To achieve the climate targets of the Paris Climate Agreement and make the transition to a low-carbon economy politically acceptable, it is crucial to consider the links between climate policy and the broader socioeconomic context. One essential aspect of climate change is that it is related to other problems, such as economic inequality. In recent years, the concept of carbon inequality has gained prominence in many countries. It mainly refers to the unequal responsibility of individuals in generating greenhouse gas emissions, though it may also be used to highlight other inequalities, such as those related to opportunities to engage in low-carbon solutions or those related to vulnerability to climate change impacts.

Here we focus on the unequal distribution of individual emissions, which tend to be driven by underlying economic differences. Furthermore, income and wealth usually increase with age, meaning that it is particularly older people who have high carbon footprints. 

So far, there has been relatively little public debate about carbon inequality in Spain. This article discusses some data relating to individual carbon footprints in Spain and how the latter vary according to income and age.

Let us start by examining the personal carbon footprint. To do this, we use publicly available data from the World Inequality Database for Spain (WID, 2022). We can see that the average carbon footprint for the last available year (2020) is about 7 tons of carbon dioxide equivalents (CO_2e). The individual footprint presented here includes emissions from both consuming goods and investment-based emissions, which attribute the emissions of a business to the individuals who own it. If we considered goods consumption only, the average footprint would be around 5 tons of CO_2e.

We continue by zooming in on the extremes of carbon footprint distribution (figure 2). The bottom 10% and 50% of emitters have a carbon footprint of around 2 and 4 tons of CO2e, respectively. In contrast, the top 10% have a value of around 18 tons of CO_2e, while the top 1% have a carbon footprint of 53 tons of CO_2e. This shows an asymmetrical distribution of individual carbon footprints across society. When we consider the total of individual emitters, we see that the top 10% of emitters are responsible for more than 25% of all emissions (figure 3).

One of the key assumptions underlying the WID estimations is that emissions grow as income and wealth increase. This is based on a great deal of evidence showing this clear relationship. For example, one study finds that millionaires have individual carbon footprints of more than a hundred tons of CO_2e (Otto et al., 2020). The reason for this may be obvious: people’s economic capacity is associated with highly mobile lifestyles (including many long-distance flights), use and ownership of above-average-sized house(s), etc. Moreover, when one goes beyond consumption-based emissions, activities such as investments in fossil fuel companies are taken into account, which adds to the footprint score.

Let us give these figures a little more perspective: if Spain wants to meet its emission-reduction targets for 2030 (a 29% decrease in emissions compared to 2019), the average footprint will have to be 5.4 tons of CO_2e. Approximately 40% of the Spanish population already emits less than this target. In contrast, the top 1% of emitters would have to reduce their footprint by a remarkable 92% over the next few years to reach the target.

As noted previously, carbon inequality is strongly linked to income and wealth. As people age, their income and wealth tend to increase. People over 65 earn about 20% more than the average Spanish income (INE, 2021). The differences in wealth across age groups are even starker. According to the Spanish Survey of Household Finances by the Bank of Spain (2022), households below the age of 35 had median wealth of slightly above 20,000 euros in 2020. For households in the 65-74 age group, median wealth was estimated to be nearly 200,000 euros. 

What about carbon footprint differences? For this, we draw on data collected and estimated by Zheng et al. (2022). It should be noted that this study covers consumption emissions and excludes emissions from investments. For this and other minor methodological reasons, the values from this source and the one presented in the previous section are not directly comparable, but still useful. As shown in figure 4, Spanish people below the age of 30 are estimated to have an average carbon footprint of 6.1 tons of CO_2e, while those over 60 have a carbon footprint of 6.5 tons. In other words, older people have slightly higher footprints, though differences are considerably less pronounced when compared to the differences based on wealth and income. In fact, age differences in carbon footprints in Spain are among the lowest compared to other rich countries. 

The reasons behind the (relatively small) footprint differences are unclear. Older people tend to possess more wealth, sometimes in the form of poorly insulated houses, resulting in higher needs for heating. At least part of the higher emissions may be explained by more resources and time to travel, and a more carbon-intensive diet. The small differences between younger and older people may be due to aspects related to the way carbon footprints are calculated, notably the exclusion of non-consumption sources of emissions (e.g., investments). 

This article has drawn attention to the differences in carbon inequality in Spain. We have shown that the carbon footprints of the top 1% of emitters may be up to 7 times higher than the average person’s footprint. In contrast, while older people tend to have higher footprints than younger people, these differences are small. Income and wealth differences are the main drivers of footprint differences. 

Focusing on individual footprints across income and age does not mean that policy action should overlook the systemic drivers of carbon emissions, such as energy generation, industrial production, etc. However, it does suggest that climate policy directed at households may need to be more targeted. In other words, it is unclear how to distribute efforts to reduce carbon emissions, and how people with the highest carbon footprints will be able to drastically reduce their carbon emissions in the coming years. Therefore, economic or regulatory policies may be needed to directly address such emissions. 

Another question is how such carbon inequality affects the social acceptance of climate actions targeting the average citizen. For example, young people or those with a lower carbon footprint may find it unfair to be pushed to reduce their own emissions when high polluters are contributing considerably more to the problem of climate change. 

In terms of concrete policy action, because of the problems identified here, it is possible that reducing carbon inequality will require the implementing of a wealth tax reform that focuses more strongly on the carbon content of assets. To address the ageing population, stronger subsidies could be provided to help older people to renovate their houses, while more low-carbon mobility could be promoted for younger people. Moreover, removing certain fossil fuel subsidies, such as those for holiday air travel – one of the most climate-damaging activities – could also be justified from a climate change perspective. These are all novel policy proposals, and it is unclear to what extent young and old people would support them or indeed how concerned they are about carbon inequalities in general.

BANK OF SPAIN (2022): Spanish Survey of Household Finances. [Last checked: 16.11.2022]

Instituto Nacional de Estadística (INE) (2021). [Last checked: 07.12.2022]

OTTO, I. M., K. M. KIM and N. DUBROVSKY et al. (2019): «Shift the focus from the super-poor to the super-rich», Nature Climate Change, 9(2), pp. 82-84.

World Inequality Database (WID) (2022). [Last checked: 01.12.2022]

ZHENG, H., Y. LONG, R. WOOD et al. (2022): «Ageing society in developed countries challenges carbon mitigation», Nature Climate Change, 12(3), 241-248.