Reply [to “Lake Agassiz meltwater”]



We thank Eric Steig for his thoughtful comments, and we would like to reply to his three points. First, Steig notes that our results may challenge the assumed importance of meltwater in abrupt climate change. Although this may be one possible outcome of our work, the ongoing nature of our work on a Lake Agassiz meltwater source makes us offer that conclusion only tentatively.

Second, Steig wonders if trying to understand the beginning of the Younger Dryas is the best approach to solving the puzzle of abrupt climate change. It may well be that cooling and warming phases of abrupt climate changes are driven by separate mechanisms. If we lack understanding, though, of the processes pushing the climate system into the cold phase, we are unlikely to have proper insight about the global boundary conditions under which the warming takes place. Because drainage rerouting from glacial Lake Agassiz has been a prime suspect for Younger Dryas climate change, it provides an appropriate first test.