20,000 BCE
At the start of our timeline, Earth is 4° C colder than during the late 20th century. If the Red Sox were still around, they would be playing under a mile of Ice, and living in NYC would give you a scenic view of the glaciers
19,500 BCE
But, the world is about to warm up. Humans have already spread across Africa, Eurasia, and Australia. Soon, changes in the Earth's Orbit mean that more sunlight will reach the polar Ice.
18,000 BCE
The ice sheets start to melt...
17,300 BCE
Temperatures have been creeping upward, but around this point, CO2 levels start to climb.
18,000 BCE
The ice sheets start to melt...
15,200 BCE
In what is now France, humans paint murals on the walls of the lascaux caves.