2.1.1. IPAT

The IPAT equation [12] takes a top-down view to understanding which driving forces have the largest impact on greenhouse gas emissions. Population, wealth, and technology are the three compounding factors:

Impact (kgCO2-eq) = Population (cap) × Affluence (\$/cap) × Technology (kgCO2-eq/\$)

Population, economic growth, and technology each contribute to greenhouse gas emissions, and conversely, strategies to reduce emissions can—at the macro level—focus on one of the variables.

Technology change, such as renewable energy replacing fossil-fuel based energy, is most often the central and dominating approach of climate change mitigation plans. Many countries, particularly but not exclusively developing countries, set reduced carbon intensity (kgCO2-eq/\$) as their climate mitigation goal, rather than absolute reduction. Studies using this framework have shown that technology change aimed at decarbonizing our economy has resulted in large and steady reductions in absolute growth of carbon emissions [6,13]. It should also be noted here that studies have pointed out that 'technology' measured by production-based carbon intensity can reduce emissions in a country due to outsourcing of carbon-intensive sectors, and hence is different to consumption-based carbon intensity which includes full supply chains [7].

The same studies have shown that economic growth, or affluence measured in \$/cap, overtakes reductions from technology and results in absolute increases in greenhouse gas emissions [6,9,14,15]. For example, Hubacek et al. show that in China, affluence drove increases in emissions by 136%, 85%, and 154% in 1979–1988, 1989–1998, and 1999–2008 respectively. In those same periods, technologies reduced carbon emissions by 44%, 29%, and 30%. Population only increases emissions by between 6–14% in each of those periods [6]. Other studies map out global trends. Lan et al. show that while energy efficiency has reduced energy use by 550 EJ between 1990 and 2010, but this was offset by changes in the production recipe, which added 40 EJ, and eclipsed by increases in energy demand driven by affluence (528 EJ) and final demand composition (56 EJ) [13]. Far reaching changes to the 'affluence' part of the equation are now considered essential to complement technological change if we are to transition to sustainability, as overconsumption by affluent consumers is the overwhelming driver of global environmental impacts [8]. Climate mitigation goals and strategies aiming at the affluence dynamics are less common, particularly in NDCs. This is despite the rise in calls for degrowth or a steady state economy [8,16].

Population does not change as dramatically as technology or affluence, and thus has moderate impacts on climate change, although there are geographic variations. It is generally not featured in climate change policy, likely due to the human rights challenges associated with population control and the economic challenges of an aging population.

In reviewing policy, 'affluence' options are most relevant to sustainable lifestyles, and would steer choices that reduce the overall volume of consumption or shift expenditures to lower impact sectors. Examples of reducing volume include downsizing housing or reducing food waste (as long as this reduces the amount of food purchased, not overeating to avoid food waste). Examples of shifting to lower impact sectors include moving from 100% personal vehicle use, to mixed mobility including car rental, public transport, and nonmotorized transport. Technology options would include shifts to more efficient goods and services within the same sector, such as switching to produce from low impact agriculture, or an electric vehicle, or an energy efficient fridge.

Nationally determined contributions mostly focus on the "T" in the IPAT equation, making goods and services low-carbon rather than invoking discernable change for people, and may as a result be missing opportunities to move closer to the absolute reductions set out in the Paris Agreement.

#### 2.1.2. Direct vs. Indirect Emissions (Carbon Footprints; Territorial vs. Imported; Scope 1, 2, 3)

Direct emissions refer to the physical emission of greenhouse gases, such as burning fossil fuels and releasing CO2. Indirect emissions are greenhouse gas emissions that are a consequence of an activity but occur at an upstream or downstream stage of a supply chain; for example, red meat consumption in households drives methane emissions from cows. A wide range of terminology exists to describe sub-classifications of direct and indirect emissions [17], such as production- vs. consumption-based accounting, carbon footprints, Scope 1, 2, or 3 emissions, and territorial vs. extraterritorial emissions. Direct emissions are associated with territorial, Scope 1, production-based accounting, whereas indirect emissions are associated with Scope 2 and 3, extraterritorial, consumption-based accounting, and carbon footprints.

