Old growth trees in the Hoh Rain Forest at Olympic National Park. (NEWSCOM)
US forests hold new evidence of global warming
Scientists see a trend in longer dry spells and winter snowpacks melting earlier than in the past.
By Peter N. Spotts | Staff writer of The Christian Science Monitor/ January 22, 2009 edition
Reporter Pete Spotts discusses new scientific research on tree life spans in the western US.
Reporter Pete Spotts
Old-growth forests in the Western United States appear to be losing ground to the regional effects of global warming.
That’s the conclusion a team of federal and university-based forest ecologists have reached after looking at long-term trends in patches of relatively pristine old-growth forests. The study sites range from northern Arizona and north central Colorado to the Olympic Peninsula and southern British Columbia.
Over the past 50 years, trees large and small in these tracts – largely untouched by wildfires or beetle infestations – have been dying at an increasing rate. And the rate at which they are being replaced has not changed. If the trend continues, researchers say, forest age, average tree size, and carbon-storing capacity of these areas will gradually fall.
After examining a range of possible causes for the region-wide pattern, the last ones standing are the West’s warming trend and warming’s effect on the amount of water these areas receive. Summer dry spells are longer. Snows melt earlier. More winter precipitation falls as rain, rather than snow, and the snow that falls has a lower water content than it once did.
More trees are dying
“Tree death rates have more than doubled in old-growth forests across the western United States” during the study period, says Phillip van Mantgem, an ecologist with the US Geological Survey’s Western Ecological Research Center in Three Rivers, Calif. The rising mortality rates spanned a range of elevations, species, and tree sizes, he continues.
“If these trends continue, forests will grow sparser over time,” says Dr. van Mantgem. And while he acknowledges that the results come from a relatively limited number of one- to two-acre plots, “our results imply that these trends could be occurring on a much broader scale.”
The team looked at data from 76 undisturbed patches of forest averaging some 450 years old. Some tracts were more than 1,000 years old.
The study represents the most exhaustive yet for this geographic range of temperate forests, notes Andrew Sugden, a botanist and international managing editor for the journal Science, which published the results in Friday’s issue.
Until now, many forest studies have looked at the role wildfires and beetle infestations have had on western forests. Others have looked at the way species are beginning to move to higher elevations. Each of these is related to warming.
But as devastating as they are, beetle infestations and wildfires are episodic catastrophic events. Despite the high profile they get, most forests appear for now to be relatively healthy, the team notes. And species migration would appear to allow for the species’ continued survival, as long as they don’t run out of higher elevations to reach.
The long-term trends in this study, however, suggest that warming is affecting the underlying demographics of the tracts the research team studied.
The results run counter to trends seen in the tropics. In undisturbed tracts there, tree mortality and replacement both are increasing.
The study adds to a growing body of research that suggests any country with extensive forests – whether tropical, temperate, or boreal – may deserve a place at the table when global climate talks discuss “avoided deforestation” as a tool for reducing greenhouse-gas emissions.
So far, the approach has been seen largely as a way to encourage developing countries with extensive tropical forests to take part in a new global climate treaty. But last September, an international team of scientists led by Sebastiaan Luyssaert at the University of Antwerp in Belgium, published a study showing that globally, old-growth forests outside the tropics actively soak up and store carbon dioxide from the atmosphere far longer than previous estimates had indicated. [Editor’s note: The original version misstated the location of the University of Antwerp.]
Indeed, for many of the tree species in the latest study, the likelihood that a tree will survive for another year increases, rather than decreases, with time, notes Jerry Franklin, a forest ecologist at the University of Washington in Seattle.
“One of the things that absolutely should be on the table in any global carbon agreement is the notion of avoided carbon releases,” Dr. Franklin says. “Old forests have very large accumulations of carbon in them.” If these forests are felled, it will lead to significant carbon emissions over the short and medium terms – emissions that can’t be recouped by turning the wood into lumber or by planting replacement trees, he says.
Housing development could be affected
If the trends continue, they have implications for the region’s efforts to adapt to climate change, adds Thomas Veblen, a biogeographer at the University of Colorado at Boulder. Particularly when the underlying die-off is accelerated by insect infestations, wildfire managers will have to rethink their strategies for reducing wildfire risks, including current policies that encourage people to build large housing developments in wildfire-prone areas.
In addition, the changes are making wildlife conservation efforts more difficult to plan.
Often, conservationists set a target by learning what an area was like in the distant past, then they try to re-create that, says Nathan Stephenson, also with the USGS research center in Three Rivers, Calif. “As climate changes and other environmental changes happen, the past may no longer be the best model for the future. We may switch from trying to keep a snapshot of the past to efforts to help guide things into the future while sustaining old forests.”
