  The ability to reliably predict critical transitions in dynamical systems is
a long-standing goal of diverse scientific communities. Previous work focused
on early warning signals related to local bifurcations (critical slowing down)
and non-bifurcation type transitions. We extend this toolbox and report on a
characteristic scaling behavior (critical attractor growth) which is indicative
of an impending global bifurcation, an interior crisis in excitable systems. We
demonstrate our early warning signal in a conceptual climate model as well as
in a model of coupled neurons known to exhibit extreme events. We observed
critical attractor growth prior to interior crises of chaotic as well as
strange-nonchaotic attractors. These observations promise to extend the classes
of transitions that can be predicted via early warning signals.
