Addressing the prevailing mode of high-carbon lifestyles is crucial for the transition towards a net-zero carbon society. Existing studies fail to fully investigate the underlining factors of unsustainable lifestyles beyond individual determinants nor consider the gaps between current footprints and reduction targets. This study examines latent lifestyle factors related to carbon footprints and analyzes gaps between decarbonization targets and current lifestyles of major consumer segments through exploratory factor analysis and cluster analysis. As a case study on Japanese households, it estimates carbon footprints of over 47,000 households using expenditure survey microdata, and identifies high-carbon lifestyle factors and consumer segments by multivariate regression analysis, factor analysis, and cluster analysis. Income, savings, family composition, house size and type, ownership of durables and automobiles, and work style were confirmed as determinants of high-footprint Japanese households, with eight lifestyles factors, including long-distance leisure, materialistic consumption, and meat-rich diets, identified as the main contributory factors. The study revealed a five-fold difference between lowest and highest footprint segments, with all segments overshooting the 2030 and 2050 decarbonization targets. The findings imply the urgent need for policies tailored to diverse consumer segments and to address the underlying causes of high-carbon lifestyles especially of high-carbon segments.Sustainability 2019, 11, 5983 2 of 25 to global GHG emissions-the average carbon footprint is almost 2.7 times larger than the global average [3]. A further study shows that over half of the average Japanese household carbon footprint results from indirect emissions induced through the purchase of products and services, with less than half caused by direct emissions such as from energy use at home [4].Transitioning towards sustainable lifestyles has been a major focal point of global sustainability policy agenda over the past few decades. The necessity for "encourage[ing] sustainable consumption patterns and lifestyles" was recognized in the United Nations Conference on Environment and Development (Earth Summit) in 1992 [5]. The Sustainable Development Goals (SDGs) adopted targets to "ensure that people everywhere have the relevant information and awareness for sustainable development and lifestyles in harmony with nature" and to "ensure that all learners acquire knowledge and skills needed to promote . . . sustainable lifestyles," among other issues [6]. In the context of the climate change policy, transitioning to sustainable lifestyles has also been adopted as part of the strategies towards net-zero carbon societies. The IPCC's Special Report on the impacts of global warming of 1.5 • C points out that "changes in human behavior and lifestyles are enabling conditions that enhance the feasibility of mitigation and adaptation options for 1.5 • C-consistent systems transitions," [7]. The European Long-term Strategic Vision for cl...