For Franklin, even that may be too gentle. “So much of conservation is focused on going back or keeping it as it is,” he says. Faced with a warming climate, “you can’t go home.”
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Comments
2. Brian Hamlin | 01.22.09
Rapid and decisive climate change has been the ruin of more than one ecosystem, species and in fact civilization. Wise and far-reaching long term planning is called for in the face of knee-jerk protectionism on one’s wallet. Thank you to the scientists and stewards who put so much good effort into this crucial report.
3. Olivia | 01.22.09
It’s not “mother nature” and it’s not “ridiculous,” Jason. It’s human self-centeredness that recent climate changes are simply mirroring.
I join Brian in thanking the scientists and stewards. I’m sure many of us are listening for sensible answers on how to be the latter — and acting upon them.
4. P. Arrington | 01.22.09
Many thanks for this timely and evocative article. We might be able to utilize the dying trees for coffins, until the critical mass of Americans gets up to speed on where our Oxygen, food, building materials, and respective livelihoods come from.
On the East Coast we see similar patterns made even worse by toxic, acidic fumes of coal-burners. Some say we can do without watershed. We merely buy more plastic bottles from the store.
More light, such as this piece, in an atmosphere of less heat from simplistic sophistry, will promote much needed clear thinking.
6. Dan | 01.23.09
Interesting abservation that snow (100% water) now has a lower water content than it once did. I thought we’d reached the limit of things to blame on warming, but now we learn our water isn’t watery enough anymore.
7. Victor | 01.23.09
Slush is wetter than Powder!
Snow is not 100% water. Snow is a crystal and the bigger the crystal the lower it’s density.
New snow ranges from about 5% when the air temperature is 14° F, to about 20% when the temperature is 32° F.
So what I find interesting is that dryer snow would seem to indicate cooler weather not warming!
8. Victor | 01.23.09
Snow is not 100% water if it were when it melted we would have a terrible mess.
New snow at 32F is about 20% water at 15F it is about 5%. So what I find interesting is that less watery snow would seem to indicate cooler temperature not warmer.
9. P. Arrington | 01.23.09
Dan, you’ve raised my curiosity to a full boil. I can’t tell whether you are kidding.
10. Charles Pierce, Australia | 01.23.09
I was interested to find the Bright Green blog. 20 years ago I had a book published on different economic concepts to point the way to a sustainable world economy. Someone who liked the book contacted me this year to suggest that I update and re-publish it as a blog. She set up the blog, and the book is now complete on the blog in a series of postings. There are now also additional pieces on global warming and other subjects. Here is the link:
http://www.economicsforaroundearth.com
With all good wishes,
Charles Pierce
12. Gordon Scott | 01.24.09
Long term climate changes recorded by the National Weather Services show that global temperatures have declined steadily for the past twelve years. A similar warming and cooling occurred during the early part of the 20th century before industrialization could possibly have had any significant effect. Al Gore and the other climate change kooks are full of it!!
13. Antonio Sosa | 01.26.09
Global Warming is a hoax
Man-made Global Warming is a hoax that threatens our future and the future of our children. Václav Klaus, president of the Czech Republic, which just assumed the presidency of the European Union, is right when he states that “environmentalism is the new communism and climate change is a myth.”
In agreement with Klaus, more than 650 international scientists dissent over the man-made global warming claims. They are more than 12 times the number of UN scientists (52) who authored the media-hyped IPCC 2007 Summary for Policymakers.
Additionally, more than 31,000 American scientists have signed onto a petition that states, “There is no convincing scientific evidence that human release of carbon dioxide, methane, or other greenhouse gases is causing or will, in the foreseeable future, cause catastrophic heating of the Earth’s atmosphere and disruption of the Earth’s climate…” http://www.pr-inside.com/the-petition-contains-the-signatures-of-r613239.htm
“Progressive” (communist) politicians like Obama seem determined to force us to swallow the man-made global warming scam. We need to defend ourselves from the UN and these politicians, who threaten our future and the future of our children. Based on a lie, they have already wasted millions and plan to increase taxes, limit development, and enslave us.
If not stopped, the global warming scam will enrich the scammers (Gore and Obama’ Wall Street friends), increase the power of the U.N. and communists like Obama, and multiply poverty and servitude for the rest of us.
14. Allen Goldberg | 01.26.09
Recently, a meteorological paper signed by over 300 meteorologists was presented detailed the “global warming” effects directly resulting from the sun’s unusual activities. In fact, the .75 degree rise was linked and answered completely.
Now they point to the planet cooling. Real science and real facts…not hoax from Gore or illogical disjointed occurrences.
