DRY FUTURE: A combination of climate change and explosive population growth could bring about a water crisis in coming decades in the U.S. Southwest.
Image: Photo by d_herrera, courtesy Flickr
A 60-year drought that scorched the Southwest during the 12th century may be a harbinger of things to come as greenhouse gases warm the Earth, according to research published December 13 in the Proceedings of the National Academy of Sciences.
The study's authors used tree rings to reconstruct a portrait of droughts that struck the Southwest over a 1,200-year period stretching back to 900 A.D. They believe that understanding the droughts of the past could help water managers plan for future dry periods that are expected to become more intense as climate change worsens.
Portions of the Southwest have suffered prolonged drought since 2001. But the medieval drought, which peaked along the Colorado River between 1146 and 1155, stands as the worst drought in the region for at least 1,200 years, according to the tree ring records.
Still, there are similarities to present-day conditions. The medieval drought occurred during a period from 900 to 1300 A.D. when the Southwest was about 1 degree Celsius warmer than average. Temperatures in the Southwest have been more than 1 degree Celsius warmer than average since 1990, and climate models suggest greater warming by the end of the century.
It's not a perfect comparison, said the study's lead author, University of Arizona paleoclimatologist Connie Woodhouse. Temperatures are warmer now than they were in the 12th century, when it was drier than it is today. But Woodhouse says the medieval scorcher represents a "conservative" worst-case scenario for future Southwest droughts, and the region's water managers should take heed.
"There's no reason to believe that we won't have a drought like that in the future," she said, "but we're going to have warming on top of that."
A region where the cost of inaction will be 'particularly high'
Woodhouse's work is one of several papers on climate change and drought in the Southwest published yesterday by PNAS. Together they sketch a portrait of a region where a combination of climate change and explosive population growth could bring about a water crisis in coming decades.
"Because climate warming will exacerbate water sustainability problems, the Southwest is likely to experience some of the highest economic expenses and environmental losses," said Glen MacDonald, director of the University of California, Los Angeles' Institute of the Environment, and an author of one of the new papers. "The ultimate costs of inaction in curbing greenhouse gas emissions will be particularly high for the Southwest."
Explosive population growth over the past century has pushed the Southwest's relatively meager water supply to unsustainable levels of use, the PNAS studies conclude.
The region's population grew from 2.1 million to more than 50 million during the 20th century. The U.S. Census Bureau estimates that, by 2030, the Southwest will be home to more than 67 million people. Within 50 to 100 years, the current population could double.
Even without the added pressure of climate change, that would stress the region's water system, said John Sabo, a senior fellow at Arizona State University's Global Institute of Sustainability, who served as lead author for one of the new studies.
His work shows the Southwest currently uses 76 percent of its surface water, a number that could rise to 86 percent when the region's population doubles. That's not enough to support the Southwest's growing communities and agriculture sector while also leaving enough water in its rivers to support healthy ecosystems.
"Part of the challenge we face in the Southwest is old-style thinking," said Peter Gleick, president of the Pacific Institute and an author of another analysis. "We brought to the Southwest very European ideas about water, developed in water-rich areas. ... That worked OK for a while, although not really. But now it's clear that green lawns and unlimited swimming pools and inefficient irrigated agriculture can't be sustained."
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53 Comments
Add CommentI wonder who was generating all those 'green house gases' in the 12th century ? ................
Reply | Report Abuse | Link to this@HowardB, you are a bit late with that B.S. That kind of idiotic statement was addressed long ago. Now it's just boring. I would think the heritage institute would have given you something better but perhaps you are just a mindless drone with his collection of catch phrases stuck in an infinite loop.
Reply | Report Abuse | Link to thisdesert and sunshine = free solar power
Reply | Report Abuse | Link to thisYeah Robert - it must have been those nasty Rad Indians... I guess. Oh but never mind, it's only Scientific American where we might expect some evidence based content in an article like this, but sadly it is no where to be found - only abusive comments.
Reply | Report Abuse | Link to thisRobert, I think I slept through that lecture too. The 12th century was a period of cooling in Europe, as I recall.One thing the article didn't mention that is going to have a profound effect on development of the west coast. The city of Monterey has already experienced a situation where the present population has depleted the ground water and it is being replaced by brackish sea water. Massive desalinations projects need to be considered if the west is to remain viable for agriculture, but I don't see that happening. As we are seeing in other aspects of our nations attitudes we have become the grasshopper who doesn't concern himself with the coming of winter. The rest of the world are the ants. When did that happen?
Reply | Report Abuse | Link to this@DarkWater and Howard,
Reply | Report Abuse | Link to thisThe class that you missed is the one on critical thinking. Allow me a brief transcript:
Teacher: Children, can a phenomena have more than one cause? Oh, I see Little Darkwater and Howard are not here. Bless their little sick hearts. Well for the rest of the class. Does anyone have an idea.
Jimmy 'booger' Johnson: Uh, no?
Teacher: Why?
Jimmy 'booger' Johnson: Well every one knows that only one thing can cause anything!
Teacher: That is incorrect. Consider that millions of years before humanity existed forest fires happened.
Jimmy 'booger' Johnson: Yes, and so...?
Teacher: It means that according to your reasoning that since forest fires happened way before humanity existed that humanity can not be the cause of forest fires now.
Jimmy 'booger' Johnson: I am sorry teacher but your premise is incorrect.
