Ice sheet-albedo feedback estimated from most recent deglaciation

• Published in: Geophysical Research Letters
• Main Authors: Booth, Alice, Goodwin, Philip, Cael, B.B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2024
• Subjects: Ice Sheet
• Online Access: https://eprints.soton.ac.uk/493550/; https://eprints.soton.ac.uk/493550/1/Geophysical_Research_Letters_-_2024_-_Booth_-_Ice_Sheet_Albedo_Feedback_Estimated_From_Most_Recent_Deglaciation.pdf

Ice sheet feedbacks are underrepresented in model assessments of climate sensitivity and their magnitudes are still poorly constrained. We combine a recently published record of Earth's Energy Imbalance (EEI) with existing reconstructions of temperature, atmospheric composition, and sea level to estimate both the magnitude and timescale of the ice sheet-albedo feedback since the Last Glacial Maximum. This facilitates the first opportunity to quantify this feedback over the most recent deglaciation using a proxy data-driven approach. We find the ice sheet-albedo feedback to be amplifying, increasing the total climate feedback parameter by 42% and reaching an equilibrium magnitude of 0.55 Wm −2 K −1 , with a 66% confidence interval of 0.45–0.63 Wm −2 K −1 . The timescale to equilibrium is estimated as 3.6 ka (66% confidence: 1.9–5.5 ka). These results provide new evidence for the timescale and magnitude of the amplifying ice sheet-albedo feedback that will drive anthropogenic warming for millennia to come.