There was an interesting story in the Las Vegas Journal Review on August 20th. which had a passage and quote from California Senator Diane Feinstein (emphasis mine):
Both U.S. Sen. Dianne Feinstein, D-Calif., and Ensign announced that they and other members of their delegations will reintroduce a bill in Congress to provide $390 million for additional preservation projects at Lake Tahoe.
Ensign said some have called the summits “publicity gimmicks,” but they are an important way to focus at what still needs to be done.
He said he has noticed how the dense forest around the Nevada side of the lake has been thinned dramatically in an effort to prevent forest fires. Feinstein praised Nevada for its efforts to stop fires, adding she wishes she saw the same results in California.
Unlike other officials, Feinstein blamed global warming for the degradation of Lake Tahoe.
“The real culprit in my mind is global warming,” she said.
Since 1970, the water temperature of the lake has risen by about three degrees, according to scientists.
I have no dispute about the temperature rise, but I do have a dispute with her assignment of blame, especially since she is my senate representative. I’ve found something interesting that leads me to think that global warming and Lake Tahoe’s water temperature are not significantly connected.
First about her statement. Perhaps Senator Feinstein is recalling this article on Lake Tahoe from 2004 in the San Francisco Chronicle.
There was a weak caveat in that article that Feinstein likely ignored if she read it:
No one can be certain if any given change is due to human activity, but the widely held assumption is that emissions of carbon dioxide and other heat-trapping greenhouse gases are involved.
I’d like to add a reason of my own for Senator Feinstein and the Chron: turbidity.
For those who don’t know, water turbidity is defined by the EPA as:
Turbidity is a principal physical characteristic of water and is an expression of the optical property that causes light to be scattered and absorbed by particles and molecules rather than transmitted in straight lines through a water sample. It is caused by suspended matter or impurities that interfere with the clarity of the water. These impurities may include clay, silt, finely divided inorganic and organic matter, soluble colored organic compounds, and plankton and other microscopic organisms.
The EPA definition comes from the publication American Society for Testing and Materials, ASTM (2000) D1899-00 Standard test method for turbidity of water. Annual Book of ASTM Standards, Vol. 11.01.
Water clarity and turbidity has been a big issue with Lake Tahoe for many years, and there have been campaigns to reduce the amount of runoff into Lake Tahoe that is a direct consequence of the building boom that has occurred around the Lake in the last century. “Keep Tahoe Blue” is one of those and you’ll see these bumper stickers all over California:
Senator Feinstein is certainly aware of this effort to reduce turbidity and maintain clarity in Lake Tahoe, in fact she is one of the champions of the cause. She drafted the Lake Tahoe Restoration Act in 1999
Her own website has quite a section on it:
http://feinstein.senate.gov/tahoe_restoration_act.html
In that web page is this passage and graph related to it:
Sediment and algae-causing phosphorus and nitrogen, all of which contaminate the water in the lake, continue to flow into Lake Tahoe from a variety of sources. Destruction of wetlands, wet meadows and stream habitat has compromised Lake Tahoe’s ability to cleanse itself of pollutants.
There’s not one word on Feinstein’s Lake Tahoe Restoration Act web page about global warming or climate change. Zilch, nada, zero. I’ll also point out that it looks like the page has not been updated in quite some time. Perhaps after passing the act in 1999 her interest waned.
The graph above can also be found in a different form from the 2009 State of the Lake Report from the UC Davis Tahoe Environmental Research Center (TERC):
TERC writes about the clarity as defined by the Secchi depth measurement:
Secchi depth (the point below the lake surface at which a 10-inch white disk disappears from view) is the longest continuous measurement of Lake Tahoe clarity. The annual Secchi depth is the average of 20 to 25 readings made throughout the year. While lake clarity has improved for brief periods since 1968, the overall long-term trend has shown a significant decline. In the last eight years, Secchi depth measurements have been better than predicted by the long-term linear trend. Statistical analysis suggests that the decline in Lake Tahoe’s clarity has slowed, and is now better represented by the curve below than a straight line. In 2008, the Secchi depth was 69.6 feet and virtually the same as 2007. With the exception of 2005 and 2006, precipitation has been low during the past 8 years. The response of the Secchi depth to a series of normal and above normal years will be very instructive.