Teacher: How?
Jimmy 'booger' Johnson: Because my Daddy tells me the Earth is only 6,000 years old.
Teacher: You fail 10th Grade.
No need to thank me for filling in that gap in your reasoning skills . No, really I mean it.
It is disheartening to see that people still buy the coal and oil lobbyists propaganda. Global warming is real despite the monetary incentives to prove otherwise. Selfish ignorance is what got us to this horrible point and people who deny scientific facts are a cancer. HowardB. for an example. Your comment was childish, uneducated, and did not contribute to the story or discussion at all. Sir, go burn some fossil fuels in your own home with all the windows shut and tell me that doesn't have a dramatic effect on you. But that is different somehow, right? Please.
Reply | Report Abuse | Link to this@HowardB, you can't find evidence if you refuse to look. The fact that you've decided to bury your head in the sand because the truth doesn't fit your distorted world view is your own issue. This is a science news magazine. Its intent is not to publish the entire body of scientific evidence for every aspect of an article it is informing its readers of what is going on. People who are not afraid of the answers are free to explore the research if they chose. The fact that you have chosen not to look at the facts but instead troll sites that don't agree with you demonstrates that you have no interest in the truth only in advancing your prejudices.
Reply | Report Abuse | Link to thisIf you act like an idiotic troll you'll be treated like one.
@trent
Reply | Report Abuse | Link to thisHoly crap! That is your critical thinking best?
Forest fires in the past or present?
Lets take something as complex as the entire planetary climate environment and yell the "sky is falling" and whittle it down to whether people believe an action can have multiple causes. oh! and don't ask any questions, don’t ask for a live debate just trust what were telling you.
Here is critical thinking for you: Truth is constant but fact is ever changing. Case in point; "The world is flat" was fact, but it was far from the truth! Just replace the notion above with "the earth is warming due to man-made actions"; but don't forget this is the same crowd that was yelling "we are headed for another ice age".
Question those who want to control how you talk. If they control how you talk, they control how you think!
I think they were reasonably clear Howard. There is normal REGIONAL variability. As Darkwater already pointed out the Southwest was in a warm drought situation in the 12th century. Europe OTOH was getting cooler? Actually I'm not sure that is strictly true, but the point is no one region of the Earth stays at a constant climate, but the overall average can still remain the same or only vary slightly.
Reply | Report Abuse | Link to thisThe problem with your whole question is that you're attacking a straw man. NOBODY at all credible denies the existence of natural climate variability. What however we see now doesn't even look like normal variability. If you want to make a case that it is, first you have to sort out answers to a few nagging questions like:
1) Why is the current climate change world wide, this isn't local/regional variability.
2) Why are global average nighttime temperatures and winter temperatures and temperatures during periods of cloud cover rising RAPIDLY, exactly what is predicted by CO2 driven AGW and NOT explainable by any other known process.
3) If by some magic increasing atmospheric CO2 is NOT causing a temperature increase, then why not? It is easily verifiable high school level physics that has been established by experiment and theory for 150+ years that CO2 insulates the surface of the Earth and blocks long wave radiation. This certainly WILL increase the surface temperature of the Earth. If you want to deny that happens then you need to present some theory or evidence as to how and why and if there is some other effect in play.
4) Why is the temperature/altitude relationship behaving exactly as would be predicted if CO2 was warming the atmosphere and the Earth? Again this OBSERVATION only seems to match with AGW and not other hypotheses.
Never have these observations been explained in any satisfactory way except the simple straightforward interpretation that rising CO2 causes rising temperatures.
@Darkwater, "The 12th century was a period of cooling in Europe, as I recall." you might want to look at something called an atlas. There you'll find the surprising fact that the southwest US is not in Europe.
Reply | Report Abuse | Link to this@bfish, when people such as yourself talk in vagaries about who was wrong in the past and allowing open debate and how these systems are just so complex, it is clear that the only thing you are trying to achieve is sowing the seeds of doubt and mistrust. If you actually had any evidence you would present that. Instead you resort to conspiracy theories and innuendo. The debate is ongoing. That is science. So far every bit of evidence has supported AGW. The system is complex but even complex systems can be understood. And these are not the same crowd that said we were heading for another ice age. That is a denialists myth. But thanks for once again demonstrating the low moral character of the denialists who will lie, misrepresent the facts and invent conspiracies in order to preserve the status quo. A psychopath is someone who will gladly sacrifice others to advance their personal agenda. Now at least we know where you stand.
Reply | Report Abuse | Link to this"Holy crap! That is your critical thinking best?
Reply | Report Abuse | Link to thisForest fires in the past or present?"
Comprehension Reading Fail.
Answer this question. Can a phenomena have more than one cause?
"Its take something as complex as the entire planetary climate environment and yell the "sky is falling" and whittle it down to whether people believe an action can have multiple causes. oh! and don't ask any questions, dont ask for a live debate just trust what were telling you."
You know what I want? I want my question answered. Can a phenomena have more than one cause? Most adults can answer this question emphatically with a YES.
Why is it you lot go off into long diatribes?
"The world is flat" was fact,..."
I am sorry but you are not entitled to your own set of facts.
"...but it was far from the truth."
No, it was wrong from the beginning. Full stop. You are confusing belief with fact and playing a semantics game with fact and truth. People can have wrong beliefs. Believing in something with all your heart does not make it any more truer. Get over it.
