  Future measurements of the nature of dark energy using Type Ia supernovae
will require a precise characterization of systematic sources of error.
  Evolutionary effects remain the most uncertain contributor to the overall
systematic error budget. Present plans to probe evolution with
cosmology-independent explosion parameters could yield absence of evidence for
evolution without definitive evidence of its absence. Here we show that
observations of Type Ia supernovae in the redshift interval 1.5 < z < 3.0,
where dark energy-dependent effects are relatively negligible, should provide
direct evidence to discern evolutionary effects. As examples of our approach to
constraining evolution, we examine the impact of changing progenitor
metallicity and age on the degree of potential luminosity evolution. We show
that the observations we propose can be carried out by existing space
telescopes, or ones that are already under development.
