Proxy-based indicators of past climate change show that current
global climate models systematically underestimate Holocene-epoch
climate variability on centennial to multi-millennial timescales,
with the mismatch increasing for longer periods.
Proposed explanations for the discrepancy include ocean–atmosphere
coupling that is too weak in models, insufficient energy cascades
from smaller to larger spatial and temporal scales, or that global
climate models do not consider slow climate feedbacks related to
the carbon cycle or interactions between ice sheets and climate.
Such interactions, however, are known to have strongly affected
centennial- to orbital-scale climate variability during past
glaciations, and are likely to be important in future climate
change. Here we show that fluctuations in Antarctic Ice Sheet
discharge caused by relatively small changes in subsurface ocean
temperature can amplify multi-centennial climate variability
regionally and globally, suggesting that a dynamic Antarctic Ice
Sheet may have driven climate fluctuations during the Holocene.
We analyzed high-temporal-resolution records of iceberg-rafted debris
derived from the Antarctic Ice Sheet, and performed both high spatial-
resolution ice-sheet modelling of the Antarctic Ice Sheet
and multi-millennial global climate model simulations.
Ice-sheet responses to decadal-scale ocean forcing appear to be less important, possibly indicating that the future response of the Antarctic Ice
Sheet will be governed more by long-term anthropogenic warming
combined with multi-centennial natural variability than by annual
or decadal climate oscillations.