Temperature of Planet Earth

Geological temperature history of Earth

Also at: https://commons.wikimedia.org/wiki/File:All_palaeotemps.png

This shows estimates of global average surface air temperature over the 540 million years of the Phanerozoic, since the first major proliferation of complex life forms on our planet. A substantial achievement of the last 30 years of climate science has been the production of a large set of actual measurements of temperature history (from physical proxies), replacing much of the earlier geological induction (i.e. informed guesses). The graph shows selected proxy-based temperature estimates, which are detailed below.

Because many proxy temperature reconstructions indicate local, not global, temperature — or ocean, not air, temperature — substantial approximation may be involved in deriving these global temperature estimates. As a result, the relativities of some of the plotted estimates are approximate, particularly the early ones.


Time scale

Time is plotted backwards from the present, taken as 2015 CE. It is scaled linearly in five separate segments, expanding by about an order of magnitude at each vertical break. The breaks are not evenly distributed; instead they are positioned at geologically relevant times:

  • At the Mesozoic – Cenozoic boundary, ~66 My ago. This is the “K-T” boundary (now called Cretaceous–Paleogene), at which the dinosaurs became extinct.
  • At the Miocene – Pliocene boundary, ~5.3 My ago.
  • One million years ago, near the onset of the current, 100 000 year-dominated, glaciation cycle (previous glaciations were shorter).
  • Near the last glacial maximum, 20 000 years ago.

Temperature scale

Surface air temperature is plotted as anomalies (differences) from the area-weighted global average over the reference interval 1960-1990 (which is about 14°C / 57°F), in both Celsius (left) and Fahrenheit (right).


Panel 1: 540 to 66 million years ago

The main panel 1 data is from stable oxygen isotope measurements from the shells of macroscopic marine organisms (“fossil shells”), collected by Veizer et al (1999), as re-interpreted by Royer et al (2004). The graph effectively reproduces the upper panel of Royer et al’s figure 4, but with an expanded range (see below). The orange band shows the effect of extreme assumptions in application of the GEOCARB carbon dioxide concentration reconstruction to interpretation, and is not representative of the full uncertainly (which would be much larger).

Because the Royer / Veizer results are indicative of the temperature of the shallow tropical and subtropical seas where the organisms lived, they are unlikely to be fully representative of global average surface air temperature variation. The anomalies are plotted here expanded by a factor of two as a very approximate conversion. Multiple confounding factors affect interpretation of samples this old, so this data is best viewed as a qualitative indication of temperature (warmer/colder – Royer pers comm, 2014).

That is emphasised by the short green trace in panel 1, which shows Cretaceous temperatures (here 115-66 My) from the Friedrich et al (2012) collection of oxygen isotope measurements on the shells of microscopic, deep-water marine organisms, interpreted using the prescription of Hansen et al (2013). That interpretation is also a relatively crude approximation (see below), but yields average surface temperature estimates nearer to the standard view of Cretaceous palaeoclimate (e.g. in Wilson et al, 2002).

Panel 2: 66 to 5.3 million years ago

This data is from the Hansen et al (2013) interpretation of the global collection of oxygen isotope data from the shells of microscopic, deep-water marine organisms of Zachos et al (2008).

This is a direct estimate of global average sea surface temperature, a close analogue of surface air temperature. Hansen et al describe it as a “first estimate”, meaning an approximate one, but limited independent corroboration (e.g. Zachos et al (2006) for the Eocene optimum) indicates that it is substantially more quantitative than the Royer / Veizer data in panel 1.

Panel 3: 5.3 to 1 million years ago

This data is from the Lisiecki and Raymo (2005a, 2005b) global stack of oxygen isotope data from microscopic, deep-water marine organisms interpreted using the Hansen et al (2013) prescription.

At this scale, the Zachos et al stack (which also covers this interval) is virtually indistinguishable from the Lisiecki and Raymo stack. This is a direct estimate of global average sea surface temperature.

Panel 4: 1 million to 20 000 years ago

Two datasets are plotted:

  1. Lisiecki and Raymo, as in panel 3.

  2. Temperature estimates from stable hydrogen isotope measurements from the EPICA Dome C ice core from central East Antarctica (Jouzel et al 2007). These temperature anomaly estimates are polar, not global, and are here divided by a standard polar amplification factor (2.0, as for example in Hansen et al 2013) to approximately convert them to global estimates.

Panel 5: 20 000 years ago to present (2015)

Five datasets are plotted:

  1. EPICA Dome C, as in panel 4.

  2. Temperature estimates from oxygen isotope measurements on the north Greenland ice core, NGRIP (Andersen et al 2004), interpreted using the simple procedure of Johnsen et al (1989). (There are more modern and complex procedures which would yield slightly different interpretations.) Like the EPICA Dome C record, this record is polar, and is shown divided by a polar amplification factor of 2.0. The difference between this and dataset 1. illustrates the polar sea-saw hypothesis.

  3. Global temperature estimates over the ~12 000 years of the Holocene from the multi-proxy collection and interpretation of Marcott et al (2013).

  4. Instrumental (not proxy) data since 1850 from the Berkeley Earth project land-ocean dataset (Berkeley Earth 2014), plotted as decadal means.

  5. Projected temperatures for 2050 and 2100 from the IPCC Fifth Assessment Report’s WG1 Summary for Policy Makers (IPCC 2013) for the RCP8.5 pathway.


Graph traces:

Permian glaciations The late Carboniferous to early Permian, about 300 million years ago, has long been known to be an interval of extensive Southern Hemisphere continental glaciation (see these interpretive maps: late Carboniferous; early Permian). There is widespread geological evidence, for example the extraordinarily well-preserved glacial erosion features in South Australia.

