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Global Temperature Highest in Millennia
An iceberg from the Portage Glacier is locked in the frozen Portage Lake south of Anchorage, Alaska in this Jan. 6, 2004 file photo. The planet's temperature has climbed to levels not seen in thousands of years, researchers report in Tuesday's issue of Proceedings of the National Academy of Sciences. (AP Photo/Al Grillo, FILE)
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- Public Discussion (20)
really? we have accurate records of the temperatures thousands of years ago? sure, sure, someone's gonna say that they can tell from ice rings or something...
but seriously. you can look me in the eye and tell me with a straight face that you know for certain what temperature it was ten thousand years ago? just because it's been warming up for the last century (along with an industrial boom unlike any before it) doesn't mean it's been doing so for the last thousand years.
- 1 vote
#1 - Mon Sep 25, 2006 5:34 PM EDTgonna say that they can tell from ice rings or something...
Um, well...
Because isotopic fractions of the heavier oxygen-18 (18O) and deuterium (D) in snowfall are temperature-dependent and a strong spatial correlation exists between the annual mean temperature and the mean isotopic ratio (18O or δD) of precipitation, it is possible to derive ice-core climate records. The record presented by Jouzel et al. (1987) was the first ice core record to span a full glacial-interglacial cycle. That record was based on an ice core drilled at the Russian Vostok station in central east Antarctica. The 2083-m ice core was obtained during a series of drillings in the early 1970s and 1980s and was the result of collaboration between French and former-Soviet scientists. Drilling continued at Vostok and was completed in January 1998, reaching a depth of 3623 m, the deepest ice core ever recovered (Petit et al. 1997, 1999). The resulting core allows the ice core record of climate properties at Vostok to be extended to ~420 kyr BP.
source:
http://cdiac.ornl.gov/trends/temp/vostok/jouz_tem.htm
Do you have any contradictory information regarding the accuracy of ice core samples in recording global temperatures?
- 2 votes
Do you have any contradictory information regarding the accuracy of ice core samples in recording global temperatures?
I do. I know, for example (though of course I can't find my original source at the moment) that ice rings can be formed several times over the course of one season instead of merely one per season.
Also, the chemistry is probably flawed:
Chemicals trapped in ancient glacial or polar ice can move substantial distances within the ice, according to new evidence from University of Washington researchers. That means past analyses of historic climate changes, gleaned from ice core samples, might not be entirely accurate.
- 1 vote
I don't buy it. It seems that the overwhelming consensus is that atmospheric carbon dioxide levels directly correlate with the global average temperatures, and that this is true both in the short and long term records (which you are disputing the accuracy of). Better to err on the side of caution, no?
- 1 vote
I do. I know, for example (though of course I can't find my original source at the moment) that ice rings can be formed several times over the course of one season instead of merely one per season.
Wouldn't that just make the difference between them thinking they had data for 12,459 years as opposed to 11,673 years? Which in the big picture doesn't make a difference.
- 3 votes
Sean - no... it would make it more like, instead of having data for 12,459 years they'd actually have data for something like 3,298 years. My numbers entirely made up just for an example, but the source that I'm forgetting discussed how they noticed rings forming over the course of days instead of years. Days instead of years makes a difference.
I know I'm not helping my case by not having a source handy... I wish I could remember where I read that.
It's weird how just a few degrees can make such a big difference.
- 2 votes
#2 - Mon Sep 25, 2006 6:31 PM EDTThere are some interesting studies coming out, some that say that the sun radically affects the Earth and the climate, this has even been stated by NASA. Not saying that humans are great stewards of this Earth, but there is evidence out there that says that we evil does are not the only thing or even the greatest contributor to the global temperature chages.
- 2 votes
#4 - Mon Sep 25, 2006 9:18 PM EDTThey only started accurately measuring the suns output around 1979 I think. Some things I haven't heard explained well are what caused the hurricanes to peak in the 1930s to 1950s and have deep sea volcanoes been taken into account in their models (if so, what data did they base it on and where did they get it).
Regarding this being the highest temperature in 1 million years, what caused the earth to be so hot then? Are they blaming humans back then too?
- 1 vote
Regarding this being the highest temperature in 1 million years, what caused the earth to be so hot then? Are they blaming humans back then too?
Remember that it's our actions of pumping CO2 into the atmosphere that lays the blame on us humans... just because we didn't cause past warming doesn't mean we're not causing this one. Even if other causes of global warming exist now, all we are doing is adding to it copiously and making matters worse.
What if natural effects overwhelm any human caused effects? It would be better to spend our money coping with it than trying to prevent our part which might not make much of a difference.
- 2 votes
ComSen: Virtually every observation made into answering that question tells us that man-made greenhouse gases are the cause for the rapid rate of climate change. Back to your previous questions, I don't really know much regarding historic hurricane intensity, but I am aware that there was a warm phase between the 1930's and 19050's, prior to cooling during the mid-to-late 20th century due to sulphate aerosols. It would follow that warm global temperatures created higher sea surface temperatures which would translate into more intense tropical storms.
Also, I understand that the amount of greenhouse gases from volcanoes is orders of magnitudes less than that created by humans. Also, there has been no sudden increase in volcanic activity that could explain the rapid rate of warming. As to where they got the data for other forcings (external, such as solar, as well as volcanic), I couldn't say for sure but I am well aware that these are included in temperature reconstructions and modeling.
