1. Introduction
Making changes to lifestyle and consumption patterns to reduce greenhouse gas (GHG) emissions plays a critical role in climate change mitigation [
1,
2,
3]. Affluence has been strongly correlated with higher carbon footprints [
4,
5,
6], and within high-income nations, the average carbon footprint has been estimated to be up to seven times the climate-sustainable limit [
7]. Studies have estimated consumption-based carbon footprints in the Nordic countries to be within a range of 8.7–18 tCO
2e per capita [
8,
9,
10]. To be in line with the 1.5 °C limits of the Paris Agreement, personal consumption-based carbon footprints would need to be limited to 2.5 tCO
2e by 2030 and 0.7 tCO
2e by 2050 [
11]. Individuals residing in affluent European countries, like the Nordics, are more likely to have individual perceived climate responsibility [
12], and high climate concern has been linked with lower consumption-based carbon footprints [
13,
14]. Affluence, however, has not been significantly associated with taking individual climate action [
15].
There is great potential to reduce emissions through demand-side mitigation measures since household consumption is responsible for between 60–72% of global emissions [
8,
9]. The consumption changes that have the highest mitigation potential include making changes in the areas of transportation, diet, and housing [
8,
9,
16], which includes actions like avoiding air travel, living car-free, and having a plant-based diet [
17,
18]. For example, studies of the potential of pro-climate actions to reduce CBCFs have found a range of reduction potential from actions including 0.2–1.5 tCO
2e for having a vegan or vegetarian diet [
17,
19,
20,
21,
22], 0.1–1.5 tCO
2e for reducing air travel [
17,
19,
20,
22], 0.08–1.7 tCO
2e for reducing home energy [
21,
23], and 0.5–2.3 tCO
2e for living car-free [
17,
19,
22]. The ranges of the reduction potentials of pro-climate actions can be significantly affected by factors such as geographical location, energy mixes, and the methodology used to estimate the reduction potential [
17]. Studies have suggested that for carbon footprints to be at 1.5-degree-compatible levels, those in affluent countries will need to have a high adoption rate of multiple pro-climate actions [
17,
22].
To study the impact of different individual mitigation actions, consumption-based carbon footprints are a useful tool since they include the emissions embodied in trade, which can better capture the emissions associated with people’s lifestyles [
24,
25,
26,
27] and can help analyze how effective different mitigation interventions might be [
11,
21]. It is important to look at the whole footprint to see how lifestyle changes interact [
28] since absolute reduction and sufficiency actions run the risk of rebounds [
29], and there can be negative and positive spillover effects from taking different climate actions. [
30]. Sociodemographic factors can have an impact on carbon footprint, and studies have found that affluence and having a higher income are strongly correlated with higher carbon footprints [
5,
6,
31]. A larger household size has been associated with lower carbon footprints due to economies of scale [
32,
33]. Living in an urban area can lead to less emissions from energy use and transportation; however, studies have found that these emissions savings can be outweighed by the consumption patterns found in more urban areas [
34,
35]. Age, gender, and education levels have often been shown to have small and mixed effects on carbon footprint [
31].
Individuals can be driven to take action to mitigate climate change through their consumption choices by their attitudes toward climate change [
36,
37,
38]. However, individuals with a high climate concern do not always make choices that align with their pro-climate attitudes, which has been described as the attitude–behavior gap or value–action gap [
39]. For example, air travel is a high-emission activity that many people are not willing to give up even though they have high levels of climate awareness [
40,
41]. Often, people are more willing to engage in low-impact pro-climate actions, which result in low emission reductions [
41,
42], even if they have a high level of environmental concern and the intent to act in an environmentally friendly way [
43]. This is due to high-impact pro-climate actions being more difficult because of cost and other contextual and demographic variables [
44]. Motivational factors are just part of understanding people’s behaviors in regard to taking climate action [
45,
46], since individuals’ actions and decisions are also influenced by economic, political, technological, and societal factors [
47,
48] and can be hindered by behavioral or technical lock-in [
11]. Understanding the motivation behind making particular climate-friendly choices is key to seeing the potential of these actions and to understanding why some people are taking these actions and some are not [
49].
