  A broad class of dark energy models, which have been proposed in attempts at
solving the cosmological constant problems, predict a late time variation of
the equation of state with redshift. The variation occurs as a scalar field
picks up speed on its way to negative values of the potential. The negative
potential energy eventually turns the expansion into contraction and the local
universe undergoes a big crunch. In this paper we show that cross-correlations
of the CMB anisotropy and matter distribution, in combination with other
cosmological data, can be used to forecast the imminence of such cosmic
doomsday.
