<p>In a word, no.</p>

<p>The graph is based on work by Chris Scotese. The climate science site RealClimate.org has this to say about it:</p>

<blockquote>
  <p>Scotese is an expert in reconstructions of continental positions through time and in creating his ‘temperature reconstruction’ he is basically following an old-fashioned idea (best exemplified by Frakes et al’s 1992 textbook) that the planet has two long-term stable equilibria (‘warm’ or ‘cool’) which it has oscillated between over geologic history. This kind of heuristic reconstruction comes from the qualitative geological record which gives indications of glaciations and hothouses, but is not really adequate for quantitative reconstructions of global mean temperatures. Over the last few decades, much better geochemical proxy compilations with better dating have appeared (for instance, Royer et al (2004)) and the idea that there are only two long-term climate states has long fallen by the wayside.</p>
</blockquote>

<p>and</p>

<blockquote>
  <p>Some better examples of long term climate change graphics do exist. This one from Veizer et al (2000) for instance (as rendered by Robert Rohde):</p>
</blockquote>

<p><img src="https://i.sstatic.net/HLXgl.png" alt="Phanerozoic Climate Change"></p>

<p>For a more detailed discussion of graphical reconstructions, see <a href="http://www.realclimate.org/index.php/archives/2014/03/can-we-make-better-graphs-of-global-temperature-history/" rel="nofollow noreferrer">this RealClimate entry</a></p>

CC BY-SA 3.0
2016-07-04T16:01:25.640Z
The web site you linked doesn't seem to have explanation, just what is the right hand scale representing?
justCal
CC BY-SA 3.0
2017-09-21T19:23:52.820Z
Anomaly in the oxygen-18 to oxygen-16 ratio -- which is used as a proxy for temperature.
Steve Emmerson
CC BY-SA 3.0
2014-05-06T17:08:45.777Z
2014-05-06T22:32:02.860Z
2014-05-06T22:32:02.860Z
Steve Emmerson
<p>Looking for a historic record of the average temperature on Earth going back millions of years, and this <a href="http://www.scotese.com/climate.htm" rel="nofollow noreferrer">2002 graphic the from the PALEOMAP Project</a> is currently the best I am able to find. Is it accurate, and if so, why? If it is not accurate, is there a graph that is?</p>

<p><img src="https://i.sstatic.net/SQZfW.png" alt="average temperature on Earth going back millions; temperature range is between 25 to 10 C"></p>

CC BY-SA 3.0
2014-05-06T16:21:07.233Z
How do you define accurate?
Peter Jansson
CC BY-SA 3.0
2014-05-06T16:24:45.777Z
Well the range given is 10-25 C, and the graph appears to show precision within 1 C, so I'd say that accurate would be the temperature stated being off by no more than 1 C at any given point in time.
blunders
CC BY-SA 3.0
2014-05-06T16:28:55.920Z
How does the graph show precision within 1° C?
BHF
CC BY-SA 3.0
2014-05-06T16:28:59.273Z
OK, I was also thinking about the time dimension since it spans from the Precambrian.
Peter Jansson
CC BY-SA 3.0
2014-05-06T16:37:39.267Z
@BHF: Under Tertiary the resolution appears to be showing sub 1 C shifts, though maybe I am wrong.
blunders
CC BY-SA 3.0
2014-05-06T16:54:03.673Z
Ok, I see. But as this is not an error bar.
BHF
CC BY-SA 3.0
2014-05-06T17:00:18.013Z
@BHF: Anyway, the intent was to show that I've put effort into finding a historic record of the average temperature on Earth going back millions of years.
blunders
CC BY-SA 3.0
2014-05-06T17:04:35.533Z
I thought it was not a historic record of temperature, but a basic rendering of various palaeo-temperature proxies. Akin to using a five-year-old's drawing of a house as architectural blue-prints.
Siv
CC BY-SA 3.0
2014-05-06T17:09:11.873Z
@Siv: Okay, point of the question is to find a find a historic record of the average temperature on Earth going back millions of years with clearly defined levels of precision and accuracy. If you know an answer, please post one.
blunders
CC BY-SA 3.0
2014-05-06T17:21:12.080Z
@Blunders: a historic record of the average temperature of the earth goes back maybe a few decades, if you're happy to just have a record for central England we can perhaps get you back 250 years. Otherwise you're looking at temperature proxies, so perhaps the question is how accurate are climate proxies in giving us a clear picture of global average temperatures throughout earth history?
Siv
CC BY-SA 3.0
2014-05-07T06:34:03.613Z
Just for information, as far as the Cenozoic is concerned (on your graph Tertiary+Pleistocene+Holocene, on Steve Emmerson's graph Pg+N), [Zachos et al 2001](http://rockbox.rutgers.edu/~jdwright/MarGeol/Old%20Marine%20Geol%20folder/Zachos.pdf) (which modifications in 2008) is still more or less considered the state of the art, though some details have been shown to be likely incorrects.
plannapus
<temperature><paleoclimatology>
Is this graph showing the average temperature on Earth going back millions of years accurate?
blunders
# Is this graph showing the average temperature on Earth going back millions of years accurate?

