More reliable evidence for absence of global warming over past 2,000 years

Discussion in 'Current Events' started by James Cessna, Jul 11, 2012.

  1. James Cessna

    James Cessna New Member

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    For the first time, researchers have now been able to use the data derived from tree-rings to precisely calculate a much longer-term cooling trend that has been playing out over the past 2,000 years.

    Their findings demonstrate that this trend involves a cooling of -0.3°C per millennium due to gradual changes to the position of the sun and an increase in the distance between the Earth and the sun."This figure we calculated may not seem particularly significant,” says Esper. “However, it is also not negligible when compared to global warming, which up to now has been less than 1°C. Our results suggest that the large-scale climate reconstruction shown by the Intergovernmental Panel on Climate Change (IPCC) likely underestimate this long-term cooling trend over the past few millennia.”

    http://wattsupwiththat.com/2012/07/09/this-is-what-global-cooling-really-looks-like/

    Discussion follows.

    Climate in northern Europe reconstructed for the past 2,000 years: Cooling trend calculated precisely for the first time

    Calculations prepared by Mainz scientists will also influence the way current climate change is perceived / Publication of results in Nature Climate Change

    An international team including scientists from Johannes Gutenberg University Mainz (JGU) has published a reconstruction of the climate in northern Europe over the last 2,000 years based on the information provided by tree-rings. Professor Dr. Jan Esper's group at the Institute of Geography at JGU used tree-ring density measurements from sub-fossil pine trees originating from Finnish Lapland to produce a reconstruction reaching back to 138 BC. In so doing, the researchers have been able for the first time to precisely demonstrate that the long-term trend over the past two millennia has been towards climatic cooling. "We found that previous estimates of historical temperatures during the Roman era and the Middle Ages were too low," says Esper. "Such findings are also significant with regard to climate policy, as they will influence the way today's climate changes are seen in context of historical warm periods." The new study has been published in the journal Nature Climate Change.

    Was the climate during Roman and Medieval times warmer than today? And why are these earlier warm periods important when assessing the global climate changes we are experiencing today? The discipline of paleoclimatology attempts to answer such questions. Scientists analyze indirect evidence of climate variability, such as ice cores and ocean sediments, and so reconstruct the climate of the past. The annual growth rings in trees are the most important witnesses over the past 1,000 to 2,000 years as they indicate how warm and cool past climate conditions were.

    Researchers from Germany, Finland, Scotland, and Switzerland examined tree-ring density profiles in trees from Finnish Lapland. In this cold environment, trees often collapse into one of the numerous lakes, where they remain well preserved for thousands of years.

    The international research team used these density measurements from sub-fossil pine trees in northern Scandinavia to create a sequence reaching back to 138 BC. The density measurements correlate closely with the summer temperatures in this area on the edge of the Nordic taiga. The researchers were thus able to create a temperature reconstruction of unprecedented quality. The reconstruction provides a high-resolution representation of temperature patterns in the Roman and Medieval Warm periods, but also shows the cold phases that occurred during the Migration Period and the later Little Ice Age.

    In addition to the cold and warm phases, the new climate curve also exhibits a phenomenon that was not expected in this form. For the first time, researchers have now been able to use the data derived from tree-rings to precisely calculate a much longer-term cooling trend that has been playing out over the past 2,000 years. Their findings demonstrate that this trend involves a cooling of -0.3°C per millennium due to gradual changes to the position of the sun and an increase in the distance between the Earth and the sun.

    "This figure we calculated may not seem particularly significant," says Esper. "However, it is also not negligible when compared to global warming, which up to now has been less than 1°C. Our results suggest that the large-scale climate reconstruction shown by the Intergovernmental Panel on Climate Change (IPCC) likely underestimate this long-term cooling trend over the past few millennia."

    source: Johannes Gutenberg University http://www.uni-mainz.de/eng/15491.php
     
  2. James Cessna

    James Cessna New Member

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    These comments were very good.

