A tree ring study estimating past rainfall and drought shows the southeast USA drought was mild compared to past events

Trees may be better rain gauges than they are thermometers.  From a press release of:

Killer’ Southeast Drought Low on Scale, Says Study

Others Were Far Worse; Population, Planning Are the Real Problems

Lake Allatoona, Ga., November 2007Lake Allatoona, Ga., November 2007

A 2005-2007 dry spell in the southeastern United States destroyed billions of dollars of crops, drained municipal reservoirs and sparked legal wars among a half-dozen states—but the havoc came not from exceptional dryness but booming population and bad planning, says a new study. Researchers from Columbia University’s Lamont-Doherty Earth Observatory defied conventional wisdom about the drought by showing that it was mild compared to many others, and in fact no worse than one just a decade ago. According to the study, climate change has so far played no detectable role in the frequency or severity of droughts in the region, and its future effects there are uncertain; but droughts there are essentially unpredictable, and could strike again at any time. The study appears in the October edition of the Journal of Climate.

“The drought that caused so much trouble was pathetically normal and short, far less than what the climate system is capable of generating,” said lead author Richard Seager, a climate modeler at Lamont. “People were saying that this was a 100-year drought, but it was pretty run-of-the-mill. The problem is, in the last 10 years population has grown phenomenally, and hardly anyone, including the politicians, has been paying any attention.”

Region wide, the drought ran from late 2005 to winter 2007-2008, though many areas in the south were still dry until last week, when the weather turned conclusively, and flooding killed at least eight people. During the height of the dry period, Atlanta’s main reservoir sank more than 14 feet, usage restrictions were declared in many areas, and states became embroiled in lawsuits among themselves and with the federal government over use of water in rivers and reservoirs.

Seager and his coauthors Alexandrina Tzanova and Jennifer Nakamura put the period in context by comparing it with instrumental weather records from the last century and studies of tree-growth rings, which vary according to rainfall, for the last 1,000 years. These records show that far more severe, extended region-wide events came in 1555-1574, 1798-1826 and 1834-1861, with certain areas suffering beyond those times. The 1500s drought, which ran into the 1600s in some areas, has been linked by other studies to the destruction of early Spanish and English New World colonies, including Jamestown, Va., where 80 percent of settlers died in a short time. The 20th century turned out relatively wet, but the study showed that even a 1998-2002 drought was worse than that in 2005-2007.

http://www.ldeo.columbia.edu/files/uploaded/image/graph.jpg

Southeast U.S. rainfall reconstructed from tree rings, 16th-20th centuries

The factor that has changed in the meantime is population. In 1990, Georgia, which uses a quarter of the region’s water, had 6.5 million people. By 2007, there were 9.5 million—up almost 50 percent in 17 years. The population is still ascending, driven largely by migration. However, little has been done to increase water storage or reduce consumption. There has been increased sewage discharge near water supplies, and vast tracts of land have been covered with impermeable roofs, roads and parking lots, which drain rainfall away rapidly instead of storing it.

Previous studies by Seager and colleagues have shown that droughts in the American Southwest and Great Plains states are controlled by cyclic changes in tropical Pacific Ocean sea-surface temperatures –the El Niño-Southern Oscillation cycle. This means that dry weather, which goes along with the cold phase of the cycle, can be predicted to some extent. However, in the current study, the scientists found only a weak correlation between Southeast weather and the tropical Pacific. Instead, says Seager, dry spells appear to be generated by random changes in regional atmospheric circulation. This means weather could dry up at any time.

Seager’s studies also suggest that manmade warming is beginning to perturb precipitation patterns across the globe. As a result, he says, the Southwest may have already entered a period of long-term aridity. In contrast, global warming does not appear to have yet affected rainfall one way or the other in the Southeast. Most climate models project that higher temperatures will actually increase rainfall there—but as temperature rises, evaporation will also increase. At best, says Seager, the two effects may balance each other out; at worst, evaporation will prove stronger, and result in drier soils and reduced river flows in the long term. “Climate change should not be counted on to solve the Southeast’s water woes, and is, in fact, as likely to make things worse as it is better,” says the paper.

“It was a lot drier in the 19th century than it has been recently, but there were so few people around, it didn’t harm anyone,” said Seager. “Now, we are building big urban centers that make us vulnerable to even slight downturns.”

The Federal Emergency Management Agency estimated that national losses due to drought ran around $8 billion a year in the 1990s, but they are probably higher now. Mark Svoboda, a climatologist at the National Drought Mitigation Center at the University of Nebraska who was not involved in the research, said of the study’s results: “This should be a wake-up call. If this is not the worst case scenario, what are we going to do when the worst-case scenario arrives?”