The GHG Protocol [18] classifies direct emissions as Scope 1. Indirect emissions can be classified into Scope 2 and Scope 3 emissions. Scope 2 emissions include emissions from purchased electricity, steam, heating or cooling, and occur very close in the supply chain from a specified activity. Scope 3 emissions are all other indirect emissions, both upstream and downstream in the supply chain that are not included in Scope 2. In the case of consuming milk, for example, there would be no Scope 1 emissions, Scope 2 emissions would include the share of electricity needed to power the fridge, and Scope 3 emissions would include the share of methane emissions from the cow, greenhouse gas emissions from any heating or cooling purchased during processing, vehicle emissions from transport, all indirect emissions from packaging, and finally emissions such as methane during waste managemen<sup>t</sup> of the portion of discarded milk and packaging.

Carbon footprints are the sum of direct and indirect emissions, though some accounting frameworks omit downstream emissions.

Another classification distinguishes between territorial and extraterritorial emissions. Territorial emissions are direct emissions within a given territory, whereas extraterritorial emissions are the indirect emissions of domestic activities that occur beyond national borders. When it comes to emissions reporting under the UNFCCC and its climate agreements, only territorial emissions that occur within a country's borders are counted. These include Scope 1, Scope 2, and Scope 3 emissions of consumption only as far as the supply chain is domestic.

Supply driven mitigation strategies align more closely with territorial emissions, whereas demand-side mitigation pathways are more closely associated with non-territorial emissions given the globalized nature of supply chains. In European countries, 25–30% of emissions related to lifestyles occur abroad, due to their highly globalized supply chains [19]. Therefore, including sustainable lifestyles in international or policy commitments is disincentivized as the emission reductions credited to the country are only 70–75% of what they may have achieved in reality. This is a potential area of opportunity in the near term, since reduction strategies for territorial emissions are rapidly reaching their limitations in developed countries with highly globalized supply chains [20,21], and it might be more cost effective to reduce extraterritorial emissions than further territorial emissions. Another indication of the growing importance of indirect emissions is the disproportionate growth of company level Scope 2 and 3 emissions compared to Scope 1. A recent study found that between 1995 and 2015, Scope 1 emissions had grown by 47%, whereas Scope 2 and Scope 3 emissions grew by 78% and 84%, respectively.

Addressing only direct or indirect emissions in climate policy leaves out significant opportunities to implement and achieve climate goals [22]. Once direct domestic emission reductions are achieved, neglecting to include the outsourced, indirect impacts will potentially undermine global mitigation efforts on climate change [8].

### 2.1.3. Final Demand Categories

At the meso, or sectoral, level, studies have analyzed the contribution of different sectors that contribute to climate change from two perspectives—supply and demand.

The supply side looks at the sectors where emissions directly occur, for instance in the conversion of fossil fuels to CO2. Energy and transport dominate the sectors contributing to direct emissions, with waste, forestry, and agriculture coming in on the next tier [23]. Nationally determined contributions tend to align well with these identified priorities with most outlining actions addressing energy, transport, and forestry.

A demand perspective, through indirect emission accounting, looks at the consumption categories that drive the volume of output of these sectors and hence the quantity of associated emissions. This is an important approach, because structural decomposition analyzes based on the IPAT equation have shown that changing the carbon intensity of supply while keeping demand constant or increasing will not result in the absolute reductions needed to achieve the Paris Agreement. Methodologies such as input-output analyses and life-cycle assessment enable quantification of the contributions of different demand sectors to overall greenhouse gas emissions. They also enable quantification of demandside climate mitigation measures [24]. The findings are consistent and "unambiguous", with food, mobility, and housing accounting for 70–80% of life-cycle carbon emissions [23]. On the demand side, buildings feature prominently as drivers of indirect emissions from electricity use and are also frequently included in nationally determined contributions.