"...but don't forget this is the same crowd that was yelling "we are headed for another ice age".
Now you are repeating a lie. A lie that has been yammered so many time that it has been the subject of peer reviewed paper:
The Myth OF The 1970s Global Cooling Scientific
Consensus:
http://journals.ametsoc.org/doi/abs/10.1175/2008BAMS2370.1?prevSearch=&searchHistoryKey=
It was a lie then and a lie now. In short it found that "The survey identified only 7 articles indicating
cooling compared to 44 indicating warming.
seven cooling articles garnered just 12% of citations"
Your lie is a lie it was never a truth. Just because you have been mislead by fossil fuel propaganda does not mean it was truth - ever.
Tharter
Reply | Report Abuse | Link to thisFirst, everyone needs to understand that the global average temperature exists as a theoretical concept. Not a childhood fact handed down through the generations as the be all and end all basic concept. It is a recent manifestation at best. http://www.numberwatch.co.uk/Temperatures.htm
How about solar output variation and its affect your global variation? I believe this has been touched on by many scientists.
http://www.skepticalscience.com/solar-activity-sunspots-global-warming.htm
How about the science behind CO2 following Temperature rather than the other way around?
http://www.noteviljustwrong.com/
Since when did a .5 global degree variable constitute a man-made catastrophe? (GISS NASA Number). The planet; as we know has been way hotter in the past. Way hotter. You must also weed out all the background noise created by climate models; which net you nothing accept what the person using them wishes to present.
For those of us trying to educate ourselves, rather than believe what may be fed to us, it is difficult to find the "Truth". There is a theory and a rebuttal for every point you make as well as the other side. In the end if we can’t predict the weather successfully do we really want people making such huge policy and finance decisions on things they don’t totally understand?
@Rober Schmidt,
Reply | Report Abuse | Link to this"This is a science news magazine. Its intent is not to publish the entire body of scientific evidence for every aspect of an article it is informing its readers of what is going on. People who are not afraid of the answers are free to explore the research if they chose"
This can not be said enough. I keep on seeing these clowns ask that every news article review the entire body of evidence. They seem incapable of using a search engine. If they had read the first paragraph they would have gotten the following clue:
"...according to research published yesterday in the Proceedings of the National Academy of Sciences."
Going to the the big G and inputting the term: "Proceedings of the National Academy of Sciences" gives the following result:
http://www.google.com/search?q=Proceedings+of+the+National+Academy+of+Sciences&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a
And look! The first result leads me right to the PNAS journal and the very article this bit of journalism is reporting on. This took me less than 15 seconds to do. Can it be any easier? What better testimony do we need for their intellectual laziness?
DarkWater, Howard & Bfish,
Four words: Google is your friend.
There is absolutely no reliable data that indicates that the Southwest will get more or less rain as a result of higher atmospheric CO2 levels. There is not even a single model that has been validated that will show the degree of warming in that region over the next 25 to 50 years.
Reply | Report Abuse | Link to thisThe headline would have been more accurate to state “Southwest may be 1st victim of warming, or it may get wetter and be 1st Beneficiary”
Good observations but again too simplistic and taken too far. Credible warmers and skeptics are coalescing their ideas down to an established natural warming trend that humans may be contributing too perhaps 20%. The fact is we have to learn to live with what we get and try not to make it worse. Our species has been dealing with this phenomenon for some 20K and did rather well. Remember, Venice was not built in the water. It was built on dry land in the middle of a swamp. The past 700 years of 1+ foot increase in ocean level per century has put it in the water. This has not been a disaster for the Venetians nor does it have to be for us.
Reply | Report Abuse | Link to thisWhat is essential is that we stop trying to prevent something that is not preventable. Tying up world GDP so we can make believe we all are little dutch boys and girls with our finger in an imaginary dike will not help. By the same token, ignoring the issue will accomplish nothing as well. Treating this issue as a penance or a prize will not help anyone in the long run.
@Sisko, what would an article on climate be without our favourite vector of the Heritage Foundation and all around pathological liar Sisko? Apparently the headline you read was "free troll food here".
Reply | Report Abuse | Link to this"First, everyone needs to understand that the global average temperature exists as a theoretical concept."
Reply | Report Abuse | Link to thisYes, just like gravity, plate tectonics, and germ theory.
"It is a recent manifestation at best. http://www.numberwatch.co.uk/Temperatures.htm"
I will have to remember that those pesky things as Ice Age's and their accompanying glaciers going far south really was just a chance thing. All that hullabaloo about Milankovitch Cycles? Just a bunch of hooey.
Here is a challenge for you: Go find the relevant peer reviewed papers that say what the web site says. Go along now.
"How about solar output variation and its affect your global variation? I believe this has been touched on by many scientists.
http://www.skepticalscience.com/solar-activity-sunspots-global-warming.htm "
Your first link contradicts what you say. Taking a perusal of the article I find the following:
"In the last 35 years of global warming, sun and climate have been going in opposite directions."
And:
"However, between the 1960s and the present day the same solar measurements have shown that the energy from the sun is now decreasing. At the same time temperature measurements of the air and sea have shown that the Earth has continued to become warmer and warmer. This proves that it cannot be the sun; something else must be causing the Earth's temperature to rise."
Then they show a graph with temperatures and solar activities diverging.
