In AR5 Section 19.6.3.5 , the transition from undetectable to moderate risk was assessed between 1.6℃ and 2.6°℃ above pre-industrial levels  based on impacts to both Earth's biodiversity and the overall global economy with medium confidence. The risk transition between moderate and high risk was set around 3.6℃ above pre-industrial levels , based on literature finding extensive species vulnerability and biodiversity damage with associated loss of ecosystem goods and services at 3.5℃ . In SR15 Section 3.5.2.4 , economic literature on potential socioeconomic threshold events and empirical studies of global economic damages, combined with new evidence on biome shifts, extinction risk, species range loss  and ecosystem degradation, were assessed, and the upper bound of the transition to moderate risk was lowered to 1.5℃ warming above pre-industrial levels, and the transition from moderate and high risk was lowered to between 1.5°C and 2.5℃ . The boundary between high risk and very high risk was not assessed in
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report