A detailed atmospheric methane record from the EPICA Dome C ice core, extending back 800,000 years, reveals orbital and millennial-scale variability in methane concentrations. Methane, a potent greenhouse gas, has varied between ~350 and ~800 p.p.b.v. over the past 650,000 years, with current levels at ~1,770 p.p.b.v. The new record shows that long-term methane variability is dominated by 100,000-year glacial-interglacial cycles, with increasing precessional influence in recent cycles. Changes in tropical methane sources and sinks, influenced by monsoon systems and the intertropical convergence zone, controlled the methane budget. Major terminations saw increased methane emissions from periglacial wetlands. Millennial-scale changes, linked to Antarctic isotope maxima, indicate widespread millennial temperature variability. The record also shows rapid fluctuations, such as those at the end of MIS 18, resembling the Younger Dryas event but with a longer duration. Methane variability is closely tied to tropical wetlands and volatile organic compound emissions, with 100,000-year cycles linked to ice sheet changes. The record highlights the role of tropical monsoons in driving methane variability, with a strong correlation between methane and monsoon records. The study underscores the importance of understanding methane sources and sinks for predicting future climate change. The new record provides a high-resolution view of methane variability over eight glacial cycles, with a time resolution of ~380 years. It confirms the link between methane and Antarctic temperature, and shows that methane variability is influenced by both tropical and boreal sources. The study also highlights the need for future model simulations to better understand the complex interactions between climate and the carbon cycle. The record is a key reference for long-term methane evolution and provides insights into past climate variability.A detailed atmospheric methane record from the EPICA Dome C ice core, extending back 800,000 years, reveals orbital and millennial-scale variability in methane concentrations. Methane, a potent greenhouse gas, has varied between ~350 and ~800 p.p.b.v. over the past 650,000 years, with current levels at ~1,770 p.p.b.v. The new record shows that long-term methane variability is dominated by 100,000-year glacial-interglacial cycles, with increasing precessional influence in recent cycles. Changes in tropical methane sources and sinks, influenced by monsoon systems and the intertropical convergence zone, controlled the methane budget. Major terminations saw increased methane emissions from periglacial wetlands. Millennial-scale changes, linked to Antarctic isotope maxima, indicate widespread millennial temperature variability. The record also shows rapid fluctuations, such as those at the end of MIS 18, resembling the Younger Dryas event but with a longer duration. Methane variability is closely tied to tropical wetlands and volatile organic compound emissions, with 100,000-year cycles linked to ice sheet changes. The record highlights the role of tropical monsoons in driving methane variability, with a strong correlation between methane and monsoon records. The study underscores the importance of understanding methane sources and sinks for predicting future climate change. The new record provides a high-resolution view of methane variability over eight glacial cycles, with a time resolution of ~380 years. It confirms the link between methane and Antarctic temperature, and shows that methane variability is influenced by both tropical and boreal sources. The study also highlights the need for future model simulations to better understand the complex interactions between climate and the carbon cycle. The record is a key reference for long-term methane evolution and provides insights into past climate variability.