[quickthrowman]

There is not a graph of prehistoric ocean surface temperatures (doesn’t seem possible to obtain this data other than collecting it as it happens as far as I can tell) but there is global historical temperature data. Here is an XKCD comic, scroll to the bottom and pay attention to the rate of change since 1850 vs the prior 20,000 years: https://xkcd.com/1732/

This Wikipedia article has a graph of the last 2000 years: https://en.wikipedia.org/wiki/Global_surface_temperature

And yes, I am aware that earth has possibly been covered in ice/slush and also that the avg global temp has been 10C (or more) higher than it is now, but humans were not around for either scenario.

[pdonis]

> there is global historical temperature data

Reconstructed from proxies. Not all experts in the field agree on how reliable the proxies actually are, especially over such long time periods.

[krupan]

How does the global temperature relate to El Nino temperature? Do we know without having El Nino data?