systems.  This is known as green-gray infrastructure.  Nature knows what it is doing when it comes to flood control as well as to pollution control.

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‘Spongy’ LA Soaked Up Tons of Water From Atmospheric River

Photo, posted December 28, 2011, courtesy of Ron Reiring via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Little ice on the Great Lakes

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In an average year, the Great Lakes end up about 40% covered in ice.  But this is not an average year.  2023 was the warmest year on record and, in fact, the global temperature was more than 1.5 degrees above the pre-industrial average for the full year.  That hasn’t happened before.  As a result of the record-breaking warmth, as of mid-February, the average ice cover on the Great Lakes was only 5.9%.

Lake Erie and Lake Ontario tied their records for the lowest ice cover, which has been tracked since 1973.  Lake Huron, Lake Michigan, and Lake Superior are at historic lows.  Some parts of the Great Lakes have experienced the winter without any ice cover.

The warming air temperatures have led to rapid ice loss and warming summer temperatures.  According to experts, if the planet continues to warm, more than 200,000 lakes may no longer freeze every winter and 5,700 lakes may permanently lose ice cover by the end of the century.

Studying the Great Lakes is important because their ice melt can be a significant indicator of the progress of global warming.  Decreasing ice cover can affect hydropower generation, commercial shipping and fishing, and have environmental impacts such as the development of plankton blooms.

Since the 1970s, there has been a 5% decline in Great Lakes ice cover per decade.  Unfrozen lakes bring more rain than snow which has environmental, cultural, and societal impacts.  The Great Lakes hold 21% of the world’s freshwater supply and over 30 million people depend on them for drinking water.  They are also linked to over $3 trillion in gross domestic product.

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Great Lakes Winter Ice Cover Averaging Just 5.9%: NOAA

Photo, posted November 7, 2007, courtesy of Jim Sorbie via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A wet January

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For the first time in a while, the monthly report on the US climate did not feature record-setting heat.  The average January temperature across the contiguous U.S. was 1.6 degrees above the average, but that only ranked it in the middle third of the climate record.  The diminishing El Niño probably helped.  On the other hand, the global average temperature in January was again the warmest on record – the 8th consecutive record-setting month.

But January still managed to be atypical weatherwise in the U.S. in that the nation’s average precipitation across the country was 3.18 inches – nearly an inch above average – which made it the 10th wettest January in NOAA’s 130-year climate record.  Thirteen states experienced top-ten rainfall amounts.  In late January, record rainfall and flooding hit the southern plains, especially in parts of Texas and Louisiana.  Meanwhile, early February brought historic rainfall and mountain snow to California with a second round later in the month.

All of the rainfall in January has made some difference to drought conditions across the country.  On January 30th, about 23.5% of the contiguous U.S. was In drought, which was 9.5% lower than the beginning of the month.  However, drought conditions expanded or intensified across northern parts of the Rockies and Plains among a few other places.

Outside of the lower-48, Alaska continued to experience historic snowfall conditions.  Between October and the end of January, Anchorage had over 100 inches of snow.

We are living in an era of weather extremes.

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The nation just saw its 10th-wettest January on record

Photo, posted February 8, 2017, courtesy of Paxson Woelber via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

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

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

Death Valley Flooding | Earth Wise

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Furnace Creek in Death Valley is the driest place in North America.  Its average annual rainfall is under two inches.  On August 5th, a thousand-year rainfall event dropped 1.46 inches of rain – about three-quarters of a year’s precipitation.  The all-time record for a single day is 1.47 inches, set in April 1988.  The storm did break the record for the most rain ever recorded in August, which averages just over a tenth of an inch of rain for the entire month.

The flash flood washed debris over roads, swept away and buried cars, knocked a water facility offline, damaged buildings, and stranded about a thousand visitors and staff in Death Valley National Park. By the next day, the flood water had mostly receded, and stranded visitors could be escorted out of the park by National Park personnel.

Death Valley sits at 282 feet below sea level.  If it were not for the extremely arid climate there, Death Valley would likely be filled with water.  However, humid air masses traveling east from the Pacific Ocean have to cross four mountain ranges before they reach the desert valley.  Those air masses lose their moisture in the form of rain on the western slopes of the mountain, leaving a dry area, or rain shadow, on the eastern sides.  By the time the air masses reach Death Valley, they are bone dry.  On rare occasions, the lowest spot in the valley fills with water forming a wide, shallow lake, known as Lake Badwater. 

