One of the key obstacles to building international cooperation for environmental problems is the fact that environmental benefits are valued differently in different countries. But where does the disparity come from? This study gives an answer to this question by analysing large-scale survey data collected across G20 countries. Combining lifecycle impact assessment and economic valuation techniques, we found that people's perceptions of environmental benefits are in fact diverse, but are highly correlated with a few social indicators such as life expectancy, the Gini index, and subjective well-being. Our findings suggest that improving these social indicators in otherwise ill-equipped countries will facilitate convergence of people's perceptions and will thereby establish a common ground for tackling global environmental issues.