Then in the concluding sentence:
"So, while there is no credible science indicating that the sun is causing the observed increase in global temperature, it's the known physical properties of greenhouse gasses that provide us with the only real and measurable explanation of global warming."
I do believe you scored what is called in soccer a 'own goal'.
"Since when did a .5 global degree variable constitute a man-made catastrophe? (GISS NASA Number)."
The natural variability for any year is about .3 degrees. But we are not looking at any one single year we are looking at the TREND. The TREND shows a unmistakable warming. That you can not tell the difference between a TREND and natural variability tells me mountains about the state of your knowledge.
http://data.giss.nasa.gov/gistemp/graphs/Fig.A2.lrg.gif
That trend is projected to continue.
"The planet; as we know has been way hotter in the past."
Yes, and this precludes humans causing the warming now, how? We have already been through this. Can the same phenomena have different causes? Why will you not answer this question?
@robert-- Another stupid comment on your part.
Reply | Report Abuse | Link to thisDo you believe that there is any reliable data that predicts that the southwest will get less rain as a result of higher CO2.
The answer is there is not, and my comment was accurate. Scientific is publishing propagagda not science.
btw fool, I have not connection to any agency or company in spite of your perception.
@Trent1492, it is just a tactic. It is very much a straw man fallacy. A science headline contains nowhere near enough data to either support or undermine its underlying hypothesis. So what they do is use that incompleteness or oversimplification to discredit the hypothesis. It would be refreshing if even one of them was scientifically literate enough to be able to argue the facts and bring something new to the table but as always they just seem to be parroting denialist blogs and acting like they just invented it today.
Reply | Report Abuse | Link to this@Sisko, "The answer is there is not, and my comment was accurate." well as long as you agree with yourself who are we to disagree? The scientists who wrote this article and who have actually studied the subject could have saved themselves some work if they had just asked your opinion. But I am starting to believe you aren't a shill for big oil. Even they aren't that desperate. A trained monkey randomly pounding on the keyboard could offer more persuasive arguments.
Reply | Report Abuse | Link to this@SSM,
Reply | Report Abuse | Link to this" Credible warmers and skeptics are coalescing their ideas down to an established natural warming trend that humans may be contributing too perhaps 20%."
Says who? What is this coalescing you speak of?
"Our species has been dealing with this phenomenon for some 20K and did rather well"
Tell me, again how New York and London did 20k years ago. Oh, wait...
"Remember, Venice was not built in the water. It was built on dry land in the middle of a swamp. The past 700 years of 1+ foot increase in ocean level per century has put it in the water."
WOW. You just claimed that sea level has risen by seven feet in the past seven hundred years. Now I am going to ask for evidence. Peer reviewed evidence. Tell me, again how the worlds coastal cities managed this seven feet again.
Now onto Venice. I am somewhat familiar with this problem Allow me to give you an excerpt from a NOVA show on why Venice is sinking:
CHARLES E. MCCLENNEN: Underneath Venice is a salt marsh. Venice is sitting on several layers. The uppermost and thinnest are the lagoon sediments, fairly muddy and, in part, salt marshes, and that's what Venice was built on. Below that is nearly a mile thick of river sediments. Those sediments are slowly compacting.
NARRATOR: In effect, Venice is sitting on a giant sponge filled with water. As the weight of Venice pushes down on the sediments, it squeezes some of the water out, and the sponge gets thinner.
ALBERT AMMERMAN: What we can always see in the archeological record is the gradual, progressive buildup of the land surface. We can see five or six floors, with just one after the other, six inches, a foot, gradually being built up. Flooding would always be a problem, so their way to deal with it was essentially to come in and continually be adjusting the ground level upward, layer after layer after layer.
NARRATOR: Anything built on these marshes would eventually sink into the sea. So when a building was too-often flooded, the Venetians would either raise up the floor or they might tear the whole thing down and build a new structure on the old foundation.
http://www.pbs.org/wgbh/nova/transcripts/2914_venice.html
End of Excerpt.
So in effect the buildings pushed down on the swampy ground and when it was too low they use to collapse the building and build on the rubble. But no one wants to do such a thing to a master piece such as the Doges Palace.
@ssm1959, "Our species has been dealing with this phenomenon for some 20K and did rather well." our species did exceptionally well after the meteorite wiped out the dinosaurs. Let's see if we can make that happen again. Our species also did very well after the second world war. We need more world wars perhaps. You need to take your own advice, "Good observations but again too simplistic and taken too far."
Reply | Report Abuse | Link to this@Sisko,
Reply | Report Abuse | Link to thisSisko Says: There is not even a single model that has been validated that will show the degree of warming in that region over the next 25 to 50 years.
From the Proceedings of the National Academy of Sciences publication that this very article talks about:
However, hydrological model runs from downscaled Intergovernmental Panel on Climate Change Fourth Assessment climate change simulations suggest
that the region is likely to become drier and experience more severe droughts than this. In the latter half of the 21st century the models produced considerably greater drought activity, particularly
in the Colorado River Basin, as judged from soil moisture anomalies and other hydrological measures.
