Aerosols are identified as a major driver of 20th-century North Atlantic climate variability. A study using the Hadley Centre Global Environmental Model version 2 (HadGEM2-ES) shows that aerosol emissions and volcanic activity explain 76% of the simulated multidecadal variance in North Atlantic Sea Surface Temperatures (SSTs) from 1860 to 2005. After 1950, simulated variability aligns with observational estimates. The study highlights the role of aerosol-cloud microphysical interactions in shaping North Atlantic SST variability, with aerosols accounting for 80% of the total surface aerosol forcing. The findings suggest that anthropogenic aerosol emissions have influenced historical climate events, such as hurricane activity and Sahel droughts. The study also indicates that decadal-scale predictions of regional Atlantic climate could benefit from incorporating aerosol-cloud interactions and future aerosol concentration data. The research underscores the importance of understanding North Atlantic SST variability, as it is closely linked to climate in neighboring regions. The study challenges previous assumptions that natural ocean oscillations, such as the Atlantic Multidecadal Oscillation (AMO), are the primary drivers of variability, showing that aerosol and volcanic forcing play a significant role. The results emphasize the need to reassess the attribution of historical climate impacts to natural ocean variability, considering the influence of anthropogenic aerosol emissions.Aerosols are identified as a major driver of 20th-century North Atlantic climate variability. A study using the Hadley Centre Global Environmental Model version 2 (HadGEM2-ES) shows that aerosol emissions and volcanic activity explain 76% of the simulated multidecadal variance in North Atlantic Sea Surface Temperatures (SSTs) from 1860 to 2005. After 1950, simulated variability aligns with observational estimates. The study highlights the role of aerosol-cloud microphysical interactions in shaping North Atlantic SST variability, with aerosols accounting for 80% of the total surface aerosol forcing. The findings suggest that anthropogenic aerosol emissions have influenced historical climate events, such as hurricane activity and Sahel droughts. The study also indicates that decadal-scale predictions of regional Atlantic climate could benefit from incorporating aerosol-cloud interactions and future aerosol concentration data. The research underscores the importance of understanding North Atlantic SST variability, as it is closely linked to climate in neighboring regions. The study challenges previous assumptions that natural ocean oscillations, such as the Atlantic Multidecadal Oscillation (AMO), are the primary drivers of variability, showing that aerosol and volcanic forcing play a significant role. The results emphasize the need to reassess the attribution of historical climate impacts to natural ocean variability, considering the influence of anthropogenic aerosol emissions.