In this paper several of the possible impacts of continued, relatively unrestrained greenhouse gas (GHG) emissions over the next half-century are explored. These impacts, though not always highly likely, are plausible. In particular, the focus is on already stressed systems that are vulnerable to being driven over the edge or past a tipping by either a radical or a gradual shifts in climate. In so doing it offers a "system vulnerability approach" to understanding and anticipating climate change disruptions. In conclusion, both the security implications of the climate change impacts discussed in this paper, and the analytic opportunities provided by the systems vulnerability approach are considered.