PRESCOTT - Droughts are common throughout the history of the Southwest, but not broad-based temperature increases such as the region has been experiencing the past few decades, leading climate scientists from the University of Arizona's Laboratory of Tree-Ring Research said last week.
Arizona's average temperature has increased 2.5 degrees since 1976, according to state climate division records. The average annual precipitation has dropped about two inches in Arizona from 1979 to 2004, said Malcolm Hughes, a U of A professor emeritus and previous lab director.
Hughes and Lab Director Tom Swetnam said these changes are leading to earlier spring runoff, widespread death of tree stands and much larger Southwestern wildfires. They spoke last Thursday night in Prescott.
In response to an audience question about the validity of a recent "Tea Party" presentation on climate change from Yavapai College business instructor Terry Lovell that disputed the human element of climate change, Hughes urged the public to look at the qualifications of speakers and scientific evidence rather than "big sweeping statements that, when analyzed, are often based on things other than science."
Swetnam added, "What we're seeing now is truly extraordinary on these (multi-century) time scales." Scientists know greenhouse gasses push up temperatures, and the gasses are producing temperature increases that scientists would predict when calculating the gasses that human activity is producing, he explained.
To understand precipitation and wildfire trends in the Southwest dating back centuries before records existed, the lab's scientists use modern dendrochronology techniques developed by lab founder Andrew Ellicott Douglass about a century ago. He realized the width between tree rings on harvested ponderosa pine logs in the Flagstaff and Prescott areas correlated to annual precipitation. Fire scars also record years of wildfires.
The trees' growth especially responds to winter precipitation, since the snow melts into water during their spring growing season.
Tree rings show numerous severe droughts before the 20th century. One around 1150 A.D. lasted for decades.
However, the shift to warmer temperatures the past few decades has caused more evaporation and earlier springs that exacerbate drought conditions.
"This is not a projection," Hughes said.
And for the next 50 years, "The pattern of drought is similar to what we've seen in some of the toughest years," he added. Climate experts forecast drought will be widespread across the West.
"The projected future normal resembles severe droughts of the past," Hughes said.
The scientists also tried to offer some hope for the future.
"There is still time to adapt and change," said Swetnam, whose talk focused on the relationship between climate and wildfires.
Analysis of tree scar data from trees across the Southwest show fires between 1600 and 1890 were highly synchronized to drought, Swetnam said. Typical ponderosa pine forests experienced fire 1-2 times per decade, thinning out the smaller trees.
"They require frequent fire," he said of ponderosa pine stands. Other types of forests to the north, such as lodgepole pines and spruce, depend more on huge stand-replacement fires every few centuries. Piñon and juniper forests are more complicated, with some experiencing natural crown fires and some not.
The ponderosa pine scars show a huge drop-off in fires in 1890.
"It lines up really closely with livestock grazing," Swetnam said. Huge numbers of livestock were eating up the grass that carried low-intensity fires between trees in the Southwest, he said. For example, seven million sheep were grazing across New Mexico in 1900.
About the same time, people started suppressing wildfires, and the military subdued Indian tribes that had used prescribed burns, he noted. Forests became more and more unnaturally dense during the 1900s as wildfire suppression continued.
With the increasing temperatures and spring arriving 1-3 weeks earlier the past 15-20 years, the sizes of wildfires are increasing and the fire season is lasting 1-2 months longer, Swetnam said.
"So it's not just (too much) fuels, it's also climate variability and climate change," he said.
Since 1998, wildfires have burned across 4.8 million acres of Arizona, and drought and bark beetles have killed many of the trees on another 3.5 million acres, he said. Arizona has only 25 million acres of forest. In many cases, 200-year-old to 400-year-old ecosystems have been destroyed, he said.
Swetnam called for adaptive management to save the remaining forestlands. The Governor's Forest Health Oversight Council's statewide strategy for restoring Arizona's forests, which he helped write, offers a good vision, he said.
"We actually need to put fire back into these forests," he said. Fire helps recycle nutrients, and in many steep or rugged areas, mechanical treatment is impossible, he noted.
Landscape-sized forest treatment plans are a necessity to catch up, and groups such as Firescape in Southeast Arizona and the Four Forests Initiative on the Mogollon Rim are working on such scales, he said. The federal Forest Landscape Restoration Act seeks to help pay for these large projects. Firewise projects also are making a difference on private lands.
More information is available online at www.ltrr.arizona.edu.
