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The UK is heating up

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June and July have both seen multiple days with temperatures in the 90s in London, England.  This is almost unheard of, but according to British scientists, record-breaking extreme weather has become the new norm in the UK.

Weather records show that the UK’s climate is different now compared with just a few decades ago.  The number of days with temperatures 9 degrees Fahrenheit above the average from 1961-1990 has doubled in the last 10 years.  For days 14 degrees above average, the number has tripled, and for 18 degrees above average, it has quadrupled. 

Apart from the higher temperatures, rain in the UK has become more intense.  The number of months where counties receive at least double their average rainfall has risen by 50% in the past 20 years.  Sea level around the UK is rising faster than the global average, worsening the impact of coastal flooding.

An estimated 600 people died as a result of the heatwave that hit England and Wales at the end of June.  Scientists calculated that the extreme high temperatures were made 100 times more likely to have occurred as a result of climate warming.

The UK has some of the longest duration meteorological records in the world.  Those records show that recent temperatures have far exceeded any in at least 300 years.  The last three years were among the UK’s five hottest years on record. 

Today’s record-breaking temperatures are likely to be average by 2050 and positively cool by 2100, according to scientists.

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‘Profound concern’ as scientists say extreme heat ‘now the norm’ in UK

Photo, posted February 4, 2018, courtesy of Hannes Flo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Hydroclimate whiplash

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Hydroclimate whiplash is a term that describes rapid swings between intensely wet and dangerously dry weather.  Global weather records show that the occurrence of hydroclimate whiplash has increased by 31% or as much as 66% since the mid-20th century. 

California’s experience is a prime example of this phenomenon.  After years of severe drought, dozens of atmospheric rivers subjected the state to record-breaking amounts of precipitation in the winter of 2022-23.  A second extremely wet winter in the southern parts of the state the following year resulted in the growth of abundant amounts of grass and brush. 2024 saw a record-hot summer which was then followed by a record-dry start to the 2025 rainy season.  The result was the catastrophic wildfires in the Los Angeles area in January.

Research by UCLA climate scientists explains that the primary driver for the increasing occurrence of hydroclimate whiplash is the expansion of the atmospheric sponge – that is, the growing ability of the atmosphere to evaporate, absorb and release water.  Every degree Celsius that the planet warms increases this ability by 7%. 

The global consequences of hydroclimate whiplash include not only floods and droughts but also the increased danger of whipsawing between the two, leading to the bloom and burn cycle that California recently faced. The risk of wildfire is twofold:  first by increasing the growth of flammable grass and brush in the months before the fire season, and then by drying it out to dangerous levels with extremely warm and dry weather.

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Floods, droughts, then fires: Hydroclimate whiplash is speeding up globally

Photo, posted January 13, 2025, courtesy of Victor Guillen / USDA Forest Service via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A sustainable and climate-friendly food

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Researchers predict that climate change will negatively impact the yield and nutritional quality of most staple food crops, including rice, corn, and soybeans, due to factors like extreme weather events, rising temperatures, and altered precipitation patterns, potentially leading to reduced food security globally.   

As a result, many experts contend that alternative food sources – like insect farming and seaweed aquaculture – are part of the solution.  Additionally, expanding production of climate resilient food crops will also have an important role to play in global food security.

According to a new international study led by researchers from University of Vienna in Austria, chickpeas – also known as garbanzo beans – are a drought-resistant legume plant with a high protein content that can help combat food insecurity amid climate change.

In the study, which was recently published in the journal Plant Biotechnology, the researchers investigated the natural variations of different chickpea genotypes and their resistance to drought stress and achieved promising results.  The research team managed to grow many different chickpea varieties under drought stress in a field experiment outside of Vienna. The results demonstrate that chickpeas are a great alternative legume plant that can complement grain farming systems in urban areas.

The study highlights how the decline of plant genetic diversity poses a major threat to plant productivity and harvests.  In fact, while there are approximately 7,000 edible crops, two-thirds of global food production is based on just nine crop species. 

According to the research team, highly nutritious and drought-resistant legumes such as chickpeas are a “food of the future.”

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Chickpeas – sustainable and climate-friendly foods of the future

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

Earth Wise is a production of WAMC Northeast Public Radio

Species range and climate change

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The geographic range of a particular plant or animal species is the area in which it can be found during its lifetime.  The range of most species is limited by climatic factors, including temperature, precipitation, soil moisture, humidity, and wind.  Any changes in the magnitude or variability of these factors will impact the species living there. 

For example, a species sensitive to temperature may respond to a warmer climate by moving to cooler locations at higher latitudes or elevations. 

