Climate change is one of the greatest environmental challenges facing our planet in the foreseeable future. yet, despite international environmental agreements, global GHG emissions are still increasing. In this context, adaptation measures can play an important role in reducing climate impacts. These measures involve adjustments to economic or social structures to limit the impact of climate change without limiting climate change itself. To assess the interplay of adaptation and mitigation, we develop AD-MERGE, an integrated assessment model that includes both reactive ('flow') and proactive ('stock') adaptation strategies as well as a range of mitigation (energy) technologies. We find that applying adaptation optimally delays but does not prevent the transition to clean energy systems (carbon capture and sequestration systems, nuclear, and renewables). Moreover, applying both adaptation and mitigation is more effective than using just one.