Now the researchers are trying to obtain more oxygen isotope data to relate to fossil pollen found in lake sediments. The paradox is the evidence in the geological record showing that liquid water existed on the Earth billions of years ago, yet calculations based on our knowledge of the Sun and other similar stars indicates that the sun radiated so little warmth back then that the Earth's surface water should have been frozen. The early Earth was widely different from today. Four differences that would have affected climate are a cooler sun, an atmosphere much higher in carbon dioxide with little oxygen, a faster Earth rotation rate, and much less land area. Hal Marshall High temperatures and high carbon dioxide levels increase the incorporation of carbon dioxide into rocks, which would lower average global temperature.
Lower temperature slows the movement of carbon dioxide into rock.
The scientists conclude that this loop could stabilize the climate, and create conditions for CO-2 levels needed to keep the oceans liquid despite the cool sun. Then, as the sun increased in luminosity, and more carbon dioxide was incorporated into rock, this same loop could cool the Earth. The researchers also found that the Precambrian Earth had enough land for this feedback loop to stabilize the Earth's climate. These differences are part of the calculations that UM researchers are using to resolve the faint young sun paradox, which indicates that the ancient Earth should have been covered with ice, not the liquid water that the geological record indicates was here. But there are other factors that must be accounted for.