  In high temperature QCD, the perturbation theory is plagued with infrared
divergences which reflect long-range non-perturbative phenomena. I argue that
it is possible to study such phenomena within a classical thermal field theory
which can be put on a three-dimensional lattice. The classical theory is an
effective theory for the soft, non-perturbative modes, as obtained after
integrating out the hard modes in perturbation theory. It is well suited for
numerical studies of the non-perturbative real-time dynamics, which cannot be
studied within the standard, imaginary-time formulations of lattice QCD.
