Extrapolating Empirical Models of Satellite‐Observed Global Mean Sea Level to Estimate Future Sea Level Change. Issue 4 (31st March 2022)

• Record Type: Journal Article
• Authors: Nerem, R. S.; Frederikse, T.; Hamlington, B. D.
• Is Part Of: Earth's future. Volume 10:Issue 4(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-03-31
• Subjects: Environmental sciences -- Periodicals; Environmental sciences; Periodicals; 550
• DOI: 10.1029/2021EF002290
• Languages: English
• ISSNs: 2328-4277

Abstract

Abstract: We estimate a quadratic model of climate‐driven global mean sea level (GMSL) change based on the satellite altimetry record (1993–2020), including a rigorous assessment of the errors in the quadratic coefficients. We then extrapolate this model 30 years into the future to 2050 and compute the 90% confidence interval. We find GMSL rise in 2050 relative to 2020 will be 16.4 cm higher, with an uncertainty range of 11.3–21.4 cm. This prediction agrees within uncertainties with IPCC SROCC and AR6 sea level projections. In addition, a hindcast extrapolation prior to 1993 agrees well with the tide gauge record of GMSL change over the 2nd half of the 20th century. We believe this shows the value of short‐term observationally driven extrapolations as an additional tool for predicting future sea level change. Plain Language Summary: The satellite altimetry record of global mean sea level (GMSL) change (1993–2020) is now of sufficient length that we can begin to average through some of the natural variability and detect the climate‐driven changes. If we model these changes using simple rate (mm/year) and acceleration (mm/year 2 ) terms, we can extrapolate the rate and acceleration into the future to predict future sea level change. This assumes that the rate and acceleration terms remain constant in the future, which probably provides a conservative assessment of future sea level change. We find extrapolated GMSL rise in 2050 relative to 2020 will be 16.4 cm higher, with a 90% uncertainty range of 11.3–21.4 cm. These numbers agree well with projections from climate models. In addition, when the rate and accelerations are extrapolated backward to 1960, we find good agreement with the tide gauge record of GMSL change. Key Points: The satellite record of global mean sea level change is quadratically extrapolated 30 years into the future This extrapolation agrees well with various IPCC model projections, as well as with 20th century tide gauge measurements in hindcast This extrapolation provides another observationally driven tool to assess ongoing and future sea level change