The lattice regularized Schwinger model for one fermion flavor and in
the strong coupling limit is studied through its equivalent representa
tion as a restricted 8-vertex model. The Monte Carlo simulation on lat
tices with torus topology is handicapped by a severe non-ergodicity of
the updating algorithm; introducing lattices with spherelike topology
avoids this problem. We present a large scale study leading to the id
entification of a critical point with critical exponent nu = 1, in the
universality class of the Ising model or, equivalently, the lattice m
odel of free fermions.