The Role of Population, Affluence, Technological Development and Diet in a Below 2 °C World

The rise in anthropogenic greenhouse gas emissions and the resultant temperature anomaly in the global climate can be simplified to a function of (1) the global population, (2) economic activity and (3) technological development for thought experiments. Diet, given the embodied process emissions in producing food, is also acknowledged as an important factor. Growth in the first two factors tends to increase environmental impacts while technological development can reduce them. In this chapter, the impact from these four variables, their interdependencies and importance are illustrated. To do so, three different model frameworks are combined namely IPAT, Ecological Footprint and Integrated Assessment Modelling, to illustrate the challenges to finding pathways to maintain a well below 2 °C world. The model setup developed for this chapter estimates the global mean temperature increase to 2100 and the needed land area to support human life as a function of population, affluence, technological development and diet. It is shown that focusing on technology development alone will likely not be enough to mitigate global warming and stay well below a 2 °C temperature increase. Therefore, the discussion about population, consumption, development and diet shifting should be high on the agenda for reducing energy demands and for increasing the feasibility of maintaining a well below 2 °C world.