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building renovations, and sustainable urban lifestyles, aiming to establish a new green and low-carbon
[1]
approach to development . Among them, measuring the carbon footprint of products is an important
initiative for assessing and documenting the greenhouse gas emissions of enterprises, compiling a regional
[2]
greenhouse gas emission inventory, and constructing a green and low-carbon supply chain system . In real
life, it holds greater value to carry out carbon footprint measurements in megacities with intensive
economic and population activities .
[3]
Since the mid-20th century, observed climate change has been driven primarily by human activities.
Relevant studies have shown that significant expansion of urban land has led to substantial reductions in
vegetation cover and in the carbon-neutralizing capacity of forests, and that the burning of fossil fuels has
increased atmospheric levels of heat-trapping greenhouse gases (GHGs), thereby accelerating carbon
emissions, surface temperature increases, and global warming. Human-induced emissions of GHGs have
contributed to an approximate temperature increase of 1.1 degrees Celsius since 1850-1900. The global
average temperature in 2023 is the highest on record, surpassing the average surface temperature of the late
19th century. According to NASA, the average global surface temperature in 2023 is about 1.36 degrees
Celsius above the pre-industrial average of the late 1800s. Global warming has already led to an increase in
extreme weather events, the melting of glaciers and ice caps, rising sea levels, and ocean acidification. From
2000 to 2004, global glaciers lost an average of 227 billion tons of ice per year, and between 2015 and 2019,
this loss increased to 298 billion tons per year. Glacial melting is responsible for 21% of the observed sea
level rise during this period. As urbanization progresses, the development of commercial districts, factories,
and other mixed-use areas generates significant carbon emissions and releases large amounts of waste heat
into the atmosphere, contributing to the greenhouse effect and urban heat island effect. The rapidly
accelerating urbanization process has also prompted many cities, previously focused on horizontal
development, to adopt models that combine both horizontal and vertical expansion. Excessive urbanization,
characterized by high building volume ratios, can hinder heat dissipation and exacerbate the urban heat
island effect. Megacities, with their dense population, high levels of economic activity, and substantial
demand for global resources, have far-reaching environmental impacts. These cities not only produce
significant direct carbon emissions locally, but also generate indirect emissions globally through their
consumption patterns.

Product Carbon Footprint is a specific application of product environmental footprinting in the context of
climate change mitigation, based on the life cycle concept. It aims to minimize and reduce the potential
transfer of greenhouse gases throughout the entire life cycle of a product. This is achieved by identifying the
carbon impacts at each stage, from raw material acquisition, energy and material production, product
[4]
manufacturing and use, to the product’s end-of-life and final disposal . As the urgency of climate
governance grows, measuring the carbon footprint of products has become a significant factor in
influencing green consumption and trade, as well as an important tool for advancing climate governance.
To enhance carbon footprint measurement and management, the National Development and Reform
Commission (NDRC) issued the “Opinions on Accelerating the Establishment of Product Carbon Footprint
Management System” in November 2023. Among other measures, this document outlines comprehensive
accounting rules and standards for key products, builds a carbon footprint database for key industries, and
implements a carbon labeling certification system.

The Chinese government has initiated product carbon footprinting from multiple angles, including data
collection, model construction, policy guidance, and management organization. Firstly, this initiative
[5]
provides a data basis for key enterprises to efficiently promote energy conservation and carbon reduction .
By clarifying the carbon footprints of key products in industries such as iron and steel, chemicals, textiles,