Unique Temperature Trend Pattern Associated With Internally Driven Global Cooling and Arctic Warming During 1980–2022

• Published in: Geophysical Research Letters
• Main Authors: Aodhan J. Sweeney, Qiang Fu, Stephen Po‐Chedley, Hailong Wang, Muyin Wang
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2024
• Subjects: internal variability; Arctic amplification; machine learning; global warming; pattern of warming; Arctic warming; Geophysics. Cosmic physics; QC801-809; Global warming; Kara Sea; Southern Ocean
• Online Access: https://doi.org/10.1029/2024GL108798; https://doaj.org/article/0ed593514f534366a02dec6d8cdf31a0

Abstract Diagnosing the role of internal variability over recent decades is critically important for both model validation and projections of future warming. Recent research suggests that for 1980–2022 internal variability manifested as Global Cooling and Arctic Warming (i‐GCAW), leading to enhanced Arctic Amplification (AA), and suppressed global warming over this period. Here we show that such an i‐GCAW is rare in CMIP6 large ensembles, but simulations that do produce similar i‐GCAW exhibit a unique and robust internally driven global surface air temperature (SAT) trend pattern. This unique SAT trend pattern features enhanced warming in the Barents and Kara Sea and cooling in the Tropical Eastern Pacific and Southern Ocean. Given that these features are imprinted in the observed record over recent decades, this work suggests that internal variability makes a crucial contribution to the discrepancy between observations and model‐simulated forced SAT trend patterns.