Expert Perspectives

Changing Behavior to Help Meet Long-Term Climate Targets

The necessity of behavior change to meet climate targets

Current projections for decarbonization of energy, combined with business-as-usual projections of growth in demand for goods and services, are incompatible with the rapid reduction in emissions necessary to meet Paris and national climate targets. Seventy-two percent of global greenhouse gas emissions come from household or “lifestyle” consumption, including mobility, diet, and housing, as opposed to government or capital and infrastructure investment (Hertwich and Peters 2009). These lifestyle emissions must aim for 2.5 tCO2e per capita by 2030 and 0.7 tCO2e by 2050 to be in line with the Paris goal of limiting global temperature increase to 1.5°C above preindustrial levels without extensive reliance on negative emissions; current lifestyle emissions are 10.4 tCO2e for Finland, 4.2 for China, and 2.0 for India (Institute for Global Environmental Strategies et al. 2019). The goal of reaching net zero emissions is unlikely to be achieved through a timely technological change alone and, in addition to policy and investment changes, will likely rely in part on reduced consumption of high-emissions goods and services (Masson-Delmotte et al. 2018).

Aviation, for example, is a difficult sector to decarbonize, and while biofuels offer one solution, they would compete for land use with other priorities like food production and biodiversity conservation (Bows-Larkin and Anderson 2013). Electrification is more promising in land transport, since electric aircraft are projected to be limited in range (Schäfer et al. 2018) and mature too slowly to achieve necessary short-term emissions reductions (Bows-Larkin 2015), indicating the need for demand reduction. Similar barriers exist in agriculture, where methane-producing livestock cannot be decarbonized like an energy grid, and expected improvements in crop yields cannot meet growing demand for animal-intensive diets. Shifts to more plant-based diets, however, remain a viable solution (Bajželj et al. 2014), particularly in high- or medium-income nations. In sum, large-scale behavior change away from today’s high-emitting lifestyles is a prerequisite for meeting our Paris climate commitments.

Why is behavior change relevant for long-term climate strategies?

Behavioral change is largely neglected in analyses of climate change mitigation for meeting international targets (Creutzig et al. 2016), despite the necessity of driving behavioral change in areas like aviation and meat consumption (Girod et al. 2013; Hedenus et al. 2014). National long-term climate strategies present an important opportunity for exploring novel approaches, potentially using multiple scenarios or backcasting techniques, to help stimulate a creative vision for what a future compatible with the Paris goals can look like. Ongoing research in many countries could inform long-term, deep emissions reductions strategies that include behavior change, but, at present, most long-term strategies do not take advantage of this opportunity. For example, researchers in Sweden have formulated four normative backcasting scenarios compatible with 1.5°C, using radically different approaches to achieve this: local self-sufficiency, circular economy in the welfare state, collaborative economy, and automation for quality of life (Francart et  al. 2018). A vision for a sustainable Nordic food system has recently been formulated in participatory, normative scenario development between researchers and agricultural stakeholders for a desirable food system. This process generated an organic, diversified local diet where animals were only fed on grazing or waste products, thus limiting competition with food for humans. The resulting diet was about 80 percent lower in both overall meat consumption and greenhouse gas emissions than today’s diet (Karlsson et al. 2018).

Long-term climate strategies offer a unique space to consider emissions that go beyond the scope of territorial borders, such as those from air travel. Aviation emissions are currently largely under voluntary airline industry self-governance, but there is increasing need for countries to take these emissions into account, and to reform policies such as the current subsidy airlines receive in the form of not paying taxes on international fuels (Gössling et al. 2017). Many current national climate plans extrapolate continued growth in aviation demand, without acknowledging the increasingly large share of the remaining carbon budget this would consume (Cames et al. 2015), thus putting greater reduction burdens on all other sectors. For realistic carbon budgets that will meet national and international goals, aviation should be included in national climate plans and should explore demand reduction in this emissions-intensive sector. Nations could begin planning for more low-carbon, regional tourism and countries currently dependent on tourism from long-distance air travel might consider scaling down these operations over time while seeking alternative livelihoods for tourism-dependent economies.

