What is the magnitude of the threat?
We do not fully know yet. However, we are seeing major impacts even now, far before we have doubled the CO2. Just look at the price of a jar of peanut butter.
What has happened in the past when the threat was realized?
There were major extinction events.
What is the cause of the threat?
A very rapid increase of GHGs in the atmosphere.
What are the direct cause effect pieces of evidence that connect the supposed cause to the stated threat?
Absorption bands of the GHGs in the IR. Paleo record of extinctions caused by rapid climate change.
What is the proposed solution and where has it worked in the past?
The solotion is to cease putting GHGs in the atmosphere. In the past, the source of the GHGs was natural, and the solution was that a high percentage of the species that existed at the time, 95% in the PT extinction event, just went extinct.
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Obviously, you have nothing.
The warming was more extreme between the years 0 and 1000 than between the years 1000 and 2000.
The CO2 in the atmosphere is higher right now than at any point in the last 10,000 years and yet we are a full degree cooler than we were at the peak of the climate temp during that period.
The temperature rises and falls across periods of decades and the CO2 continuously rises with a pretty consistent rate. There is no causation here. Even the correlation is weak.
You need to prove your case and you have not.
When you prove it, I will believe it.
No, you will not. You will continue to lie for your masters.
Surface Temperature Reconstructions for the Last 2,000 Years
Authors:
Committee on Surface Temperature Reconstructions for the Last 2,000 Years, National Research Council
Authoring Organizations
Description:
In response to a request from Congress, Surface Temperature Reconstructions for the Last 2,000 Years assesses the state of scientific efforts to reconstruct surface temperature records for Earth during approximately the last 2,000 years and the implications of these efforts ...
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Real science from the National Academy of Science. Now post something from some organization or person of equal credibility.
The graphic representation of what you have just cited with a brief description with the scientific organizations and/or people that did the research listed below the link.
The proxy records are followed a brief installment of the instrument record. This is obviously like comparing apples to oranges and there is no place for it. The proxies are the proxies and the interments are the instruments. Presenting the two on the same graph is useless.
File:2000 Year Temperature Comparison.png - Global Warming Art
Description
Expansion of the last 1000 years
Temperature variations during the preceding 12000 years.
This image is a comparison of 10 different published reconstructions of mean temperature changes during the last 2000 years. More recent reconstructions are plotted towards the front and in redder colors, older reconstructions appear towards the back and in bluer colors. An instrumental history of temperature is also shown in black. The medieval warm period and little ice age are labeled at roughly the times when they are historically believed to occur, though it is still disputed whether these were truly global or only regional events. The single, unsmoothed annual value for 2004 is also shown for comparison. (Image:Instrumental Temperature Record.png shows how 2004 relates to other recent years).
It is unknown which, if any, of these reconstructions is an accurate representation of climate history; however, these curves are a fair representation of the range of results appearing in the published scientific literature. Hence, it is likely that such reconstructions, accurate or not, will play a significant role in the ongoing discussions of global climate change and global warming.
For each reconstruction, the raw data has been decadally smoothed with a σ = 5 yr Gaussian weighted moving average. Also, each reconstruction was adjusted so that its mean matched the mean of the instrumental record during the period of overlap. The variance (i.e. the scale of fluctuations) was not adjusted (except in one case noted below).
Except as noted below, all original data for this comparison comes from [1] and links therein. It should also be noted that many reconstructions of past climate report substantial error bars, which are not represented on this figure.
The reconstructions used, in order from oldest to most recent publication are:
(dark blue 1000-1991):
[abstract] [DOI] Jones, P.D., K.R. Briffa, T.P. Barnett, and S.F.B. Tett (1998). "High-resolution Palaeoclimatic Records for the last Millennium: Interpretation, Integration and Comparison with General Circulation Model Control-run Temperatures". The Holocene 8: 455-471.
(blue 1000-1980):
[abstract] [full text] Mann, M.E., R.S. Bradley, and M.K. Hughes (1999). "Northern Hemisphere Temperatures During the Past Millennium: Inferences, Uncertainties, and Limitations". Geophysical Research Letters 26 (6): 759-762.
(light blue 1000-1965):
[abstract] Crowley, Thomas J. and Thomas S. Lowery (2000). "Northern Hemisphere Temperature Reconstruction". Ambio 29: 51-54. ; Modified as published in [abstract] [DOI] Crowley (2000). "Causes of Climate Change Over the Past 1000 Years". Science 289: 270-277.
(lightest blue 1402-1960):
[abstract] [DOI] Briffa, K.R., T.J. Osborn, F.H. Schweingruber, I.C. Harris, P.D. Jones, S.G. Shiyatov, and E.A. Vaganov (2001). "Low-frequency temperature variations from a northern tree-ring density network". J. Geophys. Res. 106: 2929-2941.
(light green 831-1992):
[abstract] [DOI] Esper, J., E.R. Cook, and F.H. Schweingruber (2002). "Low-Frequency Signals in Long Tree-Ring Chronologies for Reconstructing Past Temperature Variability". Science 295 (5563): 2250-2253.
(yellow 200-1980):
[abstract] [full text] [DOI] Mann, M.E. and P.D. Jones (2003). "Global Surface Temperatures over the Past Two Millennia". Geophysical Research Letters 30 (15): 1820.
(orange 200-1995):
[abstract] [full text] [DOI] Jones, P.D. and M.E. Mann (2004). "Climate Over Past Millennia". Reviews of Geophysics 42: RG2002.
(red-orange 1500-1980):
[abstract] [DOI] Huang, S. (2004). "Merging Information from Different Resources for New Insights into Climate Change in the Past and Future". Geophys. Res Lett. 31: L13205.
(red 1-1979):
[abstract] [full text] [DOI] Moberg, A., D.M. Sonechkin, K. Holmgren, N.M. Datsenko and W. Karlén (2005). "Highly variable Northern Hemisphere temperatures reconstructed from low- and high-resolution proxy data". Nature 443: 613-617.
(dark red 1600-1990):
[abstract] [DOI] Oerlemans, J.H. (2005). "Extracting a Climate Signal from 169 Glacier Records". Science 308: 675-677.
(black 1856-2004): Instrumental data was jointly compiled by the Climatic Research Unit and the UK Meteorological Office Hadley Centre. Global Annual Average data set TaveGL2v was used. Documentation for the most recent update of the CRU/Hadley instrumental data set appears in:
[abstract] Jones, P.D. and A. Moberg (2003). "Hemispheric and large-scale surface air temperature variations: An extensive revision and an update to 2001". Journal of Climate 16: 206-223.