هذه graph الصورة / الصورتان باستعمال رسومات متجهية ملفات رسوميات شعاعية. It is recommended to name the SVG file "Phanerozoic Carbon Dioxide.svg" - then the template Vector version available (or Vva) does not need the new image name parameter.

ملخص

This figure 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), Carbon-Oxygen-Phosphorus-Sulfur-Evolution COPSE (Bergman 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. While the GEOCARB Carbon dioxide levels in the most part of the Phanerzoic Eon shows a fit and resulting climate sensitivity similar to todays values, the early Phanerozoic includes a global ice age during the Ordovician age combined with high atmospheric carbon contents based on the same project. There have been different speculations about the reasons but no acknowledged mechanism so far.

Copyright

This figure was prepared by Robert A. Rohde from published data and is incorporated into the Global Warming Art project.

Image from Global Warming Art

This image is an original work created for Global Warming Art. Please refer to the Carbon Dioxide.png image description page for more information.

يسمح نسخ وتوزيع و/أو تعديل هذه الوثيقة تحت شروط رخصة جنو للوثائق الحرة، الإصدار 1.2 أو أي إصدار لاحق تنشره مؤسسة البرمجيات الحرة؛ دون أقسام ثابتة ودون نصوص أغلفة أمامية ودون نصوص أغلفة خلفية. نسخة من الرخصة تم تضمينها في القسم المسمى GNU Free Documentation License.http://www.gnu.org/copyleft/fdl.htmlGFDLGNU Free Documentation Licensetruetrue

	هذا الملفُّ مُرخَّص بموجب رخصة المشاع الإبداعي نسبة المُصنَّف إِلى مُؤَلِّفه - المشاركة بالمثل 3.0 العامة
	يحقُّ لك: مشاركة العمل – نسخ العمل وتوزيعه وبثُّه إعادة إنتاج العمل – تعديل العمل حسب الشروط التالية: نسب العمل إلى مُؤَلِّفه – يلزم نسب العمل إلى مُؤَلِّفه بشكل مناسب وتوفير رابط للرخصة وتحديد ما إذا أجريت تغييرات. بالإمكان القيام بذلك بأية طريقة معقولة، ولكن ليس بأية طريقة تشير إلى أن المرخِّص يوافقك على الاستعمال. الإلزام بترخيص المُشتقات بالمثل – إذا أعدت إنتاج المواد أو غيرت فيها، فيلزم أن تنشر مساهماتك المُشتقَّة عن الأصل تحت ترخيص الأصل نفسه أو تحت ترخيص مُتوافِقٍ معه.
	تمت إضافة علامة الترخيص لهذا الملف كجزء من رخصة جنو للوثائق الحرة تحديث الترخيص.http://creativecommons.org/licenses/by-sa/3.0/CC BY-SA 3.0Creative Commons Attribution-Share Alike 3.0truetrue

References

1. Bergman, Noam M., Timothy M. Lenton, and Andrew J. Watson (2004). "COPSE: A new model of biogeochemical cycling over Phanerozoic time". American Journal of Science 304: 397–437.
2. Berner, RA and Z. Kothavala (2001). "GEOCARB III: A revised model of atmospheric CO₂ over Phanerozoic time". American Journal of Science 301: 182-204.
3. Gradstein, FM and JG Ogg (1996). "A Phanerozoic time scale". Episodes 19: 3-5.
4. Gradstein, FM, JG Ogg and AG Smith (٢٠٠٥) A geologic time scale 2004، Cambridge University Press ISBN 0521786738
5. Rothman, Daniel H. (2001). "Atmospheric carbon dioxide levels for the last 500 million years". Proceedings of the National Academy of Sciences 99 (7): 4167-4171.
6. Royer, Dana L., Robert A. Berner, Isabel P. Montañez, Neil J. Tabor, and David J. Beerling (2004). "CO₂ as a primary driver of Phanerozoic climate". GSA Today 14 (3): 4-10. doi:10.1130/1052-5173(2004)014<4:CAAPDO>2.0.CO;2
7. Veizer, J., Godderis, Y. & Francois. L.M., Evidence for decoupling of atmospheric CO2 and global climate during the Phanerozoic eon. Nature 408, 698-701 (2000) [1]
8. Nir J. Shaviv, Ján Veizer: Celestial driver of Phanerozoic climate?, Geological Society of America Vol. 13, Issue 7 (Juliy 2003), S. 4–10, Online (pdf 454 KByte)[2]

Notes

1. All data except GEOCARB III appear on the 2004 geologic time scale (Gradstein et al. 2005). GEOCARB III appears on the Gradstein & Ogg (1996) time scale.
2. All models are reported in terms of the ratio of past CO₂ concentrations to "present" CO₂ concentrations, where "present" represents some average value for the last few million years. To compare to direct measurements a value of 260 ppmv is chosen for the recent period, with an uncertainty of 10-15%.
3. No models are capable of resolving changes faster than ~10 Myr.
4. Measurements based on the interpretation of paleosols sometimes result in apparent CO₂ concentrations < 0 ppmv. These were set to 0 ppmv.
5. Different measurements in the Royer et al. compilation come from different authors and involve different techniques. As such the error bars are not necessarily comparable. For example, some sources may have included only statistical measurement error, whereas others may have included statistical and systematic errors. Other measurements report no uncertainty at all. Because of these factors, the error measurements were ignored when determining the 30 Myr measurement average.