The EU long-term strategy acknowledges the need for more rail infrastructure but address aviation emissions mostly through a focus on technical solutions such as fuel switching, without exploring the need for reduced long-haul travel to meet climate goals. The current culture of cheap, prolific air travel, and the extrapolation of current aviation demand into the future, cannot coexist with meeting international climate targets. At the moment, individuals are frequently incentivized both culturally and financially to travel by air rather than staying local or using low-carbon alternatives. Tourism and business travel are associated with social prestige, and many people join frequent flyer programs that reward customer loyalty with the opportunity to generate more cheap emissions. Tourism currently constitutes 8 percent of global greenhouse gas emissions (greater than emissions from India; Le Quéré et al. 2018), and is projected to continue to grow (Lenzen et al. 2018). It is therefore necessary to rapidly find ways to change this culture, including new narratives that do not view continued high-emissions and fast long-distance travel as an inevitable good. Long-term strategies, which have no strict limits in scope, may offer a unique space for nations to consider ways that national policies can positively impact international emissions in sectors like aviation and tourism.

What do we know about what works to change behavior?

Behavioral changes may be neglected by some policymakers and researchers, since they are typically perceived as more value-laden than technological improvements and because they are more difficult to quantify and implement in models (Creutzig et al. 2016; Hardt et al. 2019). Fortunately, advances are being made in understanding what drives behavioral change. The high-impact areas for reducing existing greenhouse gas emissions through behavior change are reducing car travel, flying, and meat consumption, activities that predominate for high-income individuals and countries at present, although these actions are less commonly recommended by government resources or high school science textbooks than moderate-impact climate actions such as reducing energy consumption (Wynes & Nicholas 2017). A great deal of research shows what works to reduce home energy use (Šćepanović et al. 2017; Abrahamse et al. 2015), including providing feedback with normative comparisons to neighbors. For personal vehicle use, a small body of research shows that interventions like providing free transit passes or e-bike rentals can encourage mode shifts by interrupting entrenched habits (Wynes et al. 2018); policymakers can also support low-carbon infrastructure such as bike lanes and public transit, or use economic incentives such as congestion pricing. However, very little research has been conducted on how to encourage reductions in meat consumption (Byerly et al. 2018), and virtually no experiments have been conducted on reducing demand for air travel (Wynes et al. 2018). We have therefore compiled a preliminary list of examples of how behavioral interventions common in other domains could be applied to air travel (see Table 1). These behavioral interventions are examples of policy experiments that could be conducted at institutional or regional levels, and which national governments could support both structurally and through funding. They could also be considered when designing long-term scenarios or backcasting from 2050 targets.

What roles can government officials play in driving behavior change?

National governments have a wide palette of policy options to choose from to support behavior change toward lower-carbon lifestyles. The traditional policy tool of making high-emitting behaviors more expensive through taxation is one option. Beyond driving behavior change, such taxes can send an important cultural signal about the social acceptability of high-emitting behaviors, which may be important in reaching the critical mass of 25 percent of a population exhibiting a behavior before it becomes the social convention (Centola et al. 2018). Public health strategies used to reduce tobacco consumption offer important examples of how governments can alter social conventions in the public interest. Here, health officials have had great success through taxation and clean air laws, but best practice in this field also relies on mass-reach communication, the cessation of protobacco advertising, and well-monitored, evidence-based interventions (Levy et al. 2007; CDC 2014; Emory et al. 2015).

Another role for national governments in driving behavior change can be to incentivize regional and local governments to take appropriate action and to be centers of innovation, as well as set up databases for tracking emissions and policies to reduce them, or coordinate information sharing on best practices. Klimatklivet is a Swedish policy where the national government funds regional, local, and business programs that reduce emissions. To date, over 3,200 projects have been supported, saving 1.57 million tons of CO2e annually, at an average cost of €38/ton (Naturvårdsverket 2018). Governments can also implement advertising bans or restrictions for high-emitting behaviors (e.g., air travel) and run educational campaigns to raise awareness of the polluting costs of high-emitting behaviors and highlight low-emitting alternatives. Increased awareness may be important to generate public support for behavior change; for example, public polling shows that individuals who are more aware of the negative effects of air travel are more likely to support public policies to curtail it (Murray 2019), and willingness to eat less meat is related to perceived efficacy of this action for climate mitigation (De Boer 2016).

How should developers of long-term strategies address behavior change?

