Dust From Global Warming Increasing Speed Of Mountain Snow Melt

WASHINGTON — Dust in the wind is rewriting the cycle of life in the mountains. Throughout memory the warmth of spring has begun the mountain snowmelt, bringing life-giving water to greening plants so they can blossom and renew their species.

But now, scientists say, the timing is being thrown off by desert dust stirred as global warming dries larger areas and human activity increases in those regions.

This dust darkens the surface of winter snows, warming it by absorbing sunlight that the white surface would have reflected. That causes the snow to melt earlier than in the past, running off before the air has warmed enough to spur plant growth, researchers report in Tuesday's edition of Proceedings of the National Academy of Sciences.

"It is striking how different the landscape looks as result of this desert-mountain interaction," Chris Landry, director of the Center for Snow and Avalanche Studies in Silverton, Colo. and a co-author of the report, said in a statement.

The researchers established test plots in the San Juan Mountains in Colorado. Some plots were left alone to collect snow and dust naturally, others had extra dust added and a third group had naturally arriving dust removed.

On average, according to the study, cleaning away the naturally arriving dust delayed snowmelt by 11 days compared to the plots that were left alone. Adding dust speeded up the melt by 7 to 13 days.

Overall, dust levels in the mountains are about five times greater than they were prior to the mid-19th century, due in large part to increased human activity in the deserts, the researchers said.

And, the researchers added, climate change is likely to result in greater dust accumulation in the mountains as the Southwest warms and dries further.

With the change in timing of snowmelt and plant growth the composition of alpine meadows could change as some species increase in abundance, while others are lost, possibly forever, according to lead author Heidi Steltzer, a research scientist at Colorado State University.

The research was supported by the British Ecological Society and the U.S. National Science Foundation.

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On the Net:

PNAS: http://www.pnas.org

Comments

[RomeoMD25]

06:42 PM on 07/01/2009

# 1. Each year 186 billion tons of CO2 enter the earth's atmosphere. Of that, only 6 billion tons are from human activity (3.2%). Some 90 billion tons come from biologic activity in earth's oceans and the rest from such sources as volcanoes and decaying land plants.
# 2. CO2 is an odorless, colorless, and tasteless gas. The CO2 that goes into the atmosphere does not stay there for long. It is continually recycled by terrestrial plant life and earth's oceans -- the great retirement home for most terrestrial carbon dioxide. The buffering capacity of the oceans is enormous. The oceans currently contain about 50 times as much CO2 as the atmosphere.
# 3. Plants absorb CO2 and emit oxygen as a waste product. Humans and animals both breathe oxygen and emit CO2 as a waste product that helps keep our bodies' pH normal. It works out nice for all those involved.
# 4. CO2 is a nutrient to plants, not a pollutant. Plant-growers introduce more CO2 into their planting sheds when they want to stimulate growth. And all life -- plants and animals alike -- benefit from more of it. All life on earth is carbon-based and CO2 is an essential ingredient.

[realpolitic]

02:48 AM on 07/02/2009

You speak as if the increasing CO2 content of oceans has no ill effects like the killing off of coral reefs.

Concerning co2...

"Global GHG emissions due to human activities have grown since pre-industrial times, with an increase of 70% between 1970 and 2004"

"Carbon dioxide (CO2) is the most important anthropogenic GHG. Its annual emissions have grown between 1970 and 2004 by about 80%, from 21 to 38 gigatonnes (Gt), and represented 77% of total anthropogenic GHG emissions in 2004. The rate of growth of CO2-eq emissions was much higher during the recent 10-year period of 1995-2004 (0.92 GtCO2-eq per year) than during the previous period of 1970-1994 (0.43 GtCO2-eq per year)."

"Global atmospheric concentrations of CO2, CH4 and N2O have increased markedly as a result of human activities since 1750 and now far exceed pre-industrial values determined from ice cores spanning many thousands of years. The atmospheric concentrations of CO2 and CH4 in 2005 exceed by far the natural range over the last 650,000 years. Global increases in CO2 concentrations are due primarily to fossil fuel use, with land-use change providing another significant but smaller contribution.

http://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr.pdf
p.36

The EPA has found that co2 emissions endanger "the health and welfare of current and future generations" and the Supreme Court has agreed they can be regulated under the Clean Air and Water Act.

[ReedYoung]

11:32 AM on 07/03/2009

#2 "The buffering capacity of the oceans is enormous," not infinite.

http://www.aip.org/history/climate/co2.htm
At first sight that seemed fast enough to sweep any extra CO2 into the depths.

But Revelle had been studying the chemistry of the oceans through his entire career, and he knew that the seas are not just salt water but a complex stew of chemicals. These chemicals create a peculiar buffering mechanism that stabilizes the acidity of sea water. The mechanism had been known for decades, but Revelle now realized that it would prevent the water from retaining all the extra CO2 it took up. A careful look showed that the surface layer could not really absorb much gas — barely one-tenth the amount a naïve calculation would have predicted.

