Glacier and Ice Cap Assessments

Aaron Letterly
Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin, Madison, WI, USA
12 April 2017

Preliminary reports from the World Glacier Monitoring Service (WGMS) show that 2016 will be the 37th consecutive year of negative glacial mass balances (Figure 1). Data from Europe, Asia, and Antarctica, and the Americas continue to reveal the trend of decreasing alpine glacier volume in both long-term reference glaciers and those more recently monitored. Consistent, negative glacial mass balances correspond to glacial ablation, the process of removing snow and ice by melting or evaporation. As glaciers worldwide approach their fourth straight decade of net ablation, the reduction in mass has caused many glaciers to fragment into multiple, smaller glaciers or to disappear altogether (Pelto, 2010; Lynch et al, 2016). Accumulation, the process in which a glacier increases in size due to snowfall or increased ice formation, was reported in only 2 out of 26 glaciers in 2016-17 (so far).

Figure 1: Glacial mass balance (in mm w.e.) for all reference glaciers, worldwide. The shaded region around the zero line is the cumulative mass balance for reference glaciers relative to 1970, while the orange bars represent the number of reporting reference glaciers for that year. The orange line shows the average reference glacier mass balance mean. Data is from the World Glacier Monitoring Service.

In 2016, WGMS results show a decrease in glacial ice mass on all continents. Nigardsbreen, a glacier in Norway, and Tsentralniy Tuyuksuyskiy, in Kazakhstan, both experienced an increase in ice mass in 2016, but their increases were vastly overshadowed by mass balance decreases in other reference glaciers regionally and worldwide (Figure 2).

Figure 2: Glacial mass balance (in millimeters of water equivalent, or mm w.e.) for reference glaciers by region, 2014-2016. Darker bars show yearly mass balance averages closer to present. Preliminary data for Antarctic glaciers was not reported, and is not reflected on this diagram. Data is from the World Glacier Monitoring Service.

Warmer than average temperatures throughout 2016 in Northern Europe, Central Asia, the South American Andes, and Siberia likely contributed to sustained glacial mass balance losses in these regions. In both the Kamchatka Peninsula and in southern Chile, mean temperatures from January through December 2016 were the warmest on record (NOAA). Figure 3 shows global temperatures for 2016, where it can be seen that many important glacial regions fell into the “Much Warmer than Average” or “Record Warmest” category.

Figure 3: January-December 2016 Blended Land and Sea Surface Temperature Percentiles. 2016 was the warmest year in NOAA’s 137-year series. 2016 was the third consecutive year in which a new global annual temperature record was set. Data is from ncdc.noaa.gov.

References

Lynch, C. M., Barr, I. D., Mullan, D., and Ruffell, A.: Rapid glacial retreat on the Kamchatka Peninsula during the early 21st century, The Cryosphere, 10, 1809-1821, doi:10.5194/tc-10-1809-2016, 2016.

NOAA National Centers for Environmental Information, State of the Climate: Global Analysis for Annual 2016, published online January 2017, retrieved on March 21, 2017 from http://www.ncdc.noaa.gov/sotc/global/201613.

Pelto, M. S.: Forecasting temperate alpine glacier survival from accumulation zone observations, The Cryosphere, 4, 67-75, doi:10.5194/tc-4-67-2010, 2010.

WGMS (2015): Global Glacier Change Bulletin No. 1 (2012–2013). Zemp, M., Gärtner-Roer, I., Nussbaumer, S. U., Hüsler, F., Machguth, H., Mölg, N., Paul, F., and Hoelzle, M. (eds.), ICSU(WDS)/IUGG(IACS)/UNEP/UNESCO/WMO, World Glacier Monitoring Service, Zurich, Switzerland, 230 pp., publication based on database version: doi:10.5904/wgms-fog-2015-11.