Clarifying Demographic Impacts on Embodied and Materially Retained Carbon toward Climate Change Mitigation

Modern lifestyles demand a number of products derived
from petroleum-based
sources that eventually cause carbon emissions. The quantification
of lifestyle and household consumption impacts upon carbon emissions
from both the embodied CO2 (EC) and materially retained
carbon (MRC) viewpoints is critical to deriving amelioration policies
and meeting emission reduction goals. This study, for the first time,
details a methodology to estimate both EC and MRC for Japan, focusing
on petrochemicals and woody products utilizing the time series input-output
table, physical value tables and the national survey of family income
and expenditure, leveraging time series input-output-based material
flow analysis (IO-MFA), and structural decomposition analysis (SDA).
Findings elucidated hot spots of deleterious consumption by age of
householder and the critical factors which underpin them including
intensity effects, pattern effects, and demographic shifts over time.
Although demographic shifts associated with an aging, shrinking population
in Japan decreased EC and MRC, the negative effect reduced in size
over time during 1990–2005. Policy implications identify the
potential to mitigate approximately 21% of required household emission
reductions by 2030 through strategies including recycling initiatives
and the recovery of carbon from products covered within current recycling
laws and hot spot sectors which are not currently considered such
as apparel.