The impact of income-driven changes in global consumption patterns on Kyoto Gas emissions during the twenty-first century

Global 21st century Kyoto Gas emissions growth as forecast in SSP2 (a middle-of-the-road future climate scenario) is largely driven by expected: (a) per-capita GDP growth; and (b) energy/non-CO₂ GDP intensity reduction. While models of the former have been comprehensively critiqued, the rationale for the latter has not.

This paper uses a new consumption-based methodology to determine likely future emissions intensity reductions implicit in changing consumption patterns. Its analysis of household expenditure surveys, macroeconomic data and income elasticities inform a model of how future consumption pathways could evolve with different levels of national incomes to 2100. These pathways are then combined with existing emissions intensity data to quantify the implied impacts of consumption change on overall emissions intensity. Introducing such a consumption factor into established decomposition methodologies then allows demonstration of the scale of non-consumption intensity reductions required.

Results suggest that emissions intensity peaks at poverty-like national income levels, where household/transport fuels dominate emissions. Thereafter, intensity reduces with national income growth, though absolute emissions continue to rise.

We find that expected changes in consumption patterns will deliver less than half required consumption energy intensity reduction to meet SSP2-Baseline projections to 2100. Such implied non-consumption-pattern improvement requirements may appear relatively undemanding in total against historic performance, but for some regions and timescales this is not the case and the role of mitigation in the historic data may render a forecast baseline (where mitigation is excluded) optimistic.

The paper's methodology and findings are relevant for inequality scholars, climate modellers, and governments and policymakers, helping them facilitate a better understanding of how consumption pathways interact with climate futures for whole economies and particular sectors within those.