A recent study led by a petroleum geochemist at the U.S. Geological Survey has unveiled the potential of trillions of tons of hydrogen gas buried beneath Earth's surface. This massive amount of geologic hydrogen, estimated at around 6.2 trillion tons, could offer a sustainable alternative to fossil fuels for nearly 200 years. The study suggests that this natural hydrogen, found in rocks and underground reservoirs formed through geochemical processes, could be a low-carbon primary energy resource. While currently discovered in limited places like Albania and Mali, researchers believe these reserves could extend globally. Despite challenges in accessing these reserves due to depth and offshore locations, the study remains optimistic about the viability of utilizing geologic hydrogen to reduce carbon emissions. The study estimates that even a small fraction of this hydrogen resource could meet the projected needs for net-zero carbon emissions for two centuries. With the potential to surpass the energy content of all proven natural gas reserves on Earth, further research is encouraged to understand the global scale of geologic hydrogen resources. However, experts caution that extensive efforts would be required to extract hydrogen at a scale impactful enough to combat climate change effectively.