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This figure shows the long-term evolution of oxygen isotope ratios during the Phanerozoic eon as measured in fossils, reported by Veizer et al. (1999), and updated online in 2004 [http://www.science.uottawa.ca/geology/isotope_data/]. Such ratios reflect both the local temperature at the site of deposition and global changes associated with the extent of permanent continental glaciation. As such, relative changes in oxygen isotope ratios can be interpreted as rough changes in climate. Quantitative conversion between this data and direct temperature changes is a complicated process subject to many systematic uncertainties, however it is estimated that each 1 part per thousand change in δ18O represents roughly a 1.5-2 °C change in tropical sea surface temperatures (Veizer et al. 2000).

Also shown on this figure are blue bars showing periods when geological criteria (Frakes et al. 1992) indicate cold temperatures and glaciation as reported by Veizer et al. (2000). The Jurassic-Cretaceous period, plotted as a lighter blue bar, was intrepreted as a "cool" period on geological grounds, but the configuration of continents at that time appears to have prevented the formation of large scale ice sheets.

All data presented here have been adjusted to 2004 ICS geologic timescale [http://www.stratigraphy.org/geowhen/]. The "short-term average" was constructed by applying a σ = 3 Myr Gaussian weighted moving average to the original 16,692 reported measurements. The gray bar is the associated 95% statistical uncertainty in the moving average. The "long-term average" is a σ = 15 Myr Gaussian average of the short-term record (see notes).

On geologic time scales, the largest shift in oxygen isotope ratios is due to the slow radiogenic evolution of the mantle. A variety of proposals exist for dealing with this, and are subject to a variety of systematic biases, but the most common approach is simply to suppress long-term trends in the record. This approach was applied in this case by subtracting a quadratic polynomial fit to the short-term averages. As a result, it is not possible to draw any conclusion about very long-term (>200 Myr) changes in temperatures from this data alone. However, it is usually believed that temperatures during the present cold period and during the Cretaceous thermal maximum are not greatly different from cold and hot periods during most of the rest the Phanerozoic. However, recently this has been disputed by Royer et al. (2004), who suggest that the highs and lows in the early part of the Phanerozoic were both significantly warmer than their recent counterparts.

Common symbols for geologic periods are plotted at the top and bottom of the figure for reference.

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http://en.wikipedia.org/wiki/File:Phanerozoic_Climate_Change.png

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This figures shows estimates of the changes in carbon dioxide concentrations during the Phanerozoic. Three estimates are based on geochemical modeling: GEOCARB III (Berner and Kothavala 2001), COPSE (Bergmann et al. 2004) and Rothman (2001). These are compared to the carbon dioxide measurement database of Royer et al. (2004) and a 30 Myr filtered average of those data. Error envelopes are shown when they were available. The right hand scale shows the ratio of these measurements to the estimated average for the last several million years (the Quaternary). Customary labels for the periods of geologic time appear at the bottom.

Direct determination of past carbon dioxide levels relies primarily on the interpretation of carbon isotopic ratios in fossilized soils (paleosols) or the shells of phytoplankton and through interpretation of stomatal density in fossil plants. Each of these is subject to substantial systematic uncertainty.

Estimates of carbon dioxide changes through geochemical modeling instead rely on quantifying the geological sources and sinks for carbon dioxide over long time scales particularly: volcanic inputs, erosion and carbonate deposition. As such, these models are largely independent of direct measurements of carbon dioxide.

Both measurements and models show considerable uncertainty and variation; however, all point to carbon dioxide levels in the past that have been signifcantly higher than they are at present.

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adjust said:

Happy?

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ChuangTzu said:

About what?  None of those graphs even show what you were talking about.

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Yeah they do.

I said CO2 levels are the lowest they've been in hundreds of millions of years, it shows that.

I said the earth has only had ice at it's poles 3 or 4 times in the past few hundred million years, it shows that.

I said the current climate is more consistent with an ice age than a warm period, it shows that.

You might not agree with where the info is coming from but I did give you information how those charts were made and from which scientific studies they were drawn, which is what you asked for.

ScavengerType said:

ChangTzu: Looking at the historical data I've shown I don't know how this could confuse you.

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There are definitely no plateaus of this evenness for this length.

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This plateau is generally accepted from many anthropologists as the origin of civilization and modern man

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