Consumption-based indicators such as the energy and greenhouse gas footprint of households are largely determined by their spending levels. An inequality of household expenditures in a population therefore implies an inequality of their resource footprints. Figures 1a-c show European households by decile of expenditure and their associated resource footprints for GHGs and energy in 2015. The figures show that increasing expenditure generally translated into larger resource footprints, but that the inequality decreased from expenditure to energy to greenhouse gas emissions with 10:10 ratios (the top decile divided by the bottom decile) of `r exp_10_10`, `r energy_10_10` and `r co2eq_10_10`, respectively. Total expenditure ranged from `r exp_bottom_decile` trn€ to `r exp_top_decile` trn€ (or `r fd_pae_bottom_decile`€ to `r fd_pae_top_decile`€ per adult equivalent) across bottom and top decile, the energy footprint from `r energy_bottom_decile` EJ to `r energy_top_decile` EJ (or `r energy_pae_bottom_decile` GJ/ae to `r energy_pae_top_decile` GJ/ae), and the GHG footprint from `r co2eq_bottom_decile` MtCO2eq to `r co2eq_top_decile` MtCO2eq (or `r co2eq_pae_bottom_decile` tCO2eq/ae to `r co2eq_pae_top_decile` tCO2eq/ae). The reason for this is evident from figures 1d-f. Both the energy intensity measured as energy use per € expenditure (d) and the carbon intensity measured as GHGs per unit of energy use (f) gradually decrease from bottom to top expenditure decile. The average energy intensity of consumption decreased from `r mean_energy_intens_bottom_decile` MJ/€ in the bottom decile to less than half (`r mean_energy_intens_top_decile` MJ/€) in the top decile. Additionally, the GHG intensity of energy use was also higher in the bottom decile (`r mean_co2eq_of_energy_intens_bottom_decile` gCO2eq/TJ) compared to the top decile (`r mean_co2eq_of_energy_intens_top_decile` gCO2eq/TJ). There is a clear trend of decreasing intensities across expenditure deciles even though the variance in the lower deciles is much higher. The GHG intensity of consumption (figure 1e) combines the effects of the intensities of 1d and 1f. [*The higher GHG intensity of energy use is likely due to a larger share of emission intensive energy carriers in the energy system. The decreasing energy intensity per expenditure is due to either inefficient energy technologies or energy subsidies in poorer areas in Europe.*]
Consumption-based indicators such as the energy and greenhouse gas footprint of households are largely determined by their spending levels. An inequality of household expenditures in a population therefore implies an inequality of their carbon-energy footprints. Figures 1a-c show European households by decile of expenditure and their associated footprints for GHGs and energy in 2015. The figures show that increasing expenditure generally translated into larger footprints, but that the inequality decreased from expenditure to energy to greenhouse gas emissions with 10:10 ratios (the top decile divided by the bottom decile) of `r exp_10_10`, `r energy_10_10` and `r co2eq_10_10`, respectively. Total expenditure ranged from `r exp_bottom_decile` trn€ to `r exp_top_decile` trn€ (or `r fd_pae_bottom_decile`€ to `r fd_pae_top_decile`€ per adult equivalent) across bottom and top decile, the energy footprint from `r energy_bottom_decile` EJ to `r energy_top_decile` EJ (or `r energy_pae_bottom_decile` GJ/ae to `r energy_pae_top_decile` GJ/ae), and the GHG footprint from `r co2eq_bottom_decile` MtCO2eq to `r co2eq_top_decile` MtCO2eq (or `r co2eq_pae_bottom_decile` tCO2eq/ae to `r co2eq_pae_top_decile` tCO2eq/ae). The reason for this is evident from figures 1d-f. Both the energy intensity measured as energy use per € expenditure (d) and the carbon intensity measured as GHGs per unit of energy use (f) gradually decrease from bottom to top expenditure decile. The average energy intensity of consumption decreased from `r mean_energy_intens_bottom_decile` MJ/€ in the bottom decile to less than half (`r mean_energy_intens_top_decile` MJ/€) in the top decile. Additionally, the GHG intensity of energy use was also higher in the bottom decile (`r mean_co2eq_of_energy_intens_bottom_decile` gCO2eq/TJ) compared to the top decile (`r mean_co2eq_of_energy_intens_top_decile` gCO2eq/TJ). There is a clear trend of decreasing intensities across expenditure deciles even though the variance in the lower deciles is much higher. The GHG intensity of consumption (figure 1e) combines the effects of the intensities of 1d and 1f. [*The higher GHG intensity of energy use is likely due to a larger share of emission intensive energy carriers in the energy system. The decreasing energy intensity per expenditure is due to either inefficient energy technologies or energy subsidies in poorer areas in Europe.*]
```{r figure1, out.width="98%", fig.cap="Expenditure and resource footprints and intensities across European expenditure deciles. Total expenditures (a), energy footprint (b), and GHG footprint (c) per decile. Energy intensity as energy footprint per expenditure (d), GHG intensity as GHG footprint per expenditure (e), and GHG intensity as GHG footprint per energy footprint (f)."}
```{r figure1, out.width="98%", fig.cap="Expenditure and carbon-energy footprints and intensities across European expenditure deciles. Total expenditures (a), energy footprint (b), and GHG footprint (c) per decile. Energy intensity as energy footprint per expenditure (d), GHG intensity as GHG footprint per expenditure (e), and GHG intensity as GHG footprint per energy footprint (f)."}
Figures 1d-e show that energy and GHG intensities are particularly high in the lower four deciles, while the higher deciles do not show large differences in weighted average resource intensity. The different intensities of household consumption across European expenditure deciles can be attributed to a combination of two plausible causes: first, if the the composition of consumption baskets systematically differs according to the level of household expenditure. Second, if resource intensity within individual consumption sectors systematically differs according to the level of household expenditure.
