This talk gives an overview of the activities at IMK in Karlsruhe: scientific analysis of data from the MIPAS instrument (in orbit since 2002 onboard ENVISAT), air-borne observations using stratospheric balloons and high-altitude aircraft (GEOPHYSIKA, HALO), and ground-based FTIR measurements in frame of the NDACC. New developments concerning measurements of water isotopes and greenhouse gases will be discussed. Future missions (in particular PREMIER, one of ESA's Earth Explorer 7 candidates, and the MACE instrument for the International Space Station) will be presented.