15. P. Arrington | 01.26.09
It looks as if this site has been spammed by the Big Energy industry *****. And Big Energy has Billions of dollars to pay such operatives. To help offset the barrage of vagueness, here are some items from the FAQ at NASA/Jet Propulsion Laboratories/California Institute of Technology:
NASA data show that 2008 was the coldest year globally since 2000. Also, the Arctic ice extent was greater than the previous year. Does this indicate a change in the overall global warming trend?
No. Climate is about long-term trends, so the fact that sea ice in 2008 didn’t reach a new record low vs. 2007 tells us nothing about climate. Scientists use running averages to filter out the “noise” — i.e., weather — in the climate system.
To add some perspective: While 2008 was likely the coolest year this century, if the same temperatures had occurred in the early 1990s, it would have been the warmest year on record.
Top of Page
If climate changes naturally over time, why isn’t the current warming just another natural cycle?
Previous major global-scale changes in climate, the ice ages, were a product of orbital changes that occur over thousands of years, not tens of years as the current warming has. Shorter-scale changes, such as the “Little Ice Age,” have been linked to changes in solar output. Neither orbit variation nor solar output changes can explain the current warming, so it’s very likely that greenhouse gases are the culprit.
The industrial activities that our modern civilization depends upon have raised atmospheric concentrations of carbon dioxide and methane to higher levels than at any point during the last 650,000 years.
Top of Page
How much is the climate expected to warm?
How much the Earth’s climate will warm depends on how much carbon dioxide and methane continue to be put in the atmosphere. If carbon dioxide levels stabilized at twice the pre-industrial level, about 560 parts per million, the most probable warming is 3 degrees Celsius, globally averaged.
It’s important to understand a couple of things about that number. Due to a phenomenon called polar amplification, the poles will warm much more, with the Arctic warming much more rapidly than Antarctica. The mid-latitudes, where the United States is, would see warming of 3 to 5 Celsius.
The amount of warming also isn’t the most important aspect of global warming. Humans are very adaptable to temperature changes. But we need water for ourselves and our agricultural system, and changing precipitation patterns as a result of global warming can have enormous, and expensive, consequences for drinking water and food supplies.
As a glaciologist pointed out in 1978, long before the current concern with global warming, a warming of this magnitude at the poles would probably destabilize at least the West Antarctic Ice Sheet, resulting in a 5 meter sea level rise and forcing the migration of most coastal cities inland over the next couple of centuries. More recent evidence suggests that the Greenland ice sheet may also begin to shrink at these projected temperatures, resulting in further sea level increases.
Top of Page
What’s the difference between global change and climate change?
While global change and climate change are often used interchangeably, global change encompasses broader changes to all aspects of our world including areas such as the availability of water resources, sea-level rise, ocean acidification, and biodiversity. Climate change is used to emphasize the specific changes most commonly associated with the atmosphere and the “average weather,” including temperature, humidity, cloudiness, or precipitation changes.
Top of Page
What does ozone layer depletion have to do with climate change?
Ozone depletion, which has produced “ozone holes” above Earth’s poles, is caused by human-produced compounds that release chlorine and bromine gases in the stratosphere.
Ozone depletion does not contribute to global warming. Because ozone in the upper atmosphere absorbs heat radiating from below, stratospheric ozone depletion actually allows additional heat to escape into space. While this occurs worldwide, the depth of the springtime ozone hole over Antarctica results in Antarctica cooling while the rest of the Earth warms.
Greenhouse gases tend to cool the upper region of the atmosphere, where the ozone layer is located. Because the chemical reactions that cause ozone depletion happen more quickly in the presence of ice crystals, a colder upper atmosphere with more ice will probably cause the ozone hole to expand slightly.
16. N8 | 01.26.09
What about the decreasing number of Salmon carcasses left in the forests (by bears) to decompose and augment the trees’ nitrogen and other nutrients?
This is a big factor the study apparently failed to consider.
17. DENNIS | 01.27.09
I would not worry about warming.I would worry about the global cooling that always follows.Interuption in the gulf streams covection will fix that warming .
BTW we could always reconnect the atlantic and pacific oceans again and do away with the seasons while we are at it.
18. Gary Lear | 01.28.09
Antonio Sousa should do a little more research before he makes references to faulty science. If he had read further down on http://www.pr-inside.com/the-petition-contains-the-signatures-of-r613239.htm he’d see:
>>>>>>
Michael Nobel, executive director for Fresh Energy, a St. Paul-based policy think tank that focuses on energy solutions and also chairman of the Nobel Charitable Trust, said the petition holds little merit to those who study global warming.