As for the temperature 1 million years ago, what does that have to do with this publication or discussion? The article's title and content clearly indicate that this is the highest temperature in 12,000 years (since the Pleistocene). Further, modern Homo sapiens weren't believed to have existed one million years ago (more like about 200,000 years), so no; no one is blaming mankind for the temperature (high or low) at at the later parts of the Pliocene epoch.
- 1 vote
ComSen: Looks like I owe you a correction. I just seeded a related article at The New Scientist that does state that the current global average temperature is about 1°C lower than the high point approx. one million years ago (although I don't think it's all that relevant). Either way the answer to an anthropogenic cause of that high temperature is still clearly 'no.' Further, I strongly doubt that there is any evidence for that high point in temperature, or the one approx. 12,000 years ago, peaking in about 100 year's time as we have observed now.
I'm not sure which is more scary.
The overwhelming evidence that human's are causing global warming ... and all the consequences that go with this .... or
that so many are happy to ignore and dispute the evidence.
Frankly, given the number of people willing to argue with truly clear science like evolution, I doubt we'll ever make progress convincing people on something far more complex like this. Depressing.
- 1 vote
#5 - Tue Sep 26, 2006 4:29 AM EDTOf course its not just ice core data. Tree rings, corals, ocean and lake sediments, cave deposits, bore holes, and glaciers are all used to infer the climate of the distant past, and good agreement between such proxy records is now well established.
- 1 vote
#6 - Tue Sep 26, 2006 6:32 AM EDTIt doesn't much matter what the specific climate does. Oh it might to you and I if we happen to get in the way of the next Katrina, but that's not the real killer in carbon emissions. The killers are well understood and quite certain to cause human extinction if not promptly dealt with.
The first killer is acidic seawater. The enormous CO2 surplus in the atmosphere is causing the seas to rapidly turn to carbonic acid. By 2050 krill won't be able to form shells any more. A global sealife die-off is a big deal for every natural food chain.
The second is methane feedback. Permafrost all across Alaska and Siberia has melted for the first time in many millenia causing methane emissions on astonishing scales. Methane is 28 times more powerful as a greenhouse gas than CO2. And the warmer it gets, the faster the methane is generated.
The third is methane hydrates. These are globally distributed chunks of methane that exist in the deep sea pressure and cold. They're already starting to bubble up, but if it gets warm enough ... well, life on earth will continue, but it's gonna take dozens of millions of years to get back to anything like the complexity we need to survive.
This is of course the key point. Warming doesn't threaten life on earth. It threatens intelligent life on earth.
#7 - Sat Jan 6, 2007 6:22 AM ESTLets not forget that the Let's not forget that the "enormous CO2 emissions" in our atmosphere are not all caused my humans, as a matter of fact very small percentage of it is. Let's also not forget that CO2 is a natural part of our environment and essential to life on our planet. Farmers pump it into enclosures to promote plant growth.
Al Gore is off in left field when it comes to understanding or explaining CO2. All the scientists who have provided his "hockey stick" graphs never mention that back farther than 1,000 years there were temperature increases similar to today 2,500, 4,000, 5,200, 8,700 and 11,000 years ago.
Second, they do not include solar activity, which is at an 11,000 year high. Science has proved that there was an increase in solar activity during the same warming periods listed above.
Al Gore's circus like presentation on carbon dioxide quickly falls apart in the global warming debate. He does accurately tells how scientists measure past levels of carbon dioxide from air bubbles in ancient ice from glaciers and discusses how scientists can examine isotopes of oxygen in the ice to figure out what the temperature was when the ice formed. He also uses the Vostok ice core graph to show how, over the last several hundred thousand years, temperature and carbon dioxide are closely correlated. He interprets the data, as, "when there is more carbon dioxide, the temperature gets warmer."
What Al Gore did not mention, and what is very well known throughout the scientific community, is that higher resolution studies of the same ice cores revealed that the temperature changes came first then were followed by changes in CO2.(Mudelsee, 2001; Clark, 2003; Vakulenko et al., 2004)
The world warms first; this process naturally increases CO2 – not the other way around.
- 1 vote
#8 - Thu Jun 14, 2007 11:23 PM EDTI'm not sure which is more scary.
The overwhelming evidence that human's are causing global warming
What evidence?
If your a scientist today and you need funding you add "global warming" to your project and BANG! You got funding.
Wanna do a study on Pacific Salmon and get get funding, just add "The effects of Global warming on Pacific Salmon" and the money is as good as yours.
Is tornado activity proof of global warming?
Al Gore also claimed that tornadoes are getting worse and that global warming is increasing the number of tornadoes is also misleading because new radar and satellite technology allows us to see more of them. The numbers of severe tornadoes, the ones we have been able to track, are decreasing according to the NOAA who shows the number of strong tornadoes since 1950.
Using data from the NOAA and hurricane tracking information from Unisys Kristen Byrnes averaged out hurricanes and tropical storms in the Atlantic from 1975 to 2006. He went on to separated them by El Nino, La Nina and neutral years and found that there were no trends that show increasing numbers of hurricanes, tropical storms or strength. The only unusual year was 2005 (ENSO neutral)
http://weather.unisys.com/hurricane/atlantic/
http://www.cpc.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml
http://home.earthlink.net/~ponderthemaunderg/index.html
- 1 vote
#9 - Thu Jun 14, 2007 11:36 PM EDThttp://www.junkscience.com/Greenhouse/
A great read. This is Science.
- 1 vote
#10 - Thu Jun 14, 2007 11:49 PM EDTYou're in Easy Mode. If you prefer, you can use XHTML Mode instead. |