Future Dryness in the Southwest US and the Hydrology of the Early 21st Century Drought
PNAS 2010 107 (50) 21271-21276; published ahead of print December 14, 2010,
And then again:
We use twelve global climate models (GCMs) used in the
Intergovernmental Panel on Climate Change (IPCC)Fourth Assessment Report (10, 11) to investigate effects of climate change on the Southwestern United States. The full list of models is given in SI Text (section S3).We further analyze the output of two of the
twelve models, Geophysical Fluid Dynamics Laboratory (GFDL) CM2.1 and Centre National de Recherches Météorologiques(CNRM) CM3. These two models produce temperature and precipitation simulations falling within the larger ensemble of changes from the set of 12 GCMs, and were among the few models
that provided the continuous daily output necessary to driveVIC. More information on the simulation quality of these models is given in SI Text (section S3).
http://www.pnas.org/content/107/50/21271.full.pdf+html
Shall I list for you every model they used or have you reached your daily dose of embarrassment today?
Can a phenomenon have more than one cause? Sure, rather pointless in the grand scheme of the topic, but if it makes you feel better.
Reply | Report Abuse | Link to thisOur long diatribes are designed to get people to lift their heads out of the noise, think for themselves. They are bombarded with all this global warming crap and take it for face value. Most will not take the time to sift through and do their own research (to find the truth). Any article or noise to this end is not helping; it only serves to propagate the misinformation.
I am of the opinion, that if cooler heads are to prevail you pick apart every attempt to further the propaganda. This topic, unlike other debatable topics in our society has the potential to cause economic and real damage to the environment because of the zealots that spread this stuff. Can you believe that science is suggesting we pollute the ocean with iron to reduce CO2. http://www.futurepundit.com/archives/002056.html
This is just one example. There are a millions more.
The case for a "greenhouse problem" is made by environmentalists, news anchormen , and special interests who make inaccurate and misleading statements about global warming and climate change. Even though people may be skeptical of such rhetoric initially, after awhile people start believing it must be true because we hear it so often, from so many places. It’s the resident fad.
http://www.geocraft.com/WVFossils/ice_ages.html
Believing in something is one thing (fact, truth or whatever you wish to call it), however a scientific journal or any venue purporting to be scientific that claims anything has a consensus should be viewed with skepticism. There is no such thing as Consensus in the scientific process. Everything you are bombarded with on this subject is based on a lie and therefore should be debated; even on simple insignificant articles such as this, so some stupid scientist with a chemical set who thinks he is the center of all things doesn't step on his own phallus and really destroy it in the name of saving the planet.
Question for everyone following this article?
Reply | Report Abuse | Link to thisIs a climate model something that can accurately predict anything? or is it just a tool for scientists to tweak different variables to see what the computer thinks will happen?
Any article, journal or paper that uses climate models to predict anything should be ignored. Peer reviewed or not.
Climate models have not been shown to give us anything substantial, unless you want to count the hockey stick graph. Ask the opinion of scientists who have been in the field long enough to see the birth of climate models and how they have completely destroyed the credibility of the mainstream scientific process.
http://www.youtube.com/watch?v=3E-ryS5ehPo
Hey as long as they put Climate change in the heading it gets top billing.
Your example is wrong. Western scholars have known that the world is round since the time of Aristotle (5th Century BC) at least. The size was found by Eratosthenes in 100 AD. In Columbus's time, no one believed the world was flat. The Church (catholic) had been quoting Aristotle for a couple of hundred years on that. The Arabs, Chinese and Indians all knew about it from the Greeks. Columbus had problems in Spain because he thought the circumference was 10,000 miles less than it is. The Scholars knew he was wrong. They didn't know America was here. They thought it was all ocean, all the way to China.
Reply | Report Abuse | Link to thisYou need to find a new straw man. The one you have is broken.
Your Physics is a bit rusty.
Reply | Report Abuse | Link to thisCO2 is a "greenhouse gas" but it isn't a very good one. a greenhouse gas is one that is transparent to visible light (or ultraviolet) but opaque or scattering to infrared light. CO2 does do this, but not strongly. There are better greenhouse gasses.
The best Greenhouse gas I am familiar with is a chlorofluorocarbon, Freon. It is around 1,000 times more effective than CO2, maybe more. This was banned around 20 years ago in the US, to cure ozone depletion. Freon is also a catalyst for conversion of ozone to molecular oxygen. Freon is still manufactured and used in the "third world". It is more effecient in AC compressors than the replacements.
The next most efficent greenhouse gas that is in the atmosphere that I am familiar with is water vapor. It is around 100 times more effecient as a greenhouse gas than CO2. This is followed by Sulphates. Sulphuric acid charged water droplets are believed to be responsible for more warming on Venus than the CO2 atmosphere is, even though they are only about one part in a thousand of the atmosphere. Next is methane. CO2 comes after methane.
The total effect needs to be calculated by the concentration of the gas. Freon is only there in a few PPM. It does stay around for a century or so. Water Vapor is higher than current CO2 concentration, and higher than any known CO2 concentration for the past Billion years. Methane is less than CO2 concentration by a little bit, but is close to 10 times more effective as a greenhouse gas.
CO2 just cannot be the whole story. It is the easiest to regulate. But, regulation will not solve the problem. Freon was regulated, but is still being made. Why would CO2 be any different?
Methane regulation will never get more than token efficiency.
Water vapor reduction IS what the Article is warning of.
Thirty years ago they were worried that we would be done in by Global Cooling. We cleaned up the particulates, and the cooling stopped. Now Warming is the problem. A quick fix is to let the power plants get dirty again. That would mean other problems, however.
Wrong.
