Glaciers on the Climate Dashboard

Why are glaciers important?

Glaciers are an important shop of water. Their melt disconnected during the barren play provides h2o for quality use. Loss of glaciers could truthful lead to reduced seasonal h2o readiness affecting the lives of many. If glaciers melt, arsenic they person been doing complete the past 30 years for which we person elaborate measurements, the h2o ends up successful the oceans, raising oversea level, which tin person impacts connected coastal communities.

How person glaciers changed?

The equilibrium betwixt the accumulation of wide from snowfall falling connected a glacier and crystal loss, besides knowns arsenic the mass balance, controls really a glacier changes complete time. Melting of the little glacier tin origin the terminus to retreat to higher and colder elevation. Increased snowfall tin make the glacier beforehand downhill until it is halted by accrued pouring astatine the terminus. If the terminus is successful the ocean, warmer h2o tin melt the glacier, it past flows faster producing much icebergs. Glaciers are not only delicate to changes in temperature and snowfall fall, but besides to different elements for illustration oversea h2o temperature, humidity, cloudiness and whether precipitation falls arsenic rainfall aliases snow.

There are thousands of glaciers world-wide and it is not applicable to measurement them each successful detail. The World Glacier Monitoring Service monitors a group of reference glaciers crossed 19 upland zones. The wide equilibrium of these glaciers has been negative, i.e. they person been shrinking overall, for the past 31 years.

The cumulative nonaccomplishment of wide since 1976 amounts to astir 20m of h2o equivalent. “Water equivalent” is the depth of h2o that we’d get connected the glaciers if each the mislaid crystal and snowfall were melted. Snow and crystal tin person very different densities depending connected really compact the snowfall is, and really overmuch aerial is trapped successful the ice. Using “water equivalent” allows for consistency betwixt measurements.

Longer records show that glaciers person been successful semipermanent retreat since the 19th Century.

How is glacier wide equilibrium measured?

Mass equilibrium is measured utilizing a assortment of techniques. Ice nonaccomplishment tin beryllium measured utilizing stakes driven deep into the aboveground of the glacier. As the crystal melts, it reveals much of the liking allowing the crystal nonaccomplishment to beryllium quantified. Accumulation tin beryllium measured utilizing stakes too, by digging pits that show really overmuch fresh snowfall has accumulated, by probing done freshly fallen snowfall to the difficult aboveground of crystal beneath aliases moreover by analysing the yearly layers of snowfall revealed by crevasses. Combinations of the different techniques provide accusation astir wide summation and nonaccomplishment crossed the aboveground of a glacier.

Glaciers’ heights and shapes tin beryllium mapped from space, utilizing radars, visible ray sensors and different means. Large crystal masses tin besides beryllium monitored by dedicated technological missions that measurement the Earth’s gravitational field, specified arsenic GRACE.

Why person glaciers changed?

Glaciers respond to changes successful temperature, the spot of sunlight reaching the glacier done changes successful unreality screen and albedo, and precipitation. Rate of travel of glaciers tin besides beryllium affected by a alteration in aboveground gradient. This whitethorn hap done downstream changes specified arsenic the nonaccomplishment of buttressing crystal shelves, changes successful basal lubrication owed to meltwater, rainfall aliases infiltration of oversea water. Each glacier is taxable to a unsocial operation of the above-mentioned factors truthful location is variety successful the wide balance betwixt glaciers.

The IPCC AR5 concluded that “the robustness of the estimates of observed wide nonaccomplishment since the 1960s, the assurance we person successful estimates of earthy variations and soul variability from semipermanent glacier records, and our knowing of glacier consequence to climatic drivers provides robust grounds and, therefore, precocious assurance that a important portion of the wide nonaccomplishment of glaciers is apt owed to human influence.”

Find retired more?

More elaborate accusation is disposable from the World Glacier Monitoring Service.

Further technological accusation and references:

Glaciers

WGMS

• Information source: WGMS (2023, updated and earlier reports). Global Glacier Change Bulletin No. 5 (2020-2021). Zemp, M., Gärtner-Roer, I., Nussbaumer, S.U., Welty, E.Z., Dussaillant, I., and Bannwart, J. (eds.), ISC(WDS)/IUGG(IACS)/UNEP/UNESCO/WMO, World Glacier Monitoring Service, Zurich, Switzerland, 134 pp., publication based connected database version: doi:10.5904/wgms-fog-2023-09
• Information reference: WGMS (2023, updated and earlier reports). Global Glacier Change Bulletin No. 5 (2020-2021). Zemp, M., Gärtner-Roer, I., Nussbaumer, S.U., Welty, E.Z., Dussaillant, I., and Bannwart, J. (eds.), ISC(WDS)/IUGG(IACS)/UNEP/UNESCO/WMO, World Glacier Monitoring Service, Zurich, Switzerland, 134 pp., publication based connected database version: doi:10.5904/wgms-fog-2023-09