David Stahle, a tree-ring scientist at the University of Arkansas who made the link between 1500s-1600s droughts and the struggles of early Southeast colonies, said settlers then were particularly vulnerable because they had just arrived and lacked sufficient infrastructure or backup supplies. He called the Lamont study “a bedtime story with a moral for modern times.”

“Are we returning to a period of sensitivity and danger like the colonists experienced?” said Stahle. “In a way, yes, it looks like we are.”

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Harry Eagar

I think Reid Bryson established that the droughts during the MWP were far more severe than anything during the observed record in ‘Climates of Hunger’ about 35 years ago.
The recent drought isn’t worse than earlier 20th c. droughts, so Bryson’s analysis remains valid.

We have no clue what actual risks and variation there is in nature. Any valid graph shows the last 100 years as incredibly flat and stable. Look back 100 or 1000 years (or, gasp! 10,000 years) and you find that we have no clue what nature can deal out.
Recently, mature trees were found at the bottoms of lakes all over California and Nevada. Clear evidence of hundreds of years of drought (relative to today) that have not been seen for 1000 years…
We have not clue, but our “scientists” are worse, they think they have a clue when they don’t even have a cup of good coffee…

John Nicklin

According to the study, climate change has so far played no detectable role in the frequency or severity of droughts in the region, and its future effects there are uncertain; but droughts there are essentially unpredictable, and could strike again at any time.
Ok, so man made CC is not the cause. But wait…
“Climate change should not be counted on to solve the Southeast’s water woes, and is, in fact, as likely to make things worse as it is better,” says the paper.
It probably will be just over the horizon.
Do they have to out these kinds of speculation in their papers to get published?

“Do they have to out these kinds of speculation in their papers to get published?”
As I read this paper, I was thinking “great, a realistic, balanced study.” Then came the above, mandatory drivel. Yes, I agree, they must throw that in to get published.

rbateman

For an area that has no spring/summer runoff due to snowmelt, a -3 on the scale is tough cookies. In the Pacific Northwest, -4 to -6 are the really bad years.
There is enough known about the precipitation records. The problem isn’t so much climactic shift as it is an overly prescribed usage of resources.
Georgia and adjacent areas notwithstanding, nobody beat California for recklessly gambling with thier water supply. It’s the politicians and bureaucracies who make the mess. We got along just fine in the 76-77 drought, but can’t handle a shadow of it now.

Pamela Gray

Is “aridity” akin to “nuditity”? Can anyone tell me who coined that word?
Re: trees under water. The Cascades are filled with lakes like that. But it isn’t because of aridity versus raininity. It’s because of volcanic eruptions closing off rivers. And these are “brrrrrr cold” rivers. When the basin fills to the rim of the volcanic flow, it fills with this icy water that then finds its way through the volcanic rubble down hill somewhere. The basin stays filled with ice melt percolating to the basic from the mountain peaks above. This is the kind of water you don’t go for a swim in, especially in your nuditity, even on hotter than hell days. The submerged trees stay almost untouched from decay and you can see nearly to their trunks on the lake floor. If you ever get the chance, visit these lakes.

Pamela Gray

John, yes. They have to say, in affect, “Mother may I”. And Al the purse strings holder says, “Yes you may”.
By the way, I love this new adjective talk. Or is it verbidity. Whatever. Can we call the sleeping Sun “sleepidity”? or Blankidity?

par5

Lake Allatoona (pictured above) is now 12 ft. over normal. The reason for the low lake levels in 2005-2007 was because the gauge at Buford Dam (Lake Lanier) was broken and they (Corps of Engineers) were letting out twice as much water as reported. After fixing the gauge, the corps continued to release more than normal because of Fla and Ala filing lawsuits. The corp tried to build another reservior north of Atlanta, but a lawsuit from Ala put that on hold indefinitely. All of the lake levels in Ga are full except Lanier, which is only two ft below summer level.

