Global warming: Long-term research by CU Boulder team suggests Colorado’s alpine tundra and forests are in trouble

Snow-dependent ecosystems highly sensitive to climate change

Some research suggests that Colorado's conifer forests will have a hard time rebounding from beetle-kill impacts due to climate change.

By Summit Voice

SUMMIT COUNTY — It might not come as a total surprise that ecosystems dependent on seasonal snow and ice are among the most sensitive to climate change — but some of the impacts may be unexpected.

For example, researchers with the University of Colorado Boulder found that one of their high altitude climate stations has recorded a trend toward wetter and cooler conditions in recent years, while another site nearby, but lower in elevation, has become significantly warmer and drier.

“In the past we tried to look at pristine ecosystems, but those are essentially gone. So we’ve come up with an approach that integrates human activities with our ecological research,” said CU-Boulder Professor Mark Williams, the principal investigator on CU’s Niwot Ridge Long-term ecological research site.

Key measurements at the Niwot Ridge site — which has climate records going back more than 60 years thanks to pioneering work by CU biology Professor John Marr in the 1950s — are temperature and precipitation logs from two stations, one at 12,700 feet in elevation and a second at 10,000 feet.

Although the climate at the higher meteorological station — by far the highest long-term climate station in the United States — has been getting slightly wetter and cooler in recent decades, the station at 10,000 feet in a subalpine forest is getting significantly warmer and drier.

Williams said warming at 10,000 feet and lower may be causing enhanced surface water evaporation and transport that moves westward and higher in the mountains, with the water vapor being converted to snow that falls atop the Continental Divide. Snow cover increases reflectivity of incoming sunlight, further cooling the alpine area and overriding the overall warming signal in the West, which is believed to be a 2 or 3 degree Fahrenheit rise over the past decade due to rising greenhouse gases.

“These two Niwot Ridge stations are less than five miles away from each other — you can see one from the other — but there are totally different trends occurring,” he said. In many places in the mountainous West, only a small increase in temperature can cause the climate to cross a “threshold” that triggers earlier and more intense snow melting, said Williams, principal investigator on a 2011 grant of $5.9 million from NSF to CU to continue long-term ecological studies at Niwot Ridge.

With snowpack roughly half of normal in 2012 and snow melting in the high country that began more than three months earlier than last year, the outlook is not good for montane and subalpine forests in Colorado and other parts of the West, he said.

Low snowpack and early melt invariably have a huge impact on the Colorado economy, said Williams. Despite near record snowfall in 2010-11, warming temperatures have caused less snow and shorter winters in recent years and affected the ski industry — one of Colorado’s largest economic drivers, said Williams.

As for the future of flora and fauna in subalpine and alpine regions like Niwot Ridge, there will be “winners and losers” as the climate warms, said Williams. Animals like American pikas, potato-sized denizens of alpine talus slopes in the West, need heavy snowpack to insulate them from cold winters as they huddle in hay piles beneath the rocks. In lower, more isolated mountain ranges in Nevada, researchers are already seeing a marked decline in American pika populations.

The predictions of the study authors are that microbes, plants and animals that depend on snow and ice will decrease if they are unable to move higher into areas of snow and ice. But shallower snow could cause big game like deer and elk to move higher in altitude to browse, according to the authors.

A big concern in temperate mountains like Colorado is the heath and welfare of coniferous trees as the climate changes, said Williams. “Trees in Colorado’s mountains are under a tremendous amount of stress due to drought and pine beetle outbreaks. And the fire danger, at least now, is through the roof,” he said.

“If some of these forested areas disappear, I think the chances of them coming back are pretty low,” Williams said. “The climate they grew up in doesn’t exist anymore. As we lose trees to drought, beetles and wildfires, we are likely to see an invasion of grasses and shrubs in areas where we have never seen them, causing a complete restructuring of our forest community.”

As snowline moves up due to warming temperatures, so will parts of alpine tundra in the West, Williams said. “The tundra may be able to function reasonably well for several decades — it will be awhile before warming climate change pushes the tundra off the tops of mountains. But that is the direction we are heading.”

