https://www.pnas.org/doi/10.1073/pnas.1120177109

On the graph in this link it shows, that before industrialisation there was no big chenge in climate. So it is most probably that it would be a change similar to before where the fastest change was in 900 to approx. 100after christ, where there was almost an increase of 0.4°C in 100 years.

If it would be warming more without human intervengen since 1900 is not even cleary from this graph since before industrialisation it is almost horicontally.