When the global climate wiggles, it shakes its hips at high elevations — The Mountain Town News

Ziegler Reservoir construction via The Aspen Times
Ziegler Reservoir construction via The Aspen Times

From The Mountain Town News (Allen Best):

Jeff Pigati arrived at Snowmass, Colo., just two weeks after a bulldozer operator uncovered the first bone of a juvenile mammoth. That was in October 2010. A specialist in radiocarbon dating, Pigati remembers being immediately awed by what he saw.

“It took me about five seconds to figure out that this was something unprecedented and unique and really something that I had never seen before,” says Pigati, a geoscientist with the U.S. Geological Survey.

In time, nearly 6,000 large-animal bones, many of them of mastodons, mammoths and other now-extinct species, were eventually unearthed. What wowed him even more was the exceptional preservation of leaves, seeds and other representations of the changing climates from 140,000 to 55,000 years ago.

Those tell-tale clues have now allowed scientists to paint a picture of climates that changed in sometimes surprising ways. When it got warmer globally, it got warmer at the Snowmass site, located at 9,000 feet in elevation. And when it cooled globally, it got cooler at Snowmass.

But the lake at Snowmass swung both hotter and colder than lower-elevation sites. When the global climate wiggled, the climate at 9,000 feet threw its hips.

“The climate here doesn’t march in lockstep with global conditions. That is the absolute No. 1 take-home message,” says Pigati.

From the outset, scientists who gathered at the site in Snowmass, which is within a quarter-mile of the ski lifts, had speculated that the site might deliver valuable clues about the climate of the last interglacial period, especially 130,000 to 110,000 years ago.

Windows into the past

The American West has several important windows into that period, but none at 9,000 feet. Yellowstone National Park has one site at about 6,000 feet while Bear Lake, along the Idaho-Utah border, has another at a comparable elevation. Yet a third is at American Falls, Idaho, at about 3,500 feet.

These windows into the past, however, are more smudged. Snowmass is higher and superior in its clarity, what is called fidelity.

One portion of this window into the past, however, is revealing for what it doesn’t show. From about 90,000 to 80,000 yeas ago the Earth’s climate chilled again, as is clear from ice cores in Greenland and Antarctica as well as sediments off the shores of North America.

With this global trend clearly understood, scientists examining the timeline at the Snowmass site, called Ziegler Reservoir, expected to see evidence of plants and other life better suited to colder temperatures.

Instead, they found absolutely nothing. Even midges, the insects found along creeks and in lakes, disappeared from the record. Mormon tea, a species adapted to cold, also was absent.

What this tells scientists is that treeline had descended. Today, it is at nearly 12,000 feet. Then, it descended to below 9,000 feet. It is possible that the lake that had entombed mastodons remained frozen even during summers.

The lesson, says Ian Miller, chairman of the Earth Sciences Department at the Denver Museum of Nature & Science, is that the climate at 9,000 feet “responds dramatically to change.”

Scientists, he says, had expected evidence of a colder climate at Snowmass from 90,000 to 80,000 years ago, but not that much. “We have some records elsewhere in North America that says yes it’s going to get cold. But in the high mountain, it’s going gangbusters. This just drives home the point that the system responds dramatically at higher elevations.”

This is sobering to Miller. If the high mountains have an amplified response to climate change, he says, then how will they respond during the coming century as the global climate warms due to heat-trapping greenhouse gases now accumulating in the atmosphere.

“The implication is quite clear that the system does respond dramatically and that it does have an amplified response,” says Miller, a paleontologist who specialist in Cretaceous remains.

Confirming amplifiers

Patrick J. Bartlein, a paleoclimatologist in the geography department at the University of Oregon, says the Snowmass findings do not necessarily break ground but do emphatically confirm existing thinking about how climates change.

Bartlein talks about amplifiers. Solar radiation patterns can produce changes in climate, but at Snowmass those changes blew up into even bigger changes, both hot and cold.

Today, we have a different amplifier, the rapid accumulation of greenhouse gases in the atmosphere. Based on what has been documented at Snowmass, the Colorado Rockies might well change much more rapidly in temperatures than other, low-lying areas.

“This helps us understand better the current experiment that we are doing with the climate system by changing the concentrations of carbon dioxide and other greenhouse gases. As we have only one climate system, and it’s sort of dangerous to experiment with it, it’s useful to see these past experiments that nature did,” says Bartlein.

