Abstract
The Hadley circulation plays a key role in transporting atmospheric heat from the tropics to the subtropics, shaping the climate in low latitudes. While its projected weakening has been largely attributed to rising greenhouse gas concentrations, the long-term impact of future anthropogenic aerosol concentrations remains underexplored. Here, we show that the projected changes in anthropogenic aerosol concentrations can account for about one-third of the Northern Hemisphere Hadley circulation weakening between 1980 and 2080, emerging as a major driver of tropical circulation change throughout the 21st century. This impact is linked to altered diabatic heating patterns in the northern tropics, driven by precipitation changes under reduced aerosol forcing. These results highlight a critical trade-off of aerosol mitigation: while improving air quality, it may amplify tropical atmospheric circulation changes driven by greenhouse gases.
Similar content being viewed by others
Data availability
The data used in the manuscript are publicly available: CESM1 LENS (https://rda.ucar.edu/datasets/d651027/) and CMIP6 DAMIP (https://aims2.llnl.gov/search/cmip6/).
Code availability
The codes are provided in the figshare repository (https://doi.org/10.6084/m9.figshare.29602706).
References
Lau, W. K. M. & Kim, K. M. Robust Hadley circulation changes and increasing global dryness due to CO2 warming from CMIP5 model projections. Proc. Natl. Acad. Sci. U.S.A. 112, 3630–3635 (2015).
Bony, S. et al. Robust direct effect of carbon dioxide on tropical circulation and regional precipitation. Nat. Geosci. 6, 447–451 (2013).
Seager, R., Naik, N. & Vecchi, G. A. Thermodynamic and dynamic mechanisms for large-scale changes in the hydrological cycle in response to global warming. J. Clim. 23, 4651–4668 (2010).
Feng, S. & Fu, Q. Expansion of global drylands under a warming climate. Atmos. Chem. Phys. 13, 10081–10094 (2013).
Chemke, R. & Yuval, J. Human-induced weakening of the Northern Hemisphere tropical circulation. Nature 617, 529–532 (2023).
Chemke, R. & Polvani, L. M. Elucidating the mechanisms responsible for Hadley cell weakening under 4 × CO2 forcing. Geophys. Res. Lett. 48, e2020GL090348 (2021).
Hu, Y., Huang, H. & Zhou, C. Widening and weakening of the Hadley circulation under global warming. Sci. Bull. 63, 640–644 (2018).
Seo, K. H., Frierson, D. M. W. & Son, J. H. A mechanism for future changes in Hadley circulation strength in CMIP5 climate change simulations. Geophys. Res. Lett. 41, 5251–5258 (2014).
Hess, O. & Chemke, R. Anthropogenic forcings reverse a simulated multi-century naturally-forced Northern Hemisphere Hadley cell intensification. Nat. Commun. 15, 4001 (2024).
Lionello, P., D’Agostino, R., Ferreira, D., Nguyen, H. & Singh, M. S. The Hadley circulation in a changing climate. Ann. N.Y. Acad. Sci. 1534, 69–93 (2024).
Son, S. W., Kim, S. Y. & Min, S. K. Widening of the Hadley cell from last glacial maximum to future climate. J. Clim. 31, 267–281 (2018).
He, J. & Soden, B. J. Anthropogenic weakening of the tropical circulation: the relative roles of direct CO2 forcing and sea surface temperature change. J. Clim. 28, 8728–8742 (2015).
Seo, K. H. et al. What controls the interannual variation of Hadley cell extent in the Northern Hemisphere: physical mechanism and empirical model for edge variation. NPJ Clim. Atmos. Sci. 6, 204 (2023).
Gastineau, G., Le Treut, H. & Li, L. Hadley circulation changes under global warming conditions indicated by coupled climate models. Tellus A: Dynamic Meteorology and Oceanography 60, 863–884 (2008).
Tao, L., Hu, Y. & Liu, J. Anthropogenic forcing on the Hadley circulation in CMIP5 simulations. Clim. Dyn. 46, 3337–3350 (2016).
Ming, Y. & Ramaswamy, V. A model investigation of aerosol-induced changes in tropical circulation (Part 1). J. Clim. 24, 5125–5133 (2011).
Ying, T. et al. Fractional change of scattering and absorbing aerosols contributes to northern hemisphere hadley circulation expansion. Sci. Adv. 10 https://www.science.org (2024).
Lamarque, J. F. et al. Global and regional evolution of short-lived radiatively-active gases and aerosols in the Representative Concentration Pathways. Clim. Change 109, 191–212 (2011).