### 2.1.4. Sustainable Consumption and Production, SCP 1.0, 2.0, 3.0

Sustainable consumption and production (SCP) was first adopted as an international policy goal under Agenda 21 in 1992 [25]. Ten years later, the UN adopted the 10 Year Framework Programme of Sustainable Consumption and Production, which included a task force on sustainable lifestyles and education that aimed to advance sustainable lifestyles policy and mainstreaming. In 2015, the UN adopted the Sustainable Development Goals, which included a goal on responsible consumption and production that specifically mentioned "lifestyles in harmony with nature". Worth also mentioning here is the inclusion of material footprints as an indicator for sustainable resource managemen<sup>t</sup> (target 12.2) and resource efficiency (target 8.4), showing that international policy frameworks have included extraterritorial environmental pressures in other domains.

Over this period, the conceptual framework of sustainable consumption and production broadened from an approach anchored on industry support for cleaner production and education support for sustainable lifestyles, to creating the right enabling frameworks for sustainable consumption, including policy. Hotta et al. [26] developed a classification of the evolution of the SCP policy discourse that is useful for analyzing approaches to sustainable consumption in climate policies.

SCP 1.0 refers to more nascent stages of SCP policy development, which focus largely on cleaner production and pollution prevention. The policy discourse centered on the supply side, direct emissions, with little reference to sustainable consumption or sustainable lifestyles. Although at the international level this perspective was mainstream in the 1970s and 1980s, and later evolved to include life-cycle and demand-side, it is still a dominant approach in countries at early stages of their SCP journey.

SCP 2.0 broadened the perspective of SCP to include the product life cycle in the 1990s. A few factors led to this expansion, such as increasing globalization and fracturing of supply chains, increases in the visibility of environmental impacts, and the development of life-cycle assessment and other supply chain accounting methodologies. Another factor was the maturing of ecological economic theory, which found compatibility between economic competitiveness and environmental sustainability to be possible through resource efficiency, the 'technology' component of the IPAT equation. The introduction of life-cycle assessment made the connection between emissions from the production stage to the consumption phase and started to make the case for sustainable consumption decisions.

SCP 3.0 policy approaches are society-wide, multidisciplinary, and could have significantly higher benefits than SCP 1.0 and 2.0 paradigms. They encompass concepts such as planetary boundaries and sufficiency, which are closely linked to degrowth and dematerialization. Sustainable lifestyles also emerge as a core concept, but are closely linked with creating conducive social context and infrastructure. Sustainable lifestyles policy under this framework is less about appealing to consumers directly through awareness raising campaigns, and more about using policy to change social design. Mao et al. [27] sugges<sup>t</sup> applying this broader, societal context approach to foresight analyses that can support the formulation of sustainable lifestyles policy frameworks.

### 2.1.5. Sustainable Lifestyles, Sustainable Consumption, Individual Action

This section reviews the literature that frames sustainable consumption or sustainable lifestyles in more granular or nuanced ways. Creutzig et al. [28] distinguish between demand and supply sides, with the demand side including a broad spectrum of "technology choices, consumption, behavior, lifestyles, coupled production–consumption infrastructures and systems, service provision, and associated socio-technical transitions". Moran et al. [29] consider a slightly narrower subset of "consumer options" only including low-carbon choices that are possible for consumers today without requiring governmen<sup>t</sup> or supply-side actions. The broad categories include: reduce consumption; reduce disposal; change consumption pattern/purchase alternative product; change use behavior; change disposal behavior; purchase more efficient products.

Addressing individual (or household) action directly is shown to be worthwhile. Estimates from Dubois, Sovacool et al. [30] show that households drive 72% of global greenhouse gas emissions. Other studies [31] found that seventeen actions could collectively reduce household (territorial) emissions in the US by 20%, equating to almost 2% of global emissions and more than France's total emissions. Moran, Wood et al. found that a portfolio of household actions achievable today without infrastructure investments can reduce carbon footprints by 25% in Europe [29]. Of the 6 tons CO2-eq per capita per year that is attributed to households, 1.7 tons CO2-eq per capita could be reduced from sustainable transport choices such as car-free living, 0.9 tons CO2-eq per capita from food choices including a plant-based diet, and 1.6 tons CO2-eq per capita could be reduced in housing including shifting to renewable electricity and renovating [11]. Sector-specific studies also support the shift to demand-side policies, such as food policy which has long addressed consumption patterns in order to achieve health policy goals [32] and in household electrification [33,34].