H

We have the same “100 year drought” phenomenom here in South Eastern Australia. When one looks at rainfall patterns, it hasn’t changed much over the last 100 years. What has changed is the number of people drawing on the water without any increase in supply or storage capacity. The same can be said for our bread basket regions. Irrigators have drawn more water than is sustainable. And the politicians claim it is all about AGW.

savethesharks

Rob wrote: “It’s the politicians and bureaucracies who make the mess.”
YES. From a lifelong Southeasterner. Agreed.
And the recent SE drought was due to the warm AMO.
No big deal.
Even if Jim Cantore on the Weather Channel can blindside me with his quote about the recent Atlanta floods being due to “Climate Change.”
Get used to it, Jim. Climate CHANGES. That is what it does.
For shame you….even YOU are locking into this emotional “argument.”
Get over it…and survive with the rest of us.
CHRIS
Norfolk, VA, USA

Michael

Climatology is just my hobby. Economics is just my hobby. politics is just my hobby. My profession is machinist. Steve McIntyre’s profession is a statistician, his hobby is climatology. Hobbyists can yield some spectacular results.
Did I get that right?

Michael J. Bentley

Pamela,
You’re one of the commenters I always like to read, because you’re like a splash of cold cascade (or more rightly Blue Mountain) water on a very hot day. You improve my attentionidity.
Mike

savethesharks

Pamela Gray This is the kind of water you don’t go for a swim in, especially in your nuditity, even on hotter than hell days.
I tried to take a dip in the Deschutes River once….and it was like…..way too cold.
All of that South Sister snowmelt. BRRRRRR
The Pac NW is one of the most beautiful places on the planet, no doubt.
CHRIS
Norfolk, VA, USA
Chris
Norfolk

Gene Nemetz

It seems like there should be a bureau in Washington that advises where urban growth could do best based on the drought history of an area. Because if we don’t learn from history we’re sure to relive it. With that said, it seems the thing I learn from history is a pattern of what will be happening now and in the future—with different names of people, places, and things.
Also, a good solution to water shortages has always been wells. Well water tastes wonderful too! (Deep wells I am mainly meaning.)
p.s., this is a nice study making for an interesting post! Not all that is bad is global warming. 😉

Gene Nemetz

par5 (21:08:07) :
Thanks for the straight story. This has never been reported in the media, at least not here in California. I should remember that old saying when I watch the news :
“Don’t believe most of what you hear and hardly anything you see.”

Gene Nemetz

savethesharks (21:30:50) : Jim Cantore on the Weather Channel
Any time I see his shaved head, black rim glasses—and looks of doom on his face—I just change the channel—the two former things having nothing to do with it.

Pierre Gosselin
Philip_B

Failure to build sufficient water supply infrastructure is a worldwide problem. Environmental protests and obstructions being a major cause.
Despite all the talk and predictions of climate change and climate instability, the last 50 years has had a remarkably stable climate and outside of Africa there have been no major droughts of the size we know occured in earlier times, as recently as the 1930s.
The late monsoon in India this year should have been a wake up call to those, who while obsessing over what might happen in a 100 years, ignore the fact the world is one bad harvest away from a catastrophe.

crosspatch

Re: trees under water. The Cascades are filled with lakes like that. But it isn’t because of aridity versus raininity. It’s because of volcanic eruptions closing off rivers.

The Sierra Nevada, on the other hand, has lakes like that, as E.M. Smith pointed out. There is a post from a few years ago on Climate Audit that describes a paper on those lakes. Seems California has had periods of several centuries with rainfall greatly below today’s rainfall amounts during the Holocene. In fact, the past couple of hundred years have been quite an unusually wet period.
When rainfall patters return again to one of these dry periods, California is going to be in a world of hurt. We are talking about a hundred or hundreds of years of below what we would call “average” rainfall.
On a different subject: If we are nearing the end of this interglacial period, look for less stability in climate. We saw the Little Ice Age which appears to be the coldest period since the Younger Dryas and then we have seen warming not quite recover to what it had been before. In fact, climate was relatively stable until about 2000 years ago. Since then we seem to have experienced greater and greater swings between warm and cool periods. Each cool period seems cooler than the one preceding. Expect these swings to get even greater in amplitude as this interglacial comes to an end. Climate could vary considerably in relatively short periods of time. We could have entire areas of Canada become unusable for agriculture for several decades only to warm up again as if nothing had happened for a few decades and then slip back into freezing cold.
These cool periods may be associated with extreme drought in some areas if the oceans cool and evaporation is reduced. Storm tracks may be pushed South and areas that are currently quite arid may see an increase in rainfall (e.g. the Great Basin area).
REPLY: Got a link to that paper/post on Sierra Nevada lakes? – Anthony

Michael

So let me see if I get this straight.
“An Inconvenient Truth” is Science Fiction.
Did I get that right?

par5
Michael

An observation about the topic;
It seams to me they are trying to ease the sheeple into accepting reality.

