Bet 821

Duration 11 years (02020-02030)

“By the end of 2030, Global Mean Sea Level (GMSL) as measured by the Integrated Multi-Mission Ocean Altimeter Data will rise to 120 mm above January 1, 1993 (2 month average)”


Limbach's Argument

Sea level rise is a key indicator of climate change. Yet there is still a significant amount of people who doubt the actual occurance of GMSL rise.

The GMSL is a 1-dimensional time series of globally averaged Sea Surface Height Anomalies (SSHA) from TOPEX/Poseidon, Jason-1, OSTM/Jason-2 and Jason-3. All biases and cross-calibrations have been applied to the data so SSHA are consistent between satellites. Data are reported as changes relative to January 1, 1993 and are 2-month averages. Glacial Isostatic Adjustment (GIA) has been applied. (

GMSL data via NASA for adjudication:

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