What is interesting is that the top two values of the TERC graph occurred in 1997 and 1998, the years of the super El Nino and massive amounts of rainfall (and runoff) in California. I wasn’t surprised to see those years as the peak of low clarity of the last 40, but I was surprised that TERC does not mention it in the report. Perhaps it is counter to the TERC mission to blame nature for peak values.
So we’ve established two things:
1) The water temperature of Lake Tahoe has been increasing. From the LVJR news article:
Since 1970, the water temperature of the lake has risen by about three degrees, according to scientists.
2) As measured by TERC, the turbidity of Lake Tahoe has been increasing, thus reducing the clarity.
While lake clarity has improved for brief periods since 1968, the overall long-term trend has shown a significant decline.
I should add, I think it is a good thing to reduce the runoff issues that contribute to the reduced clarity of Lake Tahoe. This is a clear case where human activities have made a measurable impact on an ecosystem. That said, I believe that same human impact affects the lake temperature. As Dr. Roger Pielke Senior argues, land use and land cover changes have significant local and regional impacts. Lake Tahoe’s clarity decline has been established to be a result of increased runoff and pollutants resulting from the local population increase around Lake Tahoe in the last century.
This USGS publication, Stream and Ground-Water Monitoring Program, Lake Tahoe Basin, Nevada and California, defines the issue:
Lake Tahoe has long been admired for its alpine setting and the clarity of its water. During the last half-century, however, human activity in the lake basin has increased while the lake has been losing water clarity at a rate of about 1 foot (ft) per year.
Now, for a look at what I believe to be a significant contributor to the water temperature increase in Lake Tahoe.
One thing nobody seems to be talking about is the relationship between water turbidity and temperature. It is a quite simple physical mechanism, and quite well established.
For example, here is a peer reviewed study, published in International Journal of Biometeorology on mosquito larvae and increased turbidity contributing to increased water temperature.
The effect of water turbidity on the near-surface water temperature of larval habitats of the malaria mosquito Anopheles gambiae
K. P. Paaijmans &W. Takken & A. K. Githeko & A. F. G. Jacobs (full PDF here)
In that study they write in the abstract:
Water turbidity affects water temperature, as suspended particles in a water column absorb and scatter sunlight and hence determine the extinction of solar radiation. To get a better understanding of the relationship between water turbidity and water temperature, a series of semi-natural larval habitats (diameter 0.32 m, water depth 0.16 m) with increasing water turbidity was created. Here we show that at midday (1300 hours) the upper water layer (thickness of 10 mm) of the water pool with the highest turbidity was on average 2.8°C warmer than the same layer of the clearest water pool. Suspended soil particles increase the water temperature and furthermore change the temperature dynamics of small water collections during daytime, exposing malaria mosquito larvae, which live in the top water layer, longer to higher temperatures.
That is a small scale experiment in shallow water. On a larger scale there are lots of other scientific references available that demonstrate a relationship between increased water turbidity and increased water temperature. Here’s one published in BAMS from the Naval Research Lab looking at turbidity in the Black Sea and water temperature relationships. (Kara et al 2005, PDF here)
The K.P. Paaijmans et al study above writes about the Kara et al 2005 Black Sea Study:
In larger water systems, turbidity is known to change the water temperature. In seas, for example, a high turbidity changes the sea surface temperature (SST), and model simulations of the SST should include turbidity to account for variations in solar radiation extinction (Kara et al. 2004). Kara et al. (2005) demonstrated that using a clear-water constant attenuation depth assumption as opposed to turbid water type to model the SST of the Black Sea, resulted in monthly SST biases as large as 3°C in the summer period.
