Day 4

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Paper title Tracking Earth’s ice imbalance with satellite observations for climate services
Authors
  1. Thomas Slater University of Leeds Speaker
  2. Isobel Lawrence ESA - ESRIN
  3. Inès Otosaka University of Leeds, Leeds, UK
  4. Andrew Shepherd CPOM Leeds
  5. Noel Gourmelen University of Edinburgh
  6. Livia Jakob Earthwave
  7. Paul Tepes The University of Edinburgh
  8. Lin Gilbert UCL-MSSL
  9. Peter Nienow
Form of presentation Poster
Topics
  • A5. Climate
    • A5.02 The role of Earth Observation in climate services
Abstract text Climate change has caused dramatic reductions in Earth’s ice cover, which has in turn affected almost all other elements of the environment including global sea level, ocean currents, marine ecosystems, atmospheric circulation, weather patterns, freshwater resources, and the planetary albedo. Here, we combine Earth Observation data and numerical models to quantify global ice losses over the past three decades across the principal components of Earth’s ice system: Arctic sea ice, Southern Ocean sea ice, Antarctic ice shelves, mountain glaciers, the Greenland ice sheet, and the Antarctic ice sheet. Just over half of the ice loss was from the Northern Hemisphere, and the remainder was from the Southern Hemisphere. The rate of ice loss has risen since the 1990s, owing to increased losses from mountain glaciers, Antarctica, Greenland and from Antarctic ice shelves. During this period, the loss of grounded ice from the Antarctic and Greenland ice sheets and mountain glaciers raised the global sea level by more than 3.5 centimetres. The majority of all ice losses were driven by atmospheric melting (from Arctic sea ice, mountain glaciers, ice shelf calving and ice sheet surface mass balance), with the remaining losses (from ice sheet discharge and ice shelf thinning) being driven by oceanic melting. These data improve knowledge of the state of Earth’s cryosphere, a key climate indicator tracked by the EEA and ECMWF, and can be used to help improve the climate models which support decision making in climate mitigation and adaptation. Earth’s ice is also a major energy sink in the climate system; altogether, these elements of the cryosphere have taken up 3 % of the global energy imbalance. Monitoring Earth’s energy imbalance is fundamental in understanding the evolution of climate change and improving climate syntheses and models, and our improved estimates can contribute towards phase 1 of the UNFCCCs global stocktake required by Article 14 of the Paris Agreement, providing information which can be used in testing the effectiveness of climate mitigation policy.