But not all species are able to move at the same speed.  According to an international research team led by scientists from the University of Massachusetts Amherst, non-native species are expanding their ranges many times faster than native species.

The researchers found that land-based plant and animal species need to be shifting their ranges by about two miles per year just to keep up with the rapid pace of the changing climate.  Marine species need to be moving about 1.7 miles per year.  However, native species are only managing to move about one mile per year on average.  

Non-native species, on the other hand, are spreading nearly 22 miles each year on their own.  Additionally, when the role humans play in assisting the spread of non-native species is factored in, the rate jumps to a whopping 1,170 miles per year.  This is more than 1,000 times faster than the rate at which native species are spreading.   

The researchers conclude that there is no chance for native species to keep up with climate change without human help.  Assisted migration needs to be on the table if native plants and animals are to survive.   

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Non-Native Plants and Animals Expanding Ranges 100 Times Faster than Native Species

Photo, posted April 10, 2011, courtesy of Bri Weldon via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Palm oil and water quality

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Palm oil is the world’s cheapest and most widely used vegetable oil.  In fact, more than 86 million tons of palm oil was consumed last year alone.  Even though few of us cook with it, palm oil can be found in approximately half of all packaged grocery items – everything from ice creams and pizzas to detergents and cosmetics. 

This massive global demand for palm oil is driving tropical deforestation around the world.  While many studies have shown how converting rainforests to oil palm plantations causes biodiversity loss, researchers from UMass Amherst are the first to demonstrate how these plantations also cause wide-ranging disturbances to nearby watersheds.

In the study, which was recently published in the journal Science of the Total Environment, the research team focused on the Kais River watershed of West Papua, a province in the far east of Indonesia.  Approximately 25% of the watershed has been turned into oil palm plantations. The watershed is also one of the oldest continually inhabited homes for different groups of Indigenous Papuans.

The researchers found that the conversion of tropical rainforest to oil palm plantation has increased precipitation, runoff, and soil moisture. Water quality in the watershed has also gotten dramatically worse: sedimentation has increased by 16.9%, nitrogen by 78.1%, and phosphorus by 144%.

The research team hopes regulators will work to limit the use of pesticides, conduct continuous water quality monitoring, and ensure that downstream communities have access to water quality information. 

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Oil Palm Plantations Are Driving Massive Downstream Impact to Watershed

Photo, posted December 13, 2008, courtesy of Fitri Agung via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Major species turnover forecasted for North American cities

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Climate change affects animal species in many ways.  It induces habitat loss, disrupts migration and breeding patterns, threatens marine life, and facilitates an increased spread of disease.  It may also affect where animals can be found in the future. 

According to a new study led by researchers from the University of Toronto Mississauga and Apex Resource Management Solutions in Canada, climate change may dramatically affect the animal species observed in North American cities by the end of the century.

The researchers used species distribution data combined with machine learning to study the impact of human-caused climate change on more than 2,000 animal species historically found in the 60 most populous North American cities. 

According to the research team, changes in biodiversity are brewing for almost every city it studied by the year 2100.  In fact, cities with a rich history of biodiversity are predicted to have the largest declines and fewest gains in species. Cooler and wetter cities like Quebec, Ottawa, Winnipeg, Kansas City, and Omaha are expected to welcome the most new species.  Warmer cities with higher precipitation – like cities in coastal California – are projected to lose the most species. 

More than 95% of bird and insect species are predicted to experience a change in the number of cities they call home.  Canines, most amphibians, and aquatic birds are expected to experience the greatest losses.  Toads, turtles, mice and pelicans are projected to become more common overall. 

The researchers hope their findings will encourage more efforts to protect biodiversity.

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North American cities may see a major species turnover by the end of the century

Photo, posted September 29, 2013, courtesy of Jonathan Kriz via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

A surprising drop in renewable power

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Renewable power – which includes wind farms, solar farms, and hydroelectric dams – constitutes over 21% of the country’s utility-scale electricity generation, behind only natural gas power plants at 43%.  Nuclear power provides nearly 19% of our electricity and coal, which is gradually diminishing, is at 16%.

Both solar and wind power capacity have been growing rapidly in recent years and will be providing an increasing percentage of our electricity.  That being said, it turns out that utility-scale renewable electricity generation actually decreased slightly in 2023 as a result of weather-related issues.

Utility-scale renewables generated about 894,000 gigawatt hours of energy last year, which was 0.8% less than the record amount generated in 2022.

The reasons?  The biggest factor was slower wind speeds in the Midwest during the warmer weather months.  In 2023, there were fewer warm fronts and cold fronts passing through the region.  The passage of fronts is often associated with wind and precipitation. 