Some researchers have considered both the attitudes and the impact of pro-climate actions by examining the relationship between climate concern or other pro-environmental attitudes and consumption-based carbon footprints. A survey of Swedish households found that income was the most important explanatory variable of GHG emissions followed by dwelling type and geographic distance to work and other services, and that social norms around GHG-intensive activities may have a larger impact on emissions than pro-environmental attitudes [
50]. Another Swedish study found that that survey participants with strong pro-environmental norms who had engaged in four different low-carbon lifestyle options were associated with net GHG emission reductions between 0.5–1.5 tCO
2e/cap with little to no rebound effects [
19]. A study of Danish individuals showed that those with high carbon footprints were less willing to engage with voluntary emission reduction measures even though they were concerned about the effects of climate change [
51]. A study of the Nordic countries found that higher climate concern was associated with lower consumption-based carbon footprints [
13]. In the Nordics, a higher perception of a climate-sustainable lifestyle was related to lower carbon footprints, except for those with the highest perceptions [
52]. Another study in the Nordic countries found that climate concern and climate conscious behaviors were highest in urban areas where the everyday carbon footprint was found to be lower than less urbanized areas, but that the leisure travel footprints were found to be higher [
53]. A study of Chinese households found that income was a major factor in GHG emissions, and the perceived seriousness of environmental problems affected the environmental behaviors of high-income households more than those of low-income households [
54].
Although researchers have explored pro-climate attitudes and actions generally, this study will add to this body of literature by looking at the motivation to reduce one’s carbon footprint (climate motivation) regarding specific pro-climate actions to see the effect that this has on CBCFs. We also consider the engagement rates in this sample and the CBCFs as they relate to the 1.5-degree targets. The Nordic countries provide an interesting context for the study. They are highly affluent and have high CBCFs, and these are the countries where emissions need to be reduced the most. The Nordics are often seen as leaders on climate issues [
55] and a high climate concern can be found there [
12], yet CBCFs are still above the 1.5-degree limit. They are also welfare states, which provide economic security for their residents and have some of the lowest income inequality in the world [
55], which provides the opportunity to identify 1.5-degree-compatible lifestyles with a high standard of wellbeing. We use unique data from a carbon footprint calculator survey conducted in the Nordic countries with ~8000 respondents covering households with ~17,000 members, and which includes questions on the level of engagement in various pro-climate actions and whether the choice to participate in these actions was motivated by climate concern. We then study the direct impact of engaging in the actions on the overall carbon footprint, taking into account the potential rebound effects. The research questions that we will address include the following:
How is the level of engagement in pro-climate actions related to the total carbon footprint?
How significant of a driver is an individual’s motivation to engage in a pro-climate action?
How does the level of climate motivation affect the impact of engagement in the different pro-climate actions?
Who are those who engage in pro-climate actions?
2. Materials and Methods
This section first describes the data used for this study and then the statistical methods utilized for the analysis.
2.1. Survey
The survey was conducted between the fall of 2021 and the spring of 2022 and received around 15,000 responses, of which ~8000 were full responses. The online survey was distributed through social media, and an online marketing service was used. Respondents also had the option to share their carbon footprint calculations online with others, which may have influenced others in their social networks to take the survey as well. Additional participants may have been recruited by news media, which reported on the survey. The only requirement to participate in the survey was to be a resident of one of the Nordic countries of Denmark, Finland, Iceland, Norway, or Sweden and to be an adult who takes part in household finances. The survey’s aim was to obtain many high-quality responses covering a wide variety of lifestyles in the Nordics, not to be a representative sample of the general population. The survey was designed to collect data on the participants’ consumption over the past year to calculate their consumption-based carbon footprint as well as to gather information on their level of climate concern, engagement in pro-climate actions, motivation to reduce their carbon footprint, self-reported wellbeing, and other sociodemographic variables. Duplicate responses to the survey were erased and the top and bottom 0.5% of carbon footprints were removed to account for the under- or over-reporting of consumption by respondents. The data set is publicly available on an open-source data repository [
56]. All of the survey respondents consented to participating in the study.
Table 1 shows demographic information about the sample.
