TY - JOUR
T1 - Arctic summer sea ice loss will accelerate in coming decades
AU - Poltronieri, Anna
AU - Bochow, Nils
AU - Olson Aksamit, Nikolas
AU - Boers, Niklas
AU - Kristen Jakobsen, Per
AU - Rypdal, Martin
N1 - Publisher Copyright:
© 2024 The Author(s). Published by IOP Publishing Ltd.
PY - 2024/7/1
Y1 - 2024/7/1
N2 - The Arctic sea ice (ASI) is expected to decrease with further global warming. However, considerable uncertainty remains regarding the temperature range that would lead to a completely ice-free Arctic. Here, we combine satellite data and a large suite of models from the latest phase of the Coupled Model Intercomparison Project (CMIP6) to develop an empirical, observation-based projection of the September ASI area for increasing global mean surface temperature (GMST) values. This projection harnesses two simple linear relationships that are statistically supported by both observations and model data. First, we show that the September ASI area is linearly proportional to the area inside a specific northern hemisphere January-September mean temperature contour T c . Second, we use observational data to show how zonally averaged temperatures have followed a positive linear trend relative to the GMST, consistent with Arctic amplification. To ensure the reliability of these observations throughout the rest of the century, we validate this trend by employing the CMIP6 ensemble. Combining these two linear relationships, we show that the September ASI area decrease will accelerate with respect to the GMST increase. Our analysis of observations and CMIP6 model data suggests a complete loss of the September ASI (area below 10 6 km 2 ) for global warming between 1.5 ∘ C and 2.2 ∘ C above pre-industrial GMST levels.
AB - The Arctic sea ice (ASI) is expected to decrease with further global warming. However, considerable uncertainty remains regarding the temperature range that would lead to a completely ice-free Arctic. Here, we combine satellite data and a large suite of models from the latest phase of the Coupled Model Intercomparison Project (CMIP6) to develop an empirical, observation-based projection of the September ASI area for increasing global mean surface temperature (GMST) values. This projection harnesses two simple linear relationships that are statistically supported by both observations and model data. First, we show that the September ASI area is linearly proportional to the area inside a specific northern hemisphere January-September mean temperature contour T c . Second, we use observational data to show how zonally averaged temperatures have followed a positive linear trend relative to the GMST, consistent with Arctic amplification. To ensure the reliability of these observations throughout the rest of the century, we validate this trend by employing the CMIP6 ensemble. Combining these two linear relationships, we show that the September ASI area decrease will accelerate with respect to the GMST increase. Our analysis of observations and CMIP6 model data suggests a complete loss of the September ASI (area below 10 6 km 2 ) for global warming between 1.5 ∘ C and 2.2 ∘ C above pre-industrial GMST levels.
KW - Arctic sea ice
KW - climate change
KW - cryosphere
KW - future projections
UR - http://www.scopus.com/inward/record.url?scp=85196387101&partnerID=8YFLogxK
U2 - 10.1088/1748-9326/ad5194
DO - 10.1088/1748-9326/ad5194
M3 - Article
AN - SCOPUS:85196387101
SN - 1748-9318
VL - 19
JO - Environmental Research Letters
JF - Environmental Research Letters
IS - 7
M1 - 074032
ER -