Why is the earth habitable for life since at least 3.8 billion years ago while luminosity of the sun have increased by 25%? The interaction between silicate weathering and carbon cycle may have played a central role because liquid water is vital for weathering reaction. This talk will provide evidences from small basaltic catchments and deep time weathering tracers to prove the negative feedbacks between silicate weathering and the concentration of carbon dioxide in atmosphere. I will also show how weathering feedbacks have saved the Earth from Cenozoic cooling and snow ball glaciation. Finally, I will propose a hypotheses regarding why there are only two snowball earth periods.