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Published on: October 12, 2018
Temperature-dependent feedbacks drive the pattern of Antarctic temperature change.
Bradley R Markle1,2, Eric J Steig3,4
1Department of Geological Sciences, University of Colorado, Boulder, CO 80309.
Summary
Antarctic temperature variability increases with mean surface temperature, contrary to simple models. A nonlinear greenhouse effect feedback explains this pattern across all timescales, revealing insights into climate dynamics.
Area of Science:
- Climate Science
- Paleoclimatology
- Glaciology
Background:
- Antarctica's crucial role in Earth's climate system.
- Understanding temperature change across various timescales is vital for climate modeling.
- Previous models often simplify Antarctic temperature dynamics.
Purpose of the Study:
- Investigate Antarctic temperature changes from millennial to orbital scales.
- Identify patterns and drivers of temperature variability in Antarctica.
- Reconstruct past ice-sheet elevation changes in West Antarctica.
Main Methods:
- Analysis of a compilation of ice-core water-isotope records.
- Statistical analysis of temperature variability and mean surface temperature.
- Ice-sheet modeling and comparison with geological/glaciological evidence.
Main Results:
- A persistent pattern: warmer Antarctic regions show greater temperature variability.
- This pattern is inconsistent with the basic Planck response.
- A temperature-dependent feedback, linked to a nonlinear greenhouse effect, explains the observed pattern.
Conclusions:
- A nonlinear greenhouse effect at Antarctic surface temperatures drives observed temperature variability.
- This feedback mechanism operates across diverse timescales and is initiated by energetic forcing.
- Regional forcings, like ice-sheet elevation changes, cause local deviations, as evidenced by West Antarctic deglaciation reconstruction.
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