These findings make individuals key actors in reaching the 1.5-degree goal of the Paris Agreement. However, there is limited understanding and treatment of behavioral change and the relevant policies in mitigation pathways currently submitted by countries to contribute to achieving 1.5-degree ambition of the Paris Agreement. This is surprising as the Paris Agreement itself states that "*sustainable lifestyles and sustainable patterns of consumption and production, with developed country parties taking the lead, play an important role in addressing climate change*", and the IPCC's 2018 special report dedicated a chapter to behavior change strategies [1].

Numerous studies have found that citizens would accept and moreover expect governments to put in place policies that control consumption choices [35]. However, most demand-side-oriented policies use financial instruments that still largely depend on market forces to steer behavior change, crucially leave low-cost carbon-intensive options on the market, and furthermore generally target low-impact behaviors [30]. They generally neglect the most carbon-intensive consumption patterns (meat and air travel).

### 2.1.6. Environmental Kuznets Curve

A fundamental principle of the Paris Agreement is 'common but differentiated responsibility' (CBDR) with developed countries taking the lead. This principle refers to the cumulative, or historic, carbon emissions, most often higher for developed countries, which

have a higher share of the total greenhouse gas emission concentrations in the atmosphere. Based on this rationale, developing countries, or countries with low cumulative historic greenhouse gas emissions, have lower responsibility and/or economic capacity to mitigate climate change now, even if their annual emissions are high.

The environmental Kuznets curve is a hypothesis that there is an inverted U-shape relationship between economic development and environmental pollution. Countries start with small economies and small pollution levels, and both factors grow until pollution peaks, at which point economic growth continues while pollution reduces. Under this proposition, and in line with CBDR, developing countries may not include ambitious greenhouse gas mitigation goals in their NDCs. This matter is an important factor when analyzing how developing country NDCs tackle sustainable lifestyles and consumption.

Grottera, La Rovere et al. argue that developing countries have greater potential to apply demand-side mitigation strategies [36]. This is partly because developing and middle-income countries like India and China have fast-growing GDP rates, and affluence has been proven to be the driving force behind emissions. This is particularly so because, despite having emerging economy or developing country status, and low per capita GDP rates, they still are home to a large and growing absolute number of affluent consumers. For instance, there are more billionaires in China and India combined than in Europe or the US [37]. Given that affluent consumers drive environmental impacts, it is important to consider affluence in developing country NDCs where there are a large number of affluent consumers.

As countries that will grow the most, and still make decisions and policies that affect consumption patterns that are not ye<sup>t</sup> locked in, much of the mitigation potential lies with developing countries. In normal trajectories, countries may argue to follow an environmental Kuznets curve, developing first then integrating environmentally friendly practices later. However, this has been shown to be ineffectual for global environmental issues such as carbon footprints (more effective for highly local impacts like smog) [38]. As low-income consumers rapidly shift into middle- and upper-class consumption patterns, and countries that are classified as 'low-income' and ye<sup>t</sup> still are home to large numbers of high-income consumers, they will need to address the environment impacts of consumption. Particularly countries such as China and India have the opportunity for "lifestyle leapfrogging" where they skip the carbon-intensive lifestyles of the industrialized countries, but improve their quality of life [39].

This means that developing countries need to integrate climate change into their development agenda. A transition to lower carbon-intensive lifestyles is not easy due to systemic barriers: lack of existing capital, lack of awareness, upfront costs, inertia, and other priorities. Hence a proactive policy is needed at early stages of development trajectories. The dominant development approach of grow first clean up later, along a Kuznets curve, does not occur from a consumption-based perspective [38,40].

