It turns out we have known about human-caused climate change for quite a long time. In the last column we took the history of climate change research back to the late 1800s in Flagstaff, but our understanding started long before then.
In 1824, Joseph Fourier determined that the Earth is warmer than it should be, given its distance from the sun. He proposed that gases in the atmosphere hold in heat, like a glass container holds in heat when placed in sunlight. This later became known as the Greenhouse Effect. You see this effect whenever you park your car too long in sunlight.