Shared Responsibilities for Climate Change Mitigation

The dangers of climate change pose a threat to all of humankind and to ecosystems all over the world. Does this mean that all humans need to equally shoulder the responsibility of mitigating climate change and its effects? The concept of CBDR (common but differentiated responsibilities) is routinely discussed at international negotiations about climate change mitigation. The underlying principle of CBDR in the context of climate change is that highly developed countries have historically contributed far more to climate change and therefore have a greater responsibility to reduce their carbon footprint than less developed countries. The per capita rate of vehicles in the United States is approximately 90 cars per 100 people, whereas the rate in India is 5 cars per 100 people. The total per capita carbon footprint includes a plethora of factors such as carbon emissions derived from industry, air travel and electricity consumption of individual households. As of 2015, the per capita carbon footprint in the United States is ten times higher than that of India, but the discrepancy in the historical per capita carbon footprint is even much greater.

CBDR recognizes that while mitigating carbon emissions in the future is a shared responsibility for all countries, highly developed countries which have contributed substantially to global carbon emissions and climate change for more than a century have a greater responsibility to rein in carbon emissions going forward than less developed countries. However, the idea of “differentiated” responsibilities has emerged as a rather contentious issue. Some representatives of developed countries do not embrace the idea of asking their populations to steeply curb the usage of carbon fuels and achieve strict carbon emission goals, whereas people living in less developed countries face fewer restrictions merely because they are “late developers”. On the other hand, representatives of less developed countries may reject universal standards on carbon emissions which ignore their historical carbon frugality and instead perceive these standards as attempts to curtail their industrial and economic development.

Are citizens of industrialized countries willing to recognize their privileged status and thus contribute more towards climate change mitigation? A team of researchers lead by Reuben Kline at Stony Brook University recently designed a behavioral study published in the journal Nature Human Behavior with volunteer college students from the United States and China to address this question. The students participated in a version of an “economic game” to ascertain how economic advantage would affect their choices. The study consisted of two phases. In the initial “Economic Development Game”, participants were divided into groups of six players and each participant could remove either $0, $1, $2, $3 or $4 per round from a shared pool of money ($180) belonging to the group. There were a total of 10 rounds so the maximum one individual could extract during the 10 rounds was $40. The clever twist in the experimental design was that half the participants were not allowed to extract any money during the first five rounds, so that the total they could have extracted was only $20. The second group thus emulated “late developers” in terms of industrialization and economic growth which merely watched as “early developers” accumulated wealth during the first five rounds.

The second phase of the experiment consisted of the “Climate Game” in which all the participants of a group were asked to return money into the common pool (“climate account”). The amount of money that had to be replenished in each group was 53% of what the group had removed from the common pool of $180 during the “Economic Development Game”. For example, if the combined sum of money removed by all six players in a group, was $100, than the group as a whole had to return $53 during the “Climate Game”. If the group did not meet the 53% target, the group risked a “climate catastrophe” in which all players of a group would lose their earnings. The probability of a catastrophic loss depended on the amount of money extracted during the “Economic Development Game”. If, for example, players in a group depleted $150 during Phase 1 and did not meet the threshold of returning $80 (53% of $150) during Phase 2, there was a 92% chance of a “climate catastrophe” in which all players of a group would lose all earnings. This discouraged greed by individual players and instead encouraged judicious extraction of funds during Phase 1 as well as active replenishment during Phase 2 to meet the 53% target.

The fundamental goal of the study was to understand how “early developers” would act because they had additional time to accumulate wealth during the first five rounds of Phase 1 and whether this advantage would affect their willingness to donate funds into the climate account during Phase 2. The results were quite remarkable and give reasons for hope in regards to how recognizing advantage affects social behavior. “Early developers” initially accumulated funds but then chose to extract less money during the later rounds once the “late developers” entered the game. Furthermore, early developers who had accumulated more funds were also more willing to donate money in order to replenish the “climate account” and help stave off the “climate catastrophe”.

Importantly, these experiments were performed in the United States and China, with similar results in both student populations. Interestingly, a representative quote by a “late developer” participant also explains why “late developers”  had lower rates of donations in Phase 2: “I decided not to contribute any because I felt that the individuals who were able to [appropriate] more money in the first round (early developers) should contribute more because I started with a disadvantage.”

The researchers interpret their data in the context of climate change mitigation behavior and suggest that recognizing one’s privileged status does indeed motivate individuals to greater sacrifice for the common good. The strengths of the study are the elegant design of the two-phase study, the replication of findings in two different countries as well as the inclusion of control groups in which all players were given equal opportunity to extract funds (without subdividing groups into “early” and “late developers”). Reuben Kline and his colleagues recognize the limitations of a highly stylized economic game experiment in a laboratory experiment using young educated college students to infer real world acceptance of carbon frugality by broader groups of citizens and political leaders in developed countries.

However, there is one fundamental issue which is not addressed in the context of this study. The “early” and “late developers” represented highly developed and less developed countries. However, the two countries they chose – United States and China – are marred by a tremendous amount of socio-economic inequality. Fifteen percent of Americans live in poverty even though the United States are often touted as the wealthiest country in the world.  CBDR and the results of the experiment detailed above are predicated on the idea that members of highly developed groups recognize themselves as being advantaged. But if there is such a discrepancy between rich and poor in a highly developed country, how likely is it that socio-economically disadvantaged members of society in a highly developed country will accept their status being labeled as advantaged? Populist political leaders in developed countries appeal to voters who are struggling to pay their bills, and their voters often perceive themselves as marginalized victims. Their income and quality of life may be far higher than that of their counterparts in less developed countries, but it is not clear that they would recognize this as an advantage in the same sense that the “early developer” college students recognized it in the experiment.

The research study by Kline and colleagues indeed provides reason for hope when it comes to climate mitigation behavior as well as perhaps other forms of prosocial behavior. It suggests that recognizing privilege can motivate greater sacrifice for the greater good. However, future studies may need to include a more complex experimental design in which the heterogeneity of “early developers” is addressed and we can derive more insights about how individuals recognize their advantage and privilege.


Kline, R., Seltzer, N., Lukinova, E., & Bynum, A. (2018). Differentiated responsibilities and prosocial behaviour in climate change mitigationNature Human Behavior, 2: 653-661.

Note: An earlier version of this article was first published on the 3Quarksdaily blog.


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