A comprehensive investigation conducted by the University of Miami has unveiled that human-generated aerosol emissions play a pivotal role in shaping temperature fluctuations in the tropical expanse of the Atlantic Ocean. These oscillations exert a profound influence on both the precipitation patterns in West Africa’s Sahel region and the occurrence of Atlantic hurricanes.
The research findings indicate a close correlation between the emissions of aerosols and two critical climatic phenomena: Atlantic hurricane activity and Sahel rainfall. This new climate study, spearheaded by scientists affiliated with the University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science, underscores the predominant role of human-induced aerosol emissions in driving temperature variations within the tropical Atlantic Ocean, consequently impacting rainfall in the Sahel region of West Africa and the genesis of Atlantic hurricanes.
These revelations, which were disseminated in the scientific journal Nature on September 13, come during a year marked by the emergence of several hurricanes, including Hurricane Idalia, forming in rapid succession over the tropical Atlantic.
Lead author of the study, Chengfei He, a postdoctoral researcher at the Rosenstiel School, elucidated, “Our findings propose that the ebb and flow of Atlantic oceanic temperatures, the incidence of hurricanes, and the precipitation in the Sahel region are predominantly steered by human-induced emissions. These groundbreaking insights emerge from a meticulous analysis of data, employing innovative methodologies.”
Methodology and Reassessment of Previous Assumptions
The researchers employed an extensive ensemble simulation technique, aggregating results from over 400 climate model simulations conducted at climate centers worldwide. This technique, akin to noise-canceling headphones, unveiled the climate fluctuations attributed to external factors—a category primarily encompassing human activities and volcanic eruptions that affect the climate system.
Amy Clement, a professor of atmospheric sciences at the Rosenstiel School and a coauthor of the study, remarked, “For a considerable duration, alterations in West African precipitation and the frequency of Atlantic hurricanes were attributed to inherent climate system cycles, such as the Atlantic Meridional Overturning Circulation. However, we have now substantiated that the climate variations we observe in the tropical Atlantic are indeed linked to external factors, aligning closely with the patterns discerned in the real world.”
Historical Significance and Future Implications
The outcomes derived from these simulations indicate that the subdued hurricane activity in the Atlantic and a parched Sahel region during the decades following World War II were predominantly instigated by anthropogenic aerosol emissions. The Sahel region of West Africa, extending from the Atlantic to the Red Sea, bore the brunt of this climatic influence.
These climatic shifts culminated in a devastating drought in the early 1980s, leading to severe food shortages and widespread diseases that claimed hundreds of thousands of lives from West Africa to Ethiopia. The reduction in aerosol emissions that commenced after the 1980s witnessed an uptick in Atlantic hurricanes and heightened Sahel rainfall. Furthermore, the research uncovered striking parallels between sea surface temperatures, hurricane activity, and Sahel precipitation, mirroring the observations made by scientists in the tropical Atlantic.
It is imperative to note that multiple factors contribute to the dynamics of hurricane seasons, and storms can manifest even if the overall hurricane activity for a season is relatively low.
Chengfei He concluded, “In light of the continual reduction in human-induced aerosol emissions around the Atlantic and the ongoing and projected warming attributed to greenhouse gases, we anticipate that a return to a period of diminished hurricane activity in the Atlantic during the mid-century is improbable.”
This significant study, titled “Tropical Atlantic Multidecadal Variability Dominated by External Forcing,” was published in the September 13 issue of the journal Nature. The esteemed authors of this study include Chengfei He, Amy C. Clement, Lisa Murphy, and Tyler Fenske from the University of Miami Rosenstiel School, along with Sydney Kramer and Jeremy Klavans from the University of Colorado, and Mark Cane from Columbia University.
Reference: “Tropical Atlantic Multidecadal Variability Dominated by External Forcing” by Chengfei He, Amy C. Clement, Sydney M. Kramer, Mark A. Cane, Jeremy M. Klavans, Tyler M. Fenske, and Lisa N. Murphy, 13 September 2023, Nature. DOI: 10.1038/s41586-023-06489-4
It is noteworthy that this study received support from NOAA (Grant No. NA20OAR4310400), the Climate and Large-Scale Dynamics program of the National Science Foundation (Grant Nos. AGS 1735245 and AGS 1650209), and the Paleo Perspectives on Climate Change program of the National Science Foundation (Grant No. AGS 1703076).
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Frequently Asked Questions (FAQs) about Aerosol-Driven Climate Shifts
What is the main finding of the University of Miami’s research?
The main finding of the University of Miami’s research is that human-induced aerosol emissions significantly influence temperature variations in the tropical Atlantic Ocean, which in turn impact rainfall patterns in West Africa’s Sahel region and the occurrence of Atlantic hurricanes.
How did the researchers arrive at these conclusions?
The researchers used an ensemble simulation technique, combining data from over 400 climate model simulations conducted globally. This method allowed them to isolate the effects of external factors, including human-induced aerosol emissions, on climate changes.
What were the previous assumptions about the factors affecting West African rainfall and Atlantic hurricanes?
Previously, it was commonly believed that these climate phenomena were primarily driven by natural cycles within the climate system, such as the Atlantic Meridional Overturning Circulation. This research challenges those assumptions by demonstrating the influence of human-induced aerosol emissions.
What are the historical and future implications of this research?
Historically, suppressed Atlantic hurricane activity and a drier Sahel region following World War II were attributed to human-caused aerosol emissions. Future implications suggest that with the continued reduction in aerosol emissions and ongoing greenhouse gas-induced warming, a return to a period of low hurricane activity in the Atlantic is unlikely.
Where can I find the full research paper for more details?
The full research paper, titled “Tropical Atlantic Multidecadal Variability Dominated by External Forcing,” was published in the journal Nature on September 13, 2023. It provides in-depth details of the study’s methodology and findings.
What organizations supported this research?
This research received support from NOAA (Grant No. NA20OAR4310400), the Climate and Large-Scale Dynamics program of the National Science Foundation (Grant Nos. AGS 1735245 and AGS 1650209), and the Paleo Perspectives on Climate Change program of the National Science Foundation (Grant No. AGS 1703076).
More about Aerosol-Driven Climate Shifts
- University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science
- Nature Journal – “Tropical Atlantic Multidecadal Variability Dominated by External Forcing”
- NOAA (National Oceanic and Atmospheric Administration)
- National Science Foundation Climate and Large-Scale Dynamics Program
- National Science Foundation Paleo Perspectives on Climate Change Program
3 comments
wow! Impressive research, big impact on hurricanes & Africa. no more natural cycles? humans matter!
where full paper? Nature hard to get sometimes, need more data. also, where Sahel region exactly?
research need support, good job! but need stop aerosols & GHGs, climate hot! hurricanes danger.