Overview
- The Global Carbon Project’s assessment shows atmospheric hydrogen climbed about 70% from preindustrial levels to 2003, paused briefly, then rose again around 2010, with most growth since 1990 driven by human activity.
- Hydrogen indirectly warms the atmosphere by depleting oxidants that remove methane, with an estimated warming potency of about 11 times CO2 over 100 years and roughly 37 times over 20 years.
- The buildup of hydrogen has added approximately 0.02°C to global warming since the Industrial Revolution.
- Methane oxidation is the largest hydrogen source, increasing by roughly 4 million tons since 1990 to about 27 million tons per year in 2020, while soils removed around 70% of total hydrogen emissions.
- The study cautions that hydrogen’s climate benefits depend on minimizing leakage and cutting methane emissions, alongside scaling low‑carbon hydrogen production and improving measurement and monitoring.