Fifty years of Himalayan glacier mass-balance monitoring: Recommendations in honour of IYGP 2025

Since the first glacier-wide mass-balance measurement on Gara Glacier (India) in 1974, researchers have monitored 38 glaciers across the Himalaya. These glaciers show a mean wastage of −0.62 ± 0.33 m w.e. a‒1, equivalent to a cumulative mass loss of −23.95 ± 1.44 m w.e. over 1974‒2023. The wastage strongly increased from −0.31 ± 0.34 m w.e. a‒1 pre-2000 to −0.66 ± 0.33 m w.e. a‒1 post-2000, indicating an acceleration of ∼9 cm w.e. per decade since 1974. Only seven glaciers (Chhota Shigri, Hoksar, Mera, Pokalde, Rikha Samba, West Changri Nup and Yala) meet the WGMS definition of benchmark glaciers, characterized by at least 10 years of continuous mass-balance observations. Glacier-wide mass-balance analysis with geodetic estimates identifies Mera and Rikha Samba as representative of the central Himalaya, while Chhota Shigri for the western Himalaya. To honour the International Year of Glaciers’ Preservation (IYGP) 2025, it is recommended to: (i) use standardized methodologies for estimating random errors in glacier-wide mass balances; (ii) reanalyse mass-balance series spanning ∼10 years or longer; (iii) expand monitoring to underexplored regions like the Karakoram, Sikkim, Zanskar and the Bhutanese Himalaya; (iv) continue monitoring of benchmark glaciers which is vital to understanding glacier response to climate change.