10 Largest Annual Increases in Global Atmospheric Methane, 1984–2025

2021 leads at 17.69 ppb, followed by 2020 at 14.81 ppb and 1991 at 14.00 ppb. The ranking covers all 42 complete annual growth observations in NOAA’s 1984–2025 global methane series; the incomplete year 2026 is excluded.

NOAA Global Monitoring Laboratory’s October 9, 2026 data release reports the net annual change in dry-air mole fraction, in ppb, from the beginning to the end of each year. This is concentration growth after additions and removals, not annual emissions, percentage growth, or the atmospheric concentration level. The series uses globally averaged marine surface measurements with the seasonal cycle removed. Last-year estimates can be revised; 2026 is not a full-year observation.

Published one-standard-deviation uncertainties (ppb): 2021: 17.69 ± 0.36; 2020: 14.81 ± 0.51; 1991: 14.00 ± 0.60; 2022: 13.01 ± 0.36; 1986: 12.89 ± 0.67; 1984: 12.88 ± 0.91; 2014: 12.74 ± 0.55; 1985: 12.20 ± 0.85; 1998: 12.14 ± 0.65; 1987: 11.44 ± 0.64. Small gaps may be within uncertainty; ranks compare point estimates.

Sources checked October 28, 2026. Equal values are ties; display order does not break a tie.