Posted on 04/03/2002 9:57:45 AM PST by cogitator
I think you forgot about the borehole data, which is global.
------
Twentieth century 'warmest in 500 years'
Studies of temperature records preserved deep in underground rocks show that the Earth has been gradually warming over at least the last 500 years.
And the studies, by scientists in the US and Canada, show that the trend accelerated markedly during the 20th Century, which was the warmest of the past five centuries.
Since 1500, the Earth's temperature has increased by about one degree Celsius, with half of that increase occurring in the last century.
Trend picks up
Almost 80% of the net temperature increase observed occurred in the 19th and 20th centuries.
In the Northern Hemisphere, the five-century change has been 1.1 degrees, with 0.6 recorded since 1900.
The studies, reported in the science journal Nature, are based on analysis of borehole temperatures from 616 sites on every continent except Antarctica.
The scientists lowered sensitive thermometers into holes drilled down from ground level to discover how surface temperature altered in the past. A typical borehole was measured at 10-metre depth intervals down to as far as 600 m.
Records preserved
The technique is possible because of heat conduction, which means that temperature changes at the surface generate "signals" that penetrate subterranean rocks.
The signals from short-term daily or seasonal variations penetrate only a few metres and are rapidly lost. But changes over centuries are preserved in deeper rock, although the signals travel very slowly, penetrating only about 500 metres in 1,000 years.
One of the team, Professor Henry Pollack of the University of Michigan, said: "The upper 500 metres is an archive. Like any historical archive, there are of course missing pages, and the ink has run in a few places.
"But in principle, if you drilled a borehole anywhere on a continent, you could observe a temperature profile and be able to reconstruct what had happened at that location."
The team's work involved calculating averages from all the boreholes investigated, and built on a previous analysis of borehole temperature data from 358 sites. "What we show that is somewhat different is that the total temperature change over the past five centuries has been greater than some of the other methods are showing."
In an accompanying article in Nature, Jonathan Overpeck, of the University of Arizona, Tucson, says the team's results reinforce the forecast for this century: continued warming ahead.
"But they also provide unsettling indications that human alteration of the climate system over the past century will make the reliable prediction of climate change an even tougher business than expected. "Their analysis is the latest of several to indicate that late 20th Century warming is without precedent in the past 400 to 1,000 years.
"We do not know of any combination of natural mechanisms that can explain this phenomenon. So we are left with the likelihood that human-induced global warming is under way."
And he adds a warning. "The results show yet again that the 20th Century record of climate variability is too short and cloaked with human-induced influences to provide a clear indication of natural climate variability.
"Earlier studies may have underestimated the full amplitude of natural decade-to century-scale climate variability."
-----
In my experience, global warming skeptics that cite the uncertainties in the surface station data usually get somewhat tongue-tied when they read about the borehole data, which fully supports the observed trends.
In my experience Global Warmers cherry-pck data to suit their needs. Global Warmers get tongue-tied when they talk about satellite data, Medieval Warm Period, and the Little Ice Age...
Some might. I won't. I'd be glad to discuss any of these with you in detail. (The Esper tree-ring data recently published was a nice confirmation of the Medieval Warm Period, which pretty much had to have occurred to allow settlement of Greenland by the Vikings.)
You got a favorite?
So my proposal to Cogitator is this. I have a place down in Baja on the ocean where I can measure the surface level very accurately. I have access to all kinds of instruments, I have a GPS laser level and some other nifty stuff (I can accurately measure down to a millimeter). So if you can tell me how to do that I would be very appreciative.
I know that what I am asking is not very straight forward when you have to take into consideration the position of the sun and the moon, wind, waves, currents, temperature, barometric pressure, etc. But I do know that compared to predicting the weather, determining the oceans level is child's play. It also seems that some of the predictions of several meters in the next 50 years would be easy to see now, they would be close to a centimeter a month.
I will collect the data over a period of time (I like to go fishing and snorkeling) and then it should be very easy to prove or disprove the validity of global warming and even state how accurate it is. :)
Are you up to the challenge Cogitator?
You're not telling me something I don't know, LeGrande. In fact, if you want to read a bit more, read this article and thread:
Deciphering Contradictory Antarctic Climate Patterns
particularly: "Counterintuitively, global warming would actually lower sea levels at first. In warmer temperatures, evaporation of ocean water increases and more snow falls, more than offsetting the melting ice at the edges. But over the longer term perhaps centuries, perhaps thousands of years prolonged warmth in Antarctica would add to the ocean depths."
which you noted. There are also other factors, such as the thermal expansion of seawater, which could offset a lowering due to increased precipitation, (and impoundment of fresh water in reservoirs). So sea level is not a great proxy measurement by which to confirm or deny global warming.