2.2. Consumption-Based Carbon Footprint Calculations
The consumption-based carbon footprints were calculated through a hybrid method, which included both physical quantity information and process emissions with an input–output analysis [
57]. The footprints were calculated as personal consumption footprints where the emissions from consumption were allocated to the end user regardless of where the goods or services were produced [
58]. Governmental spending and capital formation were left out of the calculation to focus on the impact of personal consumption. The footprints were divided into eight domains, which included diet, housing, vehicles, public transport, leisure travel, goods and services, pets, and second homes. Only the goods and services domain was estimated using an input–output approach derived from the Exiobase multiregional input–output model [
59], and the rest of the domains used physical quantities and process emissions. The sections below provide the key information used to calculate the consumption-based carbon footprints for this study.
2.2.1. Diet
The survey asked respondents to report their diet type, and the options included vegan, vegetarian, pescatarian, or omnivore with four choices of different meat intake options ranging from 50 to 300 g per day. The GHG emissions from each diet type were taken from [
60], with the vegan or vegetarian diet having the lowest emissions of 1132 KgCO
2e/year and the omnivore diet with the highest meat intake (300 g/day) having the highest emissions of 3213 KgCO
2e/year.
2.2.2. Housing
To determine the emissions from housing energy, respondents were asked about their type of housing (apartment, detached house, etc.), size, decade of construction (to determine the average energy efficiency), and the heating and electricity sources for the home. The emission factors used to estimate the GHG emissions were taken from the lifecycle GHG values from [
61] and from each county’s official statistics for their energy and electricity mixes. Finally, the emissions from housing were divided by the number of people living in the household.
2.2.3. Vehicles
Survey participants were asked to share the type, fuel used, fuel efficiency, and annual kilometers traveled by each of the vehicles owned by their household. The lifecycle GHG emissions were derived from values from [
61] and included petrol (3.003 kgCO
2e/L), diesel (3.189 kgCO
2e/L), natural gas (3.761 kgCO
2e/L), bioethanol (1.003 kgCO
2e/L), biodiesel (1.732 kgCO
2e/L), and biogas (1.382 kgCO
2e/L). The emissions from electric vehicles were estimated by using an assumed efficiency of 0.0125 MWh/100 km along with each country’s electricity mix, and the annual kilometers driven. The emissions from the production and maintenance of each vehicle were calculated using the average values from [
62], which were divided by the assumed vehicle lifetime (184,000 km) [
62] and then multiplied by the reported distance driven by each vehicle. The overall estimated vehicle emissions were divided by the number of people in the household.
2.2.4. Public Transport
The emissions from public transport use were estimated by using the average intensity of 0.12 kgCO
2eq per passenger kilometer traveled, which was derived from the average direct emissions from public transportation methods (bus, train, etc.) based on values from [
63], and indirect values from vehicles, infrastructure, fuel production, and supply chain based on values from [
64].
2.2.5. Leisure Travel
Participants were asked to report the number of short (<1000 km), medium (<3000), and long (>3000 km) leisure trips that they had taken over the past year by car, plane, train, bus, and ferry. The emissions factors were based on values from [
63,
65] for the direct emissions and from [
64] for the indirect component.
2.2.6. Goods and Services
Respondents were asked to estimate their spending in several categories following the Classification of Individual Consumption According to Purpose (COICOP) [
66]: alcohol and cigarettes, clothing and footwear, interior design and housekeeping, health, recreation sports and culture, restaurants, hotels, electronics, and other goods and services. The categories were used in conjunction with the Exiobase IO model [
59] and followed the concordance matrix from [
29].
2.2.7. Pets
Survey respondents were asked to share the number of pets in the household including dogs, cats, and other pets. Yearly emissions per dog were taken as 630 kgCO
2e based on [
67] and 315 kgCO
2e per cat based on [
68]. Other pets were not included. The total emissions calculated for pets were divided by the number of people in the household.
2.2.8. Second Home(s)
The yearly emissions attributed to owning a second home were assumed to be 884 KgCO
2e which was derived from [
69] and divided by the number of people in the household.