The extreme heat and aridity of Death Valley evaporates the temporary lake quickly, returning the valley to its usual state.  Furnace Creek still holds the record for the highest air temperature ever recorded:  134 degrees Fahrenheit.

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Death Valley Flash Flooding

Photo, posted April 7, 2021, courtesy of Matthew Dillon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Lithium Mining And The Environment | Earth Wise

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The Salar de Atacama in Chile is a large, dry salt flat surrounded by mountain ranges and is one of the driest places on Earth. Parts of the Atacama Desert have gone without rain for as long as people have been keeping track. Water rich in dissolved salts lies beneath this flat surface and it is particularly rich in lithium salts.  Forty percent of the world’s known lithium deposits are the in the Salar.

Lithium is the key component of the batteries that power electric cars as well as cell phones and computers.  It is an essential part of the transition away from fossil fuels and towards green energy.  But it is important that this element is obtained responsibly with minimal damage to the environment.

Lithium, the lightest of the metals, tends to occur in layers of volcanic ash, but reacts quickly with water.  It leaches into groundwater and settles in flat basins where it remains in a briny solution.  This dense brine often ends up beneath pockets of fresh surface water, which are havens for fragile ecosystems.

A new study by the University of Massachusetts Amherst looked at the hydrological impact of lithium mining in the Salar.  The study found that the impact of lithium mining depends critically on how long surface water is in place.  Much of the fresh water there is at least 60 years old.  Both droughts and extreme rainfall can cause major changes to the surface water that ordinarily comes from mountain runoff.  Lithium mining itself only accounts for less than 10% of freshwater usage in the Salar. But the state of the surface water needs to be carefully monitored to protect the ecosystems as the climate continues to change.

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How environmentally responsible is lithium brine mining? It depends on how old the water is

Photo, posted February 21, 2016, courtesy of Jorge Pacheco via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

More Bleaching In The Great Barrier Reef | Earth Wise

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Australia’s Great Barrier Reef is an ecosystem that can be seen from space.  It has now suffered its 6th mass coral bleaching event since 1998.  Previous events happened in 1998, 2002, 2006, 2016, and 2017.  This latest bleaching has occurred even though this is a La Niña year, when more rain and cooler temperatures are supposed to help protect delicate corals.

An aerial survey of 750 separate reefs across much of the 1500 mile-long Great Barrier Reef system found severe bleaching among 60% of the corals.  The bleaching covers an area even wider than the back-to-back outbreaks in 2016 and 2017.

The bleaching is a product of a summer in Australia that started early.  December temperatures were already warmer than the historical February summer maximums.  Globally, 2021 was the hottest year on record for the world’s oceans for the sixth year in a row.

Bleached coral can recover if temperatures cool down for a long enough period, but this is becoming increasingly rare.  Between 2009 and 2019, 14% of the world’s coral reefs were lost for good.

In Australia, the plight of the Great Barrier Reef has become politicized.  The current government is not supportive of efforts to reduce the country’s fossil fuel dependence and has worked to keep the reef from being placed on the list of endangered world heritage sites.  Instead of pushing for emissions cuts, Australia has focused on a variety of long-shot projects aimed at helping the reef.

The fact is that coral reefs cannot cope with the current rate of warming and unless that slows down soon, they will simply not survive for long.

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Photo, posted September 28, 2009, courtesy of Matt Kieffer 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.

Cloud Seeding And The Western Drought | Earth Wise

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The massive megadrought affecting the American West is now considered to be the driest two-decade period in the past 1,200 years.  The lengthy drought has led to increased wildfires, reduced agricultural productivity, and reduced electricity generation by hydropower plants.  The historically low water levels in the largest two reservoirs in the U.S. – Lake Mead and Lake Powell – has triggered reductions in water allocations to Arizona, Nevada, and Mexico.

Several western states have expanded cloud seeding programs in an attempt to increase precipitation.  During the past two years, Idaho, Utah, Colorado, Wyoming, and California have all stepped up their cloud seeding efforts.  Outside of the US, the United Arab Emirates and China both have implemented massive cloud seeding programs.

