The birth of Climate Science

In the 1820s Joseph Fourier declared the atmosphere had to have a warming effect on the earth, later called the GreenHouse Effect. By 1896 Svante Arrhenius realized that CO2 was partly responsible for this warming, and that higher levels would cause higher temperatures. By 1938, Guy Callendar showed that increasing CO2 levels had indeed caused global land temperatures to increase over the preceding 50 years.