We study whether the sensitivity of economic, health, and livelihood outcomes to climate extremes has declined over the last half century, consistent with adaptation. Understanding whether such adaptation is already occurring is central to anticipating future climate damages, to calibrating the level of ambition needed for emissions mitigation efforts, and to understanding additional investments in adaptation that could be required to avoid additional damages. Using comprehensive panel data across diverse geographies and outcomes, including data on mortality, agricultural productivity, crime, conflict, economic output, and damages from flooding and tropical cyclones, we find limited systematic evidence of adaptation to date. Across 21 outcomes we study, six show a statistically significant declining sensitivity to a changing climate, five show an increasing sensitivity, and the remainder show no statistically significant change. Our results do not imply that specific documented adaptation efforts are ineffective or certain locations have not adapted, but instead that the net effects of existing actions have largely not been successful in meaningfully reducing climate impacts in aggregate. To avoid ongoing and future damages from warming, our results suggest a need to identify promising adaptation strategies and understand how they can be scaled.