  We present the geometry of spacetimes that are tangentially approximated by
de Sitter spaces whose cosmological constants vary over spacetime. Cartan
geometry provides one with the tools to describe manifolds that reduce to a
homogeneous Klein space at the infinitesimal level. We consider a Cartan
geometry in which the underlying Klein space is at each point a de Sitter
space, for which the combined set of pseudo-radii forms a nonconstant function
on spacetime. We show that the torsion of such a geometry receives a
contribution that is not present for a cosmological constant. The structure
group of the obtained de Sitter-Cartan geometry is by construction the Lorentz
group $SO(1,3)$. Invoking the theory of nonlinear realizations, we extend the
class of symmetries to the enclosing de Sitter group $SO(1,4)$, and compute the
corresponding spin connection, vierbein, curvature, and torsion.