Overall, long-term climate strategies should explicitly consider the possibility of behavior change in high-impact sectors (particularly in neglected areas such as aviation and diet, in addition to the more frequently studied car transport and energy use) when developing current and future policies. Modeling and scenario development should explore different possible degrees of behavior change, informed by the remaining carbon budget, to meet climate targets as well as normative social goals for how to achieve this fairly. These would help identify priority areas for more active monitoring and testing of policy and innovation designed to incentivize behavior change and reduce emissions in line with the Paris commitments.

Table 1. Eleven types of behavioral interventions studied in peer-reviewed literature to reduce personal greenhouse gas emissions, with suggested applications to reduce emissions from aviation

Type of intervention


To reduce emissions from aviation



Customers “nudged” by being given preportioned meal sizes (Friis et al. 2017).

Change defaults in government booking systems to better support booking train travel.


Participant received text-message reminders to reduce red meat intake (Carfora et al. 2017).


Display a note on a travel booking website asking customer to consider linked low-carbon options.


Carbon footprint information of meal choices displayed (Brunner et al. 2018).


Make carbon footprint of flights versus other choices more explicit in transport mapping and travel booking systems to inform travel decision.


Energy saving tips provided to households (Allcott 2011).

Design government and institutional travel policies that prioritize travel-free meetings, then ground-based travel (von Arnold 2018; Tyndall Centre 2019).


Provide instructions and technical support for institutional videoconferencing hardware and software to lower barriers for digital alternatives to air travel (Wynes and Donner 2018).


Monthly energy statement mailed to households (Carroll et al. 2014).

Give institution members individual reports about personal air travel, including a comparison to the average member of the department or with a sustainable global citizen’s annual carbon budget (with normative, encouraging messages for those whose emissions are below the average).


Make public the emissions of public sector employees who generate above a certain threshold in air travel emissions. Similar social pressure interventions have been effective in encouraging behaviors like voting (Davenport et al. 2010) and reduced household energy consumption (Delmas and Lessem 2014).

Social modeling

Neighborhood leaders model a proenvironmental behavior.  


Highlight and promote local destinations, emphasizing the economic benefits for local economies (e.g., collaboration of Swedish universities, regional governments and tourist agencies that includes 100 vacations reachable by train, and carbon calculator for travel plans) (Klimatsmart Semester 2019).


Promote positive stories of slow travel and its health, quality time, adventure, and other benefits.


Attitudes and behavior have been changed by knowing someone who flies less or doesn’t fly (Westlake 2017).

Increase institutional or leadership commitment to reduced flying.

Cognitive dissonance

Stressed the gap between an individual’s actions (driving) and values (environmental concern) (Tertoolen et al. 1998).


Require that air travel advertisements contain messages stating the environmental harms of flying, similar to the practice with cigarette packages and pharmaceutical drug commercials.


Social media campaigns can highlight high emissions from air travel by “clueless influencers” (aningslosainfluencers 2019).


Subjects committed to reduce car use (Tertoolen et al. 1998).


Sign personally formulated pledges at the individual, business, city, and regional levels.


Employees offered option to cash out parking spots (Shoup 1997).


Employers give more days off to support employees who travel slower (e.g., Climate Perks initiative by the NGO 10:10).

Replace frequent flyer programs with a financial incentive program that rewards lower-carbon options.


Group competition reduced energy use at university residence (Sintov 2016).


Stimulate interdepartmental competition to reduce air travel emissions at large public institutions.


Group goal of 5% energy reduction given to households (Abrahamse et al. 2007).


Align aviation with Paris temperature targets.

Campaign for 50% reduction by 2023 of greenhouse gas emissions from Swedish universities (including flight emissions) by university researchers (Alvesson et al. 2018) and students (Bernholz et al. 2019)

Note: These interventions are suggested for policy experiments to raise public awareness and support for, as well as catalyze individual and collective action toward, behavior change in line with meeting climate targets.

Sources: Classifications adapted from Osbaldiston and Schott (2012), with examples in better-studied domains taken from Wynes et al. (2018).


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The authors gratefully acknowledge helpful comments from Kevin Anderson, Jonas Sonnenschein, and Juan Diego Martinez, which greatly improved an earlier version of this document. All the interpretations and findings set forth in this expert perspective are those of the authors alone.