The article "Aerosols implicated as a prime driver of twentieth-century North Atlantic climate variability" by Booth et al. (2012) published in Nature, explores the role of aerosols in driving multi-decadal variability in North Atlantic Sea Surface Temperatures (SSTs). The study uses the Hadley Centre Global Environmental Model version 2 (HadGEM2-ES) to simulate SST variability from 1860 to 2005. Key findings include: 1. **Aerosol and Volcanic Forcings**: The model simulates 76% of the detrended detrended standard deviation of North Atlantic SST variability, with aerosol emissions and volcanic activity explaining 66% and 23% of the variability, respectively. 2. **Model Performance**: The HadGEM2-ES model captures more of the observed SST variability compared to previous multi-model studies (CMIP3 models), particularly in the early 20th century, where it simulates a larger warming trend. 3. **Mechanisms**: The model's ability to reproduce SST variability is attributed to the inclusion of aerosol-cloud microphysical effects, which dominate the magnitude and spatial pattern of the total surface aerosol forcing in the North Atlantic. 4. **Historical Impacts**: The study suggests that man-made aerosol emissions have contributed to significant historical climate events, such as hurricane activity and Sahel droughts, and that decadal-scale predictions of regional Atlantic climate will benefit from including aerosol-cloud microphysical interactions and future aerosol concentrations. 5. **Methodology**: The study uses ensemble simulations to separate internal variability from forced changes, demonstrating that aerosol and volcanic forcing are key drivers of the observed SST variability. 6. **Conclusion**: The findings highlight the importance of aerosols in driving North Atlantic climate variability and suggest that policy actions to reduce aerosol emissions could have significant impacts on regional climate. The research underscores the need to reassess the attribution of past climate impacts linked to North Atlantic SSTs, such as Sahel drought, and emphasizes the role of aerosols in understanding and predicting future climate variability.The article "Aerosols implicated as a prime driver of twentieth-century North Atlantic climate variability" by Booth et al. (2012) published in Nature, explores the role of aerosols in driving multi-decadal variability in North Atlantic Sea Surface Temperatures (SSTs). The study uses the Hadley Centre Global Environmental Model version 2 (HadGEM2-ES) to simulate SST variability from 1860 to 2005. Key findings include: 1. **Aerosol and Volcanic Forcings**: The model simulates 76% of the detrended detrended standard deviation of North Atlantic SST variability, with aerosol emissions and volcanic activity explaining 66% and 23% of the variability, respectively. 2. **Model Performance**: The HadGEM2-ES model captures more of the observed SST variability compared to previous multi-model studies (CMIP3 models), particularly in the early 20th century, where it simulates a larger warming trend. 3. **Mechanisms**: The model's ability to reproduce SST variability is attributed to the inclusion of aerosol-cloud microphysical effects, which dominate the magnitude and spatial pattern of the total surface aerosol forcing in the North Atlantic. 4. **Historical Impacts**: The study suggests that man-made aerosol emissions have contributed to significant historical climate events, such as hurricane activity and Sahel droughts, and that decadal-scale predictions of regional Atlantic climate will benefit from including aerosol-cloud microphysical interactions and future aerosol concentrations. 5. **Methodology**: The study uses ensemble simulations to separate internal variability from forced changes, demonstrating that aerosol and volcanic forcing are key drivers of the observed SST variability. 6. **Conclusion**: The findings highlight the importance of aerosols in driving North Atlantic climate variability and suggest that policy actions to reduce aerosol emissions could have significant impacts on regional climate. The research underscores the need to reassess the attribution of past climate impacts linked to North Atlantic SSTs, such as Sahel drought, and emphasizes the role of aerosols in understanding and predicting future climate variability.