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krahmes
Social climber
Stumptown
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Jan 26, 2015 - 09:32pm PT
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Those trees grew when streamflow in the W Walker was so low that Jeffery Pines could grow for 100-150 years. This period was known as the medieval climate anomaly and was characterized by two periods of severe drought in the western Great Basin. The two periods were broken up by an interval of increased precipitation lasted maybe 80 years and caused the river to rise and kill the first set of trees. Drier times retruned and the next set grew before the climate became wetter. Annual precipitation totals estimated during the dry times of the walker trees are not unlike the last few years, but they lasted for 100+ years. The river channel flows over bedrock and is constrained by bedrock, alluvial, and glacial landforms so the argument that the river flowed elsewhere doesn't work.
I’m intrigued by the picture of the stumps in the river but confused by the explanation. So those stumps have been carbon dated to have died 750 year before the present? As I understand the medieval warm period is defined as being between 950-1250 AD. Were the trees buried and then exhumed in the W Walker flood of 1997? While the granitic bedrock is tough material, even granite will erode. As for alluvial and glacial landforms I don’t understand why a river like W Walker wouldn’t move those; the course and banks of W Walker certainly got moved around in 1997 flood and the state highway departments put it back to the way it was.
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doc bs
Social climber
Northwest
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Jan 27, 2015 - 12:09am PT
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No snow in PNW and more sun than rain. We've been riding mt bikes instead of skiing, all the goods are on Mt Rainier and Baker right now.
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Gnome Ofthe Diabase
climber
Out Of Bed
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Jan 27, 2015 - 02:43am PT
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HOW BAD IS IT??
bad, Bad, BAD!
We sat on the fence with CFC's in aresol cans for to long as well
We never learn and never wil!
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stevep
Boulder climber
Salt Lake, UT
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Jan 27, 2015 - 07:40am PT
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Well, clearly on a geological timescale there have been severe climate changes and droughts and "California" has endured.
Even on a the scale of a bristlecone or sequoia's lifespan that may be true.
But the last 200 years have completely changed things. How well have the grizzlies or the sequoias endured over that time frame? Human effects on the environment in a place like CA totally change the equation. Maybe not for the granite, but for just about everything else.
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stevep
Boulder climber
Salt Lake, UT
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Jan 27, 2015 - 07:53am PT
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Further crazy info from the National Weather Service in SLC yesterday:
"While we did not break many temperature records in Utah's valleys due to inversion conditions, we did have record temperatures above the surface. Our office sends up weather balloons twice a day, every day, and has been doing so since 1956. On our balloon release this afternoon, we recorded a temperature of 7.8 degrees Celsius at the pressure level of 700 mb (that is, approximately 10,000 feet above sea level). This is the warmest temperature we have ever recorded at that level between December 17 and March 21."
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Mike Bolte
Trad climber
Planet Earth
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Jan 27, 2015 - 08:04am PT
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Dingus - not sure what you mean by that. Certainly the climate models for at least the past 15 years have indicated a warming leading to a higher ratio of rain/snow and an overall drying of California this century. The last three years could be on that trend.
EDIT: ah, of course we have a good historical record of a big spectrum of droughts from dry years to 200-year dry spells. Put these variations on top of a general trend and you do change the probabilities for any year or decade or century being drier than the historical averages.
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John M
climber
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Jan 27, 2015 - 08:11am PT
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I think what Dingus is saying is that, based on the evidence presented above about the stumps, that there have been severe droughts in California history pre industrial revolution, that this means that one can not rule out that this current drought is not just another one of those droughts, for which we do not know the reason.
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Flip Flop
Trad climber
Truckee, CA
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Jan 27, 2015 - 08:34am PT
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Causation vs . Correlation please.
There is obvious correlation. You can use the term causation or dependence to obfuscate the issue, but correlation is exactly how we study things like warming vs. warming.
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dirtbag
climber
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Jan 27, 2015 - 08:36am PT
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Thanks for the sierra nature notes link, dingus. Good reading!
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stevep
Boulder climber
Salt Lake, UT
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Jan 27, 2015 - 08:51am PT
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Agree, difficult to prove causation or correlation one way or the other.
But the fact there have been significant warmer and drier periods in the distant, pre-civilization past doesn't mean that this one isn't either partly driven or worsened by human-caused global warming.
Either way, I'd say that trying to definitively answer that question is somewhat irrelevant for the current and near future generations of humans and the environment in the West. Regardless of the cause, if we're entering a longish period of warmer and drier conditions, and we've made economic/resource/planning decisions over the last 100 years based off of wetter, cooler conditions, we and the environment may have some problems going forward.
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10b4me
climber
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Jan 27, 2015 - 08:54am PT
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Is there a correlation between the dry winters, in the west, and wet winters, in the east?
Also, I haven't paid a whole lot of attention, but it seems as though the middle of the country has had a pretty mild winter.
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WBraun
climber
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Jan 27, 2015 - 08:54am PT
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Today it is raining.
The drought is officially over.
Until tomorrow when it stops raining ......
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10b4me
climber
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Jan 27, 2015 - 09:12am PT
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Water conservation without controlling new users, will never solve the problem. Growth must be curtailed, agricultural growth most of all. While I agree, I don't see that happening.
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WBraun
climber
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Jan 27, 2015 - 09:19am PT
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Water never runs out.
Water is always there but not given by Nature because of your criminal activities against it.
Stop your criminal activities against Nature and all your water will come nicely ......
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10b4me
climber
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Jan 27, 2015 - 11:19am PT
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Water is always there but not given by Nature because of your criminal activities against it.
Stop your criminal activities against Nature and all your water will come nicely ......
yup,and therein lies the rub.
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krahmes
Social climber
Stumptown
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Jan 27, 2015 - 08:30pm PT
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Thanks Dingus for the paper. The C14 data confirms that the trees grew during the medieval warming period which corresponded with severe drought in California during that time. While I accept the paleoenvironmental interpretation of the paper: a drier climate near a smaller to non-existent Walker River; I remain skeptical of the inference that these stumps have been sitting exposed in the bottom of the Walker River bed for 700 years. But whatever.
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Bob Harrington
climber
Bishop, California
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Jan 27, 2015 - 08:56pm PT
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The California State Climatologist gave a briefing at the Public Policy Institute of California titled "Climate, Drought, and Change". Of the many illuminating graphics, I was most struck by this one, a scatter plot of annual precip and annual average temperature for the period 1895-2013.
There is not any correlation between precip and temperature, but look at the years since 2000 (black boxes). Since 2000, the precip is both above and below average (yellow triangle is average), but every year has been above average temperature. Droughts in the future are going to be different, because they will be hotter, which will place greater heat stress and evaporative demand on crops, reservoirs, and wildlands than a similar precipitation-year a few decades ago.
Remember that the Seager et al. study discussed a few hundred posts ago, which used modeling to conclude that the current drought was unrelated to climate change, looked only at precip anomalies. Precip is a big part of the picture, but it's not the only part. This current drought is dry, and that aridity is being exacerbated by warmer than normal (average) temperatures, that are likely at least partly a result of fossil fuel burning.
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Bob Harrington
climber
Bishop, California
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Jan 28, 2015 - 06:52am PT
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Hmmm... They work for me, so I don't know what to do to fix them. No pay wall.
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