Reply | Report Abuse | Link to thisVenice was built in a bay. That was to protect the rich folks from marauding Huns and Germans. Horses don't swim all that well. not when carrying men in armor.
Venice is sinking, and has been for centuries, but that is because the city is built on wooden piers driven into the muck on the bottom of the bay. The muck is not stable. The city has been rebuilt several times. Most recently in the 13 and 1400's.
The current flooding problems are because the city sunk below the storm surge level from the Adriatic. Italy has tried to place surge walls on the entrance to the bay as a fix. Ultimately, they will have to jack up the buildings, or rebuild again.
This example was dramatic, but wrong.
A better example might be Greece, where several 2500 year old cities are now underwater, but on the other side, there are cities equally as old that have harbors now 50 feed above water level. The ground there is tilting. There is also Cleopatra's palace in Alexandria. That sank during a large earthquake. there are historical records of when that happened. there are cities in southern Mexico that have the same problems.
Seas rise and fall, so does land. That makes it hard to give real figures.
Well Robert, who or what?
Reply | Report Abuse | Link to this@Bfish,
Reply | Report Abuse | Link to this"Can a phenomenon have more than one cause? Sure, rather pointless in the grand scheme of the topic, but if it makes you feel better."
Oh, really? Then why are you and your cohorts endlessly saying such irrational and silly things as:
"I wonder who was generating all those 'green house gases' in the 12th century ? ................"
Same thing goes for saying that temps, and sea level. Same reasoning applies.
"Our long diatribes are designed to get people to lift their heads out of the noise, think for themselves."
No they are not. They are simply the venting of fossil fuel talking points. Ignorant ones at that.
"They are bombarded with all this global warming crap and take it for face value."
Irony: You are doing it right, bfish.
"The case for a "greenhouse problem" is made by environmentalists, news anchormen , and special interests who make inaccurate and misleading statements about global warming and climate change."
This is what irony looks like. You unquestioningly parroting fossil fuel talking points. Polly want a cracker?
"I am of the opinion, that if cooler heads are to prevail you pick apart every attempt to further the propaganda."
I have come to the conclusion that you are in the running for the Unintentional World Irony Championship.
"http://www.geocraft.com/WVFossils/ice_ages.html"
Is site cobbled together by a mining engineer who is clueless about paleoclimatology.
Here try this fantastic lecture by a paleoclimatologist. This lecture was given at last years American Geophysical Union meeting. It was by the way a honors lecture.
The Biggest Control Knob: Carbon Dioxide in Earth's Climate History.
http://www.agu.org/meetings/fm09/lectures/lecture_videos/A23A.shtml
"Climate models have not been shown to give us anything substantial, unless you want to count the hockey stick graph."
Ignorance thy name is Bfish:
1. The Hockey Stick is a result of studying climate proxies. A study that has been REPLICATED a half-dozen times using different proxies and methodologies.
2. Climate Models have been substantiated repeatedly. E.g back in the 60's it was predicted that the stratosphere would cool while the troposphere would warm; that was decades later shown to be happening.
"There is no such thing as Consensus in the scientific process."
There is such a thing as a consensus of evidence.
"Ask the opinion of scientists who have been in the field long enough.."
http://www.youtube.com/watch?v=3E-ryS5ehPo"
This Year's Model
http://www.youtube.com/watch?v=D6Un69RMNSw
You know Bfish,
Reply | Report Abuse | Link to thisYou ask a lot of questions and make a lot of assertions but you never ever stop to answer any. This tactic of asking and asserting numerous subjects in the hope of something sticking is a creationist tactic called the Gish Gallop. Perhaps you should stop and think about that for a moment before you move on to your 14th talking point.
Very impressive quotations from the report, unfortunately having nothing to do with any formal verification and validation procedures applied to model predictions.
Reply | Report Abuse | Link to thisThe research report, "Future dryness in the southwest US and the hydrology of the early 21st century drought" "Supporting Information" document does state:
"VIC has been used extensively in a variety of water resources
applications; from studies of climate variability, forecasting and climate change studies (2, 4, 7–12). The model's soil moisture estimations produce reasonable agreement with the few point measurements available (4), and VIC-simulated streamflow validates well with observations when the model has been calibrated using streamflow data (4, 12)."
However, it does not appear that these iterations of the VIC model were calibrated using streamflow data.
The researchers did use historical temperature and precipitation observational data to drive the VIC model, but only to obtain model projections of unmonitored hydrological variables.
They used two of the twelve IPPC models to provide daily temperature and precipitation projections necessary to drive the VIC model. The report does include a chart of historical droughts and their durations for comparison with their projected droughts but I found no description of their model iterations being verified using historical data. The researchers did mention that they compared the projections of their model iterations with previously published results to check for proper model execution.
Their current projections of future conditions have obviously not been validated against actual future conditions. So I think that it's accurate to state that this model has not been verified or validated.
I do not specifically question any of the model's predictions, as I'm certainly not sufficiently knowledgeable of hydrology to comment. I can say, however, that I would not recommend making extensive public policy decisions based on these projections until they can be validate for at least several years against actual future conditions.
As for your pooh pooh - pooh!
This is just to set some of YetAnotherBob's 'facts' straight.