So my proposal to Cogitator is this. I have a place down in Baja on the ocean where I can measure the surface level very accurately. I have access to all kinds of instruments, I have a GPS laser level and some other nifty stuff (I can accurately measure down to a millimeter). So if you can tell me how to do that I would be very appreciative.
First of all, Baja California and southern California are not great places to do this unless you have a stable offshore platform. Why? Tectonic activity. The Northridge earthquake raised the mountains by Los Angeles 3-4 cm. The San Andreas fault runs through your backyard, doesn't it? When determining sea level rise/fall, you have to remove all the other local phenomena.
I know that what I am asking is not very straight forward when you have to take into consideration the position of the sun and the moon, wind, waves, currents, temperature, barometric pressure, etc. But I do know that compared to predicting the weather, determining the oceans level is child's play. It also seems that some of the predictions of several meters in the next 50 years would be easy to see now, they would be close to a centimeter a month.
Well, if you do it with a method like satellite laser altimetry and take into consideration all of the +/- factors, you get something like this:
I will collect the data over a period of time (I like to go fishing and snorkeling) and then it should be very easy to prove or disprove the validity of global warming and even state how accurate it is. :)
I think that more than one data point is necessary to make a respectable evaluation.
Are you up to the challenge Cogitator?
Usually.
There is a great deal of uncertainty what the underlying problem is, if indeed there is a problem. Black soot, however, is certainly undesirable, but you are in error to link it to global warming.
But I do like the idea of black soot controls. Basically, the United States leads in this area. Such controls add to the cost of manufacturing. If third world nations are required to live by the same environmental standards that we are forced to live by, then we would be competing on a more level playing field.
I am?
Soot Called Major Cause of Global Warming
"STANFORD, California, February 8, 2001 (ENS) - Soot, the familiar black residue that coats fireplaces and darkens truck exhaust, may be a leading cause of global warming. A study in the current issue of the journal "Nature" [February 2001] indicates that soot may be the second biggest contributor to global warming - just behind the greenhouse gas carbon dioxide."
Soot in the Greenhouse (a commentary from the Nature issue referenced above)
"According to the traditional view of global heat balance, greenhouse gases such as methane and carbon dioxide warm the Earth by trapping infrared (low-frequency) radiation, while aerosol particles keep it cool by bouncing visible and ultraviolet (high-frequency) radiation back into space. This balance is upset by the injection of anthropogenic greenhouse gases, which are almost certainly causing a global temperature rise.
Now it seems that air pollution is dealing the global heat balance a double-whammy. According to research by Mark Jacobson in this issue, black-carbon (soot) emissions from the burning of biomass and fossil fuels are interfering with the reflectivity of aerosols, darkening their colour so that they absorb more radiation. This reduces their cooling effect to such an extent that black carbon may be the second biggest cause of global warming after carbon dioxide."
Global Warming in the 21st Century: An Alternative Scenario
"Aerosols. It is often assumed (IPCC 1996) that aerosol forcing will become more negative in the future, which would be true if all aerosols increased in present proportions. However, it is just as likely that aerosol forcing will become less negative, e.g., if sulfates decrease relative to black carbon. Black carbon reduces aerosol albedo, causes a semi-direct reduction of cloud cover, and reduces cloud particle albedo. All these effects cause warming. Conceivably a reduction of climate forcing by 0.5 W/m2 or more could be obtained by reducing black carbon emissions from diesel fuel and coal. This might become easier in the future with more energy provided via electricity grids from power plants. But quantitative understanding of the absorbing aerosol role in climate change is required to permit reliable policy recommendations."
THOMPSON AMENDMENT STRENGTHENS GLOBAL WARMING BILL TO TACKLE BLACK SOOT POLLUTION (I think this was August 2, 2001, based on the URL)
I've been wrong before, but on this one I think I'm right.
I have heard it also claimed that global warming can cause wild swings in weather patterns (both hot and cold) or moderate the weather patterns or keep them the same.
