The 2023/24 El Niño event exhibited unusually weak extratropical teleconnections

Abstract

The El Niño-Southern Oscillation is a major driver of global climate and weather variability through atmospheric teleconnections. However, the 2023/24 El Niño event, despite ranking as the fourth strongest since 1979, exhibited an unusually weak Pacific-North American pattern. Here we show that this unexpected behavior is due to anomalously weak tropical Pacific rainfall changes, a key driver of teleconnections associated with El Niño. Through analysis of observational data during 1979–2023 and performing atmospheric model experiments, we further reveal that the suppressed tropical Pacific rainfall changes were caused by unprecedented warming in the tropical Indian and Atlantic Oceans in 2023. This warming, partly driven by long-term trends exceeding those in the tropical Pacific, has amplified the influence of these extra-Pacific basins on El Niño dynamics. Notably, current climate models fail to reproduce this interbasin warming contrast, highlighting critical challenges in their ability to predict future climate impacts associated with El Niño events.

Extreme sea surface temperature warming in the tropical Indian Ocean and Atlantic in 2023 suppressed the rainfall pattern induced by the 2023/24 El Niño, reducing its tropical and extra-tropical impacts, according to an analysis of climate reanalyses and model simulations over the period 1979-2023.

Introduction

El Niño-Southern Oscillation (ENSO) refers to the periodic development of unusually warm or cold sea surface temperatures (SSTs) in the tropical Pacific Ocean^{1, 2, 3, 4, 5, 6, 7, 8–9}. Through active atmosphere-ocean interactions, it is also accompanied by significant changes in local winds and rainfall patterns¹⁰. These anomalies typically emerge in boreal spring, develop through summer and fall, and peak in winter. ENSO represents the most prominent signal of year-to-year variability in Earth’s climate system, exerting a dominant influence on weather and climate^{5,9,11, 12, 13–14}. This global impact is mediated through extratropical teleconnections, driven by anomalous tropical Pacific rainfall that serves as the heating source for atmospheric circulation changes^{15, 16, 17, 18–19}.

In the winter of 2023, a strong El Niño event occurred, with central-eastern tropical Pacific SST anomalies peaking at over 2 °C above average (Fig. 1a). This event ranked as the fourth strongest during the satellite era since 1979, surpassed only by the three super El Niño events of 1982/1983, 1997/1998, and 2015/2016 (Fig. 1d and S1)^{20, 21–22}. However, the associated tropical Pacific rainfall anomalies were unexpectedly weak (Figs. 1c and 2). The average rainfall anomalies in the tropical Pacific were approximately 0.75 mm/day, only about one-third of those observed during the three super El Niños (Fig. 1d). Even during the fifth-strongest El Niño in 2009/2010²³, the associated rainfall anomalies in the tropical Pacific were more than twice as strong as those in 2023/2024, despite significantly lower SST warming.

Fig. 1 Observed characteristics of the 2023/2024 El Niño. [Images not available. See PDF.]

a Sea surface temperature (SST) anomalies (units: °C, shading) during winter of 2023 in December–January–February (DJF). b Percentiles of DJF-mean SST anomalies in 2023 compared to winter seasons of 1979–2023 (units: %, shading). c DJF-mean precipitation (units: mm day^–1, shading) and 850 hPa wind anomalies (units: m s^–1, vectors) in 2023. Boxes in (a–c) indicate strong warming areas over the tropical Indian Ocean (40°E-120°E, 20°S-20°N, blue box), the tropical Pacific (160°E-80°W,10°S-10°N, black box), and the tropical Atlantic (60°W-20°E, 30°S-30°N, red box). The gray shadings in (c) denote the 1500-m topography. d Scatter plot of DJF-mean Pacific SST and rainfall anomalies averaged over the black box in (c). e As in (d), except that y-axis shows DJF-mean 850hPa zonal wind anomalies averaged over 170°E-110°W, 5°S-5°N. f As in (d), except that y-axis shows the DJF-mean PNA index from 1979 to 2023 obtained from National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center (CPC). Those of top five strongest El Niño events are highlighted, including three super El Niño events (1982/1983, 1997/1998, and 2015/2016), the 2023/2024 El Niño (red pentacles), and the 2009/2010 El Niño (black dots). The thick black lines in (d–f) represent the linear regression lines between the two indices.