“It’s a sad and odd little voice shouting that there is no global warming,” he said of the institute. “Many people have apparently fallen for it.”
<<<<<
Furthermore, if he’d Googled ten randomly picked “PhD”s on the petition (as I did) he’d find the only place they show up is on “this odd little voice” of a petition. These people do not exist. This petition is a hoax.
The IPCC 2007 report had 500 lead authors and over 2000 of the world’s preeminent scientists as reviewers, not the 52 cited by Sousa.
The truth is there is no longer any debate among practicing scientists about whether climate change due to human activity is happening; the only debate is how much and how fast.
19. Jack Johnson | 01.29.09
The earth has been through a lot worse than some temperature change and melting ice. Dying trees… uh okay, What about a dying planet? How about if we got hit by a comet, How can we recover from that global disaster? Freeze our bodies for 5,000 years?
If anything I have learned that the earth can recover from even the worst disasters, Trees, global warming, seems like a small small part of the earth’s violent history.
20. Katie Chaffee | 01.29.09
It’s interesting that Dan disputes the lower water content of snow as a concern, or event that it exists. Here in Wisconsin we have experienced very little snowfall this year, and what there has been has been the light, fluffy kind with VERY LITTLE WATER CONTENT. Believe me, as an experienced snow shoveler, there is a big difference in kinds of snow. I had just commented this morning that this sparse, fluffy stuff was creepy!
21. Rod | 02.01.09
Man I cannot believe you people fall for this propaganda. When they cored the ice in the artic which is from the last ice age. How come in those samples there was more c02 during an ice age than there is now? Money making politics to empty the pockets of all the chicken littles.
22. Jeff Kurtz | 02.05.09
This research was conducted by scientists who likely know more about their observations and conclusions than anyone who comments on this article. Therefore, despite the fact that this article didn’t explain how these scientists determined that the trees are dying, I will add this information with appropriate weight to the pool of information drawn by others in the scientific community to make up my mind on the global warming issue. Based on everything I’ve read so far, I am inclined to believe that humanity is responsible to some degree for our planet’s current trend toward global warming. And if our old-growth forests are truly dying due to this trend, then this marks another death-knell caused by humanity’s collective ignorance and self-serving ways.
As members of a developed nation, we have accrued our wealth by taking advantage of a capitalist system and economy that does not account for its ecological costs. Therefore, you and I are most to blame for our current circumstances; and for this reason, we should incur the greatest cost as our global community attempts to mitigate the ramifications.
23. Shawn S | 02.06.09
Trees don’t live forever. I don’t know where the people of this study were educated but all plantss have a lifespan.
This from the article says it all…
” And while he acknowledges that the results come from a REALITIVELY LIMITED NUMBER of one- to two-acre plots, “our results imply that these trends could be occurring on a much broader scale.”
Yet yet article claims,”The study represents the most exhaustive yet for this geographic range of temperate forests, notes Andrew Sugden, a botanist and international managing editor for the journal Science, which published the results in Friday’s issue.”
You mean to tell me that even though this is a very limited study that it’s the most exaustive one to date??
Pure propaganda
24. wilbert Robichaud | 02.07.09
warmest years .
1. 1934
2. 1998
3. 1921
4. 2006
5. 1931
6. 1999
7. 1953
8. 1990
9. 1938
10. 1939
P. Arrington “Previous major global-scale changes in climate, the ice ages, were a product of orbital changes that occur over thousands of years, not tens of years as the current warming has. Shorter-scale changes, such as the “Little Ice Age,” have been linked to changes in solar output. Neither orbit variation nor solar output changes can explain the current warming, so it’s very likely that greenhouse gases are the culprit.”
This is not science it is Speculation.
A Few articles can show a “Shorter-scale changes”
1895 - Prospects of another Glacial Period (PDF) (The New York Times)
1912 - Sees Glacia Era Coming; Prof. Schmidt Warns Us of an Encroaching Ice Age (The New York Times)
1969 - New Ice Age Threat Seen (St. Petersburg Times, January 15, 1969)
1979 - New ice age almost upon us? (The Christian Science Monitor, November 14, 1979)
Boston Endures Record Cold From Frigid North Atlantic (Bloomberg, May 25, 2005)
Heaviest Snow in 18 Years Brings Much of Europe to a Halt (FOX News, February 02, 2009)
I have removed all the Warming articles so we can see that we do have a Shorter-scale changes.
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1. Jason Christensen | 01.22.09
So….the world has now deemed it necessary to spend unlimited funds to prevent climatic change, a process that has been going on for billions of years, far before man began adding CO2 into the atmosphere. Good luck beating mother nature….I’d you rather not spend my money in your ridiculous attempt.