    Since the Holocene Climatic Optimum was even warmer than the Roman & Medieval Periods, the cooling trend would be yet more pronounced if extended back another 3000 years or more. Modern warmth is not exceptional, having been exceeded in at least two periods during the past 2000 years.

    Perhaps even more tellingly, the previous Eemian Interglacial (114 to 130 kya), was much warmer than today’s Holocene Interglacial. As most here must know, Scandinavia was then an island, hippos swam in the Thames at the site of London, & the raised beaches of Alaska & fossil reefs of the Bahamas were formed. The interglacial before the Eemian (Hoxnian in the UK, Holstein in N. Europe & Mindel-Riss in the Alps, corresponding to Marine Isotope Stage 11, from 374 to 424 kya) was also warmer than our present Holocene. All this without benefit of a Neanderthal or Homo heidelbergensis industrial age burning copious quantities of coal, or even wood, & with “pre-industrial” CO2 levels.
     
  3. MisLed

    MisLed New Member

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    eh. inconvenient.
     
  4. rstones199

    rstones199 Well-Known Member

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    Watts Up With That? <----- :laughing:

    Ok Dude
     
  5. HB Surfer

    HB Surfer Well-Known Member Past Donor

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    Why again did Al Gore Jr. buy an ocean front villa?
     
  6. James Cessna

    James Cessna New Member

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    Ha-Ha!

    Al Gore Jr. must have read this latest report!

    Solar insolation changes, resulting from long-term oscillations of orbital configurations (1), are an important driver of Holocene climate (2, 3). The forcing is substantial over the past 2,000 years, up to four times as large as the 1.6&#8201;W&#8201;m&#8722;2 net anthropogenic forcing since 1750 (ref. 4), but the trend varies considerably over time, space and with season (5). Using numerous high-latitude proxy records, slow orbital changes have recently been shown (6) to gradually force boreal summer temperature cooling over the common era.

    Here, we present new evidence based on maximum latewood density data from northern Scandinavia, indicating that this cooling trend was stronger (&#8722;0.31&#8201;°C per 1,000&#8201;years, ±0.03&#8201;°C) than previously reported, and demonstrate that this signature is missing in published tree-ring proxy records. The long-term trend now revealed in maximum latewood density data is in line with coupled general circulation models (7, 8) indicating albedo-driven feedback mechanisms and substantial summer cooling over the past two millennia in northern boreal and Arctic latitudes. These findings, together with the missing orbital signature in published dendrochronological records, suggest that large-scale near-surface air-temperature reconstructions (9, 10, 11, 12, 13) relying on tree-ring data may underestimate pre-instrumental temperatures including warmth during Medieval and Roman times.

    source: Nature Climate Change (2012) doi:10.1038/nclimate1589
     
  7. rstones199

    rstones199 Well-Known Member

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    Tree-rings prove climate was WARMER in Roman and Medieval times than it is now - and world has been cooling for 2,000 years

    [quoteMeasurements stretching back to 138BC prove that the Earth is slowly cooling due to changes in the distance between the Earth and the sun. [/quote]


    Easily debunked:

    The Earth is in a clear warming pattern, when it should be cooling off. Solar activity is on a down trend, which means The Earth SHOULD be cooling off.

    The tree study does show that we WERE cooling.

    However, anyone with any kind of brain can clearly see that in the past 40 - 50 years we are warming and warming quite rapidly, when we should still be cooling off:

    [​IMG]

    Thanks for the study to confirm that we are indeed warming the planet and excess human CO2 from the Industrial Revolution is the cause.

    The OP may be his/her own worst enemy.
     
  8. Windigo

    Windigo Banned

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    Its published by Nature. The same ones who published the original hockey stick. Esper who's previous hockey stick study has been used as evidence to support Mann is also one of the coauthors Nice try though.

    As to this study. It is still a tree ring study. So I don't put much into it. I just shows that tree rings can be used to show anything.
     
