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Arctic Warming and Associated Sea Ice Reduction in the Early 20th Century Induced by Natural Forcings in MRI‐ESM2.0 Climate Simulations and Multimodel Analyses
Author(s) -
Aizawa Takuro,
Ishii Masayoshi,
Oshima Naga,
Yukimoto Seiji,
Hasumi Hiroyasu
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 - 10.1029/2020gl092336
Subject(s) - climatology , environmental science , arctic , forcing (mathematics) , global warming , sea ice , climate change , climate model , atmospheric sciences , natural (archaeology) , arctic geoengineering , arctic ice pack , oceanography , geology , sea ice thickness , paleontology
During the early 20th century, the Arctic experienced a period of remarkable warming, often called the early 20th century warming (ETCW). However, the degree of the response to external climate forcing on the Arctic surface air temperature is not well understood. Climate simulations using a state‐of‐the‐art climate model of Meteorological Research Institute (MRI‐ESM2.0) and multimodel analyses were conducted to better understand ETCW. The MRI‐ESM2.0 historical simulations successfully reproduced the observed ETCW and the corresponding decreases in sea ice extent. Detection and attribution experiments using MRI‐ESM2.0 suggest that internal climate variability and external natural forcings by solar and volcanic activities had major influences on the model‐simulated ETCW, rather than external anthropogenic forcings. Multimodel analyses indicate that the Arctic warming trend during 1911–1940 induced by natural forcings is comparable to the unforced multidecadal internal variability, suggesting major contributions of the internal dynamics and natural forcings to ETCW.