In Peter Rogers’s excellent editorial Rogers 2008 , he suggests three general classes of hypotheses associated with global warming and suggests that adaptation of water resources systems is critical regardless of the hypothesis. How do we plan for adaptation in water management, the necessity for which Peter argues is becoming increasingly apparent? In a recent Science paper, Milly et al. 2008 argue that stationarity, the cornerstone of most of our planning methods, is dead. To those of us in the hydrologic community who came of scientific age in the 1970s, the argument may seem like deja vu all over again, as we remember the contentiousness of the debate over the Hurst phenomenon, which essentially was an argument about the relevance of stationary versus nonstationary statistics to hydrologic time series analysis. Viewed 35 years later, what is apparent is that although the participants in that discussion recognized that water resources systems were susceptible to climate variability and even change, there was presumed to be no prior knowledge as to its direction. Now, at least in some contexts, we have an idea as to the direction of change a particular example is streamflow in the western United States, where most indications are that temperatures have warmed over the past 50 years and seem likely to continue to do so, resulting in shifts in the seasonality of runoff . Furthermore, climate change does not have a corner on the market for nonstationary methods—we now increasingly recognize the role that change in land cover and land use has in hydrologic variables. Certainly the profession has been slow to acknowledge these changes and acknowledge that fundamentally new approaches will be required to address them see also Howe 2008 , as well as the very interesting series of papers in the special issue of the UCOWR Journal of Contemporary Water Research and Education that follow his preface . In my experience, the response of those in the water resources planning community populated largely by engineers, meaning our students has been to dig in their heels. Further, they say that there is lots of uncertainty in the planning process; thank you, but all of that uncertainty including that attributable to future hydrologic changes is already dealt with in our traditional planning methods. What I’ve seen happen increasingly is that outside review, often by citizen or political oversight, has asked questions such as “how are you dealing with future climate change in those projections?” although it may be that climate or land cover change is just one of many terms in the uncertainty equation, that perspective is a difficult sell, especially given the widespread visibility afforded to the IPCC process. So the heat is on, so to speak, to develop new approaches that explicitly deal with climate and other types of environmental change. I think that it is reasonable to assert that understanding hydrologic change will be one of the key challenges to the hydrology