Fig. 2 Extratropical teleconnection patterns during El Niño events. [Images not available. See PDF.]

Shown are DJF-mean precipitation (units: mm day^–1, shading) and 200hPa geopotential height anomalies (units: m, contours with 20 m interval) during selected El Niño events. (a) for 2023/2024 El Niño event. (b–d) for the three super El Niño events of 1982/1983, 1997/1998 and 2015/2016. The fifth strongest El Niño event in 2009/2010 is shown in (e).

Through modulating tropical Pacific rainfall anomalies, ENSO generates distinct teleconnection patterns that profoundly impact global atmospheric circulation, thereby shaping climate conditions worldwide^11,15. The primary extratropical teleconnection pattern driven by ENSO is the Pacific-North American (PNA) pattern¹⁷, characterized by alternating high- and low-pressure anomaly centers over the subtropical North Pacific, south of the Aleutian Islands, northeastern North America, and the Gulf of Mexico (Fig. 2 and S2). During the 2023/2024 El Niño, the tropical Pacific heating source (rainfall anomalies) driving these atmospheric teleconnections was substantially weakened. As a result, the PNA pattern, including features such as the enhanced Aleutian low typically observed during El Niño, was absent (Fig. 2a). Notably, the strength of the PNA teleconnection (see Methods) in 2023/2024 was only 15–30% of that observed during the super El Niños and less than half of that during the 2009/2010 event (Fig. 1f). These observations suggest a diminished global influence of ENSO during the 2023/2024 event. This study seeks to explore the underlying factors contributing to this unusual occurrence.

Results

Unprecedented tropical Indian and Atlantic warming

The 2023/2024 El Niño was characterized by strong SST warming but only weak positive rainfall and westerly wind anomalies in the tropical Pacific (Fig. 1d, e). Given that tropical Pacific SST changes are typically closely linked to Pacific atmospheric variability through local air-sea coupling processes, this suggests that processes within the tropical Pacific alone may not fully account these observed changes^{5,10,24, 25, 26–27}. A striking feature of 2023 was the exceptional warming in the tropical Indian and Atlantic Oceans, which persisted throughout the year and reached peak during boreal winter (Fig. S3). Specifically, the western tropical Indian Ocean experienced SST warming anomalies of approximately 1.5 °C, while the tropical North Atlantic warmed by as much as 2 °C (Fig. 1a). SST anomalies in both basins ranked above the 99^th percentile since 1979, indicating that these warming events are unprecedented in recent decades (Fig. 1b and S3).

Warming in both the tropical Indian and Atlantic Oceans can significantly influence the Pacific climate system^5,24,28,29. For example, tropical Indian Ocean warming can lower local sea level pressure, with effects extending eastward into the western tropical Pacific. This enhances the zonal pressure gradient and strengthens the Pacific trade winds—a mechanism that operates on interannual, decadal, and even centennial timescales^{13,30, 31, 32–33}. Similarly, tropical Atlantic Ocean warming induces anomalous ascending motion over the region, which enhances the subsidence branch of the Pacific Walker circulation over the eastern tropical Pacific^{34, 35, 36–37}. Furthermore, tropical Atlantic warming can generate eastward-propagating atmospheric Kelvin waves through the tropical Indian Ocean to the western tropical Pacific, also leading to easterly wind anomalies and a strengthened Pacific Walker circulation^{38, 39–40}.

Hence, these previous findings indicate that the significant warming in the tropical Indian and Atlantic Oceans during the 2023/2024 El Niño event both favored a strengthening of the Pacific Walker cell. On the other hand, the strong SST warming in the central-eastern equatorial Pacific during the event reduced the zonal SST gradient, favoring westerly wind anomalies and a weakened Walker circulation (Fig. 1a). These results suggest a compensation between the influences of Pacific local air-sea coupling and tropical inter-basin interaction processes, resulting in notably weaker changes in tropical Pacific zonal winds compared to other strong El Niño events (Fig. 1e and S1).

Typically, the weakened Walker circulation during El Niño corresponds to an eastward shift of convection center from the western tropical Pacific region to the central basin (Fig. S2b), primarily due to anomalous moisture convergence associated with pronounced westerly wind anomalies over the central-western tropical Pacific. However, during the 2023/2024 El Niño, the much less evident weakening of the Walker circulation—attributable to interbasin interaction processes—led to much weaker rainfall changes in the tropical Pacific. Since these rainfall anomalies serve as the heating source driving extratropical teleconnections, the muted tropical Pacific rainfall response resulted in the absence of extratropical teleconnections during the 2023/2024 El Niño (Fig. 2).