Reader Comments
Posted: Friday, November 06, 2009
Article comment by:
Tony Krzysik
Yes indeed, the projected Southwest drought is linked to Climate Change. Two critical science articles are relevant:
Seager + 12 more authors. 2007. Model projections of an imminent transition to a more arid climate in southwestern North America. Science 316:1181-1184.
Solomon + 3 more. 2009. Irreversible climate change due to carbon dioxide emissions. Proceedings of the National Academy of Sciences 106:1704-1709.
It is revealing that active climate change deniers are either non-technical ideologues or scientists with no climatology expertise paid by special interests. These deniers do not present any data or evidence to support their claims, only blind opinions and cherry-picked info out of context. Science has associated the changing climate and ecological signals with increasing atmospheric greenhouse gases, especially carbon dioxide. There is NO DEBATE among the experts, other than VERY technical minute details.
Of course, there are many honest citizens that are unsure of the complex details of climate change, and would have difficulty comprehending the science-based IPCC Climate Change 2007 report, which by the way is extremely conservative in its predictions, because of strong policy lobbying from U.S., China, and Saudi. The almost 3000 page report was written by 450 lead scientists, 800 contributing authors, and was peer-reviewed by 2500 experts. Numerous technical and popular articles have been written using the data and conclusions from this report. Recently, two highly respected Pennsylvania State Univ. geoscientists summarized the IPCC 2007 report. Their 207-page book is directed to the public, extremely accurate and informative, has received outstanding professional and public reviews, and is exceptionally detailed with pictures and graphics. This book presents an incredible amount of clear and factual information. I urge ALL citizens that are curious, thing critically, and desire reality to read this book ($16.50 amazon.com). Of course, the two groups of deniers will not read this material - ask them WHY?
"Dire Predictions: Understanding Global Warming" by Michael Mann & Lee Kump.
I wrote a Climate Change essay in early 2007 based primarily on the IPCC 2007 report. I reformatted it in July 2008 and it is available under "Climate Change" in Tom Atkins website "PrescottsLastOasis.com.
Another very recent book by David Archer (Univ. Chicago) summarizes with authority our global carbon dioxide dilemma - "The Long Thaw". For example, "About 10% of the carbon dioxide from coal will still be affecting the climate in one hundred thousand years."
Tony Krzysik, Ph.D.
Research Ecologist
Prescott, AZ
Posted: Friday, November 06, 2009
Article comment by:
No name provided
What happened to cloud seeding to create rain during severe droughts?
Posted: Friday, November 06, 2009
Article comment by:
Hear this
"The projected future normal resembles severe droughts of the past," Hughes said.
Not dumbed down enough to understand, I suppose.
Posted: Friday, November 06, 2009
Article comment by:
Gravity is just a theory
People oppose the climate change idea and the science behind it because they want continued license to pollute and waste resources. That's it in a nutshell. We can argue the specifics of the science for ages, but it comes down to the fact that going "green" is appropriate in most cases any way you look at it. I also love how people squawk about Al Gore making money off it some crazy loon idea. Industries are being born because of our scientific knowledge and awareness of how our actions affect the planet. These industries equate to jobs and may ultimately reduce our dependence on foreign energy. Sounds like something any rational conservative could get behind. But they don't. Because it's all a political issue to them. Just like evolution and other stuff and nonsense. They are comfortable regulating our personal lives, but Koresh forbid huge industries have some pollution controls slapped on them. Yeah, that makes rational sense.
Posted: Friday, November 06, 2009
Article comment by:
No name provided
To "To all climate change non-believers" it is because the liberals are ramming global warming down our throats and trying to make us pay more taxs for a belief or religion. So leave us out of what you believe.
Posted: Friday, November 06, 2009
Article comment by:
What do pointy headed PhD climatologists know?
Yeah, what do all these pointy headed PhD level climatologists, who have reached, near-unanimous, agreement / consensus that the earth is warming and the human burning of carbon based fuel is the cause. What do they know, they have just spent their entire lives going to undergraduate schools / graduate schools, spending their entire lives doing professional research, gathering vast amounts of data, writing peer-reviewed journal articles...and coming to agreement. I am proud to be a Tea Bagger and these pointy heads don't know as much as we who listen to Rush Limbaugh, Bill O’Reilly, and Michael Savage. We have developed sort of a gut feeling about such things. Gut feelings are much more accurate in these matters than the stupid climatologists and their extensive research and data collecting. I say we fire all of these pointy headed monkeys, they are nothing but a waste of money, and hire our three heros above to tell us what our global warming gut feelings should be! That way we don’t have to think critically or even think for ourselves!
