  Swampland conjectures (SCs) of string theory require that a constant
cosmological constant $\Lambda$ be replaced by a time-dependent scalar-field
quintessence with constrained parameters. The constraints limit the duration of
the present expansion era because, although the SCs may be fulfilled at the
present time, they will be violated at a finite time in the future allowing
only an order-one number of e-foldings. In contrast, cyclic cosmology requires
$\sim94$ e-foldings of the present universe before turnaround from expansion to
contraction. This presents a dilemma to the original SCs. One possibility is
that one of the SCs, the range conjecture, be significantly weakened. A second
possibility, difficult to believe, is that cyclic cosmology vastly
overestimates the number of e-foldings. A third possibility, which is the least
disfavoured, is that string theory is not the correct theory of quantum
gravity.
