The role of historic global inequality in avoided climate destabilisation

In assessing responsibility for climate change, conventional metrics like cumulative and per-capita emissions do not capture the consequences of evolution of affluent lifestyles. Our study introduces a novel framework to assess the global mean surface warming that would have resulted if the historical lifestyles of individual countries had been the norm for the entire global population. We refer to the resultant warming as the carbon footprint temperature, T_cf. We find that universalising the carbon-intensive lifestyles of industrialised countries would have pushed the world beyond the 1.5°C threshold as early as the 1950s in some cases, and by the 2000s for many others, thereby risking significant destabilisation of the Earth's climate system. Our analysis concludes that the modest lifestyles of the global majority have contributed substantially to the experienced planetary stability, offering humanity a dual advantage: averting potential planetary destabilisation and providing a critical window for climate action extending from decades to a century.  Accordingly, we argue that affluent entities with high carbon footprint temperatures ought to have transitioned to low or even negative emissions regimes already instead of consuming the remaining carbon space. Additionally, per capita emissions across the world need to converge to collectively self-determined levels that are well below those of current affluent lifestyles.