Figures 1d-e show that energy and GHG intensities are particularly high in the lower four deciles, while the higher deciles do not show large differences in weighted average energy and GHG intensity. The different intensities of household consumption across European expenditure deciles can be attributed to a combination of two plausible causes: first, if the the composition of consumption baskets systematically differs according to the level of household expenditure. Second, if energy and GHG intensity within individual consumption sectors systematically differs according to the level of household expenditure.
```{r , fig.width=8, fig.height=2}
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@@ -458,7 +458,7 @@ Our data show that both of these factors play a role \@ref(fig:figure2). Poorer
The tendency that the emission intensity for direct energy consumption decreases with increasing affluence can be observed at the global level (XXX) between countries and also applies within Europe. In some of the Eastern European countries, between 80% and 100% of the population belong to the four lowest European expenditure deciles. This compares to less than 20% of the population in the richer European countries (Scandinavia, Germany, France, Austria, the Netherlands, Belgium, the UK, and Ireland). Note here that our analysis is based on average expenditure data from five income groups at the national level. This aggregation cuts off the lower and upper ends of the respective national expenditure distributions (Supplementary Note and Map).
The high resource intensities in the bottom four European expenditure deciles can be attributed in large part to inefficient domestic energy supplies for heating and electricity generation in Poland, Bulgaria, the Czech Republic, and Romania. Poland alone was responsible for about 40% of total coal combustion for heat production in Europe in 2015 and had a higher average GHG intensity per MJ of heat delivered than both Europe and the world (XXX). These differences in specific energy and emissions intensities in basic services sectors (especially shelter) account for the smaller inequality between expenditure deciles in terms of resource footprints compared to raw expenditures [*do we need to mention subsidies also?*].
The high intensities in the bottom four European expenditure deciles can be attributed in large part to inefficient domestic energy supplies for heating and electricity generation in Poland, Bulgaria, the Czech Republic, and Romania. Poland alone was responsible for about 40% of total coal combustion for heat production in Europe in 2015 and had a higher average GHG intensity per MJ of heat delivered than both Europe and the world (XXX). These differences in specific energy and GHG intensities in basic services sectors (especially shelter) account for the smaller inequality between expenditure deciles in terms of carbon-energy footprints compared to raw expenditures [*do we need to mention subsidies also?*].
*The consumption basket aspect has been extensively studied and mostly found to be intuitively true. This is a line of inquiry we do not currently pursue but I just remembered the analysis we did on this which is actually quite interesting: This common sense knowledge could be challenged because it is true mostly in western countries with high demand for heating and cooling and mobility both mostly fossil based and subsidized. In this case, necessities especially shelter (maybe and car based mobility (accessible to most)) have a higher intensity compared to "luxury spending" ie the average intensity of the international supply chain for manufactured goods etc.. It is not true in rich countries with high renewable energy shares (e.g. Norway) where the domestic energy system is more resource efficient than the international supply chain. It is possibly also not true in countries with low heating/cooling demand. We may want to check if that flips after applying the best technology transformation.*
In absolute terms, the various final consumption sectors contribute very differently to the total resource footprint of households (Figure 3). On average, shelter and transport are the two largest sectors, accounting for nearly two thirds of both resource footprints. However, there are big differences between the sectors when looking at the respective contributions in the expenditure quantiles. For shelter there is almost no difference (neither in GHG nor in energy footprint). Especially the lower four expenditure deciles have high GHG emissions, which can be explained by the extreme differences in resource intensity shown in Figure 2. Transport was the most unequal sector, with resource footprints `r transport_energy_10_10` times higher in the top decile compared to the bottom deciles (corroborating findings in [@ivanova_quantifying_2020] and [@oswald_large_2020]). Manufactured goods was the second most unequal consumption category (10:10 ratios around `r man_goods_energy_10_10` for both footprints), followed by services (10:10 ratios of `r services_co2eq_10_10` for GHGs and `r services_energy_10_10` for energy) and then food (10:10 ratios of `r food_energy_10_10` for both footprints).
In absolute terms, the various final consumption sectors contribute very differently to the total carbon-energy footprint of households (Figure 3). On average, shelter and transport are the two largest sectors, accounting for nearly two thirds of both footprints. However, there are big differences between the sectors when looking at the respective contributions in the expenditure quantiles. For shelter there is almost no difference (neither in GHG nor in energy footprint). Especially the lower four expenditure deciles have high GHG emissions, which can be explained by the extreme differences in intensity shown in Figure 2. Transport was the most unequal sector, with footprints `r transport_energy_10_10` times higher in the top decile compared to the bottom deciles (corroborating findings in [@ivanova_quantifying_2020] and [@oswald_large_2020]). Manufactured goods was the second most unequal consumption category (10:10 ratios around `r man_goods_energy_10_10` for both footprints), followed by services (10:10 ratios of `r services_co2eq_10_10` for GHGs and `r services_energy_10_10` for energy) and then food (10:10 ratios of `r food_energy_10_10` for both footprints).
```{r figure3, out.width="100%", fig.cap="Energy and GHG footprints by final demand sector and European expenditure decile in 2015 further broken down by emission source location."}