A study by researchers at the University of Colorado and the National Center for Atmospheric Research looked at the ability of cloud seeding to increase snowfall.  The study unambiguously demonstrated that cloud seeding can increase snowfall.  Just how effective it is in terms of how much additional snow seeding produces is less clear.

Given the dire need for water and the fact that cloud seeding is not especially expensive, governments and other users are not hesitating to make use of it.

Unfortunately, the study shed no light on the efficacy of warm weather seeding to produce rain.  There is in fact little evidence that seeding clouds to produce rain accomplishes very much.  Once again, the prevailing view is that it is worth trying.  There do not appear to be environmental downsides to seeding.

The hope is that cloud seeding may at least restore clouds to the state they had been in before industrial pollution and other human activities affected them.

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Can Cloud Seeding Help Quench the Thirst of the U.S. West?

Photo, posted November 21, 2013, courtesy of Sharon Tate Soberon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Climate Change And Hurricanes In The Northeast | Earth Wise

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According to a new study led by Yale University, more hurricanes are likely to hit Connecticut and the northeastern U.S. as global warming continues to increase temperatures in the region.

Hurricane Henri made landfall in August as a tropical storm on the Connecticut/Rhode Island border.  In September 2020, subtropical storm Alpha made landfall in Portugal, the first subtropical or tropical cyclone ever observed to make landfall in the mainland of that country.

Tropical cyclones, hurricanes, and typhoons are typically intense and destructive in the lower latitudes. 

The study concludes that violent storms could migrate northward in our hemisphere and southward in the southern hemisphere as a result of warming caused by greenhouse gas emissions.

The research predicts that tropical cyclones will likely occur over a wider range of latitudes than has been the case on Earth for the last 3 million years.

In Connecticut, Hurricane Henri was not the only tropical storm to affect the region in 2021.  The remnants of Hurricane Ida brought damaging winds and torrential rain that felled trees and flooded streets and basements.

The northern expansion of such violent storms is going on as water levels in the Atlantic Ocean and Long Island Sound keep rising.  Because of melting glaciers thousands of miles away, water levels in Long Island Sound could rise by as much as 20 inches by 2050, enough to submerge parts of Groton’s shore and cause regular flooding in roads and neighborhoods.

Future hurricane prediction is an inexact science, but the ongoing trends do not bode well for the region.

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More hurricanes likely to slam Connecticut and region due to climate change, says study

Photo, posted October 29, 2012, courtesy of Rachel via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Alaskan Icemageddon | Earth Wise

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December saw some wild weather in Alaska.  A combination of record high temperatures and torrential rainstorms resulted in the coining of the term “Icemageddon” to describe what was going on with the weather.

Kodiak Island in southern Alaska saw a high temperature of 67 degrees on December 26, which was warmer than it was in Southern California that same day.  This set an all-time record for the warmest December day in Alaska.  Such a high temperature is amazing considering how little sunlight Alaska gets at this time of year.  And with warmer air comes wetter air, as the atmosphere is capable of holding more water vapor as temperatures increase.

As a result, that same day saw the interior of the state get an inch of rain in just a few hours, something that hadn’t happened for decades.  But then, when temperatures plummeted again, all that rainwater froze.

Huge sheets of ice blocked roads and choked traffic in Fairbanks, Alaska’s second largest city.  Indeed, it was the state’s transportation department that came up with the term icemageddon to describe the situation.

The extreme warmth in December is related to the same weather pattern that brought cold, wintry weather to the Pacific Northwest and Northern California.  Those weather conditions resulted in hundreds of cancelled flights in Seattle, where temperatures dropped into the 20s, and in massive amounts of snowfall in the Sierra Nevada mountains in California.  A strong area of high pressure anchored in the Northern Pacific resulted in a clockwise flow around it drawing warmer, more tropical air from the Pacific up to Alaska.

Climate change continues to push the envelope on what sort of weather is possible all over the world.

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Alaska faces ‘Icemageddon’ as temperatures swing wildly

Photo, posted April 30, 2015, courtesy of Naql via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Floating Homes In The Netherlands | Earth Wise

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The Netherlands is a country that is largely built on reclaimed land and a third of it remains below sea level.  The Dutch have long experience with dealing with rising waters.  The city of Amsterdam has almost 3,000 houseboats in its canals.

As sea levels continue to rise across the globe, it is no surprise that the Dutch have taken the lead in creating communities composed of floating houses and buildings.