Greenhouse theory has long held that higher elevations and higher latitudes will see the effects of the reinforced greenhouse sooner and more dramatically than lower elevations, at least in terms of temperatures. Measurements have shown this to be the case in the American West but also in the Arctic. This, in turn, is causing other changes, such as the retreat of picas to higher elevations.

In the last interglacial period, absent the buildup of greenhouse gases, the climate at Snowmass got toasty enough. During the peak of warming, about 125,000 years ago, vegetation found at Ziegler Reservoir was comparable to what is now found 3,000 feet lower and 30 miles away in the Roaring Fork Valley, near Carbondale.

That was strictly based on natural variability. Now, add human intervention, in the form of elevated greenhouse gases. What temperatures might result from the combination?

This evidence and thinking of 44 scientists involved in the research at Snowmass has been summarized in a special issue of Quaternary Research, a subscription-only journal.

At the same time, the value of the Snowmass site in informing climate change models is sharpest in Colorado but recedes with points more distance. It is of some value in understanding the future of Park City, Utah, or Missoula, Mont., but most important in understanding west-central Colorado.

“My guess is that the farther your get away for our study site, the less secure you can be about making these interpolations,” says Pigati.

Tools of no use here

When Pigati first arrived at Snowmass four years ago, he knew that the remains would be older than 15,000 years old. That is roughly when mammoths disappeared in North America and there was, for sure, a mammoth bone.

This meant Pigati’s radiocarbon dating equipment was of no value. The technique only works on material less than 45,000 years old. Everything in the depths of what is now Ziegler Reservoir was older. For that, scientists needed a different dating technique, called thermoluminescence, which measures the accumulated radiation dose of the time elapsed since material containing crystalline minerals was either heated or exposed to sunlight. It provides dating that is less precise but deeper in time than radiocarbon dating.

Those green leaves that had so captivated Pigati when he first got to Snowmass? They were 100,000 years old.

Using this same luminescence technique, the scientists discovered that the remains of tree-browsing mastodon bones that were found lower in the reservoir site had been deposited 140,000 to 90,000 years ago.

“We didn’t find a single mammoth (bone) during that time period,” says Pigati.

Mammoths bones found at Snowmass were deposited 80,000 to 55,000 years ago, before the climate veered colder once more and the Earth entered the most recent ice age, only to emerge again about 16,000 years ago.

Absolutely nothing was found from 90,000 to 80,000 years ago, the time when the curtain of ice descended.

Both mastodons and mammoths, who are both related to elephants of today, disappeared from North America about 10,000 years ago, or soon after the first known arrival of humans in the Western Hemisphere. They may not have been well-suited to the new shift in climate, although many scientists think their demise can be explained by the new presence of humans and their increasing technological prowess in the form of projectiles.

Does another site with the same riches as Snowmass exist somewhere else, say in Montana? Pigati says that researched looked for other sites in the West where the same characteristics of glaciation could have yielded a similar circumstances and a comparable window into the past.

“We found nothing,” he says. “That’s not to say they (the sites) are not out there, but it’s not obvious. This might truly be one of a kind.”

Former Cotter Mill employees to get compensation for job-related illnesses

Lincoln Park/Cotter Mill Site via The Denver Post
Lincoln Park/Cotter Mill Site via The Denver Post

From The Colorado Springs Gazette (Tom Roeder):

Benefits for workers sickened by Cañon City’s atomic legacy will be outlined at a federal Department of Labor town hall Wednesday morning.

The department oversees a program designed to compensate nuclear workers for cancer and other maladies associated with mining, hauling and processing uranium. Over the years, dozens of workers at Cañon City’s Cotter Mill have claimed their illnesses were caused by exposure to uranium and other toxic substances.

Now, the federal government wants to make sure sick workers get paid.

“The goal of the meeting is to make current and former nuclear weapons workers living in Colorado aware of the program and to assist them in finding information to determine eligibility for available compensation and medical benefits,” the Labor Department said in a news release.

Miners hit massive uranium deposits along the Front Range in the 1950s and the mill in Cañon City was built to process it into “yellow cake” – uranium oxide – which can be refined into fuel for reactors and weapons parts.

Processing uranium, though, left the mill in Cañon City marred by toxic leach fields and tailing ponds that were later deemed to be a federal Superfund cleanup site.

