Quantcast
Environmental News for a Healthier Planet and Life

Help Support EcoWatch

How Hydropower Contributes to Climate Change

Climate
How Hydropower Contributes to Climate Change

Methane has been attracting attention recently as the "It" greenhouse gas. It's been exposed as being almost 35 times the driver of climate change as carbon dioxide emissions. And while that doesn't mean we should stop acting on carbon, researchers have begun taking a closer look at where the methane is coming from. And while stories about methane blowholes in the Arctic are dramatic, the U.S. Environmental Protection Agency (EPA) ranks oil and gas operations as the top source of methane emissions in the U.S. followed by livestock.

The manmade Harsha Lake provides watch and flood abatement to southwestern Ohio but may also be a major source of methane emissions. Photo credit: U.S. Army Corps of Engineers

But there's another source that doesn't readily come to mind and may be emitting far more methane than previously thought. That's manmade reservoirs, including those built to generate supposedly clean hydropower, the largest source of renewable energy in the world.

Precisely how much they contribute to methane pollution is a mystery though. It was estimated for a long time that 20 percent of all manmade methane emissions were generated from the surface of reservoirs. But now scientists think it may be even higher than that, although few studies have been done so there's not enough data to attach a number to it. The EPA doesn't even both to estimate reservoir-generated methane.

Now a small-scale study published in late August offers some clues. Researchers from the EPA's National Risk Management Research Laboratory in Cincinnati and the University of Cincinnati studied methane emissions from Harsha Lake near Cincinnati during a 13-month period spanning 2012. They found that Harsha Lake emitted more methane than had ever been recorded at any reservoir in the U.S., perhaps, one of the study authors suggested, because it's located in an agricultural area.

“When you compare the annual scale of the methane emission rate of this reservoir to other studies, it’s really much higher than people would predict,” EPA research associate and study lead author Jake Beaulieu told Climate Central.

"Reservoirs are a globally significant source of methane (CH4), although most measurements have been made in tropical and boreal systems draining undeveloped watersheds," said the study's summary. "We measured CH4 and carbon dioxide (CO2) emission rates from William H. Harsha Lake, an agricultural impacted reservoir, over a 13 month period. The reservoir was a strong source of CH4 throughout the year. ... We estimate that CH4 emissions from agricultural reservoirs could be a significant component of anthropogenic CH4 emissions in the U.S.A."

Extrapolating from the methane they found at Harsha Lake, the researchers estimated that worldwide, all large reservoirs could emit as much as 104 teragrams of methane each year, compared to estimates of 80-120 teragrams of methane from fossil fuels.

The source of the methane is bacteria feeding on carbon-based organic plant material and breathing out methane. Agricultural runoff, such as that found in Harsha Lake, contains nutrients that allow algae to thrive, providing a wealth of food for microbes.

“There are a very large number of these reservoirs in highly agricultural areas around the U.S.,” Amy Townsend-Small, another of the study's authors, told Climate Central. “It could be that these agricultural reservoirs are a larger source of atmospheric methane than we had thought in the past.”

And there's little information yet about how the amount of methane generated by reservoirs varies in different parts of a reservoir. But Beaulieu said the EPA will undertake a more comprehensive study next year, looking at emissions from 25 reservoirs across the Great Lakes region and the south.

YOU MIGHT ALSO LIKE

Methane Blow-Holes Sign of Runaway Climate Change?

Massive Methane Hot Spot Detected by Satellite

Global Boom in Hydropower Poses Serious Threat to the Planet

EcoWatch Daily Newsletter

Visible satellite image of Tropical Storm Kyle and Tropical Storm Josephine as of 9:10 a.m. EDT Saturday, August 15, 2020. RAMMB / CIRA / Colorado State University

By Jeff Masters, Ph.D.

The record-busy 2020 Atlantic hurricane season brought another addition to its bevy of early-season storms at 5 p.m. EDT August 14, when Tropical Storm Kyle formed off the coast of Maryland.

Read More Show Less
The Ocean Cleanup

By Ute Eberle

In May 2017, shells started washing up along the Ligurian coast in Italy. They were small and purple and belonged to a snail called Janthina pallida that is rarely seen on land. But the snails kept coming — so many that entire stretches of the beach turned pastel.

Read More Show Less
Feeding an orphaned bear. Tom MacKenzie / USFWS

By Hope Dickens

Molly Craig's day begins with feeding hungry baby birds at 6 a.m. The birds need to be fed every 15 minutes until 7 at night. If she's not feeding them, other staff at the Fox Valley Wildlife Center in Elburn, Illinois take turns helping the hungry orphans.

Read More Show Less
Pexels

By Douglas Broom

"Forests are the lungs of our land, purifying the air and giving fresh strength to our people," said former U.S. president, Franklin Roosevelt.

Read More Show Less
A bald eagle flies over Lake Michigan. KURJANPHOTO / iStock / Getty Images Plus

A Michigan bald eagle proved that nature can still triumph over machines when it attacked and drowned a nearly $1,000 government drone.

Read More Show Less
The peloton ride passes through fire-ravaged Fox Creek Road in Adelaide Hills, South Australia, during the Tour Down Under cycling event on January 23, 2020. Brenton Edwards / AFP / Getty Images

A professional cycling race in Australia is under attack for its connections to a major oil and gas producer, the Guardian reports.

Read More Show Less

Trending

UQ study lead Francisca Ribeiro inspects oysters. The study of five different seafoods revealed plastic in every sample. University of Queensland

A new study of five different kinds of seafood revealed traces of plastic in every sample tested.

Read More Show Less