1824, Joseph Fourier calculated that an Earth-sized planet, at our distance from the Sun, ought to be much colder. He suggested something in the atmosphere must be acting like an insulating blanket. In 1856, Eunice Foote discovered that blanket, showing that carbon dioxide and water vapor in Earth's atmosphere trap escaping infrared (heat) radiation.
1860s, physicist John Tyndall recognized Earth's natural greenhouse effect and suggested that slight changes in the atmospheric composition could bring about climatic variations.
1896, a seminal paper by Swedish scientist Svante Arrhenius first predicted that changes in atmospheric carbon dioxide levels could substantially alter the surface temperature through the greenhouse effect.
1938, Guy Callendar connected carbon dioxide increases in Earth’s atmosphere to global warming.
1941, Milutin Milankovic linked ice ages to Earth’s orbital characteristics.
Gilbert Plass formulated the Carbon Dioxide Theory of Climate Change in 1956.