Future sea level rise constrained by observations and long-term commitment.

Area of Science:

• Climate Science
• Oceanography
• Environmental Science

Background:

• Global sea level has risen over the past century, primarily driven by human-induced climate change.
• Continued global warming will accelerate sea level rise, with long-term impacts expected for centuries even with stabilized temperatures.
• Accurate sea level rise projections are essential for coastal planning, mitigation, and adaptation strategies.

Purpose of the Study:

• To constrain projections of future sea level rise by combining equilibrium responses with observed contributions.
• To provide robust estimates of sea level rise for the 21st century under different greenhouse gas emission scenarios.
• To enhance understanding of discrepancies between different sea level rise modeling approaches.

Main Methods:

• A "constrained extrapolation" approach was used, integrating equilibrium responses of major sea level rise components with their observed contributions over the last century.
• The model was calibrated using observational data for each sea level rise component.
• Observational and climate uncertainties were combined to generate uncertainty ranges for future sea level rise projections.

Main Results:

• Projected anthropogenic sea level rise by 2100 ranges from 28-56 cm (RCP26), 37-77 cm (RCP45), and 57-131 cm (RCP85).
• The derived uncertainty ranges for total sea level rise are consistent with estimates from the Intergovernmental Panel on Climate Change (IPCC).

Conclusions:

• The "constrained extrapolation" method offers a generalized approach compared to previous semi-empirical models.
• This methodology can contribute to a better understanding of the differences between semi-empirical and process-based sea level rise projections.
• The findings provide critical data for assessing climate change impacts and informing policy decisions regarding coastal areas worldwide.