Atmospheric model experiments

The findings above suggest that the unprecedented pan-tropical warming (Fig. S4) was pivotal in suppressing ENSO-driven tropical Pacific rainfall changes and the associated extratropical teleconnections during 2023/2024. To further isolate and quantify the relative contributions of the three tropical ocean basins to the tropical Pacific rainfall changes during the winter of 2023, we conducted numerical experiments using an atmospheric general circulation model forced with observed tropical SST anomalies from 2023 to 2024 (Fig. S5; see Methods).

We first assessed the influence of tropical Pacific SST anomalies alone. The simulated atmospheric response reveals a significant weakening of the Pacific Walker circulation, indicated by prominent low-level westerly wind anomalies (Fig. S5d). This leads to enhanced rainfall over the central-eastern equatorial Pacific and reduced rainfall over the western equatorial Pacific. These changes are accompanied by pronounced anomalous upper-level divergence over the central tropical Pacific (Fig. 3a), which further drives prominent extratropical teleconnections, notably amplifying the Aleutian low (Fig. 3b).

Fig. 3 The role of tropical Indian and Atlantic Oceans. [Images not available. See PDF.]

a DJF-mean 200 hPa velocity potential anomalies (units: 10⁶ m² s^–1, vectors). Shown are differences between experiment forced with Pacific SST anomalies alone and the control simulation (see Methods). b As in (a), except for 200hPa geopotential height anomalies (units: m, shading). c, d As in (a, b), except for changes caused by SST anomalies in tropical Indian and tropical Atlantic Oceans, represented by the differences between experiment forced by three oceans and Pacific Ocean alone. e, f The role of SST anomalies in the three tropical oceans. The black boxes in (a, c, e) indicate the area of 160°E-140°W, 15°S–15°N, which is used to represent the tropical Pacific heating source. Stippling denotes results that are statistically significant at the 95% confidence level. The black boxes in (b, d, f) indicate the area of 150°E–130°W, 35°N°–60°N. g The 850 hPa zonal wind anomalies averaged between 5°S and 5°N due to SST anomalies in the three tropical oceans (gray shading), the tropical Pacific (black line), the tropical Indian Ocean (red line), and the tropical Atlantic (blue line). Units are m s^–1.

In contrast, model simulations isolating the role of the unprecedented warming of the tropical Indian and Atlantic Oceans during 2023/2024 exhibit prominent easterly wind anomalies over the tropical Pacific, indicating a strengthened Walker circulation (Fig. S5c). This leads to positive rainfall changes primarily concentrated over the western equatorial Pacific—a tropical rainfall anomaly pattern opposite to that driven by the Pacific forcing. These rainfall changes in turn generate high-pressure anomalies over the mid-latitude North Pacific and weakens the Aleutian low (Fig. 3c, d). Additional sensitivity experiments, specifically designed to isolate the respective effect of warming in the tropical Indian and Atlantic Oceans (see Methods), further reveal distinct contributions from the two basins. The tropical Indian Ocean predominantly drives easterly wind anomalies across the tropical Pacific, whereas the tropical Atlantic warming induces a dipole pattern of wind anomalies, characterized by anomalous westerlies over the eastern tropical Pacific and easterly wind anomalies over the western tropical Pacific (Fig. 3g, S5e, and S5f). These results align with previous findings^30,31,34,35. Hence, both tropical ocean basins contribute to a strengthening of the Pacific Walker circulation.

When accounting for the combined effects of the three tropical ocean basins in 2023/2024, the model simulation shows a weakened Pacific Walker circulation, accompanied by enhanced rainfall over the tropical Pacific, resembling the patterns observed in the Pacific-alone experiment (Figs. 3a, e, S5b, and S5d). This result highlights the dominant role of local atmosphere-ocean interactions in driving tropical Pacific changes. However, the upper-level velocity potential anomalies are reduced by approximately 47% compared to those driven solely by tropical Pacific SST anomalies. Consequently, the changes in the Aleutian low are significantly weakened when the influences of the tropical Indian and Atlantic Oceans are incorporated (Fig. 3f). These findings confirm that the remote forcing from the tropical Indian and Atlantic Oceans effectively counteracts the local effects of tropical Pacific dynamics, ultimately contributing to the diminished ENSO-driven teleconnection observed in 2023/2024.