  9. Windigo

    Windigo Banned

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    Fallacy of a single cause. There is no evidence to suggest that the earth has only one driver of temperature. As your graph clearly shows that while CO2 was rising rapidly from the late 30s to the end of the 70s temperature was flat and only took off in the 80s. The flat period from the last 30s to the 80s totally falsifies any argument that CO2 is driving the warming. Any who has tried to do a correct coingratiation of CO2 and temperature has failed to find a correlation between the two due to this 40 year disconnect.

    [​IMG]

    Pretty clear that for 40 years temperature was unresponsive to CO2.
     
  10. Windigo

    Windigo Banned

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    While I said I don't put much faith in tree rings it is a good visual as there are other non tree proxies that show the same thing. Warmongers like to say that our present warming is unprecedented but we can clearly see that at least according to this tree ring study there were equally sharp rises in temperature at multiple times in history.
     
  11. James Cessna

    James Cessna New Member

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    You are mistaken, stones.

    You should know this by now.

    The data you have presented have been discredited time-and-time again and is no longer accepted as fact today.

    Here are the most recent reconstructions that are accepted today by the world's most credible global climate scientists.

    [​IMG]

    The reconstruction provides a high-resolution representation of temperature patterns in the Roman and Medieval warm periods, but also shows the cold phases that occurred during the Migration Period and the later Little Ice Age.
    credible source: http://www.uni-mainz.de/eng/15491.php

    Since Princeton&#8217;s Dr. Michael Oppenheimer conflated weather with climate last week, proclaiming a short lived heat wave as &#8220;This is what global warming really looks like&#8221; in a media interview, it seems only fair to show what real science rather than what he and Dr. Trenberth&#8217;s government funded advocacy looks like. I can&#8217;t wait to see how Dr. Michael Mann tries to poo-poo this one. &#8211; Anthony Watts
     
  12. rstones199

    rstones199 Well-Known Member

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    :laughing: first off 'my' graph:

    [​IMG]

    Only shows temperatures that are rising, and does not show anything at all about CO2...

    This is sufficient to say the cooling trend the OP is so proud about, has ended.

    However, CO2 it the atmosphere has risen dramatically since 1850:

    [​IMG]

    CO2 is a greenhouse gas. The more CO2 we dump in the atmosphere, the higher the temps will be on this planet and the more extreme the weather will get. To say there is no correlation is just plane STUPID.
     
  13. rstones199

    rstones199 Well-Known Member

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    Your nonsense was debunked back in Post #7.

    Why don&#8217;t you tell the PF World how the Earth can be warming, while the sun is cooling.

    I notice you do not have an answer for this.
     
  14. Piscivorous

    Piscivorous New Member

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    So those scientists in the 1970s who told us all we would be entering a mini-Ice Age are convinced we're getting hotter now? Don't trust Gubemint scientists. They only have half a brain.
     
  15. Piscivorous

    Piscivorous New Member

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    The tree rings of a tree in the Redwood Forest has successfully predicted the last 20 Presidential Elections. It has also predicted the winner of the NCAA Basketball tournament successfully the past 60 years. Bet on University of Pacific next year. It's a lock.
     
  16. James Cessna

    James Cessna New Member

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    Ha-Ha!

    You and the "warmies" obviously believe in superstitions and fairytales.

    We on the other hand believe in established science!
     
  17. DonGlock26

    DonGlock26 New Member Past Donor

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    Easily debunked:

    The Earth is in a clear warming pattern, when it should be cooling off. Solar activity is on a down trend, which means The Earth SHOULD be cooling off.

    The tree study does show that we WERE cooling.

    However, anyone with any kind of brain can clearly see that in the past 40 - 50 years we are warming and warming quite rapidly, when we should still be cooling off:

    [​IMG]

    Thanks for the study to confirm that we are indeed warming the planet and excess human CO2 from the Industrial Revolution is the cause.

    The OP may be his/her own worst enemy.[/QUOTE]

    [​IMG]
     
  18. James Cessna

    James Cessna New Member

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    You are correct, Windigo.

    There are several accepted plausible theories by the scientfic community of the principal causes of global warming.

    The mind of a liberal can only consider and comprehend one single source at a time.
     