Posted: Friday, November 06, 2009
Article comment by:
George
I attended the Tree Ring seminar and did not hear any statement made about evidence to support a continued trend toward an extreme drought. There were statements made about there having been longer and worse droughts in the past. The particular pattern we are in is worsened by an increase in temperature during a dry period, which amplifies the impact.
Posted: Thursday, November 05, 2009
Article comment by:
The earth will change, with or without us
All I can say is if you think man can change the earth this easy, you need to look back. For millions of years the earth changed without us. Many years ago, CO2 levels were higher than they are now, and there weren't cars then (ice core samples). The earth will continue to change, with or without us. The current schemes are all about raising taxes and the lucky few who profit from this (like Al Gore).
Posted: Thursday, November 05, 2009
Article comment by:
To all climate change non-believers
I believe climate change is real and humans are causing it. I trust the science. If you don't, fine. My question is, why are "non-believers" so adamant about de-bunking this idea? If you want to keep polluting because you think it doesn't matter, then do it. Why are you so bent on trying to convince everyone who does believe it that their beliefs are wrong. You resist the idea so strongly. Why? What is your motivation?
There are many people out there that don't beleive in a god, yet I don't see the same reaction from religious non-believers towards people of faith. They typically let them be.
I honestly would like to hear from those of you who think climate change is purely natural.
Posted: Thursday, November 05, 2009
Article comment by:
No name provided
If this paper is so liberal, why did it run a front page story a few weeks back when that business professor gave his two-cents opposing climate change? I don't seem to recall people screaming how liberal it was then. I guess if you are used to watching FOX news though, anything with actual scientific data behind it seems pretty liberal.
Posted: Thursday, November 05, 2009
Article comment by:
To Bombastic -- one clue
Just one, because there's not space to help you all the way out of your muddle.
Joanna reported on one event, which took place last Thursday. Exactly because she was presenting a "NEWS" piece about that event, it wasn't her assignment to present opposing views.
A normal person reading her story would not make any conclusion about what she personally believes. This explains much about your response. -- Candace McNulty
Posted: Thursday, November 05, 2009
Article comment by:
Guitfiddle1
In the 1950's, as a grade school student, I was taught that we were still coming out of the last ice age. Not a huge fan of Gore but at least he is brave enough to mention the number one problem--population. You can only put so many rats in a cage before they begin to devour each other.
Posted: Thursday, November 05, 2009
Article comment by:
ljackson
Well no wonder the USFS is trying to completely destroy all the trees in the Prc Nat'l Forest. The dang things are drinking up all our water. Bad bad trees!
Posted: Thursday, November 05, 2009
Article comment by:
The Rev
Yes the Apache and Navajo practiced prescribed burns in harmony with nature by the chocolate river and gumdrop forest. Additionally, in this mural, we can see Aztec elders helping that poor man with his chest pain. What you not agree with these knowledgable experts? Sacrilege! Well at least until the scientific community changes its collective mind again and again and again. Until then you are found guilty of ignorance and hereby sentence to a critical thinking lashing in the public square.
Posted: Thursday, November 05, 2009
Article comment by:
Steve
For every "expert" on one side, there is an equally qualified "expert" on the other. I agree that we should reduce our pollution and be smarter with our natural resources, what really bothers me is the people that are complaining about the earths condition while polluting as much if not more than the average person ie...Al Gore and mike moore
Posted: Thursday, November 05, 2009
Article comment by:
No name provided
I won't argue whether or not global warming is real but predicting the future by reading tree rings?
Posted: Thursday, November 05, 2009
Article comment by:
Bombastic
What? Dry, warm temperatures in the Desert Southwest portion of the U.S.? NO WAY! I know it's hard for liberals to understand that even though it's a pretty fair spell between 1976 and today, that it really isn't even a microscopic note on the grand scale of time and the age of this planet. "YES", they shriek, "SEE, that's PROOF", they clamour when they hear another leftist quote data that serves their agenda! And then what's with the gloomy thing about rain fall measurements between 1979 and 2004? Say what? It seems that in reality the leftists are just cherry-picking snippets of time and data to support that which gives meaning to their lives? What about that situation back in "1150 A.D."? Did they have cars, airplanes and air conditioning back then? What about the stuff going on between "1600 and 1890"? What the heck? I thought that all the evil polluting stuff being utilized (chiefly in the U.S. of course, not in the pristine rest of the world, oh no) wasn't really around much during that period. And of course we are avoiding the REALITY that even though there's some information about Arizona's average temperatures over a span of time being selectively mentioned here, what about the EARTH'S average temperature fluctuations during that or similar time frames, or the annual rain fall figures? The liberals just love the convenience of selective data. And George, it is YOU from whom we shall hear the "chorus". You just can't wait to read something like this and INSTEAD of adding anything substantive, you just want to preceed anything that opposing voices might say. That's brilliant George and thus I suspect you are too. Your "chorus" is empty and weak. You believe your scientists and we'll believe our's, George. And remember something very, very important: the scientists that you believe in also have a vast array of other "beliefs" that you may want to look at a little bit closer. They tend to share very leftist philosophies and a clear disdain for the U.S. and our way of life. Is this a proud moment for you George? p.s. Joanna Dodder is obviously someone who believes in man-caused "Global Wa...OOPS, sorry, "Climate Change"? Joanna, next time you write a NEWS piece, maybe you should consider something from an opposing point of view instead of just a totally one-sided, albeit it rather weak, argument from just one viewpoint.