Glaciers

Zemp et al. (2019)

• Information source: Zemp, M., Huss, M., Thibert, E. et al. Global glacier wide changes and their contributions to sea-level emergence from 1961 to 2016. Nature 568, 382-386 (2019). https://doi.org/10.1038/s41586-019-1071-0
• Information reference: Zemp, Michael, Huss, Matthias, Thibert, Emmanuel, Eckert, Nicolas, McNabb, Robert, Huber, Jacqueline, Cogley, J. Graham. (2019). Global and location glacier wide changes from 1961 to 2016 (Version 1.0.0) [Data set]. Zenodo. http://doi.org/10.5281/zenodo.1492141

Sea Level

CSIRO

• Information source: Watson, Christopher S., Neil J. White, John A. Church, Matt A. King, Reed J. Burgette, and Benoit Legresy. Unabated world mean sea-level emergence complete the outer altimeter era. Nature Climate Change 5, no. 6 (2015): 565. http://dx.doi.org/10.1038/nclimate2635

AVISO

• Information source: Legeais, J.-F., Ablain, M., Zawadzki, L., Zuo, H., Johannessen, J. A., Scharffenberg, M. G., Fenoglio-Marc, L., Fernandes, M. J., Andersen, O. B., Rudenko, S., Cipollini, P., Quartly, G. D., Passaro, M., Cazenave, A., and Benveniste, J. (2018). An improved and homogeneous altimeter oversea level grounds from the ESA Climate Change Initiative. Earth System Science Data, 10, 281-301. DOI: 10.5194/essd-10-281-2018

CMEMS

• Information source: Pujol, M.-I., Faugere, Y,. Taburet, G., Dupuy, S., Pelloquin, C., Ablain, M., and Picot, N.:DUACS DT2014: the caller multi-mission altimeter information group reprocessed complete 20 years, Ocean Sci., 12, 1067-1090. doi: 10.5194/os-12-1067-2016, 2016.
• Information source: Ablain, M., Legeais, J.-F., Prandi, P., Marcos, M., Fenoglio-Marc, L., Dieng, H.-B., Benveniste, J. and Cazenave, A.: Satellite altimetry-based oversea level astatine world and location scales, Surv Geophys., 38, 7-31. doi: 10.1007/s10712-016-9389-8, 2017.
• Information source: Escudier, P. A. Couhert, F. Mercier, A. Mallet, P. Thibaut, N. Tran, L. Amarouche, B. Picard, L. Carrere, G. Dibarboure, M. Ablain, J. Richard, N. Steunou, P. Dubois, M. H. Rio, J. Dorandeu (2017) Satellite radar altimetry: principle, geophysical correction and orbit, accuracy and precision, In CRC Book connected outer altimetry, impermanent editors Stammer, D. and Cazenave, A.

Colorado

• Information source: Nerem, R. S., B. D. Beckley, J. T. Fasullo, B. Hamlington, D. Masters, and G. T. Mitchum. Climate-change–driven accelerated sea-level emergence detected successful the altimeter era. Proceedings of the National Academy of Sciences (2018).

NASA

• Information source: Beckley, B. D., Callahan, P. S., Hancock, D. W., Mitchum, G. T., & Ray, R. D. (2017). On the 'cal-mode' correction to TOPEX outer altimetry and its effect connected the world mean oversea level clip series. Journal of Geophysical Research: Oceans, 122. https://doi.org/10.1002/2017JC013090
• Information source: Beckley, B.D., N. P. Zelensky, S. A. Holmes, F. G. Lemoine, R. D. Ray, G. T. Mitchum, S. D. Desai & S. T. Brown, Assessment of the Jason-2 Extension to the TOPEX/Poseidon, Jason-1 Sea-Surface Height Time Series for Global Mean Sea Level Monitoring, Marine Geodesy, Vol 33, Suppl 1, 2010. DOI:10.1080/01490419.2010.491029
• Information reference: Beckley, B.; Yang, X.; Zelensky, N.P.; Holmes, S.A.;Lemoine, F.G.; Ray, R.D.; Mitchum, G.T.; Desai, S.; Brown, S.T.. 2021. Global Mean Sea Level Trend from Integrated Multi-Mission Ocean Altimeters TOPEX/Poseidon, Jason-1, OSTM/Jason-2, and Jason-3 Version 5.1. Ver. 5. PO.DAAC, CA, USA. Dataset accessed [2025-06-30] astatine https://doi.org/10.5067/GMSLM-TJ151.