The paper by Berger et al. (2006) explores the role of equatorial insolation in driving climatic variations, particularly focusing on the 100-kyr, 11-kyr, and 5.5-kyr cycles. The authors argue that these cycles are not solely driven by obliquity and precession variations but also by eccentricity. They demonstrate that the double maximum in daily irradiance received at tropical latitudes over the course of a year is responsible for these longer-term climatic cycles. The 100-kyr cycle is linked to eccentricity, while the 11-kyr and 5.5-kyr cycles are related to harmonics of precession. The study uses spectral analyses of climate proxy records to support these findings, highlighting the importance of tropical regions in glacial-interglacial cycles and recent climate warming. The authors also discuss the implications of these cycles for understanding long-term climatic variations, suggesting that the tropical regions may play a leading role in generating these cycles.The paper by Berger et al. (2006) explores the role of equatorial insolation in driving climatic variations, particularly focusing on the 100-kyr, 11-kyr, and 5.5-kyr cycles. The authors argue that these cycles are not solely driven by obliquity and precession variations but also by eccentricity. They demonstrate that the double maximum in daily irradiance received at tropical latitudes over the course of a year is responsible for these longer-term climatic cycles. The 100-kyr cycle is linked to eccentricity, while the 11-kyr and 5.5-kyr cycles are related to harmonics of precession. The study uses spectral analyses of climate proxy records to support these findings, highlighting the importance of tropical regions in glacial-interglacial cycles and recent climate warming. The authors also discuss the implications of these cycles for understanding long-term climatic variations, suggesting that the tropical regions may play a leading role in generating these cycles.