July 7, 2017 (Phys.org) -- Throughout the last 800,000 years, Antarctic temperatures and atmospheric carbon dioxide concentrations have showed a similar evolution. However, they were different during the transition to the last ice age -- approximately 80,000 years ago, temperature declined while the carbon dioxide content of the atmosphere remained relatively stable.
An international research team led by the GEOMAR Helmholtz Centre for Ocean Research Kiel and the Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine Research has now discovered that a falling sea level may have caused enhanced volcanic activity in the ocean, which can explain the anomaly. The results are published today in the journal Nature Communications.
Climate evolution shows regularities that can be traced throughout long periods of Earth's history. One of them is that the global average temperature and the carbon dioxide concentration in the atmosphere usually go hand-in-hand. Generally, if the temperatures decline, the CO2 values also decrease, and vice versa.