The other factor affecting renewable generation was a 5.9% drop in hydropower in 2023.  The main reason for the decrease was a drop in water levels at many hydroelectric dams in areas experiencing drought.

Experts explain that there is no reason to overreact to a one-year blip in renewables generation.  All three major sources of power – sun, wind, and hydroelectric – are tied to natural forces and all of them fluctuate over time.  Putting aside minor variations year-over-year, renewable electricity is on pace to more than double by the end of this decade.

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Federal Data Reveals a Surprising Drop in Renewable Power in 2023, as Slow Winds and Drought Took a Toll

Photo, posted July 5, 2014, courtesy of Patrick Finnegan 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

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

Adirondack lakes becoming inhospitable for trout

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A combination of the warming climate and the phenomenon of lake browning are making the bottom of most lakes in New York’s Adirondack Mountains unlivable for cold water fish – such as trout, salmon, and whitefish – in the summer.

Lake browning occurs when dissolved organic matter from forests turns the water tea-brown.  Browning is the legacy of a century of acid rain and subsequently the fact that forest soils have suffered reduced capacity to absorb weak organic acids, leading to more dissolved plant matter flowing into lakes.  Climate change has increased the frequency of extreme precipitation events and the length of growing seasons, leading to more runoff of organic matter.

Browner water traps more of the sun’s heat at the top of the lake and blocks the sun’s rays from reaching deeper.  The result of the browning is lakes that are either too warm or too deoxygenated to support trout populations.

A study of 1,467 Adirondack lakes by Cornell University researchers found that only about 5% of them may continue to maintain water that is cold and oxygenated enough to support cold-water fish.

Deeper lakes fare much better because they have so much water that their oxygen is hard to deplete, but only 1% of all Adirondack lakes are deeper than 30 meters.  Another 4% are very clear because the influx of cold water outpaces the expansion of low-oxygen zones and limits the effects of browning.

The study urges the protection of as many lakes as possible from species invasions, nutrient and salt pollution, and other forms of environmental degradation. 

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Most Adirondack lakes will likely become unsuitable for trout

Photo, posted July 17, 2011, courtesy of Lida via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Glacier Loss Day | Earth Wise

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Glaciers are sensitive indicators of climate change that respond to changes in both temperature and precipitation.  But they are not only affected by climate change, they also affect climate change.  As glaciers melt, they contribute to sea level rise, alter regional hydrology, and influence the global energy balance.

A group of glacier experts from the University of Innsbruck in Austria introduced a concept called “Glacier Loss Day” or GLD as a way to measure the annual mass balance of glaciers.  Mass balance is the difference between the amount of snow and ice that accumulates on a glacier and the amount that melts or sublimates.  If the mass balance is positive, the glacier is growing.  If the mass balance is negative, the glacier is shrinking.

GLD is the day during the year when the glacier has lost all the mass it gained during previous winter.  This is a similar concept to Earth Overshoot Day, which marks the date when humankind’s demand for ecological resources exceeds the amount the planet can regenerate during the year.

The Hintereisferner, a glacier in the Tyrolean Alps, has been monitored for more than 100 years and there are continuous records of its mass balance since 1952.  In 2022, the GLD on the Hintereisferner was measured on the 23rd of June.  In the two previous years, it was reached in the middle of August.  Even in years with large negative balances, such as 2003 and 2018, GLD did not occur until the end of July.

Every summer in the future may not be like 2022, but the trend is clear.  Climate change is taking its toll on glaciers.  Experts project that the Hintereisferner will lose half of its volume in the next 10 to 20 years.

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Glacier Loss Day indi­cates record break­ing glacier melt

Photo, posted July 20, 2023, courtesy of Pedro Szekely via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

El Niño Will Likely Return | Earth Wise

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El Niño, a weather phenomenon triggered by warm waters in the eastern Pacific, is likely to return this year, according to the World Meteorological Organization.  The Pacific has been in the cooler La Niña phase for the past 3 years, which is unusual, but that appears to be coming to a close.  According to the WMO, there is an 80% chance that the Pacific will shift to the El Niño phase before fall.

Record hot years typically coincide with El Niño, which adds to the ongoing warming trend in the climate.   There is not yet a clear picture of how strong the forthcoming El Niño event will be or how long it might last, but even a mild El Niño could affect precipitation and temperature patterns around the world.

The hottest year on record, 2016, occurred during a particularly strong El Niño.  Experts expect that 2024 is likely to see soaring temperatures again.  El Niño generally leads to drier conditions in Australia, Indonesia, and southern Asia, but greater amounts of rainfall in South America, the U.S., and parts of Africa.  Despite the presence of a cooling La Niña for the past three years, the last eight years have been the hottest on record.