Role of long-term warming trend

It is worth noting that many other strong Pacific El Niño events were also accompanied by warming in the tropical Indian and Atlantic Oceans, yet Pacific impact still predominated during those events (Fig. S1). This contrast can be attributed to the unprecedented warming levels in the tropical Indian and Atlantic Oceans during 2023/2024, exceeding those observed in recent decades (Fig. 4c). In the tropics, the relationship between SST anomalies and local rainfall changes is nonlinear—the higher the SST, the more effectively it drives rainfall variations^{41, 42–43}. Consequently, the exceptional tropical Indian and Atlantic Ocean warming during 2023/2024 caused significant atmospheric responses that counteracted El Niño’s influence, thereby effectively weakening its global dominance.

Fig. 4 Long-term SST trend during 1979-2023. [Images not available. See PDF.]

a Linear trend of SST anomalies (units: °C per three decades, shading) in observations. b Ensemble mean of SST trend using CMIP6 results (see Methods). Stippling denotes results statistically significant at 95% confidence level based on Mann-Kendall test. c DJF-mean SST anomalies averaged over the tropical Indian Ocean (blue), tropical Pacific Ocean (black), and tropical Atlantic Ocean (purple). Domains are shown in Fig. 1. Shown are normalized results. Dashed lines denote the linear trends of the three indices. Horizontal dotted lines denote values of each line in 2023. Circles denote the five strong El Niño events.

Warming of the tropical Indian and Atlantic Oceans in 2023/2024 can be partially attributed to pronounced long-term warming trends in both basins, which contributed approximately 32–35% of the total observed warming in these regions (Fig. S6). By contrast, the warming rates of SSTs in the tropical Pacific have been notably lower compared to those in the other two tropical basins over recent decades^{30,44, 45, 46–47} (Fig. 4a). This resulted in higher warming levels in the two basins in 2023 compared to other strong El Niño events (Fig. 4c). Consequently, this inter-basin warming contrast further favored the formation of deep convection in the tropical Indian and Atlantic Oceans relative to the tropical Pacific, contributing to the pronounced active influences of these regions on the 2023/2024 El Niño. Indeed, when model simulations were forced with detrended SST anomalies in the three tropical ocean basins (see Methods), the associated changes in tropical Pacific winds and the strengthening of the Aleutian low were significantly more pronounced compared to simulations forced with total (non-detrended) SST anomalies (Fig. S7).

On the other hand, state-of-the-art climate models predominantly simulate an El Niño-like SST warming trend pattern during the historical period^{44,48, 49, 50–51} (Table S1; see Methods), with the amplitude of warming in the tropical Pacific comparable to or even exceeding that in the tropical Indian and Atlantic Oceans (Fig. 4b). Consequently, these models may underestimate the active roles of the tropical Indian and Atlantic Oceans in influencing other regions, including their impacts on ENSO and its associated atmospheric teleconnections. These discrepancies between model simulations and observational data may stem from the influences of natural climate variability and/or biases in the models’ ability to accurately simulate externally forced SST warming pattern^{44,51, 52–53}. Nevertheless, our findings highlight the critical importance of identifying and addressing these biases, particularly in simulating interbasin warming contrasts. Such improvements are essential for enhancing projections of ENSO-related climate impacts.

Discussion

The year 2023 was the warmest on record since the industrial revolution^{54, 55–56}, marked by an unprecedented amplitude of pan-tropical warming that played a critical role in suppressing ENSO-driven extratropical teleconnections. Notably, the 2023/2024 El Niño peaked during boreal fall and slightly weakened in the following winter (Fig. S3), failing to meet the threshold for a super El Niño. This lack of further development in winter 2023 has been partly attributed to the warming of tropical Indian and Atlantic Oceans, despite the favorable warm water accumulation in the western tropical Pacific during the triple-dip La Niña from 2020 to 2023^57,58. Nevertheless, 2023/2024 El Niño was still classified as a strong event with significant Pacific warming. However, it exhibited a much weaker-than-expected atmospheric response in the tropical Pacific and extratropical teleconnections compared to other strong El Niño events (Fig. 1f).

