Radhika Sudheendran

Simulation of historical and future climate changes with the Earth system model and  model-data comparison with historical measurements of carbon isotopes

My Ph.D. project is in the framework of the Cluster of Excellence and comes under the research unit Ocean Floor as RECORDER.

Through my project, I intend to simulate the Earth system from the pre-industrial climate state through the present to the future using the isotope-enabled Community Earth System Model (iCESM 1.2v), in which the focus will be on the carbon isotopes in planktonic and benthic foraminifera. These isotopes can be a reliable proxy for determining the past climate. Ultimately, the aim of the project is to collect evidence that can help us to demarcate the beginning of the much debated “Anthropocene” epoch in terms of the δ13C/Suess effect, whose imprint we hope to find in the water masses as well as in the marine sediments.

The Suess effect refers to the dilution of heavy carbon isotopes like 13C and 14C in the atmosphere due to the burning of fossil fuels, which releases carbon sequestered for millions of years and has a different isotopic composition than contemporary carbon. This decrease is also reflected in the oceans, which absorb and mix with atmospheric carbon. By studying these changes, we can track the extent of human influence on the global carbon cycle and use this information to support the argument that we are living in a new geological epoch, the Anthropocene. Although it is possible that the deep sea sediments remain untouched by the anthropogenic Suess effect, we can use the model to estimate the potential future incursion of the same into this natural archive. Comparison of the model results to the instrumental data will also help to solidify our case.