  Aims: Jets are excellent signposts for very young embedded protostars, so we
want to identify jet-driving protostars as a tracer of the currently forming
generation of stars in the Carina Nebula, which is one of the most massive
galactic star-forming regions and which is characterised by particularly high
levels of massive-star feedback on the surrounding clouds.
  Methods: We used archive data to construct large (> 2 deg x 2 deg) Spitzer
IRAC mosaics of the Carina Nebula and performed a spatially complete search for
objects with excesses in the 4.5 micron band, typical of shock-excited
molecular hydrogen emission. We also identified the mid-infrared point sources
that are the likely drivers of previously discovered Herbig-Haro jets and
molecular hydrogen emission line objects. We combined the Spitzer photometry
with our recent Herschel far-infrared data to construct the spectral energy
distributions, and used the Robitaille radiative-transfer modelling tool to
infer the properties of the objects.
  Results: The radiative-transfer modelling suggests that the jet sources are
protostars with masses between ~1 M_sol and ~10 M_sol that are surrounded by
circumstellar disks and embedded in circumstellar envelopes.
  Conclusions: The estimated protostar masses < 10 M_sol suggest that the
current star-formation activity in the Carina Nebula is restricted to low- and
intermediate-mass stars. More optical than infrared jets can be observed,
indicating that star formation predominantly takes place close to the surfaces
of clouds.