What I find amazing is that Senator Feinstein, who championed a bill to save Lake Tahoe from reduced clarity, apparently has no idea of the relationship between water clarity and water temperature. Apparently TERC doesn’t see it either, and prefers to blame increased water temperatures on climate change.
Of course, if we take the “global warming” route followed by Senator Feinstein, it can be argued that Lake Tahoe’s increasing air temperature is a significant contributing factor to the Lake Water temperature:
Source: NASA GISTEMP
But then you see what the measurement station looks like. Then of course that station’s data purity is brought into question for reasons of siting as well as local development nearby in Tahoe City.
Of course, we don’t know exactly what the magnitude of contribution to warmer temperatures at this station from those siting issues are, and the burn barrel has since been removed from the USHCN station enclosure shortly after I highlighted it in June 2007. The tennis courts surfaces nearby may have an effect on air temperature also.
What is important to note though, and this fact is lost on many politicians, is that the lake itself, as a large solar insolation heat sink, has more effect on local air temperatures than the other way around. The reduced clarity contributing to increased water temperature issue likely is a factor in the USHCN weather station data, given it is just a few feet from the lake.
And that brings us back to the quote from the original newspaper article:
Since 1970, the water temperature of the lake has risen by about three degrees, according to scientists.
Eyeballing our Tahoe City USHCN station graph from GISS above, it looks like we have a trend since 1970 not far from that value. Using air temperature from our world renowned center for global warming data, NASA GISS, one can certainly draw a correlation between the air temperature of the Tahoe City station and the water temperature of the lake.
But as we’ve heard so many times, correlation is not causation.
Feinstein appears to completely miss the physical connection between increased water temperature and the Lake Tahoe water clarity cause she championed. Now the need for an additional $390 million. Before she spends more citizen’s money chasing this global warming issue, let us hope she gets some “clarity” on the issue soon.
Ever wonder where some of that money goes? See TERC’s headquarters. Nice digs for studying a lake. The field station is not too shabby either.
While TERC has a really nice LEED certified HQ, I can’t find a single publication on their website about water temperature and turbidity. Unfortunately I can’t scan the content of the papers on their website since so few are posted in full text form, just titles.
Given the huge public relations effort to preserve Lake Tahoe’s clarity and, by the view of the lake’s most famous patron, Diane Feinstein, and the apparent connection to global warming, one would think that a water turbidity-temperature study would be something they would want to pursue. Either to confirm it, or to rule it out.
If I’ve missed such a study, please feel free to post it in comments.
Addendum: Additional References on turbidity (originally from comments)
Here is one where reflectivity is examined in the context of turbidity.
Citation: Witte, W. G., C. H. Whitlock, R. C. Harriss, J. W. Usry, L. R. Poole, W. M. Houghton, W. D. Morris, and E. A. Gurganus (1982), Influence of Dissolved Organic Materials on Turbid Water Optical Properties and Remote-Sensing Reflectance, J. Geophys. Res., 87(C1), 441–446.
http://www.agu.org/pubs/crossref/1982/JC087iC01p00441.shtml
“From these data it is clear that dissolved organic materials decrease upwelled reflectance from turbid waters. ”
Here is a primer on suspended solids in water from the City of Boulder Water Quality Monitoring:
http://bcn.boulder.co.us/basin/data/BACT/info/TSS.html
“High TSS (total suspended solids) can also cause an increase in surface water temperature, because the suspended particles absorb heat from sunlight.”
Here is another identical passage from the New York Harbor Survey that cites TSS and water temperature:
http://www.nynjcoast.org/NYCDEPHarbor_survey/docs/water_clarity/total.htm
“High TSS can also cause an increase in surface water temperature, because the suspended particles absorb heat from sunlight.”
From Brockport University
http://vortex.weather.brockport.edu/~jzollweg/oakorchard/docs/waterquality.pdf
On page 1 under TDS (Total Dissolved Solids):
“Similar to TSS, high concentrations of TDS may also reduce water clarity, contribute to a decrease in photosynthesis, combine with toxic compounds and heavy metals, and lead to an increase in water temperature.”