El Niño and La Niña form an intermittent cycle known as the El Niño Southern Oscillation, or ENSO, that is highly influential in shaping the year-to-year variations in weather conditions around the world.  ENSO is a natural phenomenon and scientists are still trying to understand how human-caused climate change might be impacting the behavior and dynamics of the cycle.

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‘A New Spike’ in Global Temperatures in the Forecast

Photo, posted October 11, 2015, courtesy of Harshil Shah via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

California Storms And The Megadrought | Earth Wise

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California experienced its wettest 10-day period in 25 years as a result of a series of storms driven by atmospheric rivers in January.  The Rocky Mountains got buried in snow from the same weather pattern.   For the drought-stricken West, the storms were good news.  But they are not the cure for what’s been ailing the region.

In California, the snowpack in the Sierra Nevada mountains has been greatly enhanced, containing twice as much snow as is considered average for this time of year.  Without a doubt, it will reduce the impact of the drought that has plagued the state for 23 years.  But one big storm or even a series of them is not enough to undo years of minimal precipitation and rising temperatures.  Many of the states’ largest reservoirs remain well below historical averages despite the record-breaking rain.  It would take several wet years to really allow the state to recover from the drought.

The snowfall in the Rockies is crucial because it is the source of more than two-thirds of the water in the Colorado River.  The Colorado River is the water lifeline for 40 million people from Wyoming to Mexico.

The ongoing shrinking of the Colorado River is a crisis that has created massive problems for the multibillion-dollar agriculture industry and for many large cities, including Denver, Phoenix, Salt Lake City, Las Vegas, and Los Angeles.  Two of the nation’s largest reservoirs – Lake Mead and Lake Powell – are filled by the Colorado River.  The historic low levels of these reservoirs have threatened the functioning of hydropower facilities that provide electricity to millions of people.

The January storms were good news for the West, but its problems are not over.

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This Winter’s Rain and Snow Won’t be Enough to Pull the West Out of Drought

Photo, posted September 18, 2022, courtesy of Sarah Stierch via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Insects In A Changing Climate | Earth Wise

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Insects can be found in every environment on Earth and are critical components of many ecosystems.  They perform countless important functions, including aerating and fertilizing soil as well as pollinating flowers.  In fact, according to the USDA, 75% of the world’s flowering plants and about 35% of the world’s food crops depend on animal pollinators, the majority of which are insects, to reproduce.

According to a study published in the journal Nature earlier this year, the combination of climate change and intensive agriculture is having a profound impact on both the abundance and diversity of insects.  In regions where substantial warming had occurred and where land had been converted for intensive farming, insects were nearly 50% less abundant and more than 25% fewer species were observed.  Tropical regions were among those most at risk for heavy losses.

According to a new study recently published in the journal Global Change Biology, tropical insects will be even more susceptible to climate change than previously thought.  In a five-year study conducted in Peru, researchers from the Florida Museum of Natural History found that insect populations declined 50% following short periods of drought and following short periods of heavy rainfall.  Insect populations decreased after three months of dry weather, but also decreased after three months of exceptionally wet weather.   

Researchers have known that tropical insects don’t tend to do well when their habitats dry out.  But the researchers were surprised to discover that these insects were equally averse to increased precipitation.  Alarmingly, precipitation is expected to become more frequent and more intense as a consequence of the changing climate. 

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Tropical insects are extremely sensitive to changing climates

Photo, posted June 11, 2016, courtesy of Z. Leng via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Climate Change And The Color Of Lakes | Earth Wise

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According to a new study recently published in the journal Geophysical Research Letters, blue lakes around the world are at risk of turning green-brown if climate change continues unabated. 

For the study, the research team used over five million satellite images of more than 85,000 lakes and reservoirs around the globe between 2013 and 2020 in order to determine each lake’s most common water color.  Since lake color can change seasonally, the researchers assessed the most frequent lake color during those seven years. 

Algae and sediments affect the color of lakes.  But the study found that precipitation, air temperature, lake depth, and elevation also play major roles in determining a lake’s most common water color. 

The research team found that blue lakes account for less than one-third of lakes worldwide.  Blue lakes tend to be deeper and are often found in cool, high latitude regions with high precipitation and winter ice cover.  Meanwhile, green-brown lakes, which account for 69% of all lakes, are found in drier regions, continental interiors, and along coastlines. 

As global temperatures rise, lakes will warm, and warmer water produces more algal blooms.  As a result, the researchers expect the changing climate to decrease the percentage of blue lakes, many of which are found in the Rocky Mountains, northeastern Canada, northern Europe and New Zealand. 

