Early solar mass loss: A potential solution to the weak sun paradox

The weak sun paradox, in which early planetary temperatures are known to have remained above the freezing point of water despite presumably lower early solar luminosity, has customarily been resolved by imposing high early CO2 atmospheric abundances. Speculative new solar models incorporating early solar mass loss provide a possible solution to the case of "missing" solar lithium; at the same time, they predict higher early (4.5-3.8 Gyr BP) solar luminosities. These higher luminosities have the potential to produce planetary temperatures within the liquid water range indicated by observations without requiring extremely high CO2 concentrations.