The atmosphere contained little carbon dioxide (CO
2) during the last Ice Age 20,000 years ago. Why did it rise when the Earth’s climate became warmer? Processes in the ocean are responsible for this, says a new study based on newly developed isotope measurements.
Around 20,000 years ago, the atmospheric CO2 concentration was distinctly lower than in the following warm period, showed measurements from Antarctic ice cores. An international team of glaciologists looked even further back and found that the close connection between carbon dioxide and temperature has existed over the past 800,000 years: with low CO2 concentrations during the Ice Ages and higher CO2 values during warm periods.