  19. politicalcenter

    politicalcenter Well-Known Member

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    This data is at best inconclusive.

    You would also have to check how much particulate matter there was in the air, how much heat was absorbed by the ocean, volcanic activity, and I am sure several other variables....if your data is correct to begin with.

    You are just like a creationist....you only have objections to data and research, and very little data or research of your own.

    Everything is just an argument saying AGW/CC is wrong.

    If it is wrong what will be the average global temerature in 2100? Will the temps rise or fall?
     
  20. GraspingforPeace

    GraspingforPeace Well-Known Member

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    http://www.realclimate.org/index.ph...e-rings-and-climate-some-recent-developments/

    "Another interesting finding is that N-Scan exhibits a substantially larger pre-industrial (pre 1900) millennial cooling trend (around -0.31C/1000yr) than a tree ring width (TRW) based summer temperature reconstruction from the same trees. This seems a plausible conclusion,... Yet the article extrapolates quite a bit, in terms of its conclusions regarding proxy-based temperature reconstructions more generally... They argue that TRW data which fail to record this forced long-term cooling might therefore underestimate variability on millennial timescales more generally, and potentially underestimate the warmth of past warm periods (e.g. medieval and Roman periods).
    Orbital forcing is indeed substantial on the millennial timescale for high-latitudes during the summer season, and the theoretically expected cooling trend is seen in proxy reconstructions of Arctic summer temperature trends (Kaufman et al, 2009). But insolation forcing is near zero at tropical latitudes, and long-term cooling trends are not seen in non-tree ring, tropical terrestrial proxy records such as the Lake Tanganyika (tropical East Africa) (Tierney et al, 2010)."


    Basically, the authors used local samples and then applied it globally.
     
  21. Lunchboxxy

    Lunchboxxy Well-Known Member

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  22. James Cessna

    James Cessna New Member

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    This is a normally accepted practice by members of the scientific community. If it were not, the paper would not have been accepted for publication by a peer-reviewed journal.

    Here is the crux of the discussions.


    An international team including scientists from Johannes Gutenberg University Mainz (JGU) has published a reconstruction of the climate in northern Europe over the last 2,000 years based on the information provided by tree-rings. Professor Dr. Jan Esper&#8217;s group at the Institute of Geography at JGU used tree-ring density measurements from sub-fossil pine trees originating from Finnish Lapland to produce a reconstruction reaching back to 138 BC. In so doing, the researchers have been able for the first time to precisely demonstrate that the long-term trend over the past two millennia has been towards climatic cooling.

    The annual growth rings in trees are the most important witnesses over the past 1,000 to 2,000 years as they indicate how warm and cool past climate conditions were. The researchers were thus able to create a temperature reconstruction of unprecedented quality.

    &#8220;We found that previous estimates of historical temperatures during the Roman era and the Middle Ages were too low,&#8221; says Esper. &#8220;Such findings are also significant with regard to climate policy, as they will influence the way today&#8217;s climate changes are seen in context of historical warm periods.&#8221;
     
  23. Windigo

    Windigo Banned

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    Look at his graph

    [​IMG]

    Now look at your graph

    [​IMG]

    Now tell me what is his graph of and what is your graph of?

    They aren't the same thing at all. His graph is of cycle length yours is of TSI.

    The theory on solar forcing, see Svenmark, is that it is an indirect forcing. The suns magnetic field effects the earths albedo. Its not the incoming radiation of the sun as much as it is the amount of sun that is absorbed into the earths crust vs. what is reflected back into space.

    The earth has an albedo of approximately 30% a plus or minus 1% change in the earths albedo is 13.6 watts per square meter which dwarfs the proposed forcing from all anthropogenic greenhouse gases by an order of magnitude. The sun and its indirect effect on the earths albedo is the 500 pound gorilla in the room that no warmmonger wants to talk about. Which is why that lying son of a (*)(*)(*)(*)(*) john cook immediately changed the subject from indirect forcing of the sun to direct forcing.
     

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