Abstract
AbstractThe Coupled Model Intercomparison Project (phase 6) (CMIP6) global circulation models (GCMs) predict equilibrium climate sensitivity (ECS) values ranging between 1.8 and 5.7 $${^\circ }$$
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C. To narrow this range, we group 38 GCMs into low, medium and high ECS subgroups and test their accuracy and precision in hindcasting the mean global surface warming observed from 1980–1990 to 2011–2021 in the ERA5-T2m, HadCRUT5, GISTEMP v4, and NOAAGlobTemp v5 global surface temperature records. We also compare the GCM hindcasts to the satellite-based UAH-MSU v6 lower troposphere global temperature record. We use 143 GCM ensemble averaged simulations under four slightly different forcing conditions, 688 GCM member simulations, and Monte Carlo modeling of the internal variability of the GCMs under three different model accuracy requirements. We found that the medium and high-ECS GCMs run too hot up to over 95% and 97% of cases, respectively. The low ECS GCM group agrees best with the warming values obtained from the surface temperature records, ranging between 0.52 and 0.58 $${^\circ }$$
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C. However, when comparing the observed and GCM hindcasted warming on land and ocean regions, the surface-based temperature records appear to exhibit a significant warming bias. Furthermore, if the satellite-based UAH-MSU-lt record is accurate, actual surface warming from 1980 to 2021 may have been around 0.40 $${^\circ }$$
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C (or less), that is up to about 30% less than what is reported by the surface-based temperature records. The latter situation implies that even the low-ECS models would have produced excessive warming from 1980 to 2021. These results suggest that the actual ECS may be relatively low, i.e. lower than 3 $${^\circ }$$
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C or even less than 2 $${^\circ }$$
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C if the 1980–2021 global surface temperature records contain spurious warming, as some alternative studies have already suggested. Therefore, the projected global climate warming over the next few decades could be moderate and probably not particularly alarming.
Funder
Università degli Studi di Napoli Federico II
Publisher
Springer Science and Business Media LLC
Reference61 articles.
1. Bezdek R, Idso CD, Legates D, Singer SF (2019) Climate change reconsidered II: fossil fuels. Nongovernmental International Panel on Climate Change (NIPCC). The Heartland Institute. http://climatechangereconsidered.org/climate-change-reconsidered-ii-fossil-fuels/
2. Brohan P, Kennedy JJ, Harris I, Tett SFB, Jones PD (2006) Uncertainty estimates in regional and global observed temperature changes: a new data set from 1850. J Geophys Res 111(D12):D12106. https://doi.org/10.1029/2005JD006548
3. Büntgen U, Allen K, Anchukaitis KJ et al. (2021) The influence of decision-making in tree ring-based climate reconstructions. Nat Commun 12(1):3411. https://doi.org/10.1038/s41467-021-23627-6
4. Christy JR, Spencer RW, Braswell WD, Junod R (2018) Examination of space-based bulk atmospheric temperatures for climate research. Int J Remote Sens 39:3580–3607
5. Connolly R, Soon W, Connolly M et al (2021) How much has the Sun influenced Northern hemisphere temperature trends? An ongoing debate. Res Astron Astrophys 21:131. https://doi.org/10.1088/1674-4527/21/6/131
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