Image of Thwaites glacier_Eos/Rob Larter

Opinion: Quit Worrying About Uncertainty in Sea Level Projections

Emphasizing uncertainty in model projections of long-term sea level rise is a misguided approach. Instead, we should focus on communicating what we do know while improving model confidence.


Written by Prof. Jeremy Bassis for Eos magazine.

As ice sheets lose mass at increasing rates, scientists are growing increasingly concerned that portions of these massive reservoirs of frozen water are poised to begin irreversibly retreating [Cornford et al., 2015; DeConto et al., 2021]. To adapt to the ensuing changes along shorelines, authorities responsible for coastal planning and climate mitigation efforts need actionable sea level rise projections. However, recent studies using climate and ice sheet models are, more and more often, coming to very different conclusions about future rates of sea level rise and even about the sensitivity of ice sheets to future warming [DeConto et al., 2021; Edwards et al., 2021].

Focusing on uncertainty in model projections of long-term sea level rise is a trap we must avoid.

How can climate scientists help decision-makers navigate vague or conflicting information to develop practical response strategies in the face of large uncertainties? One solution that may provide needed clarity is to change our emphasis from what we do not know to what we do know.

Large discrepancies among model projections of long-term sea level rise have spawned calls among the scientific community for scientists to work on reducing uncertainty. However, focusing on uncertainty is a trap we must avoid. Instead, we should focus on the adaptation decisions we can already make on the basis of current models and communicating and building confidence in models for longer-term decisions.

Read the full op-ed piece in the November 30, 2021 Eos magazine:

An ice cliff at Thwaites Glacier in West Antarctica. Credit: Rob Larter