Reply | Report Abuse | Link to thisYAB says that CO2 is a weak greenhouse gas compared to CFC-12, CFC-12 is ~10,000 more effective as a greenhouse gas than CO2. That is true on a per-molecule basis. What he hasn't told you is that CFC-12 is around 533 ppt (parts per trillion) and CO2 is around 388 ppm (parts per million). In a representative sample of atmosphere with 1 trillion molecules in it, there would be
~388000000 molecules of CO2
533 molecules of CFC-12
Let's take that times the CO2 equivalency value of 10,000.
388,000,000 CO2
5,330,000 CO2 equivalency of CFC-12
So, even if on a per-molecule basis CFC is 10,000 times more effective, it contributes a tiny fraction of the IR absorption that CO2 does. It's like YAB is pointing out that a $1,000 bill is worth more than a $1 bill and expects to make some point with that. Which is more, 1 $1,000 bill, or 100,000 $1 bills?
There are other un-facts in YABs comment, but you can decide for yourself if they are worth the trouble of fact-checking.
Evening Sisko. I see little trent and smitty are ranting again and still calling names. So sad. Site trolls, you just have to laugh at them. I went to the site little trent mentioned and found this quote in the first paragraph-"Although the high temperatures and aridity are consistent with projected impacts of greenhouse warming, it is unclear whether the drought can be attributed to increased greenhouse gasses or is a product of natural climatic variability." Guess he missed that part. Computer modeling is highly over rated. I'll sign off now so the trolls can scream. Keep up the good work, Sisko.
Reply | Report Abuse | Link to this@Jt Dwyer,
Reply | Report Abuse | Link to this"Their current projections of future conditions have obviously not been validated against actual future conditions."
Do you read what you write? You how could they validate their future projections unless they had a time machine?
Further in the paper they say about there model:
"VIC has been shown to produce realistic simulations of the hydroclimate’s mean and variability in this region (8, 19, 20). We will referto these estimates as VIC-OBS. SI Text (sections S1 and S2) contains details on the hydrological modeling process."
You might just want to peruse those references. Such as the finding that last fifty years of climate behavior in the Southwest can not be explained by natural variability alone.
"However, it does not appear that these iterations of the VIC model were calibrated using streamflow data."
From the VLC model web site:
River Routing Model
* Routing of stream flow is performed separately from the land surface simulation, using a separate model, typically the routing model of Lohmann, et al. (1996; 1998)
* Each grid cell is represented by a node in the channel network
* The total runoff and baseflow from each grid cell is first convolved with a unit hydrograph representing the distribution of travel times of water from its points of origin to the channel network
* Then, each grid cell's input into the channel network is routed through the channel using linearized St. Venant's equations
http://www.hydro.washington.edu/Lettenmaier/Models/VIC/Overview/ModelOverview.shtml
So a stream flow model is produced separately yet is integrated with the findings.
Shorter Postman: I can call people names but I object when the like is returned.
Reply | Report Abuse | Link to thisThe process of model validation for a model that predicts future conditions requires that its predictions be compared with actual future results.
Reply | Report Abuse | Link to thisMy quotation and comments were based on the "SI Text (sections S1 and S2) contains details on the hydrological modeling process". Perhaps you should refer to your own references so you can understand what I've explained!
This research paper stated:
"VIC-simulated streamflow validates well with observations _when_ the model has been calibrated using streamflow data."
I infer from this that these researchers _did_not_ clibrate their iterations of the VIC model with streamflow data, a seperate process requiring an enormous amount of additional data.
Your quotations only indicate that a streamflow model _can_be_ separately produced and integrated into the VIC model, but it is not required and in this case apparently was not.
Regardless, I included that quotation from the supporting information because it was the _only_ reference to model validation, and it referred to validation of previously published results from reports of VIC based analyses, _not_ this research.
The results of this study _have_not_been_validated_ with actual conditions.
That does not invalidate these results: they cannot be reasonably evaluated prior to formal validation.
@darkwater: "The 12th century was a period of cooling in Europe, as I recall."
Reply | Report Abuse | Link to this===================
Nah, you recall wrong.
Between AD 950 to 1250, the Medieval Climate Optimum was a time of warm climate in the North Atlantic region, that may also have been related to other climate events around the world during that time, like the southwestern U.S.
@sisko: "The headline would have been more accurate to state Southwest may be 1st victim of warming, or it may get wetter and be 1st Beneficiary ."
Reply | Report Abuse | Link to this=========================
WoW!....quite a leap of faith by sisko, to predict the possibility of a DESERT turning into a rain forest!
Ever been to the desert southwest?
@sisko: "Scientific is publishing propagagda not science."
Reply | Report Abuse | Link to this=================
Another of your attacks on SciAm, when they clearly are publishing research published December 13 in the Proceedings of the National Academy of Sciences?
The study's lead author, is University of Arizona paleoclimatologist Connie Woodhouse, who's work is one of several papers on climate change and drought in the Southwest published yesterday by PNAS.
Glen MacDonald, director of the University of California, Los Angeles' Institute of the Environment, is an author of another one of the new papers. Geography professor Glen MacDonald specializes in the study of water scarcity, and is an expert on the effects of global warming and drought on ecosystems.
John Sabo, a senior fellow at Arizona State University's Global Institute of Sustainability, served as lead author for another one of the new studies published. He is a stream and riparian community ecologist, who typically uses experimental and comparative approaches in field settings to answer questions about how the land-water boundary in riparian zones mediates energy or water fluxes and between rivers and riparian habitats.