2.3. Level of Engagement in Pro-Climate Actions and Climate Motivation
Participants were asked questions regarding their level of engagement with a selection of pro-climate actions followed by a question asking them whether they perform this action to reduce their carbon footprint. Both questions were asked on a scale of 1 to 5 (1—not at all, 2—very little, 3—somewhat, 4—to a great extent, 5—completely). The actions relate to the domains in the consumption-based carbon footprints of diet, housing, leisure travel, and goods and services. The actions cover individual actions that have been studied in the literature as having the potential to reduce emissions [
17,
21,
70].
Table 2 lists the questions from the survey used in this analysis regarding the level of engagement with pro-climate actions and climate motivation.
2.4. Analysis
The statistical methods utilized in this study include Spearman’s rank correlation, bivariate, structural equation modeling, and regression analysis. Spearman’s rank correlation was used to examine the strength of the relationship between the level of engagement in each pro-climate action and the level of climate motivation to perform each action. Categorical regression was used to confirm this relationship while controlling for sociodemographic variables and to determine those who are likely to engage in pro-climate actions. Bivariate analysis, multivariate regression, and structural equation modeling (SEM) were utilized to examine the relationship between the level of engagement in pro-climate actions and carbon footprint and to study whether climate motivation to engage affects this relationship.
Because of the categorical nature of our data, categorical regression (CATREG) was used to examine the relationship of the engagement level in pro-climate actions and climate motivation while controlling for sociodemographic variables. CATREG can address the limitations of traditional regression techniques for data that are categorical. Traditional regression techniques frequently presuppose that variables adhere to rigid assumptions like linearity, homoscedasticity, or the normality of residuals. CATREG differs from traditional regression methods in that it makes no assumptions about the precise distribution of the variables and can yield more relevant findings when the relationships between variables are non-linear or more complex. As a result, nominal, ordinal, and continuous variables may all be analyzed in a single model. This method’s use of optimum scaling, which alters the variables to enhance the fit of the regression model, is a crucial component. As a result, the altered variables allow for linear regression analysis, which can better represent data connections than other techniques.
To study the impact of climate motivation on the level of engagement in pro-climate actions, regressions models were run for each of the pro-climate actions with the level of engagement as the dependent variable along with the independent variables of income, household size, degree of urbanization, age, gender, level of education, and country, since these have been found to have an impact on carbon footprint [
31,
33,
34], and income especially has been found to have more of an impact than environmental attitudes [
54,
71]. The climate motivation variable was added to the second model (1a–8a). The description of the independent variables can be seen in
Table 1.
Multivariate regression was conducted to simultaneously consider the impact of all pro-climate actions, climate motivations, and demographic variables on carbon footprint. Unlike the pairwise analyses, this approach allows for a more holistic understanding of the relative importance of different factors in explaining the variance in carbon footprint. It provides insights into which actions and factors have the strongest associations with carbon footprint when controlling for other variables.
SEM was chosen for its ability to model complex relationships among variables, including direct and indirect effects. This method allows for testing a theoretical model that links climate motivation, pro-climate actions, and carbon footprint, while simultaneously accounting for measurement errors and latent constructs identified in the factor analysis. SEM provides a comprehensive framework for understanding the interplay between motivation, actions, and carbon footprint.
4. Discussion
This study aimed to see the how the level of engagement in pro-climate actions relates to CBCFs, how significant of a driver is an individual’s motivation to engage in a pro-climate action, how the level of climate motivation affects the impact of engagement in various pro-climate actions, and who is engaging in pro-climate actions. The main results show that a higher engagement in pro-climate actions was associated with lower carbon footprints. Climate motivation and the level of engagement were highly correlated with the actions of avoiding meat and trying not to fly, which were also associated with the lowest carbon footprints. The highest engagement was seen in pro-climate actions that had less impact on carbon footprint. Sociodemographic variables were mostly weak predictors of engagement in pro-climate actions, and climate motivation often had a stronger effect. The motivation to take one climate action was often highly correlated with the motivation to take other actions, but the engagement in climate actions did not show this same relationship. Even though both high engagement and high climate motivation were related to lower carbon footprints, the footprints were still above 1.5-degree-compatible levels.
