What can the anthropic principle tell us about the future of the dark
  energy universe?
  An anthropic explanation for evident smallness of the value of the dark
energy implies the existence of a time-dependent component of the scalar field,
serving, together with a negative-valued cosmological constant, as one of two
components to the overall density of the dark energy. The observers (i.e. us)
might then only evolve in those regions of the universe where the sum of those
two components (a positive and a negative ones) is sufficiently close to zero.
However, according to Vilenkin and Garriga, the scalar field component has to
slowly but surely diminish in time. In about a trillion years this process will
put a cap to the now-observable accelerated expansion of the universe, leading
to a subsequent phase of impending collapse. However, the vanishing scalar
field might also produce some rather unexpected singularities for a finite
non-zero scale factor. We analyse this possibility on a particular example of
Sudden Future Singularities (SFS) and come to a startling conclusion: the time
required for SFS to arise must be "comparable" to the lifetime of observable
universe.