Posted: Thursday, November 05, 2009
Article comment by:
Yes, look at the qualifications!
Okay, George, I'll bite. You say "two very qualified people..." On what do you base this statement? That they are the current and prior directors of the "tree ring lab"? I'd say that leads to a conclusion that they may be "very qualified" to count tree rings and draw conclusions about historic drought and wildfire activity. So far so good, George. But proving that those droughts will be made worse by man made greenhouse gasses still seems a stretch to me, and I see no particular qualification for their opinions about the complexities of atmospheric science. Maybe they do have such qualifications, but they are not disclosed in this article.
Posted: Thursday, November 05, 2009
Article comment by:
There are problems we shoudl address that have priority
In terms of things we should be worrying about a natural warming cycle of the earth is way, way down on the list. Mostly because at the end of the day, there is little we can do about it. And remember, the policies regarding wildfire supression in our wild lands over most of the 20th century was based on the "science" of the time. Science that is now agreed to have been pretty much dead wrong and a huge mistake. People are getting rich riding the "man made global warming" bandwagon. Al Gore is now projected to be the first to reach a BILLION dollars in personal income selling his "science" to the proverbial "one born every minute". As regards qualifications, anybody that has spent time in the real world knows that qualified people are wrong all the time about many things. Qualifications do not equal scientific fact. They just, at best, support opinions and you know what they say about those.
Posted: Thursday, November 05, 2009
Article comment by:
honkybrujo
Chris, Just to much science for you to digest? Why don't you just block out the present and revert to your bible and the past! There are some really stupid people that live in this town.
Posted: Thursday, November 05, 2009
Article comment by:
Gravity is just a
Psuedo-science? Really? . Dollars to donuts you worship some invisible deity - but this, this is "psuedo-science?".
Pray tell, who is micro-managing your life in response to this supposed psuedo-science? In truth - it's nobody - you are just uncomfortable with getting ugly stares will driving your gas guzzling, air polluting, truck to the desert where you'll damage and litter the earth with quads, spent ammo and beer cans.
Wheee! Hippies are losers. I'm cool.
Posted: Thursday, November 05, 2009
Article comment by:
Tom Steele
If you only look at data from biased organizations, you will only know biased data. One or two facts disprove global warming is caused by CO2. One, ice core samples from Anartica going back millions of years prove CO2 rises only after decades or centuries of temperature rising; most likely due to sun spot cycles. And, two, global temperatures have dropped over 1 degree "C" since 1998 which was ignored by a flawed formula by the promoters of the UNICC. Tree rings don't lie but the causal evidence is a lack of water; period.
Posted: Thursday, November 05, 2009
Article comment by:
I. M. Aware
Chris, if you want people to seriously consider your thoughts, you need to learn the language. We use capitols, periods and thought to promote our ideas. It is, however, evident by your thoughts you do not understand science so this is way over your head that is buried in the sand.
Posted: Thursday, November 05, 2009
Article comment by:
caveman
You are never going to convince the conservitives that the climate is changing so why bother, you can only beat a dead horse so much before it starts to really stink.
Posted: Thursday, November 05, 2009
Article comment by:
Scotty
Amazing the folks who bow down to Mr. Darwin's theroy of evolution. think the planet earth should never evolve. The planet is constantly changing, and humans cannot change or stop it. Just look at what the "solution" is... more taxes, more government power, less freedom. Espoused by people who fly around in jumbo jets to attend environmental summits where they ride around in limos and suvs,dine on prime rib and lobster off fine china, in thousand dollar suits. FYI George, it's not called global warming anymore 'cuz the planet hasn't got any warmer in over a decade, it's now "climate change." The hottest years on record in the U.S. occurred in the 1930's! Look it up.
