  We numerically investigate the impact of scale evolution on double parton
distributions, which are needed to compute multiple hard scattering processes.
Assuming correlations between longitudinal and transverse variables or between
the parton spins to be present at a low scale, we study how they are affected
by evolution to higher scales, i.e. by repeated parton emission. We find that
generically evolution tends to wash out correlations, but with a speed that may
be slow or fast depending on kinematics and on the type of correlation.
Nontrivial parton correlations may hence persist in double parton distributions
at the high scales relevant for hard scattering processes.