For a fairly recent and mostly comprehensive study of Lake Tahoe’s warming, see Coats et al 2006
http://www.springerlink.com/content/6384855p5513l393/fulltext.pdf
enduser,
The pallet does not mean that the barrel was never used at the location.
And, the heating of the barrel during the day assures that the temp sensor is receiving the heat from the barrel’s cooling during the evening. And what is one of the tenets of AGW?
That night time temps are a *proof* of AGW.
Have any of you wonder that this is a psychological “projection” of your senator?
We can not stop the unavoidable course of time….
Robert Wood (15:31:48) :
“When these people speak of Lake Tahoe being 3 degrees warmer, I expect they only mean the surface temp.”
Good point. Has anyone done a water temp vs depth study? (I suspect not) SST’s are a factor, but represent only a minute fraction of the total energy content of the water. What has happened 1,10,100 meters down? And where did they measure the water temperature? Near the shore? All over? Without additional information, the “3 degrees warmer” is not useful.
Not to defend Sen. Feinstein as a whole, since she has done plenty to sensationalize the AGW cause while ignoring good published science, but I think that she needs to be cut a little slack here. I work as a water resource engineer, and when I began reading the article that turbidity was somehow involved in warming, I was dubious, since I had never considered the impact of turbidity on water temperature. My initial thought was “what kind of brownies has Anthony been eating this morning?” But after reading the article, I agree that he may be on to something, and that this is a valid hypothesis worth testing.
However, the point must be made very clearly: this hypothesis has not yet been tested. I think that it is entirely unreasonable to blame a politician for not making this connection, especially when it has not been documented in any peer-reviewed journals or properly sanctioned and controlled studies. Notwithstanding the fact that she has championed the “Keep Tahoe Blue” cause in the past, I think it is entirely unfair to blame her for not understanding the scientific correlation between turbidity and water temperature.
Rowland Pantling (UK) (07:35:45) : Tahoe is over 1,500 feet deep and the deepest or one of the deepest in the USA. I fished on it once and wondered if fish would be at the bottom.
The physics of the article is totally wrong.
The transmittance coef. air-water is 95-97%,(depends on the angle)and does NOT depend on the turbidity.The incoming flux of energy does not change.
In fact the mean temperature of a lake DIMINISHES with the increasing turbidity because the heat is trapped in the first centimeters of water increasing the night cooling by thermal radiation.
(The article cited is about the 2 mm water near surface and thus has no relevance)
Retired Engineer (09:20:47) :
Robert Wood (15:31:48) :
“When these people speak of Lake Tahoe being 3 degrees warmer, I expect they only mean the surface temp.”
Good point. Has anyone done a water temp vs depth study? (I suspect not) SST’s are a factor, but represent only a minute fraction of the total energy content of the water. What has happened 1,10,100 meters down? And where did they measure the water temperature? Near the shore? All over? Without additional information, the “3 degrees warmer” is not useful.
Anyone interested in understanding the link between climate warming and Lake Tahoe temperature should read the Robert Coats et al. (2006) paper which is available for everyone as a PDF (try Coats and Lake Tahoe) in Google scholar. Of course, the temperature profiles from 0-400 m have been measured at at least monthly intervals over the last 30+ years. Such data are available for most of the large lakes in the world.
One of the main issues is the effects of both turbidity and temperature on the stabililty of stratification and thickness of the upper mixed layer of homogenious temperature. In small lakes, a thinner mixed lake due to increased turbidity and less solar penetration can lead to greater solar heating of the thinner surface layer (See paper by Mazumder in Science among others). However, in large lakes, such as Tahoe, the mixing depth is mainly determined by the effect of lake size on wind fetch. For Lake Tahoe, the surface layer with uniformly warm temperature during the warm seasons is the upper 20-30 m. For this reason, results from mosquite ponds are not useful for understanding the temperature budgets of lakes and oceans. If you read the Coats paper, you learn that the upper 30 m of Lake Tahoe has heated the most quickly, but that heating is occuring in the upper 400 m.
