Glacial - Interglacial Climate Oscillations
Paced by its periodically changing orbit, the Earth has undergone glacial cycles throughout the past 1.8 million years. Climate reconstructions of the past 1 million years reveal a saw-tooth periodicity with the following cycle of around 100,000 years:
Climate reconstructions of glacial cycles also reveal climate variations on millennial timescales which are particularly prominent in the last glacial period.
Simulating glacial-interglacial and millennial scale climate variations, always using climate reconstructions as a reference, allows us to study the multitude of feedbacks coming into play in a globally changing climate, such as:
- biogeochemical feedbacks that cause glacial-interglacial variations in atmospheric CO2 from ~180ppm to ~300ppm
- vast northern hemispheric ice sheets that influence the atmospheric circulation and the radiative budget of the Earth
- substantial amounts of meltwater that influence ocean currents during teminations and millennial climate fluctuations.
Examples from our research:
Butzin, M., P. Köhler, and G. Lohmann, 2017: Marine radiocarbon reservoir age simulations for the past 50,000 years, Geophysical Research Letters, 44, doi: 10.1002/2017GL074688.
Zhang, X., G. Knorr, G. Lohmann, and S. Barker, 2017: Abrupt North Atlantic circulation changes in response to gradual CO2 forcing in a glacial climate state, Nature Geoscience, 10, doi: 10.1038/ngeo2974.