Two approaches to assigning responsibility for global carbon emissions provide complementary insights. Individual-level analyses highlight the disproportionate emissions of the wealthy, and country-level ones highlight the growing importance of emissions from middle-income countries. We propose the concept of reasonable vs. excessive consumption as a way to integrate these approaches into a synergistic and less divisive perspective on how to address the current climate challenge. Commonly advocated efficiency improvements should be supplemented by cutting excessive consumption and acknowledging the role of population in sustainability goals in both high-income and poorer nations.

Attitudes and expectations towards others are major drivers of political polarization. However, there is limited understanding of their relevance when decisions with high stakes are taken. In this study, we compare self-reported attitudes against economically incentivized estimates of data coming from official sources and offer participants financial rewards for accuracy. Our methodology yields three principal findings. (i) Extreme attitudes from a small partisan subgroup primarily account for the observed partisan divide; this subgroup diminishes when incentivized estimates are considered. (ii) There is a weak correlation between economically incentivized and unincentivized measures within individual respondents. (iii) We introduce a novel metric for assessing perceived polarization. This metric allows participants to estimate data points for those with opposing political views, rewarding accurate predictions financially. Interestingly, this measure of perceived polarization correlates with attitudes but not with incentivized data estimates. This is in line with the concept of ‘false polarization’, attributing polarization more to expectations towards others than to genuine differences. These findings challenge the reliability of standard attitude surveys and suggest avenues for mitigating perceived polarization in contentious issues.

To reach the UN’s Sustainable Development Goals, humanity should improve its capacity to achieve well-being and development while reducing its environmental impact. This calls for increased efficiency in the process of transforming natural resources into well-being. We present here a novel indicator called Ecological Efficiency and developed to capture this important aspect of the human-environment relation. We found large differences in efficiency among world countries. We then analyzed the relation between our indicator and several country-level variables encompassing different human dimensions, such as economic, political, and demographic. Results highlighted that demography affects Ecological Efficiency more than other factors.

Serious concerns have been raised on the potentially negative impact of public measures to contain the COVID-19 pandemic on academic research, including the closure of research facilities, and the challenges of lockdown. However, it is unclear whether COVID-related mobility restrictions have penalized academic productivity, and if this is the case, whether it has had an equal impact on all research areas and countries. Here, we examined about 9.2 million submissions to 2689 Elsevier journals in all research areas in 2018-2021 and estimated the impact of anti-COVID mobility restriction policies on submissions to journals. Results showed that anti-contagion public measures had a positive impact on academic productivity. However, submission patterns changed more in non-Western academic countries, with the exception of Italy, which had stringent lock-down measures. During the early stages of the pandemic, the abnormal peak of submission was dominated by health & medical researchers, whereas later, there was an increase in submissions to social science & economics journals. Although anti-contagion public measures have contributed to change academic work, it is difficult to estimate whether they will have any potentially long-term effect on the academic community- either positive or negative.

A dominant narrative in the climate change debate is that addressing population is not relevant for mitigation because population is only growing in the poorest countries, whose contribution to global carbon emissions is negligible, while the largest contribution comes from rich countries where the population no longer grows. We conducted an analysis of 30 years of emission data for all world countries showing that this narrative is misleading. Splitting the countries into four income groups according to the World Bank’s standard classification, we found that: (i) population is growing in all four groups; (ii) low-income countries’ contribution to emissions increase is indeed limited; (iii) the largest contribution to global carbon emissions comes from the upper-middle group; (iv) population growth is the main driver of emissions increase in all income groups except the upper-middle one; (v) the successful reduction in per capita emissions that occurred in high-income countries was nullified by the parallel increase in population in the same group. Our analysis suggests that climate change mitigation strategies should address population along with per capita consumption and technological innovation, in a comprehensive approach to the problem.

The relationship between environmental attitudes and behaviour is known to be weak, especially when these variables are measured as self-report items in surveys. In addition many environmental questions are highly polarised, making it even more problematic to use survey data to inform policy making. To better explore the attitude–behaviour gap in the context of environmental policies, along with its interaction with partisan identity, we ran an online experiment with 805 U.S. residents. Four key variables – environmental attitudes, self-reported environmental behaviour, observed environmental behaviour (in the form of carbon-offset credit purchase), and partisan identity – were measured, and their interactions in promoting pro-environmental behaviour were analysed. We found that (1) self-reported and real behaviour are almost uncorrelated and (2) partisan identity mainly predicted self-reported not actual environmental behaviour. These results suggest that policy-making needs to rely more on behavioural insight to test policies’ actual effects and to promote real improvement of the local and global environment.

Human societies and natural ecosystems are under threat by growing populations, overexploitation of natural resources and climate change. This calls for more sustainable utilization of resources based on past experiences and insights from many different disciplines. Interdisciplinary approaches to studies of historical commons have potential to identify drivers of change and keys to success in the past, and offer advice about the management and use of shared resources in contemporary and future systems. We address these issues by applying an ecological perspective to historical data on social-ecological systems. We perform comparisons and time series analyses for nine successful Dutch commons for which high-resolution data on the regulatory activities and use of shared resources is available for on average 380 years (range 236 to 568) during the period 1300 to 1972. Within commons, institutional developments were oscillating, with periods of intense regulatory activity being separated by periods of low activity, and with the dynamics of regulations being largely independent across commons. Ecological theory posits that species that occupy similar niches should show correlated responses to environmental challenges; however, commons using more similar resources did not have more parallel or similar institutional developments. One notable exception was that sanctioning was more frequent in commons that directed more regulatory activities towards non-renewable subsoil resources, whereas there was no association between sanctioning and the use of renewable resources. This might indicate that commoners were aware of potential resource depletion and attempted to influence freeriding by actively trying to solve the underlying social dilemmas. Sanctioning regulations were more frequent during the first than during the second part of a common’s life, indicating that while sanctioning might have been important for the establishment of commons it was not key to the long-term persistence of historical commons.

The effectiveness of public health measures to prevent COVID-19 contagion has required less vulnerable citizens to pay an individual cost in terms of personal liberty infringement to protect more vulnerable groups. However, the close relationship between scientific experts and politicians in providing information on COVID-19 measures makes it difficult to understand which communication source was more effective in increasing pro-social behaviour. Here, we present an online experiment performed in May 2020, during the first wave of the pandemic on 1131 adult residents in Lombardy, Italy, one of the world's hardest hit regions. Results showed that when scientific experts recommended anti-contagion measures, participants were more sensitive to pro-social motivations, unlike whenever these measures were recommended by politicians and scientific experts together. Our findings suggest the importance of trusted sources in public communication during a pandemic.