While our primary focus is on the role of tropical Indian and Atlantic Ocean warming in counteracting the weakening of the Pacific Walker circulation driven by tropical Pacific SST anomalies, these two basins can also directly influence the Aleutian Low through atmospheric teleconnections. For instance, previous studies have shown that warming in the tropical Indian Ocean can induce high-pressure anomalies over the mid-latitude North Pacific, partially offsetting the strengthening of the Aleutian Low caused by El Niño’s remote impacts⁵⁹. Similar processes may have occurred during the winter of 2023, further diminishing El Niño’s influence on the Aleutian Low.

Our findings highlight the increasingly significant role of tropical basin interactions in modulating ENSO dynamics and shaping its remote impacts. Over recent decades, the tropical Indian and Atlantic Oceans have experienced much more pronounced warming trends compared to the tropical Pacific (Fig. 4a). Due to the nonlinear dependence of rainfall changes on local SSTs, this interbasin warming contrast allows SST anomalies in these two basins to more effectively drive substantial changes in local rainfall and winds, subsequently influencing tropical Pacific and ENSO dynamics. Interestingly, the warm SST anomalies in the tropical Indian and Atlantic Oceans in 2023 remain significant even after removing long-term linear warming trends (Fig. S6). While natural climate variability could be a contributing factor, a recent study has partly attributed these anomalies to the reduction in sulfate emissions from international shipping routes following regulatory changes⁶⁰.

As noted previously, large-scale positive rainfall anomalies in the tropics tend to concentrate over regions where SST anomalies exceed the tropical mean warming⁶¹. Hence, the role of observed interbasin warming contrast can also be understood as effectively raising the threshold that tropical Pacific SST warming must surpass, resulting in a muted rainfall response in 2023. These results further suggest that examining ENSO-related SST anomalies relative to the tropical mean may offer more meaningful insights into local rainfall variations. Indeed, after removing the tropical mean SST anomalies, Pacific SST changes exhibit a better agreement with local rainfall and wind changes, including those in 2023 (Fig. S8). This finding aligns well with previous studies^28,29,62.

The underlying cause of the inter-basin warming contrast in the tropics over recent decades remains uncertain. Natural climate variability, such as the phase transition of the Interdecadal Pacific Oscillation from positive to negative, may have contributed to this pattern⁴⁴. Additionally, anthropogenic greenhouse gas emissions could be driving uneven warming trends across tropical ocean basins^49,63. However, notable discrepancies persist between current climate models and the observed tropical warming patterns of recent decades. Nevertheless, our findings underscore the critical role of this pattern in modulating the relative influence of the three tropical ocean basins on the global climate system. Future research should continue to focus on identifying the physical mechanisms driving the tropical warming pattern to enhance our ability to predict its evolution. Moreover, further investigations into how these distinct interbasin warming contrasts between models and observations affect ENSO-driven teleconnections—both in the past and in future projections—are also warranted.

Methods

Observational data

To characterize ENSO and document its temporal evolution, we used monthly sea surface temperature (SST) data from Hadley Centre Sea Ice and SST (HadISST)⁶⁴. To explore ENSO-driven atmospheric changes, we analyzed monthly winds and geopotential heights at 500 hPa and 850 hPa, using data from the National Centers for Environmental Prediction (NCEP)/National Center for Atmospheric Research (NCAR) Reanalysis 1⁶⁵. Additionally, we examined monthly precipitation data from the National Oceanic and Atmospheric Administration (NOAA) Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP)⁶⁶. Our main findings remain consistent when using different SST and precipitation datasets (Figs. S9 and S10). Given the uncertainties in observational data from earlier periods due to the sparse observational records⁶⁷, our analysis focuses on the more recent period from 1979 to 2023, which serves as the base period for calculating long-term averages and anomalies in this study. Additionally, the PNA index was obtained from the NOAA CPC.

CMIP6 models

Our findings underscore the pivotal role of the long-term tropical warming trend pattern in enhancing the active influences of tropical Indian and Atlantic Oceans on ENSO dynamics and its associated teleconnections. To explore whether current generation of climate models can simulate the observed interbasin warming contrast, we examined 152 members from 36 climate models that participate in the Coupled Model Inter-comparison Project Phase 6 (CMIP6) (Table S1). The analysis included historical simulations (1979–2014) and future projections (2015–2023) under the Shared Socio-economic Pathway 5-based Representative Concentration Pathway 8.5 (SSP585) forcing scenario⁶⁸. We used monthly SST from the models, which was linearly interpolated onto a common 1° × 1° grid.

