The challenge of understanding our environment requires global measurements of increasing numbers of trace species and requires some priority to be given to new observations of classes of species which may play fundamental roles in climate and chemistry interactions. Such compounds include "new" ozone depleting substances (ODS), greenhouse gases (GHGs) and indirect controlling influences such as key chemical oxidants. For many of these gases, relevant spectral signatures had, until recently, either not been well characterised globally or never been observed in the atmosphere. The launch of high-resolution spaceborne spectrometers, such as the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on ENVISAT, is providing an unprecedented opportunity to examine spectra of the atmosphere and to determine new observable trace species. In this paper, MIPAS infra-red spectra of the upper troposphere are examined, methods for detecting weak spectral signatures in atmospheric spectra are discussed and key trace gas signatures demonstrated for HCFC-22 and ethane as examples of the potential for three-dimensional daily data of trace gases.