Keith Minto

“Seager and his coauthors Alexandrina Tzanova and Jennifer Nakamura put the period in context by comparing it with instrumental weather records from the last century and studies of tree-growth rings, which vary according to rainfall, for the last 1,000 years.”
Do they now ?.After the exhausting tree-ring/temperature discussion we have this. What’s next, tree rings and the abundance of reindeer droppings ?

Neil Jones

Pamela Gray (20:59:04)
Aridity is akin to Nudity, it is a valid word long established in the Complete Oxford English Dictionary.
Perhaps it’s new to the Colonies?

John F. Hultquist

For years we have taught that the Southeast USA is generally short of precipitation while being resupplied by tropical storms with haphazard timing. And politicians can’t solve known problems. Not much new in this paper.
I wonder, did they use Bristlecone Pines or Larch in this study?
Just kidding!

Seager’s studies also suggest that manmade warming is beginning to perturb precipitation patterns across the globe. As a result, he says, the Southwest may have already entered a period of long-term aridity.
How does he recognize between natural and man made warming? 2008 in US was colder than 1900 and 2009 will be even colder. Wheres the man made warming, except man made hockey sticks and manipulated records?
http://data.giss.nasa.gov/gistemp/graphs/Fig.D.lrg.gif
“It was a lot drier in the 19th century than it has been recently.
So colder probably means drier in general. This explains relation between evaporation and precipitation. Where is the proof it will be now dry because of being warmer, oh sorry colder?

Claude Harvey

Re: Pamela Gray (20:59:04) :
Is “aridity” akin to “nuditity”?
“Warmidity” generally encourages both “aridity” and “nudity”. Conversely, “coldidity” discourages “nudity” although there remains a possibility of concurrent “aridity”.
I’ve given up entirely on tree rings and am now focusing my efforts on petrified naked people. Find yourself a wad of those in some bog and you’ve got yourself a bonafied “warm period”.

CodeTech

Michael (22:26:56) :
So let me see if I get this straight.
“An Inconvenient Truth” is Science Fiction.
Did I get that right?

I wouldn’t characterize it as Science Fiction, as much as a sort of fantasy fiction along the lines of “Chariots of the Gods” or most of Michael Moore’s work: ie, string together a lot of relatively factual things, then guide the viewer/reader into making his/her own completely incorrect conclusion.
Science Fiction (often also called Speculative Fiction) usually either attempts to place a story in a future world, or shows how disfunctional a future would be if current social trends continue.
I’ve written some Science Fiction, some Fantasy, and am currently working on a Science Fiction story about a future where nothing predicted has actually happened, and yet oddly enough they still believe it will.

Tenuc

The historic record shows that of the amount of water available for use has always varied over time, just as climate varies. Some places get droughts while others are getting floods at the same time.
As the study says, the pressure of extra population has a major effect on water useage, but modern farming techneques, often requiring massive use of water for irrigation to get the high yields are also a big factor.
To reduce the impact of this problem on the population, money needs to be spent on an infrastructure of pipes, so that what water is available can be distributed to the places where it’s needed.
Any chance of this happening anytime soon? I don’t think so – those in power would rather spent our taxes on the already falsified hypothesis of AGW. What a waste.

crosspatch

Got a link to that paper/post on Sierra Nevada lakes? – Anthony

I believe this is it but I am tired and not reading carefully right now.

Stas Peterson

Why am I NOT surprised that useless lawyers and enviro- ignoramuses hav j ointly conspired to creat the consequences of the predictable drought by denying, delaying, and preventing, the construction of proper reservoir storage.
Why can’ t someone sue these incredible monkey wrenches for the damages that they have predictably caused. Lets attach all their future earnings singly and collectively, and all the contributors to their cock-eyed causes as well.

crosspatch

So let me see if I get this straight.
“An Inconvenient Truth” is Science Fiction.
Did I get that right?

Mostly. Except for the science part.

Don S.

Gene Nemetz: “It seems like there should be a bureau in Washington………….”
Step away from the bottle, Gene. If such a bureau were created it would be be an office of the GISS or the NCDC or NOAA. Its first recommendation would be development of the four corners region.

par5

The picture above is of a small shallow cove usually about six feet deep. It does not represent the lake at all. You can see the private boat docks in the background, but the photo does not show the water behind the photographer. Take a good look at the bouy, its anchor and the length of the supply line.

Skeptic Tank

As my handle might suggest, I have to question whether trees make any better rain gauges than they do thermometers. My inclination is that they do, but only slightly.