The best data on effects of climate effects on lake temperatures is work on David Livingsone on European lakes. Some of his papers are directly available as PDFs. Papers in Limnology and Oceanogrphy before 2005 are also available at the http://www.ASLO.org website. You can find free pdfs of papers on the heat budgets and thermal stratification of Lake Tahoe and other lakes by searching for the pre 2005 papers in Limnology and Oceanography.
I’m surprised they haven’t blamed the boom in house building on global warming…
Alexandriu, I’ve triple checked this. Increased water turbidity equals increased water temperatures, and the effect is not limited to 2mm of the surface.
Pamela Gray (08:31:27) :
Before Europeans came, the natives on the East coast would regularly burn out the underbrush. The forests in the area I have in mind were mostly chestnut and able to withstand fire quite well. The forest floors would then be used to plant various things such as squash and corn. After a couple of years, another section would be burned out and the planting areas moved.
One interesting fact is that the Eastern forests had no earthworms as we know them prior to Europeans arriving. Those were brought by settlers. Leaf litter would pile up year after year along with the debris from fallen twigs/limbs, etc. Burning the forest floor allowed the nutrients locked up in this debris to be returned in a soluble form to the soil where they could be used by the plants. Once production began to drop at that location, another area was burned (fertilized) and used. Fire was basically a fertilizer used by the native population to increase food production both on the ground and for the chestnut trees that also provided food for both the natives and game.
The really scary thing is Feinstein is the ‘better’ senator form the former golden state.
When you have surface water being directed into the lake in an express fashion by a storm drain system, you end up with a different chemical mix going into the lake than if it is allowed to percolate through the soil and enter slowly via springs.
Pet and bird excrement is one thing that would be washed in at higher concentrations as water is washed off roofs, down driveways, into gutters, down the storm drain and out into the lake.
It also causes boom/bust runoff events where a huge amount of water is washed in. The lake only rises a certain amount because the runoff increases into the Truckee River. Once the level returns to “normal” there is less “sustaining” inflow from springs because the water that would be recharging the ground water has already washed into the lake and down to Reno. Also, water that is filtered through the ground has less nutrient load from things like animal droppings.
We are, in effect, hosing off several towns and directing the runoff directly into the lake with each rainstorm. The lake HAS to get cloudier.
For Watts.
You must check the Fresnel formulas, which are basic physics.
They will tell you that even in a zero impurity water ,practically ALL the energy of a electromagnetic wave penetrates WITHOUT reflection:
-at angle 0-Reflectivity=[(n-1)/(n+1)]^2=(0.3/2.3)^2=1.7%
_at angle 30deg-Reflectivity=(rt+rp)/2
rt=(sin(B-A)/sin(B+A))^2
rp=(tg(B-A)/tg(B+A))^2
B=30 deg
A=22.6 deg
rt=2.6%
rp=2.8%
rt=2.7% which is practically 0
Thus,turbidity cannot influence the light reflectivity because it is already almost zero.
If anybody says different he is not a reliable source
REPLY: My name is Anthony, please. There are several papers which cite a water turbidity to water temperature correlation. Here is one where reflectivity is examined in the context of turbidity.
Citation: Witte, W. G., C. H. Whitlock, R. C. Harriss, J. W. Usry, L. R. Poole, W. M. Houghton, W. D. Morris, and E. A. Gurganus (1982), Influence of Dissolved Organic Materials on Turbid Water Optical Properties and Remote-Sensing Reflectance, J. Geophys. Res., 87(C1), 441–446.
http://www.agu.org/pubs/crossref/1982/JC087iC01p00441.shtml
“From these data it is clear that dissolved organic materials decrease upwelled reflectance from turbid waters. ”
Here is a primer on suspended solids in water from the City of Boulder Water Quality Monitoring:
http://bcn.boulder.co.us/basin/data/BACT/info/TSS.html
Here is another from the New York Harbor Survey thats cites TSS and water temperature:
http://www.nynjcoast.org/NYCDEPHarbor_survey/docs/water_clarity/total.htm
Then there’s this one, from Brockport University
http://vortex.weather.brockport.edu/~jzollweg/oakorchard/docs/waterquality.pdf
On page 1 under TDS:
It seems the water quality people disagree with your assertion. – Anthony
Re:watts:
I did an error of calculation.In fact Rp =0.0098 so R=1.8%
crosspatch (12:34:37) : Ants (some other insects and fungi) on the north American continent would be doing what worms do before their arrival. Much the same thing with honey bees before they arrived around the same time. I think both came with Apple trees.