So is there anything that can definitively prove global warming or cooling? It seems to me that even a downturn in all the measured temperatures for a few years could could be explained away as a temporary aberration. I am a professional gambler (day trader) and I look for trends and aberrations all the time and all the data that I have seen looks just like random noise. Furthermore It seems that all the data is well within a normalized range and that trying to predict it is foolish.
It would be nice if Mankind were actually changing the climate because that means that we can eventually optimize it for our benefit. :)
I had a trap set for you that you deftly walked away from :)
I fear you greatly underestimate the "Chicken Little" Sheeple phenomenon.
If I had to change, I'd prefer "investigator".
You're welcome, and you're right (short-term). Taking the long-term view of 1000s and 10,000s of years, global warming will cause sea level to rise.
I have heard it also claimed that global warming can cause wild swings in weather patterns (both hot and cold) or moderate the weather patterns or keep them the same.
I've read similar.
So is there anything that can definitively prove global warming or cooling? It seems to me that even a downturn in all the measured temperatures for a few years could could be explained away as a temporary aberration. I am a professional gambler (day trader) and I look for trends and aberrations all the time and all the data that I have seen looks just like random noise. Furthermore It seems that all the data is well within a normalized range and that trying to predict it is foolish.
One of the nicest "proofs" is stratospheric cooling, which is observed by satellites. The stratosphere warms and cools radiatively. It cools via radiation to space; it warms by receiving longwave radiation from the Earth's surface. If an increasing amount of longwave radiation is being trapped near the Earth's surface by greenhouse gases, the stratosphere should cool. And that is exactly what the satellite data shows (and these are the same satellites that provide a different dataset that is constantly cited as indicating that no significant warming is taking place).
Another example is the freeze/thaw data that is showing trends toward earlier spring and later winter freeze, i.e. shorter winters.
It would be nice if Mankind were actually changing the climate because that means that we can eventually optimize it for our benefit. :)
What is it they say about absolute power?
I had a trap set for you that you deftly walked away from :)
Inadvertently, I assure you.
"quantitative understanding of the absorbing aerosol role in climate change is required to permit reliable policy recommendations"
read=> This is a possibility, but we have no data to prove it.
IPCC scientists believe that atmospheric soot has relatively little effect on world climate (IPCC, "Climate Change 1995" and Jan 21, 2002). Jacobson's studies do not include sulfates, which offset the effects of atmospheric black soot (LBL and Lawrence Livermore National Laboratory Research Review, 1992). Jacobson's study provides no discusion of atmospheric black soot loading, no discussion of night time radiation release, and no discussion of soot loading historical trends in relation to observed warming trends. It simply observes that soot absorbs radiation (a well known fact) and then he performed some very simplistic modelling. Its almost as if he had a desired result in mind and used whatever methods he could to get that result.
I won't deny the benefits of reducing soot emmisions for cleaner air, but soot as a contributor to global warming is highly speculative at this point.
Secondly, I don't think the international community will buy into this. They will eventually realize it means that third world nations will have to live up to United States soot emmision standards. Since the unstated goal of Kyoto and its supporters is global wealth redistribution, and soot emmisions would end up hurting third world economies but not the US, this will never gain acceptance.
I'm not an earth scientist. My reply to LeGrande was quite casual and non-specific. Saying "the San Andreas Fault is in your backyard" isn't equivalent to providing an exact location. I was actually thinking of the spreading center in the Sea of Cortez as part of the San Andreas system, so if it meets the San Andreas at the triple junction that's what I was thinking.
I also thought that Baja was somewhat earthquake-prone, but your reply indicates that's not the case. I was thinking of some of the earthquakes that occur in the El Centro vicinity (my father used to go to El Centro for business).
I even remember seeing a picture similar to the one on this page:
The Imperial Valley Earthquake of October 15, 1979
That's because there is a triple junction there, with a subduction zone paralleling the Mexican mainland along its west coast,
That's the subduction zone I was thinking about.
and a weak oceanic ridge / spreading center down the middle of the Sea of Cortez. In fact Baja is quite stable, with little tectonic activity of note with the exception of the extreme northern portion. Most of Baja is eroding into the sea and within a couple of million years will be a flatish area not unlike the east coast of the US (at least geologically speaking). It is becoming a stable margin.
That does adjust my idea that Baja California wouldn't be a good place to measure sea level rise due to tectonic activity. I had thought that it was an extension of the basin and range province in California, and it's obviously a different geological setting. Thanks for the correction.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.