Will technology help us adapt to future climate conditions? We examine irrigation—an essential technology for adapting agriculture to climate change- and find a "hump-shaped" adoption pattern: irrigation use increases at mild dryness levels and declines under severe dryness despite increasing benefits and willingness to pay for irrigated land. We provide evidence that water scarcity, itself worsened by climate change, drives these dynamics by limiting the effectiveness of irrigation technologies and their adoption in the United States.
This "window of opportunity" pattern —where adaptation technologies are most effective under moderate climate change and lose effectiveness thereafter— holds true for many climate adaptation strategies. Incorporating this feature into a stylized macro-finance model yields diverging adaptation strategies at different levels of global warming: adaptation investment is high for moderate global warming and low for severe warming. Hence uncertainty about future climate discourages adaptation investment by making its returns uncertain. Our results highlight the benefits of commitment mechanisms that can reduce climate uncertainty as they encourage more proactive adaptation efforts.