Interesting question somewhere up there about air heating water. In short, the air cannot heat water, since the heat capacity of water is so great that only shortwave radiation can heat a body of water. On the other hand, oceans can heat the atmosphere, since water retains heat whilst air doesn’t . Air temperature itself cannot penetrate water, particularly so called re-emitted longwave radiation, which, for some odd reason, is the basis of the AGW case
Rowland Pantling (UK) (07:35:45) : You wrote:
“I have no idea of the size of the lake”
Use Google Earth and go here: 39.097641 N, 120.025191 W
then back away to about an altitude of 44 km. which allows you to see the Lake from north to south. At an elevation of about 5 km. you can move to the SE part where the light blue line is the boundary between Calif and Nevada. The major urban area is here. The north end of the lake also has much development.
This Google images link provides a visual tour:
http://images.google.com/images?hl=en&source=hp&q=%22lake+tahoe%22&um=1&ie=UTF-8&ei=R6-RSsnpGIHEsQOStpAM&sa=X&oi=image_result_group&ct=title&resnum=16
“In short, the air cannot heat water, since the heat capacity of water is so great that only shortwave radiation can heat a body of water. ”
But if higher troposphere temperatures inhibited a process that cooled the ocean, namely ITCZ cu-nims, then solar heating would get through to the oceans.
There is almost something of a transistor here. The main heating of the Earth is tropical ocean heating from the sun with a large heat-flux or power. With no tropical clouds for a few months I think everyone would agree that the Earth would warm significantly, conversely a solid tropical cloud belt would cause severe cooling.
Thus tropical cu-nims act like the ‘gate’ in a source-gate-drain field effect transistor, regulating much more energy than they themselves contain.
I first visited Lake Tahoe about 1/2 century ago. Then it was crystal clear. I vaguely remember (heck, I was not yet in kindergarden then…) the story that you could see the bottom (a few hundred feet down?) from a boat in the lake. (Any errors in that statement ought to be attributed to being a kid at the time 😉
So, about 1970 it was getting very turbid, largely due to “people pee and poo” from all the development fertilizing the lake. There was a building moratorium and then some requirements added for better sewage treatment.
Now, we have a bit of an improvement, but it’s still not anything like it was. You can’t have that much development and that much runoff of garden / lawn fertilizers and deposition of sulphates and nitrates from car exhaust and runoff from logging and… without getting some growth in the lake. That, and the stuff that in the lake from the past does not just wash out in a decade…
Yup, I’d call it “turbidity denial”…
BTW, some of that “temperature rise” might come from using Airports in their UHI “correction” as “rural” stations. Out of 2179 records used for “correcting” other stations (a few thousand times) “only” 500 are marked as Air Stations in the v2.inv file…
http://chiefio.wordpress.com/2009/08/23/gistemp-fixes-uhi-using-airports-as-rural/
Maybe DiFi could fly into Truckee-Tahoe airport and check on the status of the thermometer…
Take a look at the graph from the UC Davis Tahoe Environmental Research Center — the one with a boat floating on the surface of Lake Tahoe. Notice where the surface of the lake is, the implied zero point of the graph. Notice the depth calibrations at the sides of the graph. Where should the real zero point of the graph be located? If there’s ever a new edition of Huff’s How to Lie with Statistics, this graph should be included as an example.
Oddly enough, this presentation from a government-funded environmental agency just happens to make an environmental problem look worse than it really is. Yes, it’s still a problem, but wouldn’t it be nice if we could make decisions without being misled?
