NIGK26005U Climates of the Past

The course is composed of theory and case-studies. The theory part comprises an introduction to selected climate archives, mainly recorded in marine sediments. Important sedimentary and geochemical proxies, including stable isotopes, are covered and students are trained in critical reading of scientific key literature. Cases may deal with past climate change, long term carbon cycle and/or seawater geochemical changes, on time scales ranging from thousands to multi-millions of years. Focus will be mostly on pre-Quaternary systems, but items treated may change from year to year.

The aim of the course is to provide an overview of past climate changes focused on how these changes are observed in the sedimentary records, and what processes, interactions and feedbacks between the components of the climate system may have led to the signal in the sedimentary archives. The theory part comprises an introduction to climate archives and marine and terrestrial system processes available on Absalon prior to the course start. Important sedimentary and geochemical proxies, including isotopes, are explained during the course and students are trained in the evaluation of such data. Examples may deal with past climate changes, long-term carbon cycle perturbations and/or modifications of seawater geochemistry on time scales ranging from thousands to multi-millions of years. Milankovitch (orbital) cycles and their role on Earth’s climate are explored through theory and practicals. In the last weeks of the course, students read key papers and produce a literature review report on one of the many dramatic paleoclimatic events in Earth History. The students have the necessary background for understanding the importance of observations and hypothesis testing. They should have developed skills in analysing multiple datasets and in interpretation of which process feedbacks lead to the observations; and they should be able to evaluate the validity of geological data archives and to model results through comparative studies.

A series of lectures and practicals consist in signal analysis (data preparation, Fast fourier transforms or FFT, evolutive FFT, Filter design) of sedimentary climatic signals with the aim of extracting orbital components to better understand the influence of insolation on climate through time.