There are many approaches to examine the ecological impacts of changing climate from simulations in mesocosms, field experiments, long term monitoring to modeling. There is however, little substitute for the ecological insights gained from rigorously studying the influence of large-scale climate shifts on ecosystems through sustained fieldwork. As a global driver of weather, we assert that El Niño Southern Oscillation (ENSO) events provide a rich opportunity for testing hypotheses about the ecological effects of climate change in the ocean. Due to the convergence of several major oceanic currents, the marine biota of the Galapagos Islands experience a wide range of temperature, nutrient and productivity variation that is dramatically increased during ENSO events. There is some evidence that the intensity of El Niños is increasing. ENSOs are frequent enough so that impacts, resistance and resilience from multiple events can be studied. As such, they likely represent a model system for examining ecological effects of climate change in the ocean. This symposium brings together ecologists, oceanographers and climatologists to present, integrate and synthesize the results of their sustained research on ENSO effects in the Galapagos with the goal of developing fundamental lessons for understanding impacts of global climate change in the oceans. The sequence of presentations begins with a synopsis of oceanographic forcing created by ENSOs over the past several decades to set the stage for scenarios of ecological change up to the present 2009-2010 El Niño. The most profound ecological impacts were caused by the 1982-83 and 1997 - 98 El Niños, and so this historical perspective is provided early on as a context for understanding the current state of coral populations and the entire benthic ecosystem of the Galapagos. A module of talks on ENSO impacts to rocky intertidal and subtidal benthic communities follows, with a focus on bottom – up, top down coupling, non-linear effects and resilience. The ramifications of ENSO driven changes in water column productivity, pelagic trophic pathways and fisheries for human societies will be covered in subsequent talks. To facilitate the formulation of general lessons on climate change in the oceans, the symposium concludes with two integrated syntheses of the presentations. One will focus on ENSO climate effects at the individual –community level of ecological organization while the final talk synthesizes effects at larger scales of the ecosystem- climate interface.