It is not correct to cite the mosquito experiment(which is completely non-relevant on the issue)
Their pool was only a few cm deep and had p[lastic on the bottom.
The reflectivity of plastic is ~50%.Roughly 49% of the light is coming out of the water if the water is pure.If the water is muddy ,the heat is trapped and the pool will warm up.
In a lake,the opposite occurs:the light coming up from the deep water is practically 0.The backscattering is negligible.The heat will remain in the water and the only difference will be an increasing thermal gradient which will enhance the cooling of the lake by nighttime.So,the assumptions of the article are totally flawed.
REPLY:True, they have an experimental setup versus an in situ, but I’m still not convinced. Since you didn’t mention them, did you not read any other citations on turbidity and water temperature I posted? Please offer some citation of your own that show that increased turbidity equals a cooler water temperature. – Anthony
EM–It’s a bit of exageration to say that Lake Tahoe was getting very turbid when the Secchi depth has always been deeper than 20 m (60 Ft.). Anyone interested in the general relationship between water clarity and solar heating of lake should read the following paper:
Mazumder and Taylor, 1994, Thermal structure of lakes varying in size and water clarity. Limnology and Oceangraphy 968-976.
Variation in lake water temperature is directly related to air temperature and to solar radiation. There is a lot of argument on this blog about issues that have been well know and worked out 15-20 years ago or more. There is lots of information on these topics in the peer reviewed literature and in basic text books on aquatifc ecology and limnology.
It is easy to find 50 peer reviewed articles relevant to these issues.
So if I understand correctly from what you’ve written:
(1) the lake is warmer by about 3 degrees due to increased turbidity of the water;
(2) the air temperature above the lake is about 3 degrees warmer;
(3) the temperature sensor for the area that is used in calculations of global warming hysteria, er, hypothesis is just a few feet from said warmed lake;
Thus one can form a hypothesis for testing that this station’s weather data is skewed upward not by “global warming” but by the increased turbidity of the water in Lake Tahoe.
While correlation might not be causation correlation can sure be a huge hint of causation that should be taken seriously and tested by scientists.
I wonder how much this Lake Tahoe station contributes to the overall trend of the global warming hysteria, oh, hypothesis?
How many other stations are in this area?
If this correlation is in fact a causation of human development causes increased turbidity of the water and thus increased lake temperatures and thus increased local air temperatures that caused increased science thermometer temperatures then sure humans are contributing to global warming temperatures WITHOUT C02 emissions! How ironic that bad local data leads to bad science with the illusion of it being global!
I wonder how far the Lake Tahoe air temperatures extend in miles? Any idea? How does it effect the wider region? How local or far reaching is this Lake Tahoe heat island? (A lake being an island how quaint ;-).
Very illuminating and educational article Anthony. Please send a copy to your representatives, U.S. Sen. Dianne Feinstein, D-Calif., and Ensign, and any others.
Oh, might increasing the water turbidity of lakes up here in Canada be a way to cause local warming around human settlements by about 3 degrees? That could be a huge win to reduce energy costs while increasing the local temperatures. Just a thought of turning what is a negative to some into a positive for others.
I’ve adding the additional citations about turbidity to temperature relationships discussed in replies to Alexandriu Doru to the main article.
I’ve also added a sentence, noting that the mosquito experiment was small scale. An an additional passage noting what the authors of the small scale mosquito experiment say about the large scale Kara et al 2005 study.
Kara et al 2005 shows that in Figure 1, turbidity decreases the shortwave radiation penetration depth, and thus concentrates the solar energy in the nearer the surface rather than distributing it to greater depth. More solar energy extinction near the surface would thus increase the temperature nearer the surface.
Alexandriu suggests that I have the effect backwards, that turbidity actually cools the water surface. I’ve provided some citations from water quality organizations showing increased turbidity equal increased water temperature, and asked him to provide citations that show the opposite, which I will happily investigate if provided.