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The Northwestern Pacific Warming Record in August 2020 Occurred Under Anthropogenic Forcing
Author(s) -
Hayashi Michiya,
Shiogama Hideo,
Emori Seita,
Ogura Tomoo,
Hirota Nagio
Publication year - 2021
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl090956
Subject(s) - forcing (mathematics) , climatology , environmental science , pacific decadal oscillation , sea surface temperature , greenhouse gas , oceanography , climate change , global warming , climate model , atmospheric sciences , geology
In August 2020, the northwestern Pacific (NWPac; 120°E‐180°E, 20°N‐35°N) experienced its highest sea surface temperature (SST). Although the NWPac Ocean has warmed due to human‐induced greenhouse forcing since the mid‐20th century, the extent to which historical anthropogenic effects increase the occurrence probability of such regionally unprecedented warm temperatures is unclear. In this study, using state‐of‐the‐art climate models, we estimate that the August 2020 record high SST in the NWPac likely occurred once per 12–18 years in 2001–2020 owing to historical anthropogenic forcing, and this record SST unlikely occurred without human influences. In the 20th century, anthropogenic effects on the NWPac SST were not distinguishable from internal variability since warming caused by greenhouse gases was largely canceled by aerosol cooling. Furthermore, the 2020 warm SST is projected to be the new normal by 2031–2050, or even if the 2.0°C goal of the Paris Agreement is achieved.