Some of the actions in which respondents participated the most primarily included maximizing the lifetime of products (85%), avoiding food waste (78%), and avoiding buying (66%). These actions correlated less with climate motivation and had a lower impact on carbon footprint than the actions that had lower engagement rates. These behaviors can be classified as frugal behaviors, which have been associated with lower carbon footprints for everyday consumption and in leisure travel [
45]; however, there can be a potential for the rebound effect with these actions [
53]. Compared to the high-impact lifestyle change to a vegan or vegetarian diet (0.5–0.9 tCO
2e) or taking less flights (0.8 tCO
2e), these actions have a lower reduction potential for the personal carbon footprint [
19]. Food waste reduction on the household side may mitigate an average of 0.3 tCO
2e per capita, and purchasing fewer items and more durable items may mitigate an average of 0.1 tCO
2e [
17]. People are often more willing to take low-impact actions [
33] that do not require much sacrifice and are less likely to make more significant changes such as changes to diet [
32] or leisure travel [
40,
72]. Avoiding meat was one of the actions that was the least participated in; however, the correlation between engagement in the action and the climate motivation to do so was strong. The behavior of eating less meat has not been widely adopted in the Nordic countries; however, the willingness to eat less meat is slowly increasing [
73,
74,
75]. Some studies have shown a strong link between reducing meat consumption and environmental concerns [
54,
55], while other studies have found a weaker connection [
56] and that stronger predictors of engagement include habit [
57], social norms [
58], or health reasons [
59]. A study of German individuals found that higher climate knowledge only led to lower carbon footprints in the diet domain and not in terms of the aggregate carbon footprint [
14]. Similar to a study in Norway, we found that it was younger, urban, female consumers who were more likely to consume less meat [
59]. Although sociodemographic variables are weak predictors of participation, they can reveal lifestyle types who might be more likely to adopt different actions or lifestyles.
Avoiding air travel, taking less flights, or changing leisure travel modes to less carbon-intensive modes has a high mitigation potential [
17,
18,
53,
60]. In wealthy countries like the Nordic countries, a high level of emissions can be attributed to air travel [
61]. The pro-climate action of trying not to fly was highly correlated with climate motivation, meaning that the more people trying to avoid flying, the more they are doing it to lower their carbon footprint rather than for other reasons. Recently there has been an increased awareness of the impact of air travel in society [
63], although people are often unwilling to give up flying even if they have high climate awareness [
40,
72]. Higher emissions from long-distance leisure travel are often associated with living in more urban areas [
61,
64], and studies in Norway and Iceland have found that air travel is a habituated part of life that is supported by social norms, living in an urban environment, and that individuals’ desire to reduce flying for climate reasons only has a small and indirect effect [
64,
65]. Also, being an island nation, respondents in Iceland do not have access to low-carbon leisure transportations to travel abroad such as the trains that are available in the other Nordic countries.
Climate motivation had the highest correlation coefficients with some of the changes that people might be less willing to make such as reducing their air travel or having a vegan or vegetarian diet, indicating that those who engage in these high-impact mitigating behaviors are also highly motivated to mitigate climate change. This is also an interesting finding since individuals do not often understand the impact of their actions and overestimate the impact of low-impact actions on carbon footprint [
42]. However, the level of engagement was low for avoiding meat and moderate for trying not to fly. The climate motivation for one pro-climate action often had higher correlation coefficients with the climate motivation for other pro-climate actions, which could indicate a potential positive spillover effect [
26] and that people concerned about climate change are willing to take multiple individual mitigation actions. This could also be seen in the domain of carbon footprint since they generally decreased with more engagement in each of the pro-climate actions and increased in the domain of public transport, which is a low-carbon alternative to fossil fuel vehicles [
17]. However, the engagement in pro-climate actions had lower correlation coefficients with each other. The SEM and factor analysis results showed these relationships as well. The pro-climate actions that were grouped together in the ACM group consisted of the actions that had a higher impact on carbon footprint and a higher correlation with climate motivation but included actions with less participation than those in the RC group, which consisted of actions with less impact on carbon footprint and less correlation with climate motivation. This relationship could be because of the value–action gap [
39], or due to the unique nature of these actions, it may be easier or more desirable to engage in some rather than others because of the social, economic, and physical factors that individuals exist within. For example, an individual may be motivated to reduce their home energy use, but they may be limited in doing so because of their housing situation (i.e., renting vs. owning), or because of social norms and the culture surrounding food, individuals may be more likely to conform to the predominant diet rather than make significant diet changes [
76]. Due to the complex interplay of motivational and contextual factors, more research is needed to see what barriers individuals are facing to taking certain pro-climate actions.