Ed H

This study points out one of many ways in which people overbuild in areas that are poor choices from the standpoint of climate and geological timescales. From over building relative to water supply, to building below sea level, to one of my favorites…. If you ever fly into Cincinnati airport approaching from the north, observe the topology and building pattern in southern Ohio near Cincinnati. You’ll see plateau-ish looking areas with serpentine valleys that clearly were once rivers. The past riverbeds are where all the houses are with little on the elevated areas. I keep thinking that someday in the next several hundred years, they might regret that…

Alvin

Put Mr Saegar at the armist (kiddie table) pool. Smell the agenda? I do.

maz2

“Southeast Drought Study Ties Water Shortage to Population, Not Global Warming”
“Instead, they wrote, any variation in rainfall in the Southeast commonly “arises from internal atmospheric processes and is essentially unpredictable.””
Fin.
http://www.nytimes.com/2009/10/02/science/earth/02drought.html?_r=1
PDF link.

Richard Heg

It was only a matter of time before someone used the latest earthquake/tsunami to push AGW. http://www.medicalnewstoday.com/articles/165932.php

wws

The chart at the top of this post only goes back to the 1500’s; iirc the worst north American drought in human terms is probably the drought that’s believed to have occurred in southwest in the second half of the 13th century, starting soon after 1250 ad. Tree ring data suggests a long period of extended drought, which is probably what eliminated the Anasazi culture which had been doing fairly well up until that time.
“When this cycle of drought began, Anasazi civilization was at its height. Communities were densely populated. Even with good rains, the Anasazi were using their land to its limits. Without rain, it was impossible to grow enough food to support the population. Widespread famine occurred. People left the area in large numbers to join other pueblo peoples to the south and east, abandoning the Chaco Canyon pueblos and, later, the smaller communities that surrounded them. Anasazi civilization began a long period of migration and decline after these years of drought and famine. By the 1300s, it had all but died out in Chaco Canyon.”
http://www.learner.org/interactives/collapse/chacocanyon.html
to be fair regarding the Anasazi, “The Great Drought may have been the last straw,” said Dr. John Ware, another archeologist at the Museum of New Mexico. “But in and of itself, it just wasn’t enough.”
http://raysweb.net/canyonlands/pages/drought.html

Tamara

Another interesting link about Western droughts:
http://blogs.kqed.org/climatewatch/2009/05/08/decoding-californias-drought-history/
Mentions that the COOL PDO was to blame. Well, what d’ya know?

Well, I live right near Lake Allatoona GA, and wish to report that the lake is now completely full to its seasonal average by last November. Yes, it was low for a while. Yes, we had a drought. Then it ended.
Further, Lake Allatoona did its needed job of protecting houses and cities downstream when 30+ inches of rain fell in a five day continuous storm this Sept. Now? Up to the spillway.

tallbloke

I’m probably being stupid or ignorant here, but can anyone explain to me how it can be that we have one group of paleodendroclimatologists who believe trees measure temperature, and another who believe trees measure precipitation, and neither of them know the detail of temperature or precipitation prior to say 1800, how do they separate the supposed temperature signal from the supposed precipitation signal in tree ring widths?
Or do they believe that some trees are good thermometers and others are good precipitation guages? How do they tell the difference. And if trees are both thermometers and precipitation guages, how do they assign relative values to each trait?
Do these two groups hold joint conferences? And can I have some please.

red432

John Nicklin: Do they have to out these kinds of speculation in their papers to get published?
It’s like the way Soviet era academic publications always included mandatory praise for Lenin. The quantum physicists were spared because Lenin couldn’t possibly have contributed to quantum physics…

Stephen Skinner

Only slightly OT, in as far as the region. I thought the most significant drought to hit the US in recent history was the Dust Bowl of the 1930s, which also hit Canada. I understood it to be devastating and was brought about by the farming practices of the time, although I have heard it was Climate Change also. This event is surely the bench mark for drought in North America?

Aron

Yes, it should be obvious that tree rings record rainfall quite well. When rain falls bark absorbs water and expands. When the rain stops and weather dries the bark hardens in its expanded state.

There is no water shortage. There is only inadequate water distribution.
http://energyguysmusings.blogspot.com/2009/02/westward-ho-water-transfer-system.html

Henry chance

Briffa begs using a tree as a thermometer. Now it is a rain guage also? Some of the drought effect has to do with timing. I do not deny a water crisis. We have always had droughts but we have not abused water suppiels like we do now. It takes a lot of water to please a newly planted sod lawn. It takes a lot of water to supply rare fishies when there is a court order.

JimInIndy

“studies of tree-growth rings, which vary according to rainfall, for the last 1,000 years” ???
Somebody needs to tell the Hockey Team.