Atmospheric model experiments

To isolate the contributions of the three tropical ocean basins to Pacific rainfall changes and their subsequent impacts on extratropical teleconnections, we conducted a series of numerical experiments using the NCAR Community Atmosphere Model version 5 (CAM5)⁶⁹. While atmospheric models do not include air-sea interactions and generally tend to overestimate the role of SST anomalies in driving local rainfall changes in some regions⁷⁰, they offer valuable insights into interbasin interactions and the influence of tropical SSTs on extratropical regions through atmospheric teleconnections.

The model was run at a resolution of approximately 1°x1°, with each experiment integrated for 50 years. Given that it takes a few years to reach the model equilibrium, the initial 6 years of each simulation were discarded, and analyses were performed on the outputs from the final 44 years. In these sensitivity experiments, buffer zones were applied at the boundaries of each basin to minimize the influence of artificial gradients in SST anomalies. The SST forcing field followed a two-year cycle: from June in year 1 to May in year 2, observed SST anomalies from June 2023 to May 2024 were added to the model climatology. To ensure smooth temporal transitions in SST, half of the June anomalies were applied in May of year 1, and similarly, half of the May anomalies were applied in June of year 2. No SST anomalies were added during January–April of year 1 and July–December of year 2.

In addition to the control run, which was forced with monthly SST climatology, we conducted five sensitivity experiments. The Pacific-only experiment was forced with SST anomalies during 2023/2024 in the tropical Pacific Ocean (Fig. S5). In the second and third experiment, we further included SST anomalies in the tropical Indian and Atlantic Oceans in addition to the tropical Pacific, respectively. The role of the tropical Indian (Atlantic) Ocean was quantified as the differences between the second (third) experiment and the Pacific-only experiment.

Additionally, we conducted another experiment incorporating SST anomalies from all three tropical ocean basins. This experiment aimed to investigate the role of tropical SST anomalies in driving extratropical teleconnections during 2023/2024. Note that the combined effect of the tropical Indian and Atlantic Oceans on ENSO was quantified as the difference between the three-ocean experiment and the Pacific-only forcing experiment. The final experiment was also forced with SST anomalies in all three tropical ocean basins, but with the SST anomalies detrended. This experiment was designed to evaluate the contribution of long-term warming trends to the enhanced influence of the tropical Indian and Atlantic Oceans on ENSO.

Acknowledgements

This work is supported by the National Natural Science Foundation of China (42376021, W2441014), the GuangDong Basic and Applied Basic Research Foundation (2024B1515040024), the Development fund (SCSIO202203) and Special fund (SCSIO2023QY01) of South China Sea Institute of Oceanology of the Chinese Academy of Sciences. We acknowledge the modeling groups, the Program for Climate Model Diagnosis and Intercomparison (PCMDI), and the World Climate Research Programme (WCRP) for their roles in making available CMIP6 datasets. The numerical simulation is supported by the High Performance Computing Division in the South China Sea Institute of Oceanology.

Author contributions

L.Z. conceived the study and wrote the initial manuscript in discussion with C.W. L.Z. and Y.C. conducted the analysis and prepared the figures. Y.C. conducted the atmospheric model experiments. K.K., M.C., and X.L. contributed to interpretating results and improving the paper.

Peer review

Peer review information

Communications Earth & Environment thanks Ji-Won Kim and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Primary Handling Editors: Kyung-Sook Yun and Aliénor Lavergne. A peer review file is available.

Data availability

The observational data and climate model simulations used in this study are publicly available and can be downloaded from the following websites: HadISST SST data (https://www.metoffice.gov.uk/hadobs/hadisst/), NCEP reanalysis data (https://psl.noaa.gov/data/reanalysis/reanalysis.shtml), and CMIP6 outputs (https://esgf-node.llnl.gov/projects/cmip6/). The atmospheric model results are available upon request. Source data for figures presented in this study are available in the online repository at https://doi.org/10.5281/zenodo.15863687.

Competing interests

The authors declare no competing interests.

Supplementary information

The online version contains supplementary material available at https://doi.org/10.1038/s43247-025-02584-8.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

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