Precision cosmological measurements: independent evidence for dark   energy
  Using recent precision measurements of cosmological paramters, we re-examine whether these observations alone, independent of type Ia supernova surveys, are sufficient to imply the existence of dark energy. We find that best measurements of the age of the universe $t_0$, the Hubble parameter $H_0$ and the matter fraction $\Omega_m$ strongly favor an equation of state defined by ($w < -1/3$). This result is consistent with the existence of a repulsive, acceleration-causing component of energy if the universe is nearly flat. 
Greg Bothun, Stephen D.H. Hsu, Brian Murray