Unique Temperature Trend Pattern Associated with Internally Driven Global Cooling and Arctic Warming during 1980-2022

• Main Authors: Sweeney, Aodhan John, Fu, Qiang, Po-Chedley, Stephen, Wang, Hailong, Wang, Muyin
• Format: Other/Unknown Material
• Language: unknown
• Published: Authorea, Inc. 2024
• Subjects: Arctic; Kara Sea; Pacific; Southern Ocean; Global warming
• Online Access: http://dx.doi.org/10.22541/essoar.170808511.12522359/v1

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 the observationally derived 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 pattern of SAT change features enhanced warming in 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 model-simulated forced SAT trend pattern and observations.