The IPCC first highlighted the concept of transformational adaptation in SREX. SREX generally used the phrase transformation to refer to fundamental societal changes that advance climate adaptation, disaster risk management and sustainable development. Transformation was seen as one part of the solution space alongside options such as reducing vulnerability and exposure, and increasing resilience for managing risk. WGII of the IPCC Fifth Assessment Report used the phrase 'transformational adaptation' to contrast with 'incremental adaptation'. That report used the former term to refer to:  adaptation
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report