In the summer of 2023, western North America endured an unprecedented heat wave that shattered temperature records and pushed the region’s ecosystems and infrastructure to their limits. Recent research published in Nature Communications has revealed a surprising culprit behind this extreme atmospheric phenomenon: the record-warm waters of the Atlantic Ocean. The study, spearheaded by Lopez, Lee, West, and their colleagues, has unveiled intricate teleconnections linking the tropical and subtropical Atlantic Ocean’s extraordinary warmth with the longevity and intensity of this heat wave, rewriting conventional understanding about how distant oceanic conditions can influence continental climate extremes.
This groundbreaking research challenges the prevailing notion that such persistent heat events in western North America are primarily driven by local or Pacific Ocean-related phenomena, such as the infamous “Ridiculously Resilient Ridge” and Pacific sea surface temperature anomalies. Instead, the data demonstrate that the Atlantic’s thermal state can exert a powerful influence through atmospheric bridges across the continent. These bridges modulate jet stream patterns, atmospheric circulation, and ultimately surface temperature extremes thousands of kilometers downstream, revealing a previously underappreciated climate teleconnection mechanism with significant implications for seasonal weather forecasting and climate projection models.
At the core of the study lies an extensive analysis of sea surface temperature (SST) anomalies, revealing that the Atlantic Ocean experienced its warmest conditions on record in 2023 during the critical months preceding the heat wave. Using state-of-the-art coupled ocean-atmosphere models and observational datasets, the researchers identified a robust link between the Atlantic SST anomalies and the reinforcement of an atmospheric ridge that settled persistently over western North America. This ridge funneled hot, dry air masses from lower latitudes into the continental interior, effectively igniting and sustaining the heat wave over an alarming period that exceeded any in recorded history.
Delving deeper into the mechanisms, the study highlights how the increased Atlantic SST enhanced convection and altered the Walker circulation patterns, leading to shifts in the position and strength of the North American jet stream. These changes suppressed the typical west-to-east progression of weather systems, locking the atmospheric pattern in place for weeks on end. As a result, the heat wave exhibited remarkable persistence, contributing to prolonged heat stress that not only devastated local communities but also exacerbated wildfires, drought conditions, and public health risks across multiple U.S. states and Canadian provinces.
The authors meticulously disentangled the Atlantic Ocean’s role from other factors by running controlled climate model experiments where Atlantic SST anomalies were isolated from other ocean basins. These simulations consistently showed that the Atlantic’s warmth alone was sufficient to trigger the formation and sustainment of the atmospheric ridge responsible for the heat wave. This finding underscores the ocean’s integral role as a climate driver, urging meteorologists and climate scientists to incorporate Atlantic SST variability more prominently in predictive models for the western North American region.
Such insights carry profound implications given the context of climate change. As global temperatures rise, the frequency and intensity of marine heatwaves in the Atlantic are expected to escalate, potentially increasing the likelihood and severity of similar continental heat extremes. The study’s results therefore serve as a sobering forecast, emphasizing the interconnectedness of oceanic and atmospheric systems and the cascading impacts they can produce on regional climates far from the source of initial warming.
Furthermore, the research elucidates the complex feedback loops that amplify the heat wave conditions. For example, the drought-induced reduction in soil moisture and vegetation facilitated further heating by diminishing evaporative cooling, while heightened atmospheric stability further suppressed convective cloud formation, reinforcing the heat dome established by the atmospheric ridge. These amplifying processes created a near-perfect storm of climatic conditions that locked western North America into a prolonged and destructive heat episode, the likes of which had never been fully anticipated.
At the intersection of climatology and atmospheric dynamics, this study pioneers a new understanding of how extratropical teleconnections can be influenced by tropical oceanic anomalies. The quantification of the Atlantic Ocean’s signal in the setup of the 2023 heat wave expands the toolkit for climate researchers attempting to predict and mitigate the impacts of extreme weather. It opens fresh avenues of inquiry into the role of ocean-atmosphere coupling across basins, as well as the cascading effects of such phenomena on hydrology, agriculture, and urban infrastructure resilience.
The methodology employed by Lopez and colleagues incorporated advanced satellite data, reanalysis products, and machine learning techniques to isolate patterns and forecast impacts with unprecedented precision. This interdisciplinary approach allows for greater confidence in the attribution of cause and effect, contrasting previous studies that often struggled to untangle the multiple overlapping influences shaping heat waves. The integration of these diverse datasets exemplifies the future of climate research, where converging technologies accelerate the understanding of global climate interdependencies.
Moreover, the results highlight an urgent need for climate adaptation strategies that consider the long-range influences of ocean warming. Urban planners, public health officials, and emergency management agencies must now grapple with the reality that warming in one ocean basin can propagate climate extremes to geographically distant regions. Enhanced early warning systems, increased investment in heat-resilient infrastructure, and targeted public communication campaigns become indispensable tools in mitigating the human and ecological toll of these mega-heat waves.
In addition, the findings raise important questions about the role of anthropogenic greenhouse gas emissions in modulating the observed Atlantic warmth and its teleconnections. While natural variability has always played a role in shaping SSTs, the observed unprecedented temperatures coincide with a background of accelerating global warming, pointing to the compounded impact of human activity in deepening and extending extreme events. This nuanced perspective reinforces the complexity of climate change impacts and the critical importance of continued greenhouse gas mitigation efforts.
Notably, the study also invites reassessment of historical heat wave records with a fresh lens, exploring how Atlantic SST anomalies may have contributed to past heat extremes also previously attributed primarily to Pacific influences. By reexamining decades of climatological data, researchers can refine predictive models and develop more comprehensive risk assessments for future heat waves, potentially transforming regional climate preparedness.
The implications also extend to biodiversity and ecosystem services that have been and will be increasingly strained by such persistent heat events. The prolonged exposure to extreme temperatures disrupts phenology, reproduction cycles, and survival thresholds for flora and fauna, thereby threatening the stability of entire ecological communities. Understanding the Atlantic’s role adds a crucial piece to this puzzle, enabling conservationists to anticipate stressors that transcend local or immediate environmental conditions.
Finally, the research underscores the value of international collaboration in climate science. The Atlantic’s influence crosses multiple countries and crosses hemispheres, demanding coordinated monitoring and data sharing to capture the full scale of climatic teleconnections. The synergy between oceanographers, atmospheric scientists, climatologists, and policymakers will be vital in addressing the holistic nature of climate extremes and forging resilient responses.
The study by Lopez, Lee, West, et al., thus stands as a landmark contribution to understanding the dynamics of one of the most devastating heat waves in recent memory. By spotlighting the central role of the warming Atlantic Ocean, it opens new frontiers for climate research and highlights the urgent necessity for integrated approaches in confronting the multifaceted challenges posed by a rapidly changing planet.
Article References:
Lopez, H., Lee, S.K., West, R., et al. The longest-lasting 2023 western North American heat wave was fueled by the record-warm Atlantic Ocean. Nat Commun 16, 6544 (2025). https://doi.org/10.1038/s41467-025-61859-y
Image Credits: AI Generated