Cretaceous hothouse The mid-Cretaceous, about 80-100 million years ago, is known to have been an extraordinarily hot period in earth’s history, with very high sea levels and crocodiles and turtles living in Arctic latitudes (Wilson et al, 2002).

K-T This is the Cretaceous–Paleogene boundary (previously called Cretaceous-Tertiary, “K-T”) at which the dinosaurs became extinct, around 66 million years ago.

PETM The Paleocene-Eocene thermal maximum is a much-studied spike in global temperature about 58 million years ago, thought to have produced the highest global temperature since the dinosaur extinction.

Early Eocene optimum In palaeoclimate jargon, an “optimum” is an extended period of high or “equable” temperatures (as opposed to a short temperature spike). The Early Eocene climatic optimum, around 50 million years ago, appears to have been the warmest world since the dinosaurs, excluding the PETM.

Eemian The Eemian, about 130 000 to 115 000 years ago was the previous or penultimate interglacial — the last brief warm period before the one in which we live, separated by the Last Glacial period.

LGM The Last Glacial maximum about 20 000 years ago was the interval of maximum extent of continental ice sheets, near the end of the Last Glacial period.

YD The Younger Dryas, about 12 000 years ago, was a brief return to near LGM temperatures in parts of the Northern Hemisphere, interrupting the overall global deglaciation.

Holocene optimum The Holocene climatic optimum was a slightly warmer interval centred on about 8000 years ago.

Top bar:

Cm Cambrian
O Ordivician
S Silurian
D Devonian
C Carboniferous
P Permian
Tr Triasic
J Jurasic
K Cretaceous
Pal Paleocene
Ol Oligocene


  1. Veizer, J, Ala, D, Azmy, K, Bruckschen, P, Buhl, D, Bruhn, F, Carden, GAF, Diener, A, Ebneth, S, Godderis, Y, Jasper, T, Korte, C, Pawellek, F, Podlaha, O & Strauss, H (1999). 87Sr/86Sr, d13C and d18O evolution of Phanerozoic seawater. Chemical Geology 161, 59-88.
  2. Royer, DL, Berner, RA, Montañez, IP, Tabor, NJ & Beerling, DJ (2004). CO2 as a primary driver of Phanerozoic climate. GSA Today July 2004, volume 14, number 3, pages 4-10, doi:10.1130/1052-5173(2004)014<4:CAAPDO>2.0.CO;2
  3. Royer, Dana (2014). Dana Royer comment at RealClimate. Retrieved on 26 March 2014.
  4. Friedrich, O., Norris, R.D. & Erbacher, J. (2012). Evolution of mid- to Late Cretaceous oceans – A 55 million year record of Earth’s temperature and carbon cycle. Geology 40: 107-110.
  5. Wilson, P. A., Norris, R. D., & Cooper, M. J. (2002). Testing the Cretaceous greenhouse hypothesis using glassy foraminiferal calcite from the core of the Turonian tropics on Demerara Rise. Geology, 30(7), 607-610.
  6. Hansen, J, Sato, M, Russell, G & Kharecha, P (2013). Climate sensitivity, sea level, and atmospheric carbon dioxide. Phil. Trans. R. Soc. A, 371, 20120294. doi:10.1098/rsta.2012.0294
  7. Zachos JC, Dickens GR & Zeebe RE (2008). An Early Cenozoic perspective on greenhouse warming and carbon-cycle dynamics. Nature 451, 279–283. doi:10.1038/nature06588
  8. Zachos, JC, Schouten, S, Bohaty, S, Quattlebaum, T, Sluijs, A, Brinkhuis, H, Gibbs, S & Bralower, TJ (2006). Extreme warming of mid-latitude coastal ocean during the Paleocene-Eocene Thermal Maximum: Inferences from TEX86 and isotope data. Geology, 34(9), 737-740.
  9. Lisiecki, LE & Raymo, ME (2005a). A Pliocene‐Pleistocene stack of 57 globally distributed benthic δ18O records. Paleoceanography, 20(1).
  10. Lisiecki, LE & Raymo, ME (2005b). Correction to “A Pliocene-Pleistocene stack of 57 globally distributed benthic d18O records”. Paleoceanography: PA2007. doi:10.1029/2005PA001164
  11. Jouzel, J, Masson-Delmotte, V, Cattani, O, Dreyfus, G, Falourd, S, Hoffmann, G., … & Wolff, EW (2007). EPICA Dome C ice core 800kyr deuterium data and temperature estimates. IGBP PAGES/World Data Center for Paleoclimatology data contribution series, 91, 2007.
  12. Andersen, KK, Azuma, N, Barnola, JM, Bigler, M, Biscaye, P, Caillon, N, … & White, JWC (2004). High-resolution record of Northern Hemisphere climate extending into the last interglacial period. Nature, 431(7005), 147-151.
  13. Johnsen, SJ, Dansgaard, W & White, JWC (1989). The origin of Arctic precipitation under present and glacial conditions. Tellus B, 41(4), 452-468.
  14. Marcott, SA, Shakun, JD, Clark, PU & Mix, AC (2013), A reconstruction of regional and global temperature for the past 11,300 years. Science, 339(6124), 1198-1201.
  15. Berkeley Earth land-ocean dataset (2014). Retrieved on 21 March 2014.
  16. IPCC Fifth Assessment Report WG1 Summary for Policy Makers (2013). Retrieved on 21 March 2014.


The spreadsheet that produced this graph can be downloaded here: http://gergs.net/?attachment_id=4310


Also see:

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