Kathmandu, August 28, 2025
A new study has confirmed that global sea-level rise projections made nearly 30 years ago were remarkably accurate, underscoring the reliability of climate science even when early models were far less sophisticated than today’s.
Researchers from Tulane University, writing in Earth’s Future (a journal of the American Geophysical Union), compared sea-level rise projections published in the 1996 Intergovernmental Panel on Climate Change (IPCC) report with satellite observations spanning three decades. The result: the prediction of about 8 centimeters of rise by 2025 closely matches the 9 centimeters actually observed.
“The ultimate test of climate projections is to compare them with what has played out since they were made, but this requires patience - it takes decades of observations,” said lead author Professor Torbjörn Törnqvist.
Key Findings
Accuracy of Early Models: Despite limited data and computing power, mid-1990s models successfully captured the pace of long-term sea-level rise.
Ice Melt Underestimated: The largest gap was in ice-sheet contributions, particularly from Greenland and Antarctica, which were underestimated by around 2 centimeters. Scientists now recognize that rapid ice-sheet instability is a major uncertainty for future projections.
Accelerating Trend: Satellites show that sea-level rise, averaging about 3 millimeters per year, is no longer steady-it is accelerating.
Regional Impacts Differ: While global averages align with forecasts, regional variations remain strong. Coastal areas like South Louisiana, South Asia’s deltas, and Pacific island nations face unique and disproportionate risks.
The Role of Satellites
Since the 1990s, missions such as TOPEX/Poseidon and the Jason satellite series have transformed how scientists track the oceans. These instruments provide precise, global-scale data, enabling both validation of past forecasts and sharper regional projections.
Looking Forward
The study reinforces the credibility of climate science while emphasizing the need to better understand ice-sheet physics. Future efforts must:
1. Refine local projections so vulnerable regions can prepare for flooding and land loss.
2. Improve ice-sheet modeling to account for abrupt collapses and rapid melt.
3. Sustain long-term monitoring through satellites and coastal gauges.
Bottom Line
Sea-level rise is not a distant threat-it is happening now, at nearly the exact pace climate scientists warned about three decades ago. The message is clear: early science was right, and the urgency to act on today’s projections has never been greater.