4.1. Uncertainties and Limitations
Some uncertainties and limitations to the data collection and analysis of the study have been identified. Individuals who are concerned about climate issues may have been more inclined to participate in the survey, which may have led to a higher representation of people who are motivated to reduce their carbon footprints; however, there were a number of respondents who also had low climate concern and motivation. Respondents self-reported their consumption and engagement levels in pro-climate actions, so they could have been over- or under-reporting their actions. However, the footprints in general are fairly well in line with those found in previous studies. The answer scale for the pro-climate actions and climate motivation was a simple five-point scale, which could have been interpreted differently by different respondents and may not have been nuanced enough to reflect their actual engagement or motivation level. The survey was conducted during the COVID-19 pandemic, which could have influenced people’s lifestyle and consumption patterns, particularly in the domain of leisure travel, so the engagement in trying not to fly might have been at a higher level than is typical for the respondents.
This survey was conducted within the Nordic countries, which may affect the generalization of these results to other populations. The Nordic countries are highly affluent and have high carbon footprints, so like many other high-income countries, there are numerous high-impact actions to engage in with high reduction potential (500–1500 kgCO
2e/person/yr) [
11]. However, in low- and middle-income countries, a different approach to living 1.5-degree-compatible lifestyles may be necessary since the majority of reduction options will have a lower impact (less than 250 kgCO
2e/person/yr) and many people in low-income countries will need to consume more in order to reach basic wellbeing standards [
11]. The carbon intensity of goods and services and the consumption habits of the residents of the Nordics may differ from those in other climates with different environmental conditions. For example, the colder climate limits the variety and growing season of foods that can be locally grown, harsh winters can make active transport modes unattractive or inaccessible for those with limited mobility, and the dark, cold winters may motivate people to fly abroad more often to warmer destinations. The Nordic countries have a highly decarbonized energy system, so pro-climate actions like reducing home energy have more potential to have a larger impact on carbon footprint than as seen in this study. Diets in affluent countries, such as the Nordics, often consist of more animal products such as dairy and meat, which contribute more emissions to CBCFs than plant-based diets, so countries with predominantly vegetarian diets will need to focus on other pro-climate actions to achieve reductions [
11]. In addition to geographical and cultural differences, the colder base climate in the Nordic countries may reduce residents’ sense of urgency to mitigate climate change, which in turn could lower engagement in pro-climate actions [
40].
In the analysis, it is also difficult to isolate the effect of each pro-climate action. If people are motivated by climate concern, then they may be participating in multiple actions that would lead to lower emissions than those who are not, which can be seen in the results that the climate motivation to engage in the various pro-climate actions were highly correlated. This is also the trend seen in most of the domains of carbon footprint in terms of decreasing emissions, with higher engagement levels in actions that do not impact these domains. Although the respondents could rank how much of their motivation was due to wanting to reduce their carbon footprint, it is unknown what other motivations they might also have to take these actions and whether they are stronger drivers than climate motivation. There are uncertainties in the methods and data used to calculate the carbon footprints, including the values used from the literature and the Exiobase model used.
4.2. Policy Recommendations
Policy instruments should consider that climate-compatible lifestyles must be facilitated by institutions, governments, infrastructure, and social norms [
11,
66], and an individual’s consumption cannot be separated from the physical, economic, and social structures that they exist within [
40]. Policies must remove barriers to climate-compatible living [
67]. For example, to encourage reducing meat consumption, policies must address the perception that meat is the cheapest, easiest, and most appropriate food to eat through changes in social, physical, and economic structures [
58]. The motivation to engage in pro-climate actions can be complicated and requires further research. For instance, given the complexity of the drivers of air travel, voluntary change may be difficult, and policies that promote multi-stakeholder action may be more successful rather than isolated initiatives, which are less effective [
68]. Policies focusing on knowledge alone will probably not be effective on their own and instead need to encourage individuals to actively engage with climate issues [
14] and understand what actions they can personally take to mitigate climate change [
69].