Peruvian Ice Core Yields 2,000-Year Global Methane Record

A 2,000-year atmospheric methane (CH4) concentration record has been established from a Peruvian ice core, offering the first historical global CH4 data originating from the low latitudes. This groundbreaking research, published online on August 19, 2026, in the journal Nature (doi:10.1038/s41586-026-10938-1), provides a crucial new perspective on past atmospheric composition. Previously, global methane records were predominantly derived from ice cores extracted from polar regions, which may not fully represent the atmospheric dynamics of the tropics.

The analysis of this Peruvian ice core reveals that methane concentrations in the equatorial regions were likely higher than previously inferred from polar-only records. This finding is supported by the implementation of a four-box model, a scientific tool used to simulate and understand global atmospheric processes. The model's simulations, incorporating the new equatorial data, indicate a stronger "equatorial methane strength," meaning that the contribution of methane sources and sinks in the tropics to the global atmospheric burden was more significant than previously understood.

Methane is a potent greenhouse gas, with a warming potential significantly higher than carbon dioxide over shorter timescales. Understanding its historical fluctuations and geographical distribution is vital for accurately reconstructing past climate changes and for refining future climate projections. The Peruvian ice core record, spanning two millennia, allows scientists to observe long-term trends and variations in atmospheric methane, including periods of natural variability and potential anthropogenic influence.

This research contributes to a more comprehensive understanding of the global methane cycle. By incorporating data from a new geographical location, scientists can better assess the spatial heterogeneity of atmospheric methane and improve the accuracy of climate models. The findings suggest that future climate modeling efforts should place greater emphasis on the role of tropical regions in regulating global methane levels. The study's lead authors and affiliated institutions are detailed within the Nature publication, which serves as the primary source for these findings. The methodology involved extracting and analyzing trapped air bubbles within the ice layers, each representing a specific period in Earth's history, to determine the atmospheric composition at that time.