Archiv: George Mullen

21.02.2021 - 14:10 [ Carl Sagan, George Mullen / University of Texas at Austin ]

Earth and Mars: Evolution of Atmospheres and Surface Temperatures

(7. Juli 1972)

Indeed, detailed global climatic models (17) suggest that a relative increase in A of only 2 percent is enough to induce extensive glaciation on Earth, which implies that the present climate is extremely sensitive to albedo. This leaves changes in atmospheric composition as a possible explanation. Major variations in the CO2 abundance will have only minor greenhouse effects because the strongest bands are nearly saturated. A change in the present CO2 abundance by a factor of 2 will produce directly a 2° variation in surface temperature (18). The CO2 abundance is highly controlled by silicate-carbonate equilibria; by buffering with seawater, which contains almost 100 times the atmospheric CO2; and by the respiration and photosynthesis feedback loop (19).