美国国家公共电台 NPR--Climate change and a population boom could dry up the Great Salt Lake in 5 years（在线收听）

Climate change and a population boom could dry up the Great Salt Lake in 5 years

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Trekking along the shoreline of the Great Salt Lake — the largest remaining saltwater lake in the western hemisphere — can feel eerie and lonely.

"These might even be my footprints from last week," says Carly Biedul, pointing to indents in the mud. Biedul is a biologist with the Great Salt Lake Institute. She's bundled up in an orange puffy jacket, gloves and hat. Most important she's wearing thick, sturdy, rubber boots.

The mud with a frozen, slick layer of ice on top gets treacherous. One thing that's hard to prepare for though, is the stench: a pungent odor like sulfur and dead fish. But it's actually a good thing, a sign of a biologically healthy saline lake.

"People have been saying that they miss the lake stink because it just makes them feel like home," Biedul says. "It's just not here [much] anymore, so you're lucky that it gets to smell so bad."

Lucky? Maybe one small bright spot in an otherwise grim story of a looming ecological disaster. The lake doesn't really stink anymore because it's drying ... and dying.

Scientists point to climate change and rapid population growth — Utah is one of the fastest growing states and also one of the driest — as the culprits. A recent scientific report from Brigham Young University warned that if no action is taken, the Great Salt Lake could go completely dry in five years.

Over two decades of the western megadrought, water diversions from rivers that feed the lake have increased in order to support farms and thirsty, growing cities.

Utah leaders and activists are springing into action.

A drying lake could lead to an environmental and economic collapse

Carly Biedul and her team of researchers and students from Westminster College are on the front lines of the crisis and the fight to save the state's signature lake.

Once a week they hike out to try to collect brine fly larva samples, with the idea that they could keep some alive in their lab back in the city should more water re-enter the lake in the near future.

The larvae are harder and harder to find. On a recent cloudy, bitter cold morning, Biedul pointed out mounds or "lumps" of lake deposits called microbialites. They should be mostly submerged, but this day were protruding out along the receding shore. She dug out a refractometer to measure the water's salinity. Researchers have been worried the current levels — upwards of 17% in places — are too salty to sustain life.

"We're kind of at the threshold," Biedul says. "If things get any saltier we're super worried."

Consider the disappearing brine flies as an indicator species. They're at the bottom of the food chain, and feed the brine shrimp, which sustain the thousands of migrating birds and so on. The environmental consequences of a dried up lake are far reaching, and the economic fallout scenarios are dizzying — from the lake's brine shrimp fishing industry to mineral harvesting, to Utah's famous ski resorts that benefit from extra lake effect snow.

But the most pressing concern right now in the Salt Lake Valley as the lake dries is shaping up to be air pollution. Salt Lake City already has some of the dirtiest air in the country. In the winter its natural topography causes cold air inversions, and emissions from vehicles and industrial sources form a haze in its bowl-like valley.

The big unknown is how bad dust storms could get from a dried up lake bed. There is precedent. Along California's Eastern Sierra Nevada mountains, years of water diversions from the Owens River by the city of Los Angeles caused downstream saline Owens Lake to dry up. Dust storms from that lake bed became the largest single source of dust pollution in the nation.

In Utah, the Great Salt Lake is more than seven times larger than the historic footprint of Owens Lake.

"This other piece of the dust coming in really scares people," Biedul says.

Doctors sound the alarm about vulnerable populations

Scientists warn the Great Salt Lake has high concentrations of neurotoxins and cancer causing carcinogens — including arsenic and mercury.

"If the lake bed dries up, and we're having winds blowing dust storms into our neighborhood, the heavy metals are going to land right on top of this neighborhood," says Turner Bitton, a community activist in Glendale, a traditionally working class neighborhood in Salt Lake City's west valley.

Much of the area is zoned for manufacturing, but it's also one of the last bastions of affordability in the city. Bitton's neighborhood is already hemmed in by two busy freeways, an international airport, and it's close to Utah's largest oil refinery.

He says many local families are alarmed at the prospect of the air getting even worse.

"We're talking about something that could potentially make these neighborhoods, I don't want to say uninhabitable, but for those that are vulnerable, for those that have lung issues, uninhabitable," Bitton says.

Researchers have found higher rates of asthma and cardiovascular disease in neighborhoods like these. One University of Utah study even showed that students in schools here scored lower on tests during bad air days.

"We need to put more water in the lake now, we cannot let this wait," says Dr. Brian Moench, president of the group, Utah Physicians for a Healthy Environment.

Moench says the state should have declared an emergency years ago.

"A lot of people think that dust is pretty benign because it's quote — natural," he adds. "Well that's not the case, and in the case of dust from the Great Salt Lake, it is particularly toxic, because we know that it is laced with high concentrations of heavy metals."

The majority of Utah's 3.3 million population lives near the lake, just to the east along the Wasatch Mountains. The lake is about nine feet lower than normal. And locals are already complaining of dust storms. Moench counted more than a dozen in the past year — when a decade ago there were none.

Utah leaders insist they won't let the lake dry up

At the state capitol, lawmakers this session are facing pressure to save the lake, and Gov. Spencer Cox is under the gun to call a state of emergency. In his state of the state address last month, Cox nodded to the BYU study which warns that in just "five short years," the Great Salt Lake will completely disappear: "Let me be absolutely clear, we are not going to let that happen." Cox said.

Earlier this week, a bipartisan group of state lawmakers unveiled bills ranging from expanding turf-reduction programs in cities, to providing more incentives to farmers to divert less water from rivers that feed the lake. Some pledged to spend upwards of a half billion dollars to save the lake.

"Even though the Great Salt Lake has risen a foot so far, we know that one wet winter is not going to wipe out two decades of very, very, very dry climate here in Utah," said Brad Wilson, the Republican House Speaker.

Some ideas that have been floated sound like something out of a science fiction novel — including cloud seeding, and even a plan to build pipelines to pump in water from the Pacific Ocean.

"We are getting some really fantastical suggestions from some of our lawmakers as to how to solve this," says Moench, of Physicians for a Healthy Environment.

Moench and environmental activists are arguing for buying out alfalfa farmers so more water will return to the Great Salt Lake. But some are encouraged that at the very least saving the lake is one of the top priorities of this legislative session.

From Utah's Capitol Hill, there's a sweeping view of the Salt Lake City skyline, and to the west, past the airport, the receding lake is visible, shimmering gray at dusk. It's an ominous sight, but if nothing else, hard for state leaders to ignore.

Down at the lake, Carly Biedul of the Great Salt Lake Institute is doing her best to keep positive. She thinks there's still time to save this lake, but not much.

"It's really pretty right now, you can see the reflections of the mountains on the water," she says. "And that's kind of what we're been trying to do is find these moments of beauty when it's so ... sad."