Peter Gleick, president of the Pacific Institute and is an author of another analysis. He is a scientist working on issues related to the environment, economic development, and international security, with a focus on global freshwater challenges.
What are your qualifications sisko, to attack these learned scientists, and experts in their fields, and just how can you call their published work in the PNAS "propaganda?"
Of course, you just parrot the usual blog propaganda!
FYI - such a shift would not be unprecedented: as I understand, for a duration of about a thousand years somewhere around 5,000 years ago, the Sahara desert had an annual monsoon season and supported a significant population of cattle herders.
Reply | Report Abuse | Link to this"for a duration of about a thousand years somewhere around 5,000 years ago, the Sahara desert had an annual monsoon season"
Reply | Report Abuse | Link to this========================
So what? The desert southwest has an annual monsoon season now during the summer, but it's still a desert!
Have you ever been to the desert southwest?
"I do not specifically question any of the model's predictions, as I'm certainly not sufficiently knowledgeable of hydrology to comment."
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Why not, since everyone one else with less knowledge of hydrology than those scientists publishing peer-reviewed research papers in the Proceedings of the National Academy of Sciences, have done exactly that?
As climate scientist Richard Seager said, "Over the past three decades, a trend toward more frequent La Niña weather patterns has helped drive Southwestern drought, by influencing sea surface temperatures in the tropical Pacific Ocean."
Reply | Report Abuse | Link to thisWhether that trend will continue in coming decades isn't clear.
So what?
Reply | Report Abuse | Link to thisSo I don't think you know what you're talking about! There is no region defined as "the desert southwest". Even the area defined by "the Southwest" is regionally variable. It is most often considered to include only AR, NM, NV, UT and CO. To reasonably answer your challengingly ignorant question, I have been to the Southwest many dozens of times. Have you ever been there? Do you know where it is?
Only a few relatively tiny true deserts exist within the Southwestern U.S., whereas the Saharan desert spans the entirety of North Africa. I have seen the deserts of the Southwestern U.S. bloom with wildflowers following a rare gully washer, which never occurs these days in the Sahara. So, have you ever been to the Sahara?
Obviously, if the Sahara could sustain grasslands, lakes, cattle, alligators, giraffes and large populations of people for a thousand years, it could also occur in the Southwestern U.S. I expect increasing drought and widespread desertification in the Southwestern U.S. for the rest of this
century, but none of us (including climatologists) know with any certainty what will unfold - least of all you.
"So I don't think you know what you're talking about! There is no region defined as "the desert southwest". Even the area defined by "the Southwest" is regionally variable. It is most often considered to include only AR, NM, NV, UT and CO. To reasonably answer your challengingly ignorant question, I have been to the Southwest many dozens of times. Have you ever been there? Do you know where it is?"
Reply | Report Abuse | Link to this============================
As usual, all we can expect from you is juvenile attacks, spewing more of your vile and willfully ignorant remarks, much like including Arkansas(AR) in the desert southwest. Since I've lived in the desert southwest my entire adult life, did all my scientific research in that section of the U.S., and still continue to monitor Rocky Mtn. snowpack and spring runoff, as well as the devastating beetle kill in the mountains due to warmer winters and a prolonged drought since 2001, I'd say you are totally clueless and much more comfortable in your own little delusional world.
Since deserts are defined as areas with an average annual precipitation of less than 250 millimetres (10 in) per year, and much of the southwestern U.S. is classified as semi-arid to arid terrain, with more rainfall associated with higher terrain and mountains throughout the region, it is generally thought of as the "desert southwest." That's a fact, no matter how much you want to fight it with your anti-science rhetoric and continuous juvenile ad hominem attacks!
So what!
Reply | Report Abuse | Link to this@trent— I have attached a link to a good summary of why you and others should not readily accept the results from the IPCC models you posted.
Reply | Report Abuse | Link to thishttp://judithcurry.com/2010/10/03/what-can-we-learn-from-climate-models/
@trent— I have attached a link to a good summary of why you and others should not readily accept the results from the IPCC models you posted.
Reply | Report Abuse | Link to thishttp://judithcurry.com/2010/10/03/what-can-we-learn-from-climate-models/
Lakota—since you ask, I live in Tucson AZ, so yes I am very familiar with the southwest .
Reply | Report Abuse | Link to thisThe quote you referenced has to do with short term weather patterns and not long term climate change due to higher CO2 levels. CO2 levels will undoubtly continue to rise, so it will be interesting to see what climate will be like in 25 years.
The headline by Scientific American is meant to be sensational. There is no reliable data or model than is able to predict what the rainfall will be in the southwest even 2 years from now, much less 25 years from now.
Let's move a bit further north and talk about Lake
Reply | Report Abuse | Link to thisMead for a minute. At current trends, in seven years there will be insufficient water to produce electricity at Hoover Dam. Las Vegas will go dark. A plan being studied proposes to pump the aquifier into the lake to sustain the electric output. But the planning and construction will take more than seven years to complete and the aquifier can never be replenished.
As a rancher in Western Colorado, I resent the fact that our agricultural water is being stolen by all the fools and suckers who are entertained by the greedy and criminal gambling industry. I want to see Las Vegas die. What don't you get about "WE GROW YOUR FOOD"?
Civilization, by necessity, began at places where water was plentiful and the land fertile. In the American Southwest, civilization grows where water is scarce and the land barren. Proves that most modern people are stupid and easily manipulated.