Buchholz, R. R. et al. Air pollution trends measured from Terra: CO and AOD over industrial, fire-prone, and background regions. Remote Sens. Environ. 256, 112275 (2021).
Shi, J. R., Kwon, Y. O. & Wijffels, S. E. Two distinct modes of climate responses to the anthropogenic aerosol forcing changes. J. Clim. 35, 3445–3457 (2022).
Samset, B. H. et al. East Asian aerosol cleanup has likely contributed to the recent acceleration in global warming. Commun. Earth Environ. 6, 543 (2025).
Kang, S. M., Xie, S. P., Deser, C. & Xiang, B. Zonal mean and shift modes of historical climate response to evolving aerosol distribution. Sci. Bull. 66, 2405–2411 (2021).
Persad, G. G. The dependence of aerosols’ global and local precipitation impacts on the emitting region. Atmos. Chem. Phys. 23, 3435–3452 (2023).
Hwang, Y. T., Frierson, D. M. W. & Kang, S. M. Anthropogenic sulfate aerosol and the southward shift of tropical precipitation in the late 20th century. Geophys. Res. Lett. 40, 2845–2850 (2013).
Diao, C., Xu, Y. & Xie, S. P. Anthropogenic aerosol effects on tropospheric circulation and sea surface temperature (1980-2020): separating the role of zonally asymmetric forcings. Atmos. Chem. Phys. 21, 18499–18518 (2021).
Choi, J., Son, S. W. & Park, R. J. Aerosol versus greenhouse gas impacts on Southern Hemisphere general circulation changes. Clim. Dyn. 52, 4127–4142 (2019).
Xia, Y., Hu, Y. & Liu, J. Comparison of trends in the Hadley circulation between CMIP6 and CMIP5. Sci. Bull. 65, 1667–1674 (2020).
Myhre, G. et al. Multi-model simulations of aerosol and ozone radiative forcing due to anthropogenic emission changes during the period 1990–2015. Atmos. Chem. Phys. 17, 2709–2720 (2017).
Hawkins, E. & Sutton, R. Decadal predictability of the Atlantic Ocean in a coupled GCM: forecast skill and optimal perturbations using linear inverse modeling. J. Clim. 22, 3960–3978 (2009).
Grise, K. M. et al. Recent tropical expansion: natural variability or forced response? J. Clim. 32, 1551–1571 (2019).
D’Agostino, R., Scambiati, A. L., Jungclaus, J. & Lionello, P. Poleward shift of northern subtropics in winter: time of emergence of zonal versus regional signals. Geophys. Res. Lett. 47, e2020GL089325 (2020).
Chemke, R. & Polvani, L. M. Opposite tropical circulation trends in climate models and in reanalyses. Nat. Geosci. 12, 528–532 (2019).
Zaplotnik, Ž., Pikovnik, M. & Boljka, L. Recent Hadley circulation strengthening: a trend or multidecadal variability? https://doi.org/10.1175/JCLI-D-21 (2023).
Needham, M. R., Cox, T. & Randall, D. A. Aerosol-induced changes in atmospheric and oceanic heat transports in the CESM2 large ensemble. J. Clim. 6395–6412 (2024) https://doi.org/10.1175/JCLI-D-23.
Deser, C. et al. Isolating the evolving contributions of anthropogenic aerosols and greenhouse gases: A new CESM1 large ensemble community resource. J. Clim. 33, 7835–7858 (2020).
Gillett, N. P. et al. The Detection and Attribution Model Intercomparison Project (DAMIP v1.0) contribution to CMIP6. Geosci. Model Dev. 9, 3685–3697 (2016).
Held, I. M. & Soden, B. J. Robust responses of the hydrological cycle to global warming. J. Clim. 19, 5686–5699 (2006).
Chou, C. & Neelin, J. D. Mechanisms of global warming impacts on regional tropical precipitation. J. Clim. 17, 2688–2701 (2004).
Ma, J., Xie, S. P. & Kosaka, Y. Mechanisms for tropical tropospheric circulation change in response to global warming. J. Clim. 25, 2979–2994 (2012).
Allen, R. J. A 21st century northward tropical precipitation shift caused by future anthropogenic aerosol reductions. J. Geophys. Res. 120, 9087–9102 (2015).
Allen, R. J., Evan, A. T. & Booth, B. B. B. Interhemispheric aerosol radiative forcing and tropical precipitation shifts during the late twentieth century. J. Clim. 28, 8219–8246 (2015).
