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Antarctic model finds ice-loss risk persists under strong emissions cuts

An Antarctic ice-sheet model calibrated against satellite observations estimated at least a 0.92 probability of net mass loss this century, even with strong emissions cuts. Higher emissions increased modeled losses. Under a very high-emissions path, the median Antarctic contribution to sea-level rise by 2100 was 15.7 centimetres. Those values depend on the study’s model choices and scenarios.

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A crevassed Antarctic ice shelf meeting blue sea.

Satellite-linked modeling points to net ice loss

A new Antarctic ice-sheet study found continued net mass loss this century even under strong emissions reductions. Researchers compared ice-sheet simulations with satellite observations to assess the range of outcomes. The peer-reviewed work was published in Nature Geoscience on September 30.[1], [2]

The team used a machine-learning emulator to compare combinations of climate, ocean and ice-physics assumptions. Bayesian calibration weighted these combinations against satellite measurements. The estimated probability of net mass loss was at least 0.92 with strong emissions cuts; the probability that higher emissions brought greater loss by 2100 was at least 0.89.[1]

Very high emissions raise the modeled sea-level contribution

Under a very high-emissions scenario, the median ice-sheet contribution to sea-level rise by 2100 was 15.7 centimetres, with a 95 per cent upper-percentile value of 25.4 centimetres. The figures cover this ice sheet’s contribution rather than total global sea-level rise. They are projections conditional on the study’s model family and emissions scenarios.[1]

Ice movement and shelf melting shape the range

Different assumptions about climate forcing, ice sliding over its bed and melting beneath floating ice shelves changed the outcomes. The authors argue that ensembles concentrated on commonly used choices can understate uncertainty. Satellite monitoring and tests of ice physics provide the observations used to constrain these assumptions and update estimates of the ice sheet’s future mass.[1]

For more information on this topic, you can read the related columns.

References

  1. News sourceNature GeoscienceAntarctic ice-loss model measures the gap between emissions scenarios↩1↩2↩3↩4
  2. News sourceThe ConversationAntarctic model finds continued ice loss even with strong emissions cuts↩
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