Revelle did not at first recognize the full significance of his work. He made a calculation in which he assumed that industry would emit CO2 at a constant rate (like most people at the time, he scarcely grasped how explosively population and industry were rising). This gave a prediction that the concentration in the air would level off after a few centuries, with an increase of no more than 40%. Revelle did note that greenhouse effect warming "may become significant during future decades if industrial fuel combustion continues to rise exponentially."

[MGhamma]

01:13 PM on 07/01/2009

Where's fumes? I would have thought he'd be all over this. Oh yeah, it's not soot.

[realpolitic]

02:29 AM on 07/02/2009

Maybe fumes will adopt dust and keep soot on the sidelines for awhile?

[fumes]

02:19 PM on 07/02/2009

soot's darker..

[sc300nc]

11:21 AM on 07/01/2009

And who do you think supported this dust project? Adding dust to snow, removing existing dust from snow, thanks for the chuckle.

Another example of why scientists are so enthused about this global warming hoax. They love doing these inane studies at the taxpayers expense.

[Exusian]

11:37 AM on 07/01/2009

The right-wingnut war on science is built on ignorance such as this.

[sc300nc]

12:30 PM on 07/01/2009

The truth hurts...so you dismiss it. That's fijne.

[Rhetticent]

05:54 PM on 07/02/2009

I just want to get the feedback from you proponents of global warming when you realize that Congress has created the new version of the sub-prime mortgage fiasco by selling a bill of junk science goods. They have gutted Waxman-Markey, with virtually no impact on CO2 for years, yet allowing the creation of a vast trading empire for offsets AND a muli-billion dollar income stream immediately. Banks, and the new green gods, will rapidly make their huge bucks on the backs of the poor, who can least afford what will happen economically if this bill becomes law. Of course, global warming will then fade away, immediately cured by prompt government action. The left-wingnut war on liberty and freedom is built on ignorance such as this.

[ReedYoung]

01:04 PM on 07/01/2009

What, does your superstition prevent you from believing that darker materials absorb more Solar irradiance and lighter materials reflect more?

[sc300nc]

01:32 PM on 07/01/2009

of course it does...do we need to fund studies to prove that?

[guinganbresil]

10:53 AM on 07/01/2009

Feedbacks come in both the positive and negative variety.
Our existence shows without a doubt that the the net climate feedback to an increase in temperature is negative. I suspect that the dominant (negative) feedback is an increased cloud albedo due to more H2O evaporating from the oceans.

[Exusian]

11:36 AM on 07/01/2009

Written without the benefit of reference to any evidence what so ever.

Perhaps that's because there is none to support your suspicion?

[ReedYoung]

01:20 PM on 07/01/2009

Well, there is actually some evidence that higher water vapor content in the atmosphere will work partially as guianganbresil suggests, but water is also a greenhouse gas and not a perfect reflector, so some light will still get in, including infrared frequencies, and then the greater cloud cover will be an even greater obstacle to re-radiating into space. It is also difficult to measure, and present methods are so complicated that they aren't considered very trustworthy.
http://www.esrl.noaa.gov/csd/instruments/wv_dial/
http://www.cdc.noaa.gov/people/dezheng.sun/clouds.html

Granting guinganbresil the benefit of the doubt, for sake of discussion, and assuming that water vapor IS a negative feedback mechanism, it is nevertheless not an adequate one.
http://www.sciencedaily.com/releases/2007/12/071213101419.htm

Politically, the bottom line is that the cloud "solution" to global warming is absolutely unacceptable because it means more of our fresh water and mountain snow caps will be permanently in the atmosphere, not where they belong in our natural ecosystem.

It's worth noting that when the carbon dioxide greenhouse effect was first discovered, while trying to understand the causes of the previous Ice Age, the hypothesis was that oceans would absorb all or effectively all industrial CO2. They just didn't count on the scales of modern industry and vehicle combustion of hydrocarbons.
http://www.aip.org/history/climate/co2.htm

[guinganbresil]

02:53 PM on 07/01/2009

Feedbacks are both positive and negative - FACT
Net climate feedback to increase in temperature is negative - FACT (otherwise any increase would 'run away')
Dominant feedback is negative and due to cloud albedo - ASSERTION (qualified by 'I suspect')

Assertions do in fact need support - I agree. The cloud albedo is a very strong effect (reflecting ~30% of incoming light) - a small change in albedo could easily swamp the CO2 forcing. (see http://www.eoearth.org/article/Albedo )
Evaporation of water is a temperature dependent effect. Higher temperature (on average), more water in the atmosphere. H2O is a greenhouse gas, but at ~4% atmospheric concentration I expect it is doing all it will (saturated) on its greenhouse contribution.

The information I have read on climate modeling indicates that clouds are not considered well in the models, and most modelers assume the feedback is small negative or positive (without any justification!)

[realpolitic]

02:53 AM on 07/02/2009

Good, I am sure you even took a science course or two way back in high school. You conservatives have a scary personality trait in that you have absolute certainty and so little actual knowledge.

[Exusian]

10:24 AM on 07/01/2009

Welcome to the scientific concept "feedback."

This is just one of many feedbacks that are already in play or soon will be.

[Rhetticent]

06:03 PM on 07/02/2009

And the predictors of the future have no idea how to model it, one of the reasons why the outcomes they predict are all over the place.