Sea Level Rise in 2024

Sea level rise is one of the most visible and consequential indicators of climate change, affecting coastal communities, ecosystems and economies worldwide1. Global mean sea level (GMSL) has risen more than 10 cm since 1993, the rate at which GMSL is increasing has doubled over the same time period2. These changes are driven by two key factors, both closely linked to the increase in atmospheric greenhouse gases and subsequent planetary warming3: thermal expansion associated with the absorption of roughly 90% of excess atmospheric heat; and mass increases associated with warming-driven glacier and ice sheet melt. Accordingly, sea levels have risen in over >98% of the world’s ocean since 1993; exceptions include small regions in the higher latitudes of the north and south Pacific. On top of this higher foundation of sea level are naturally occurring fluctuations from tides, storms and large-scale climate variability (amongst others). These increases drive impacts for coastlines around the world with increasing frequency and severity4, necessitating firm understanding of their observed changes. Here, we assess changes in sea level over 2024 using the satellite radar altimeter record. The satellite record now spans from 1993 to present following the launch of Sentinel-6A/Michael Freilich in 2020 (ref 5). Global and regional changes are estimated using a near-global (latitudes between +/- 65) dataset of sea surface height on a half-degree grid6 which merges observations from several different satellite altimeter missions. To better understand these changes, additional observations are used to track the sea level change resulting from changes in ocean mass as collected by the GRACE/GRACE-FO satellites7 and changes in the temperature of the ocean as collected by Argo profiling floats8.

海平面上升是气候变化最显著且影响深远的表征之一，对全球沿海社区、生态系统与经济体系均造成显著冲击¹。自1993年以来，全球平均海平面（Global Mean Sea Level, GMSL）累计上升超10厘米，且同期其上升速率已翻倍²。上述变化由两大核心驱动因素构成，二者均与大气温室气体浓度升高及随之而来的全球变暖密切相关³：一是因吸收约90%过剩大气热量引发的海水热膨胀效应；二是气候变暖驱动冰川与冰盖消融导致的海水质量增量。据此，自1993年以来，全球超98%的海域海平面均出现上升，仅北太平洋与南太平洋高纬度的小片区域属于例外。在这一升高的海平面基准之上，还叠加了潮汐、风暴及大规模气候变率等多种因素引发的自然波动。这类海平面上升正以愈发频繁且严重的程度对全球海岸线造成影响⁴，因此亟需精准掌握其观测到的变化特征。本研究借助卫星雷达高度计观测序列，对2024年的海平面变化展开评估。得益于2020年Sentinel-6A/迈克尔·弗赖利希（Michael Freilich）卫星的发射，当前的卫星观测记录已覆盖1993年至今的完整时段⁵。研究采用近全球范围（纬度区间为±65°）的半度网格海面高度数据集⁶来估算全球及区域海平面变化，该数据集整合了多颗不同卫星高度计任务的观测数据。为进一步明晰上述变化的成因与特征，本研究还辅以其他观测数据：分别追踪由海洋质量变化引发的海平面变化（数据由重力恢复与气候实验（Gravity Recovery and Climate Experiment, GRACE）/重力恢复与气候实验后续计划（GRACE-Follow On, GRACE-FO）卫星采集），以及由海洋温度变化引发的海平面变化（数据由Argo剖面浮标（Argo profiling floats）采集）⁷⁸。

搜集汇总

背景与挑战

背景概述

该数据集提供了2024年全球海平面上升的详细分析，结合了卫星雷达高度计、GRACE/GRACE-FO卫星和Argo浮标的数据，揭示了海平面上升的主要驱动因素和区域变化特点。数据集特别强调了海洋变暖和冰川融化对海平面上升的贡献，以及气候现象如厄尔尼诺和印度洋偶极子对区域海平面的影响。