The leaching left water contaminated with heavy metals and solvents in unlined storage ponds that continue to drive worries over groundwater contamination.

The site, under supervision from the Colorado Department of Health and Environment, has been at the center of a controversy over how to clean up the damage.

A settlement agreement reached over the summer says Cotter will pay for continued cleanup under state supervision.

Taking care of workers falls under the Labor Department, which has administered health care and compensation for nuclear workers since Congress in 1990 approved the Radiation Exposure Act.

The act offers lump-sum payments and health care coverage for those sickened by radiation work that fell under the federal Department of Energy.

In recent years, Labor Department experts have held regular meetings in Cañon City to advise workers on the payments.

More nuclear coverage here.

“Conservation is definitely part of the package. But it is not the silver bullet” — James Eklund #COwaterplan


From The Denver Post (Bruce Finley):

Water conservationists are calling on Colorado leaders to set a clear target in the state’s first water plan: reduce use by 1 percent a year through 2050. But state officials crafting the plan to address a 163 billion gallon projected shortfall are reluctant to commit — even though Gov. John Hickenlooper has called conservation a priority.

An aggressive water-saving goal, if it spurred action, could put Colorado on course to closing its growing gap between water supply and demand, which looms as a barrier to future economic and population growth. Conservation as a strategy also would ease degradation of Colorado’s Western Slope, where water in mountain streams increasingly is siphoned to sustain Front Range cities.

“We definitely can save more water,” Conservation Colorado director Pete Maysmith said. “The state needs to put into the plan a high conservation goal if we’re going to fill that gap. It’s not like everybody has to get to a certain number. It’s just that, overall, we’ve got to be cutting 1 percent a year.”

Other states have set targets: Utah committed to cutting water use by 25 percent before 2025. Texas aims for the same. California plans to cut use by 20 percent by 2020. Oklahoma plans to cap water use at today’s level through 2060.

Colorado not only has yet to set a target but also remains the last of the arid Western states to complete an official water plan.

However, Hickenlooper consistently has cast water conservation as essential. State planners’ efforts over the past year have embraced water-saving in principle — increased efficiency from low-flow toilets to smarter irrigation — to avoid massive projects that divert more mountain snowmelt out of rivers for people and industry.

“Conservation is definitely part of the package. But it is not the silver bullet,” said James Eklund, director of the Colorado Water Conservation Board, who is coordinating state planning.

A nearly completed draft of the Colorado Water Plan, to be unveiled next week, does not set a specific goal because “that doesn’t keep with what we are trying to do” in regional river basin discussions, Eklund said. “And each basin is unique.”

The state still may end up committed to a water-saving goal after further deliberation, he said. The plan is to be finalized next year.

Among the complications: Some areas are drier than others, requiring more water to sustain people. Climate change is affecting natural water flows. And residents in some cities who already have reduced water use could be hard-pressed to make further cuts.

The 1.3 million metro Denver residents served by Denver Water cut average daily use to 85 gallons a person, down from 104 gallons in 2002 — compared with an estimated 123 gallons a day in Parker and 111 in Grand Junction.

While comparisons can be difficult due to different counting methods, utility data showed Denver’s average daily use ranked less than water use in Salt Lake City (117 gallons), San Diego (136 gallons) and Los Angeles (123 gallons), but more than in Albuquerque (70 gallons).

Historically, Colorado has relied on massive federally funded engineering projects, dams and diversions that pump about 500,000 acre-feet a year west-to-east under the Continental Divide with devastating consequences for ecosystems.

Agriculture uses the largest share of water in Colorado, roughly 85 percent of developed supplies. But Colorado’s population of 5.2 million is expected to reach 10 million by 2050 and companies seek water for industry, including the oil and gas boom.

Denver Water was taking the same position as state planners on water-saving goals. The utility favors a “tailored approach” rather than a statewide water-saving target because some communities conserve more than others, spokeswoman Stacy Chesney said.

“Those who have not taken steps toward water conservation could more easily reduce their use than those who have already made significant strides in becoming efficient,” Chesney said.

“We believe a better approach would be if every water user — from municipalities to agriculture, industrial users and more — knows their current use and establishes goals, such as investing in new water-saving technologies and striving for more water-use efficiencies.”

More Colorado Water Plan coverage here.