A floating house is a structure fixed to the shore, often resting on steel poles, and usually connected to the local sewer system and power grid.  They are much like ordinary houses except that instead of a basement, they have a concrete hull that acts as a counterweight, allowing them to remain stable in the water.

The ones in the Netherlands are often prefabricated, square-shaped, three-story townhouses.  Rotterdam, which is 90% below sea level, is home to the world’s largest floating office building as well as a floating farm.

Floating buildings have their challenges, not the least of which are the effects of severe wind and rainstorms, or even the passing of large ships which can make the buildings rock.  Infrastructure like electricity and sewer service is not that simple to implement for the buildings.  But the benefits of floating buildings may outweigh the costs.

For cities facing worsening floods and a shortage of buildable land, floating homes are a potential solution for expanding urban housing in the age of climate change.  Dutch engineers are spearheading floating building projects in Britain, France, and Norway, as well as in threatened island locations like French Polynesia and the Maldives.

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Embracing a Wetter Future, the Dutch Turn to Floating Homes

Photo, posted May 23, 2007, courtesy of Jeff Hutchison via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

Bomb Cyclones | Earth Wise

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It seems like we are hearing about new weather phenomena pretty frequently these days.  One name that has popped up lately is “bomb cyclones.”  Bomb cyclones, it turns out, are storms that undergo “bombogenesis.”  What that means is a low-pressure area (in other words, a storm) that undergoes rapid strengthening and can be described as a weather bomb, or popularly, a bomb cyclone.

These things usually take place over remote tropical ocean areas but a really intense one struck the Pacific Northwest on October 24th.  The storm off the coast of Washington, with a barometric pressure reading equivalent to a category 4 hurricane, was the second extreme low-pressure storm in the North Pacific in a single week.  Both storms involved pressure drops of more than 24 millibars in 24 hours, making them bomb cyclones.

These storms brought high winds and extreme precipitation that doused wildfires and provided some relief to the extreme drought in Central and Northern California.  Along with these positive effects, however, the storms also caused power outages, flooding, landslides, and mud and debris that washed out roads.

The October 24-25 event brought 16.55 inches of rain to Mount Tamalpais in Marin County, California in a 48-hour period.  Sacramento got 5.44 inches of rain, breaking a 140-year-old record.  And the city had just broken another extreme weather record for the longest dry spell in history.

The storms directed streams of moisture from north of Hawaii toward the West Coast in long, narrow bands of moisture known as atmospheric rivers.  We are learning about all sorts of unfamiliar weather phenomena as extreme weather events become increasingly common.

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Extratropical Cyclones Drench West Coast

Photo, posted January 4, 2018, courtesy of NOAA/CIRA 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.

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.

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The Pandemic And Global Temperatures | Earth Wise

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The early months of the Covid-19 pandemic last year saw dramatic reductions in travel and many forms of commerce.  With much of human activity greatly curtailed, greenhouse gas emissions were greatly reduced.   And yet, all of that did not slow down global warming: 2020 ended up tied with 2016 as the warmest year on record and atmospheric greenhouse gas levels reached a new high.

In order to understand how this came about, it is necessary to understand the complex climate influences of different types of emissions from power plants, motor vehicles, industrial facilities, and other sources.  The fact is that some types of pollution actually have a cooling effect rather than contributing to global warming.

Tiny industrial pollution particles called aerosols actually make clouds brighter, causing them to reflect away more solar heat from the surface of the planet.   During the drastic shutdown last year, the biggest emissions decline was from the most polluting industries.  The reduction of aerosols had immediate, short-term effects on temperatures.  These types of pollutants are very bad for human health, but when they are present, they do have the effect of reducing temperatures.

It is important to keep in mind that carbon dioxide spreads through the Earth’s atmosphere and stays there for a century or more, trapping heat on a global scale.  Industrial aerosols stay relatively concentrated in the region where they are emitted and are often removed by rain and winds within a few weeks.  So, their cooling effect doesn’t spread very far or last very long.

Overall, the initial pandemic slowdown probably didn’t have any real long-term impact on the climate but over the short term, the effects were not as simple as one might expect.

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Covid-19 Cut Gases That Warm the Globe But a Drop in Other Pollution Boosted Regional Temperatures

Photo, posted July 7, 2020, courtesy of Joey Zanotti 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...)