Ice cores at a fist glance are almost ideal paleoclimate archives. They not only record temperatures of the past in a relatively direct way, they also keep the atmospheric composition intact. In the end it is only a question how smart we are in using appropriate analytic techniques to unravel the complete atmospheric record – greenhouse gases, aerosols and dust. Another advantage of ice cores is that we can count on very high resolution in time and although we have no direct dating method we can fairly confidently ascribe an absolute time to samples retrieved from a certain depth. From the first ice cores drilled in the sixties until today results from ice cores have helped us to better understand the climate system in particular its inherent global teleconnections. Ice cores are also our climate conscience – they show us without doubt how humankind is altering climate boundary conditions i.e. the greenhouse gas concentrations at an unprecedented rate. In my presentation I will briefly touch on techniques from drilling to analytics and show some of the most important results.