Science Explains Earth’s Cooling Shift !

Scientists have solved a long-standing climate mystery dating back 66 million years, explaining how Earth transitioned from a hot tropical “greenhouse” world to the present ice-capped climate. A research team led by the University of Southampton found that calcium levels in the world’s oceans declined by more than 50 percent over this period. The study, published in the journal Proceedings of the National Academy of Sciences (PNAS), reveals that this reduction in ocean calcium helped remove large amounts of carbon dioxide from the atmosphere, triggering long-term global cooling.

The researchers analyzed chemical signals preserved in ancient marine fossils and discovered that early Cenozoic oceans contained nearly double the calcium levels seen today. Computer simulations showed that higher calcium levels caused oceans to store less carbon and release more CO₂, whereas falling calcium levels allowed oceans to absorb more carbon. Changes in marine life, seafloor spreading, and deep-Earth chemistry further influenced this process, confirming that ocean chemistry played a crucial role in shaping Earth’s past climate and driving its cooling trend.