### *2.2. Framing the UNFCCC Policy Process*

The policy instrument this paper focuses on, the NDC, generally does not refer to demand-side mitigation to a large extent. In order to identify where barriers to inclusion of demand-side measures might occur, we will present and refer to the policy cycle and how it applies to the Paris Agreement. The Paris Agreement is a policy framework managed by the UNFCCC, which follows a typical policy cycle to shape and implement. UNEP describes a typical environmental policy as follows [41]:

1. Problem framing. This is when information is gathered, analyzed and the nature of the problem is agreed on. In the context of global cooperation on climate change, this is done through the science policy interface called the Intergovernmental Panel on Climate Change, which was established in 1988 "to provide policymakers with regular assessments of the scientific basis of climate change, its impacts and future risks, and options for adaptation and mitigation [1]. IPCC assessment reports help to shape the PA, and subsequent assessment reports are intended to provide independent scientific evidence to support national action and global cooperation.


#### *2.3. Reviewing Climate Policy Documents to Identify How Sustainable Lifestyles Are Integrated*

Reviews of climate policies mostly assess their headline targets on absolute or intensity reductions. There has not ye<sup>t</sup> been a review of whether the call to include sustainable lifestyles has been reflected in climate change policy under the Paris Agreement.

In order to determine whether climate policies are including sustainable lifestyles, we first differentiated between different types of climate policies relevant to international climate change policy development and monitoring. Table 1 summarises which types of policies have been included in the study.

Climate policies exist at the international, national, sectoral, and local level. It was beyond the scope of this paper to determine which levels are the most effective on climate change mitigation. Local and sectoral policies may have a closer alignment between mitigation options and the respective mandates and budgets. However, only headline NDCs are counted in the UNFCCC and third-party international monitoring of climate change policy therefore this was selected as a first step. In some cases, particular for non-Annex 1 countries, the NDCs did not offer significant details, but the biennial update report submissions from non-Annex I parties [44] compiled significant detail on mitigation strategies (India, Indonesia). This might be because they are reports, rather than binding commitments. Particularly for Annex 1 countries, NDCs do not always include details of strategies or policy measures that will be applied in order to reach the targets. Therefore, the second tier of policies to review includes the national climate change policies. This was particularly useful in the case of EU NDCs, which all follow a common template despite each country having vastly different contexts and mitigation plans. In some cases (Malaysia, China), national socioeconomic policies were useful to include since they included commitments on sustainable lifestyles that were missing in the climate change strategies and were considered binding enough to include.


**Table 1.** Climate change policy instruments under consideration.

The second step was to determine the country selection of the study. Given that 187 countries had submitted NDCs, it was not possible to review each of them. Three criteria were used to determine the geographic scope. First was alignment of other reviews of NDCs to facilitate cross referencing. The Climate Action Tracker [47], for instance, reviews 7both the headline commitments of countries to GHG reductions as well as actions in five sectors—energy, industry, transport, buildings, and forestry. This omits two sectors key to demand-side managemen<sup>t</sup> and affluence: food and consumer goods/waste. The UN Emissions Gap report reviews the NDCs of G20 countries, mainly analyzing the headline commitments, and reviewing the national policies most relevant [48]. This report reviews progress against key sectoral climate change goals in energy, industry, transport, buildings, and agriculture, but limited targets related to demand-side management. This aligned closely with the second criterion, which was to capture the bulk of global GDP, given that carbon-intensive lifestyles requiring policy attention are more likely to be in wealthier countries. Our third criterion was to include countries that had relevance to sustainable lifestyles, but were not included in the above two criteria. This included countries with carbon-intensive lifestyles, or countries known for a compelling approach to sustainable lifestyles.

The final scope included the following selection: first, G20 member states, in line with the UN Emissions Gap report (Argentina, Australia, Brazil, Canada, China, India, Indonesia, Japan, Mexico, Republic of Korea, Russia, Saudi Arabia, South Africa, Turkey, USA, EU28 (countries with recent climate change strategies available in English: Germany, Netherlands, Norway, Sweden, Denmark, Estonia, Portugal, France, Slovakia, Austria)). Secondly, additional countries that had high per capita carbon footprints (Monaco, Qatar), and thirdly those with a compelling approach in their climate change mitigation policy (Norway, Bhutan, Seychelles, Sri Lanka, Thailand, Vietnam, Kenya, Israel, Pakistan, Switzerland, Malaysia, New Zealand).
