pumping

The doomsday glacier

October 9, 2024 By EarthWise Leave a Comment

The Thwaites Glacier is an enormous Antarctic Glacier. Its area is larger than that of Florida – in fact, larger than 30 other U.S. states – and it is melting. It has been retreating for 80 years but has accelerated its pace in the past 30. Its shedding of ice into the ocean already contributes 4% of global sea level rise. If it collapsed entirely, it would raise sea levels by more than 2 feet. For this reason, it has been dubbed the Doomsday Glacier.

A team of scientists has been studying it since 2018 in order to better understand what is happening within the glacier. They sent a torpedo-shaped robot to the glacier’s grounding line, which is the point at which the ice rises up from the seabed and starts to float. The underside of Thwaites is insulated by a thin layer of cold water. However, at the grounding line, tidal action is pumping warmer sea water at high pressure as far as six miles under the ice. This is disrupting the insulating layer and is speeding up the retreat of the glacier.

The potential collapse of the glacier is not even the only massive risk it poses. It also acts like a cork, holding back the vast Antarctic ice sheet. If that ice sheet were ever to collapse, sea levels could rise 10 feet.

A critical unanswered question is whether the ultimate collapse of Thwaites Glacier is already irreversible. There are regular heavy snowfalls that occur in the Antarctic which help replenish ice loss. Whether nations’ progress in slowing climate change can change the balance between ice accumulation and ice loss on the glacier remains to be seen.

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‘Doomsday’ glacier set to melt faster and swell seas as world heats up, say scientists

Photo, posted January 3, 2022, courtesy of Felton Davis via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Global groundwater depletion

March 4, 2024 By EarthWise Leave a Comment

Groundwater is found underground in aquifers and it bubbles up naturally into springs, streams, and rivers. It’s also often pumped out for use by people.

Researchers from UC Santa Barbara have conducted the largest assessment of groundwater levels across the globe, spanning 170,000 wells and nearly 1,700 aquifers across more than 40 countries. The team compiled and analyzed data, including 300 million water level measurements taken over the past 100 years.

In the study, which was recently published in the journal Nature, the researchers found that groundwater is rapidly declining across the globe, often at accelerating rates. In fact, they found that groundwater is dropping in 71% of the aquifers studied. The rates of groundwater decline observed in the 1980s and ’90s sped up from 2000 to the present, highlighting how a bad problem became even worse.

But there are some reasons to be optimistic. That’s because in 16% of the aquifers studied, the researchers found that the rate at which groundwater levels are falling in the 21st century had slowed down compared to the 1980s and ‘90s. The research team highlighted specific success stories in Thailand, Arizona, and New Mexico, where groundwater has begun to recover after interventions to better regulate water use or redirect water to replenish depleted aquifers.

While groundwater depletion isn’t inevitable, the researchers stress that aquifer recovery will require interventions. They hope this study will help scientists, policy makers, and resource managers better understand the global dynamics of groundwater.

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Global groundwater depletion is accelerating, but is not inevitable

Photo, posted October 4, 2016, courtesy of Deborah Lee Soltesz / Coconino National Forest via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Protecting coastal areas with tidal range electricity generation

February 13, 2024 By EarthWise Leave a Comment

Tidal range electricity generation uses the water level difference between high and low tides to operate generator turbines. The method requires the construction of barrages and sluices to capture water during high tides and then release it during generation at low tide. Tidal range generation is predictable renewable energy driven by the gravitational pull of the moon and sun.

It is only a practical scheme in those places that have large tidal ranges. The largest tidal range in the world is in the Bay of Fundy in Canada. The second largest is the Severn Estuary, in the UK. Tidal ranges are large in many places around Britain’s coasts. But they are also vulnerable to flooding and surges from rising seas.

A new study by Lancaster University in the UK has found that the environmental and economic benefits are huge because tidal range barrages can protect coastal areas from flooding and sea level rise. With two-way generation and pumping, the full range of existing tides can be maintained to protect and support low-lying intertidal areas such as saltmarshes and mudflats. High tides can be limited to existing levels simply by closing sluices and running turbines and low tide levels can be maintained by pumping. The study determined that with modern technology and operating procedures, these so-called estuarine barrages may be the only practical way to protect vital coastal habitats.

Earlier work by the researchers found that tidal range projects under commercial consideration in the UK can produce about 5% of the country’s electricity use and additional projects are feasible for 4 or 5 times as much generation.