The six papers appeared in the April issue of the journal BioScience. The papers were tied to data gathered at sites in North America, Puerto Rico, the island of Moorea near Tahiti, and Antarctica, which are known as Long-Term Ecological Research, or LTER, sites and are funded by the National Science Foundation. CU-Boulder’s Niwot Ridge site, one of the five original LTER sites designated by NSF in 1980, encompasses several thousand acres of subalpine forest, tundra, talus slopes, glacial lakes and wetlands stretching up to more than 13,000 feet on top of the Continental Divide.

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11 Responses

  1. so, what part of AGW or any type of global warming will prevent the local pines from regrowing? actual warming? well, show me any in the last decade. or, what about an increase in in CO2? well, CO2 is plant food. dryness? is that actually conected to global warming? proof? or, cycles? any word on the aspen trees? how will they do? i’m still confused as to why the GW propaganda push. i think i know. it’s not about the climate, it’s about control.

    • A little paranoid today?

      • Nope. Just tired of the BS propaganda.

        • Fair enough – me too. I just can’t imagine a global conspiracy to control the world based on climate science, but perhaps my imagination is lacking.

          Other than that, I thought your questions about forest regeneration were valid.

          • I was wondering how many times throughout history the forests, and the glaciers for that matter, have come and gone? We’re here to witness this particular phase. I do know that there was a forest where we have a petrified one now.

      • I’d say so.

    • Yes, dryness connected to temperature change. My question to you is this – did you actually read the article or did you see the phrase “global warming” and shut down your brain since you don’t believe that it’s happening at an increased rate due to human activity, and then skim through without actually reading? Taken from the article above: ” warming at 10,000 feet and lower may be causing enhanced surface water evaporation “. Another question you asked, if you could call it a question, is “actual warming??” Yes, actual warming, like the kind measured at the long term monitoring staion at 10,000 feet on the Niwot Ridge mentioned in the study.

      You seem very closed minded. This alone leads me to believe that you are not as intelligent as you would like to belive. Add to that your apparent inability to read and interpret the results of a scientific study that are written in plain english and the point becomes even more well made.

      • yes, i’m the close minded one. and, yes i did. dryness? like the kind you might possibly get at elevation where the air is so thin it can hardly hold much moisture to begin with. is your ego so large that you believe humans can actually change the “climate”? what has been constant on the planet over the millenium is that the climate changes. most of the time rapidly and drastically. we have been very lucky to have lived during a time of reletive climate calmness. you all are grasping at straws now. no global warming for at least ten years. where do you get this stuff. the AWG crew is trying to control the population by demanding conformity. and, since when is CO2 a pollutant? do you really beleive this. H2O is the largest heat retainer anyway. i read lord monckton’s work

        • Wow lord monckton’s work… now I know you are a kook. Yes 7 billion human beings burning millions of years worth of fossil fuel in a century could not possibly have any impact on the earth…. Get a grip on reality dude you are losing it.

  2. Not the kind of dryness found at altitude that is due to low atmospheric pressure (not “thin” air, genius), the drying TREND that was observed through long term observation, something that is done in scientific studies. It has been getting more and more dry at the same place over time – that’s a trend. How old are you and what is your education level, I’m curious. I’m not talking about doomsday, neither is this paper. Have a nice life pal.

    • god are you dumb. why does it even matter to you. i’ve flown airplanes in thin air and do know the difference. dumbass. it’s just a phrase. now you’ll tell me that cold air holds more moisture. but you’re too smart for that. so, warm air is drier? i do know how relative humidity works. doomsday? who the hell is talking about that? i guess i’m a denier. oh well. watch out for those chem trails too! this paper is a liberal rag. al gore has made hundreds of millions on the backs of the stupid like you. isn’t he the so-called 1% or is it ok that he’s rich because you agree with his politics. i’m not paranoid i just can see through the political bullshit people like you have made an issue of, what are you calling it these days? global warming? oh yeah, no evidence of that. climate change? do really think the world is that stupid?

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