EGU21-2399
https://doi.org/10.5194/egusphere-egu21-2399
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Earth's ice imbalance

Thomas Slater1, Isobel Lawrence1, Inès Otosaka1, Andrew Shepherd1, Noel Gourmelen2, Livia Jakob3, Paul Tepes2, Lin Gilbert4, and Peter Nienow2
Thomas Slater et al.
  • 1Centre for Polar Observation and Modelling, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
  • 2School of GeoSciences, University of Edinburgh, Edinburgh, EH8 9XP, UK
  • 3Earthwave Ltd, Edinburgh, EH9 3HJ, UK
  • 4Mullard Space Science Laboratory, Department of Space & Climate Physics, University College London, London, WC1E 6BT, UK

Satellite observations are the best method for tracking ice loss, because the cryosphere is vast and remote. Using these, and some numerical models, we show that Earth lost 28 trillion tonnes of ice between 1994 and 2017. Arctic sea ice (7.6 trillion tonnes), Antarctic ice shelves (6.5 trillion tonnes), mountain glaciers (6.1 trillion tonnes), the Greenland ice sheet (3.8 trillion tonnes), the Antarctic ice sheet (2.5 trillion tonnes), and Southern Ocean sea ice (0.9 trillion tonnes) have all decreased in mass. Just over half (58 %) of the ice loss was from the northern hemisphere, and the remainder (42 %) was from the southern hemisphere. The rate of ice loss has risen by 57 % since the 1990s – from 0.8 to 1.2 trillion tonnes per year – owing to increased losses from mountain glaciers, Antarctica, Greenland, and from Antarctic ice shelves. During the same period, the loss of grounded ice from the Antarctic and Greenland ice sheets and mountain glaciers raised the global sea level by 34.6 ± 3.1 mm. The majority of all ice losses were driven by atmospheric melting (68 % from Arctic sea ice, mountain glaciers ice shelf calving and ice sheet surface mass balance), with the remaining losses (32 % from ice sheet discharge and ice shelf thinning) being driven by oceanic melting. Altogether, these elements of the cryosphere have taken up 3.2 % of the global energy imbalance.

How to cite: Slater, T., Lawrence, I., Otosaka, I., Shepherd, A., Gourmelen, N., Jakob, L., Tepes, P., Gilbert, L., and Nienow, P.: Earth's ice imbalance, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-2399, https://doi.org/10.5194/egusphere-egu21-2399, 2021.

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