The latter. I suggest reading https://en.wikipedia.org/wiki/Paleoclimatology#Reconstructing_ancient_climates https://en.wikipedia.org/wiki/Paleoclimatology#Reco

The latter. I suggest reading https://en.wikipedia.org/wiki/Paleoclimatology#Reconstructing_ancient_climates https://en.wikipedia.org/wiki/Paleoclimatology#Reconstructin...