Sea level rise is a direct consequence of human-induced climate change: global warming. It is relentless and very hard to stop. It arises from human-induced warming and the consequential expansion of the ocean, plus the addition of more and more water from melting glaciers and ice sheets. It will continue long into the future.
An international team of climate scientists has fully accounted for what is driving global sea level rise across the past six decades — resolving a stubborn mystery that has clouded our understanding of one of climate change's most consequential impacts.
AT A GLANCE
▸ Sea level rise is accelerating. The pace has doubled — from 2mm/year since 1960 to 4 mm/year since 2005.
▸ Ocean warming is a leading cause. Thermal expansion of seawater accounts for 43% of the rise since 1960.
▸ Melting ice and glaciers contribute most of the rest. Mountain glaciers (27%), Greenland Ice Sheet (15%), Antarctic Ice Sheet (12%), and land water storage (3%) round out the picture.
▸ A long-standing mystery is solved. Instruments' bias corrections and improved estimate methods have closed the budget gap that emerged after 2015.
The study, led by researchers in China, and published in Science Advances , finds that global average sea level has risen by 2.06 millimeters per year since 1960 — but with the pace doubling in recent decades to reach 3.94 millimeters per year between 2005 and 2023. Ocean warming is the largest driver, accounting for 43 percent of the rise as warmer water expands and takes up more space.
The study also explains why global sea level rise accelerated. Since 1960, the primary contributors have been accelerated ocean warming and reduced land water storage. In recent decades, since 1993, ice loss, including the accelerated melting of glaciers and ice sheets in Greenland and Antarctic, has become increasingly important. These worrisome trends are likely to persist over the coming decades.
"For years, there has been a frustrating gap between how much the oceans were observed to be rising and how much we could explain from the individual causes. This work shows that, with better instruments, processes, and smarter analysis, this knowledge gap can be closed. We can explain sea level rise with greater confidence."
— Prof. John Abraham, School of Engineering, University of St. Thomas; co-author
The team — led by researchers at the Institute of Atmospheric Physics, the Chinese Academy of Sciences and including scientists from Tulane University, the NSF National Center for Atmospheric Research, the University of St. Thomas, and partners in France — credits their findings to advances in observing technology: corrections to satellite measurements that had been subtly changing since 2015, improved methods for estimating land motion at coastal tide gauges, and improved estimates of ice loss from Greenland and Antarctic. These advances resolve a worrying gap between observed sea level rise and its known causes.
Even if increases in greenhouse gases are stabilized, the large inertia of the ocean and the world's ice means that sea level rise will continue for many centuries as the oceans slowly warm throughout their depths and land ice continues to melt.