(Asked by: username_0 on 2014-05-06)

Looking for a historic record of the average temperature on Earth going back millions of years, and this [2002 graphic the from the PALEOMAP Project](http://www.scotese.com/climate.htm) is currently the best I am able to find. Is it accurate, and if so, why? If it is not accurate, is there a graph that is?

![average temperature on Earth going back millions; temperature range is between 25 to 10 C](https://i.sstatic.net/SQZfW.png)

**Tags:** temperature, paleoclimatology

> **Comments:**
> **username_1**: How do you define accurate?  
> **username_0**: Well the range given is 10-25 C, and the graph appears to show precision within 1 C, so I'd say that accurate would be the temperature stated being off by no more than 1 C at any given point in time.  
> **username_2**: How does the graph show precision within 1° C?  
> **username_1**: OK, I was also thinking about the time dimension since it spans from the Precambrian.  
> **username_0**: @username_2: Under Tertiary the resolution appears to be showing sub 1 C shifts, though maybe I am wrong.  
> **username_2**: Ok, I see. But as this is not an error bar.  
> **username_0**: @username_2: Anyway, the intent was to show that I've put effort into finding a historic record of the average temperature on Earth going back millions of years.  
> **username_3**: I thought it was not a historic record of temperature, but a basic rendering of various palaeo-temperature proxies. Akin to using a five-year-old's drawing of a house as architectural blue-prints.  
> **username_0**: @username_3: Okay, point of the question is to find a find a historic record of the average temperature on Earth going back millions of years with clearly defined levels of precision and accuracy. If you know an answer, please post one.  
> **username_3**: @username_0: a historic record of the average temperature of the earth goes back maybe a few decades, if you're happy to just have a record for central England we can perhaps get you back 250 years. Otherwise you're looking at temperature proxies, so perhaps the question is how accurate are climate proxies in giving us a clear picture of global average temperatures throughout earth history?  
> **username_4**: Just for information, as far as the Cenozoic is concerned (on your graph Tertiary+Pleistocene+Holocene, on username_5 username_5's graph Pg+N), [Zachos et al 2001](http://rockbox.rutgers.edu/~jdwright/MarGeol/Old%20Marine%20Geol%20folder/Zachos.pdf) (which modifications in 2008) is still more or less considered the state of the art, though some details have been shown to be likely incorrects.  

---

## 1 answers

### Answer by username_5 on 2014-05-06. Score: 12 | Accepted answer

In a word, no.

The graph is based on work by Chris Scotese. The climate science site RealClimate.org has this to say about it:

> Scotese is an expert in reconstructions of continental positions through time and in creating his ‘temperature reconstruction’ he is basically following an old-fashioned idea (best exemplified by Frakes et al’s 1992 textbook) that the planet has two long-term stable equilibria (‘warm’ or ‘cool’) which it has oscillated between over geologic history. This kind of heuristic reconstruction comes from the qualitative geological record which gives indications of glaciations and hothouses, but is not really adequate for quantitative reconstructions of global mean temperatures. Over the last few decades, much better geochemical proxy compilations with better dating have appeared (for instance, Royer et al (2004)) and the idea that there are only two long-term climate states has long fallen by the wayside.

and

> Some better examples of long term climate change graphics do exist. This one from Veizer et al (2000) for instance (as rendered by Robert Rohde):

![Phanerozoic Climate Change](https://i.sstatic.net/HLXgl.png)

For a more detailed discussion of graphical reconstructions, see [this RealClimate entry](http://www.realclimate.org/index.php/archives/2014/03/can-we-make-better-graphs-of-global-temperature-history/)

> **Comments:**
> **username_6**: The web site you linked doesn't seem to have explanation, just what is the right hand scale representing?  
> **username_5**: Anomaly in the oxygen-18 to oxygen-16 ratio -- which is used as a proxy for temperature.  

---

