The First Type Ia Supernovae: An Empirical Approach to Taming   Evolutionary Effects In Dark Energy Surveys from SNe Ia at z>2
  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. 
Adam G Riess and Mario Livio