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How tidal range electricity generation can protect coastal areas from flooding

Photo, posted August 17, 2014, courtesy of Andrea via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

The Bengal Water Machine | Earth Wise

October 31, 2022 By EarthWise Leave a Comment

Over the past three decades, the owners of 16 million small farms in the Bengal Basin of Bangladesh have been pumping shallow groundwater during dry seasons to irrigate rice paddies. By lowering groundwater levels in this way during the dry season, the ability of leakage from rivers, lakes, and ponds to replenish the groundwater was greatly enhanced. Capturing surface water not only improved the recovery of groundwater levels but only helped to reduce flooding during monsoons.

The net result of this enormous collective groundwater pumping by millions of farmers has been the creation of vast natural reservoirs underground that are comparable to what is contained by many of the world’s largest dams. This system of sustaining irrigation has transformed what was previously a famine-prone country into a food-secure nation.

The details of this remarkable transformation have been laid out in a study by University College London recently published in the journal Science. According to the study, over the course of 30 years, more than 75 cubic kilometers of fresh water was captured by this process, which is equivalent to the combined reservoirs of China’s Three Gorges Dam and the Hoover Dam in the U.S.

The authors of the study described the water cycling process as “The Bengal Water Machine” and argue that it can be a sustainable alternative to conventional approaches to seasonal river flow storage for irrigation, which typically involve dams and reservoirs. Such approaches are difficult to implement in densely populated alluvial plains where sand, silt, and clay are laid down by annual floodwaters.

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Millions of farmers “replumb” world’s largest delta

Photo, posted February 2, 2010, courtesy of Melanie Ko via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Oil Drilling In Los Angeles | Earth Wise

February 24, 2022 By EarthWise Leave a Comment

Movies were not the first industry to boom in Los Angeles. Oil was. There was a lot of it, and it flowed close to the surface triggering rampant drilling all over the area. By the 1920s, Los Angeles was one of the largest oil-exporting regions in the world.

A century later, there are over 20,000 active, idle, or abandoned wells spread across LA county, home to 10 million people. Some are hidden behind facades; others are plainly visible, pumping away day and night. About a third of Angelenos live less than a mile from an active well site. In the last 20 years, improved oil extraction technology has actually led to a resurgence of oil drilling in Los Angeles.

Studies of the health impact of LA’s oil wells found that asthma is significantly more common among people living near oil wells than elsewhere in the county. Surveys of residents’ lung functions revealed lower function on average when people live near wells. Measurements of toxins in the air – such as benzene, toluene, and n-hexane – showed that levels of these substances were significantly reduced when oil production at a site stopped.

This issue has finally come to the forefront after a nearly a decade of community organizing and studies of adverse health effects. In a unanimous vote on January 26, the Los Angeles City Council took the first step toward phasing out all oil and gas extraction in the city by declaring oil extraction a nonconforming land use. The LA County Board of Supervisors voted unanimously to phase out oil extraction in unincorporated county areas. Los Angeles’ long, troubled history with urban oil drilling appears to be nearing an end.

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Los Angeles’ long, troubled history with urban oil drilling is nearing an end after years of health concerns

Photo, posted March 26, 2016, courtesy of Giuseppe Milo via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.

A Global Assessment Of Groundwater Wells | Earth Wise

May 19, 2021 By EarthWise Leave a Comment

Water is a fundamental need for every human being on the planet. Each person requires more than five gallons of clean and safe water a day for drinking, cooking, and keeping clean.

Groundwater wells remain one of the primary sources of drinking water. In fact, more than half of the world’s population gets its drinking water from groundwater wells. Groundwater wells also sustain more than 40% of irrigated agriculture.

Researchers from UC Santa Barbara have recently compiled the most comprehensive assessment of groundwater wells to date. Their research, which was recently published in the journal Science, spanned 40 countries, which collectively account for more than 50% of all groundwater pumping.

According to the survey’s findings, many wells are at risk of running dry – up to one in five wells, to be exact. The researchers compared the depths of water tables against well depths. They found that 6% to 20% of the wells in the study were at risk of running dry if water levels continue to decline by just a few meters.

In many areas where groundwater levels are declining, the research team found that new wells are not being drilled deeper to keep pace with the falling water table. As a result, newer wells are just as vulnerable as older wells should groundwater levels continue to decline.

The researchers hope to expand on this study to include data from China, Iran, and Pakistan, three major users of groundwater from which the researchers could not obtain records. The researchers also plan to investigate how quickly water tables are dropping and where the trend is accelerating.

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The largest assessment of global groundwater wells finds many are at risk of drying up

Photo, posted January 20, 2018, courtesy of François Molle via Water Alternatives Photos on Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.