Chung, E. S. & Soden, B. J. Hemispheric climate shifts driven by anthropogenic aerosol-cloud interactions. Nat. Geosci. 10, 566–571 (2017).
Rotstayn, L. D. & Lohmann, U. Tropical rainfall trends and the indirect aerosol effect. J. Clim. 15, 2103–2116 (2002).
Rotstayn, L. D., Collier, M. A. & Luo, J. J. Effects of declining aerosols on projections of zonally averaged tropical precipitation. Environmental Research Letters 10, 044018 (2015).
Davis, N. A. & Birner, T. Eddy influences on the Hadley circulation. J. Adv. Model. Earth Syst. 11, 1563–1581 (2019).
Dittus, A. J., Hawkins, E., Robson, J. I., Smith, D. M. & Wilcox, L. J. Drivers of recent north pacific decadal variability: the role of aerosol forcing. Earth's Future 9, e2021EF002249 (2021).
Takahashi, C. & Watanabe, M. Pacific trade winds accelerated by aerosol forcing over the past two decades. Nat. Clim. Chang. 6, 768–772 (2016).
Kalik, V. et al. Understanding the response of tropical overturning circulations to greenhouse gas and aerosol forcing. Environmental Research: Climate 3, 045009 (2024).
Wilcox, L. J. et al. The Regional Aerosol Model Intercomparison Project (RAMIP). Geosci. Model Dev. 16, 4451–4479 (2023).
Wilcox, L. J., Highwood, E. J., Booth, B. B. B. & Carslaw, K. S. Quantifying sources of inter-model diversity in the cloud albedo effect. Geophys. Res. Lett. 42, 1568–1575 (2015).
Fyfe, J. C., Kharin, V. V., Santer, B. D., Cole, J. N. S. & Gillett, N. P. Significant impact of forcing uncertainty in a large ensemble of climate model simulations. Proc. Natl. Acad. Sci. U.S.A. 118, e2016549118 (2021).
Kim, S. Y. & Son, S. W. Breakdown of the linear relationship between the Southern Hemisphere Hadley cell edge and jet latitude changes in the Last Glacial Maximum. J. Clim. 33, 5713–5725 (2020).
Held, I. M. & Zurita-Gotor, P. Misuse of Kuo-Eliassen Equation in studies of the climatological mean meridional circulation. J. Atmos. Sci. https://doi.org/10.1175/JAS-D-24-0246.1 (2025).
Kay, J. E. et al. The community earth system model (CESM) large ensemble project: a community resource for studying climate change in the presence of internal climate variability. Bull. Am. Meteorol. Soc. 96, 1333–1349 (2015).
Riahi, K. et al. RCP 8.5-A scenario of comparatively high greenhouse gas emissions. Clim. Change 109, 33–57 (2011).
Simpson, I. R. et al. The CESM2 single-forcing large ensemble and comparison to CESM1: implications for experimental design. J. Clim. 36, 5687–5711 (2023).
Eyring, V. et al. Overview of the Coupled Model Intercomparison Project Phase 6 (CMIP6) experimental design and organization. Geosci. Model Dev. 9, 1937–1958 (2016).
Acknowledgements
We thank Dr. Isla Simpson (NCAR) and Dr. Chanil Park (Boston College) for their helpful discussions and comments on earlier versions of the manuscript. S.Y.K. and S.W.S. are funded by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) 2023R1A2C3005607. S.W.S. and R.J.P. are funded by Korea Environment Industry &Technology Institute (KEITI) through “Climate Change R&D Project for New Climate Regime.”, funded by Korea Ministry of Environment (MOE) 2022003560004.
Author information
Authors and Affiliations
Contributions
S.Y.K. and S.W.S. conceptualized the study. D.C.H. provided the original script for the Kuo-Eliassen analysis, and S.Y.K. performed the analysis. The manuscript was written by S.Y.K. and revised by S.W.S., Y.M., D.C.H., X.G., and R.J.P. All authors contributed to the interpretation and discussion of the results.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Peer review
Peer review information
Nature Communications thanks the anonymous reviewers for their contribution to the peer review of this work. A peer review file is available.
Additional information
Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary information
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
About this article
Cite this article
Kim, SY., Son, SW., Ming, Y. et al. Declining anthropogenic aerosols amplify Northern Hemisphere Hadley circulation weakening in the 21st century. Nat Commun (2026). https://doi.org/10.1038/s41467-026-69990-0
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41467-026-69990-0
