Estimating the carbon footprint of household activities in Japan from the time-use perspective

Abstract

The household sector is a major driver of energy consumption and greenhouse gas (GHG) emissions. However, most existing studies have only estimated households’ carbon footprint from their expenditures. Households’ daily activity time, a scarce resource that limits and determines their consumption behavior, has rarely been integrated into the estimation. Incorporating the daily time-use patterns should thus provide a more practical perspective for mitigation policies aiming at promoting sustainable household lifestyles. In this study, by linking household time-use data and expenditure data of Japan, the carbon footprint and the GHG intensity of time of 85 daily household activities constituting the 24 hours in a day are estimated. Compared to the maximal 20-activity disaggregation in existing studies, our detailed 85-category disaggregation of daily time enables unprecedented details on the discrepancies between the carbon footprint from daily activities, many of which have previous been treated as one activity. Results indicate significant carbon mitigation potential in activities with a high GHG intensity of time, such as cooking, bathing, and mobility-related and activities. Average daily GHG emissions were also found to be higher on weekends as time-use patterns shift from paid work to free-time activities, highlighting the need for mitigation strategies on a weekly scale.

Input–output modelling for household activity-level environmental footprints: a systematic literature review

“…The burgeoning interest in estimating consumption-based environmental footprints at the household activity level, also now for Asia (Yu et al 2019, Jiang et al 2022 makes it plausible that future modelling of environmentally extended inputoutput tables will detail household activities. Scrutinising the old household input-output literature that aims at providing complete and detailed structures of households' use of time and products is an obvious starting point.…”

“…Creating the link between feelings and environmental footprints is important to identify options for reducing footprints or increasing wellbeing without compromising the other factor. Studies have furthermore compared resource use and emissions per activity across countries (showing the lowest carbon intensities in China) (Yu et al 2019), across different areas of a country (Heinonen et al 2013a, 2013b), weekdays (showing the highest carbon footprints of weekends) (Jiang et al 2022), years (showing increasing energy footprints over time) (Jalas 2005, Aall 2011, Jalas and Juntunen 2015, and household sizes (Jalas 2005).…”

“…The allocation of inputs to activities has been based on purely a priori reasoning (Gershuny 1987b) and with the exclusion of expenditures that were difficult to allocate (Yu et al 2019). Jiang et al (2022) found only limited sensitivity of the carbon footprint to three different ways of matching expenditures and time use. Kazemier and Exel (1992) considered all durable goods as inputs to household production.…”

“…The method suffers from allocating disproportionate value to activities that take much time. Jiang et al (2022) used specific surveys on the use of electricity and water to allocate utilities. Druckman et al (2012) allocated most expenditures to activities partly using the time-use method and e.g.…”

“…Jiang et al (2022) noted that some household expenditures, such as clothes, are consumed in the worktime, but not included in the workplace's expenditure statistics. Therefore, the relevant expenditures should also be distributed partly to paid work time (Jiang et al 2022). While household activities use intermediate inputs produced in the households (Landefeld andMcCulla 2000, Stahmer 2010), most studies did not include this activity structure.…”