A recent study led by a petroleum geochemist at the U.S. Geological Survey suggests that Earth could be sitting on a vast reserve of hydrogen gas, estimated to be around 6.2 trillion tons, hidden in rocks and underground reservoirs. This discovery opens up the possibility of reducing human dependence on fossil fuels for several decades. While most of this hydrogen is expected to be deep underground or far offshore, researchers believe that even a small fraction could significantly contribute to meeting net-zero carbon emission goals. The study, published in Science Advances, indicates that the estimated amount of hydrogen surpasses all proven natural gas reserves on Earth in terms of energy content. By combining knowledge of how hydrogen occurs naturally with geologic data, researchers predict a potential of around 5.6 × 106 metric tonnes of hydrogen globally. These findings emphasize the importance of exploring and understanding geologic hydrogen resources further to harness this alternative low-carbon energy source. Despite potential limitations in accessibility and economic viability, the study remains optimistic about the vast energy potential that geologic hydrogen could offer for the future.