The Antarctic ice sheet (AIS) lies on a solid Earth that displays large spatial variations in rheological properties, with a thin lithosphere and low-viscosity upper mantle (weak Earth structure) beneath West Antarctica and an opposing structure beneath East Antarctica. This contrast is known to have a significant impact on the ice-sheet grounding-line stability. Here, we embed within an ice-sheet model a modified glacial-isostatic Elastic Lithosphere-Relaxing Asthenosphere model that considers a dual pattern for the Earth structure beneath West and East Antarctica supplemented with an approximation of gravitationally consistent geoid changes, allowing to approximate near-field relative sea-level changes. We show that this elementary GIA model captures the essence of global Self-Gravitating Viscoelastic solid-Earth Models (SGVEMs) and compares well with both SGVEM outputs and geodetic observations, allowing to capture the essential features and processes influencing Antarctic grounding-line stability in a computationally efficient way. In this framework, we perform a probabilistic assessment of the impact of uncertainties in solid-Earth rheological properties on the response of the AIS to future warming. Results show that on multicentennial-to-millennial timescales, spatial variability in solid-Earth deformation plays a significant role in promoting the stability of the West Antarctic ice sheet (WAIS). However, WAIS collapse cannot be prevented under high-emissions climate scenarios. On longer timescales and for unmitigated climate scenarios, continent-wide mass loss projections may be underestimated because spatially uniform Earth models, as typically considered in numerical ice sheet models, will overestimate the stabilizing effect of GIA across East Antarctica, which is characterized by thick lithosphere and high upper-mantle viscosity.

中文翻译：

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南极西部和东部冰盖对冰川均衡调整的对比反应

南极冰盖 (AIS) 位于固体地球上，流变特性的空间变化很大，在南极西部下方有薄岩石圈和低粘度上地幔（弱地球结构），在南极东部下方有相反的结构。已知这种对比对冰盖接地线稳定性有重大影响。在这里，我们将修改后的冰川等静压弹性岩石圈松弛软流圈模型嵌入到冰盖模型中，该模型考虑了南极西部和东部下方地球结构的双重模式，并辅以重力一致的大地水准面变化的近似值，允许近似场相对海平面变化。我们表明，这个基本的 GIA 模型捕捉了全球自引力粘弹性固体地球模型 (SGVEM) 的本质，并与 SGVEM 输出和大地测量结果进行了很好的比较，从而可以捕捉到影响南极接地线稳定性的基本特征和过程。计算效率的方式。在这个框架中，我们对固体地球流变特性的不确定性对 AIS 对未来变暖的响应的影响进行了概率评估。结果表明，在百年到千年的时间尺度上，固体地球变形的空间变异性在促进西南极冰盖 (WAIS) 的稳定性方面起着重要作用。然而，在高排放气候情景下无法防止 WAIS 崩溃。在更长的时间尺度和未缓解的气候情景中，