Graph showing average temperature during the Mesoproterozoic. Blue line uses atmospheric CO2 concentration of 5 times current levels, and red line 10 times current levels and 140 ppm methane. Red circle shows average temperature of tropics region
Michael T. Hren and Nathan D. Sheldon
CC BY-SA 4.0
<a rel="nofollow" class="external free" href="https://doi.org/10.1002/dep2.79">https://doi.org/10.1002/dep2.79</a>