Water color is a simple but viable way to measure water quality that can be done on a global scale using satellites.  This approach provides researchers with a way to study how lakes – even the remote ones – are changing.  

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Climate change is making lakes turn green-brown

Photo, posted August 27, 2011, courtesy of Paul Schultz 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.

Bumblebees And Climate Change | Earth Wise

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

Bumblebees are among the most important plant pollinators.  They pollinate many food crops, including apples, tomatoes, blueberries and legumes, as well as countless types of trees, shrubs, and wildflowers.

According to a new study by researchers from Simon Fraser University in Canada, temperature changes have negatively impacted most bumblebee species during the past 120 years.  The research, which was recently published in the journal Biology Letters, found that these changes in temperature had more of a negative impact than other factors such as precipitation or floral resources. 

The research team analyzed existing data on 46 bumblebee species across North America between 1900 and 2020.  The researchers created two occupancy models – one that was focused on time and the other that focused on environmental factors – to see how climate change and land-use variables impacted species’ occupancy.  They found that six bumblebee species decreased through time, 22 increased, and 18 remained stable.

Temperature changes had primarily negative impacts on bumblebees.  In fact, 37 of the 46 species studied exhibited declines or less positive occupancy increases under observed changes in temperature when compared with temperatures remaining constant.  Approximately half of the bumblebee species were negatively impacted by changes in precipitation or floral resources while the other half were positively impacted.

Bumblebee populations are changing as a consequence of climate change. 

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The American Bumblebee

Climate change negatively impacting bumble bees: Study

Photo, posted July 14, 2019, courtesy of Dmitry Grigoriev via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

The Atmosphere Is Thirstier | Earth Wise      

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The American West is in the throes of a two-decade-long drought.  The climate there is getting warmer and drier, which has led to increasing demand for water resources from both humans and ecosystems.  According to a new study by the Desert Research Institute and collaborators, the atmosphere across much of the U.S. is also demanding a greater share of water than it used to.

Evaporative demand, which is also called atmospheric thirst, is a measure of the potential loss of water from the earth’s surface up to the atmosphere.  It is a function of temperature, humidity, wind speed, and solar radiation.  The study, published in the Journal of Hydrometeorology, assessed trends in evaporative demand during a 40-year period from 1980-2020.

The study’s findings showed substantial increases in atmospheric thirst across much of the Western U.S. over that period, with the largest increases centered around the Rio Grande and Lower Colorado rivers.  This is important because atmospheric thirst is a persistent force in pushing Western landscapes and water supplies toward drought.

The study found that, on average, increases in temperature were responsible for 57% of the changes observed in atmospheric thirst, humidity 26%, and the other factors playing lesser roles.

For farmers and other water users, increases in atmospheric thirst mean that, in the future, more water will be required to meet existing water needs.  Crops already require more water than they did in the past and can be expected to require more water in the future.  Over time, for every drop of precipitation that falls, less and less water is likely to drain into streams, wetlands, aquifers, or other water bodies.

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New study shows robust increases in atmospheric thirst across much of U.S. during past 40 years

Photo, posted August 9, 2007, courtesy of William Clifford 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.

A Historic Western Drought | Earth Wise

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The American Southwest has suffered from drought conditions since the year 2000.  The drought has reduced water supplies, devastated farmers and ranchers, and it has helped to fuel numerous wildfires across the region.  It has generally been considered to be worst in 500 years.

According to a recent analysis, the drought has become so severe that it has actually led to the driest two decades in at least 1,200 years and the changing climate is largely responsible.  The summer of 2021 was especially dry; about 2/3 of the West was in severe drought conditions.

Scientists at UCLA used tree ring data to gauge drought.  Based on that analysis, 2000-2021 is the driest 22-year period since 800 A.D. which is as far back as the data goes.

The study confirmed the role of temperature, more than precipitation, in driving exceptional droughts.  Precipitation levels can go up and down over time and can vary in different regions.  But the ongoing emissions of greenhouse gases into the atmosphere are causing temperatures to generally rise over time.  Warmer temperatures make the air more capable of pulling water out of the soil, out of vegetation, out of crops, and out of forests.  All of that makes drought conditions more severe.

A megadrought is generally considered to be one that is both severe and long.  But even during one, there can be wet years.  2005 was a notable one.  But there must be enough consecutive wet years to actually end a drought.

Several previous megadroughts over the past 1,200 years lasted as long as 30 years.  So, the current drought is in full swing and may go on for a long time to come.

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Web Links

How Bad Is the Western Drought? Worst in 12 Centuries, Study Finds.

Photo, posted September 25, 2021, courtesy of David Sierralupe via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

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