Scientists Unlock 3 Million Years of Climate Secrets Hidden in Antarctic Ice

Two new Nature papers report analyses of multi-million-year Antarctic ice and trapped air from Allan Hills.

Noble-gas measurements imply the global ocean cooled about 2–2.5°C over the past 3 million years.

Direct ice-core CO2 and methane records show long-term CO2 likely stayed below 300 ppm while methane stayed near 500 ppb.

The results indicate factors beyond greenhouse gases contributed to long-term cooling and motivate further COLDEX work.