In 1896 Arrhenius was the first person to ever suggest that the combustion of fossil fuel had any sort of correlation with increased global warming. He believed that carbon dioxide in our atmosphere had a connection to the earth’s temperature.
Arrhenius discovered that the average temperature of the surface of the earth is about 15oC due to the infrared absorption capacity of CO2 and water vapor, also known as the (natural) greenhouse effect. He proposed that a doubling of the amount of carbon dioxide would bring about a 5oC temperature increase. Thus bringing the earth’s surface temperature to an astounding 20oC (15+5=20).
He then determined that humans could also create a greenhouse effect of their own by releasing carbon dioxide into the air. Before such discoveries, it was widely believed that humans had little to no effect on the warming of the earth, but instead it was caused by nature.
Silly humans!