The escape of solitons over a potential barrier is analysed within the framework of a nonlinear Klein&-Gordon equation. It is shown that the creation of a kink&-antikink pair near the barrier through an internal mode instability can be followed by escape of the kink in a process analogous to Hawking radiation. These results have important implications in a wider context, including stochastic resonance and ratchet systems, which are also discussed.