by Daniel Brouse
Comparing Two Approaches to Measuring Humanity’s Climate Footprint
Climate responsibility depends on how emissions are assigned. Traditional territorial accounting attributes emissions to the country where they occur, but globalization has made that approach increasingly incomplete. Modern supply chains, international trade, and service-based economies often separate where emissions are produced from who ultimately benefits from them.
To explore this problem from two different perspectives, I developed two complementary accounting frameworks.
The first paper, The True Climate Footprint: Measuring Per Capita Total Contribution Beyond Territorial Emissions, introduces the Per Capita Total Contribution (PCTC) framework. PCTC seeks to estimate an individual’s or nation’s complete climate responsibility by incorporating not only consumption, but also several major sources of emissions that are frequently omitted from conventional carbon accounting.
The True Climate Footprint: Measuring Per Capita Total Contribution
The PCTC framework includes:
- Consumption-based emissions
- Land-use change and deforestation
- Upstream fossil fuel extraction (methane leakage, flaring, and coal mine emissions)
- International aviation and maritime shipping
- All major greenhouse gases (CO₂, CH₄, N₂O, and others expressed as CO₂-equivalent)
- Responsibility associated with fossil fuel production where appropriate
The second paper, The Carbon We Own: Why Consumption Matters More, examines climate responsibility from a different perspective. Rather than estimating total climate contribution, it focuses specifically on the carbon footprint required to support modern lifestyles using a consumption-based accounting approach.
The Carbon We Own: Why Consumption Matters More
This framework emphasizes:
- Multi-Regional Input-Output (MRIO) accounting
- Direct household energy use
- Embedded emissions in imported goods
- Public and private services
- Lifestyle and purchasing choices
Unlike PCTC, this framework intentionally places less emphasis on fossil fuel extraction and producer responsibility in order to better isolate the climate impacts associated with everyday consumption.
After completing the first paper, I wanted to examine the climate footprint from the perspective of the consumer rather than the entire climate system. The PCTC framework provides a comprehensive measure of total responsibility, but it does not distinguish as clearly between emissions driven by individual lifestyle choices and those associated with resource extraction or national production.
A consumption-based framework highlights decisions that individuals and societies can influence more directly. Choices such as lowering a home’s thermostat, improving insulation, selecting public transportation or electric vehicles instead of internal combustion vehicles, reducing air travel, or purchasing fewer carbon-intensive goods become more visible within the accounting. It also better captures the increasingly important role of service-based economies. While services may appear less energy-intensive than manufacturing, sectors such as healthcare, finance, telecommunications, cloud computing, and artificial intelligence rely on extensive digital infrastructure—including energy-hungry data centers—that can be substantially underrepresented in traditional emissions inventories.
Finally, I wanted a more detailed comparison among developed economies, particularly within Europe. Countries such as Norway and France illustrate why accounting methodology matters. Norway has one of the world’s cleanest domestic electricity systems, powered primarily by hydropower, yet it is also a major exporter of oil and natural gas. France, by contrast, derives much of its electricity from nuclear power, resulting in comparatively low-carbon domestic energy while maintaining a high standard of living. Comparing these countries under both frameworks reveals how different accounting methods assign responsibility and helps illustrate the strengths and limitations of each approach.
Taken together, these two papers do not compete—they answer different questions. Per Capita Total Contribution (PCTC) asks, What is humanity’s full climate responsibility? Consumption-based accounting asks, What emissions are required to sustain the lifestyle of the average resident? Used together, they provide a more complete understanding of climate responsibility than either framework alone.
Conclusion
Although The True Climate Footprint and The Carbon We Own both seek to improve upon traditional territorial emissions accounting, they answer different questions because they are built on different accounting frameworks.
The True Climate Footprint uses the Per Capita Total Contribution (PCTC) framework to estimate an individual’s or nation’s complete contribution to climate change. It extends beyond consumption to include land-use change, upstream fossil fuel extraction, international shipping and aviation, and the full spectrum of greenhouse gases. In some cases, it also attributes responsibility associated with fossil-fuel production, providing a broad measure of humanity’s total climate impact.
By contrast, The Carbon We Own focuses specifically on consumption-based climate responsibility. Using Multi-Regional Input-Output (MRIO) accounting, it assigns emissions to the final consumer by emphasizing direct household energy use, embedded emissions in imported goods, services, and lifestyle choices. It intentionally deemphasizes extraction and producer responsibility in order to better represent the carbon footprint required to sustain modern patterns of consumption.
Because these frameworks measure different aspects of climate responsibility, their rankings are not expected to be identical.
Mexico provides a useful illustration. Under the PCTC framework, Mexico’s estimated footprint includes domestic industry, fossil fuel production, growing consumption, and upstream emissions, resulting in an estimated contribution of approximately 4–6 tonnes of CO₂-equivalent per person per year. In the consumption-based analysis, however, Mexico does not appear among the highest-ranking countries because the focus is limited to end-user consumption, and the published rankings emphasize the world’s largest per-capita consumption footprints.
Similar differences appear elsewhere. Norway’s position changes substantially because one framework incorporates the climate responsibility associated with fossil fuel production, while the other emphasizes domestic consumption. France benefits in the consumption-based analysis because its low-carbon nuclear electricity reduces household emissions despite maintaining a high standard of living. Saudi Arabia ranks differently depending on whether responsibility is assigned to oil production or to energy consumption. Singapore rises dramatically under consumption accounting because imported goods, international aviation, finance, logistics, and digital infrastructure contribute heavily to its consumption footprint despite relatively limited domestic manufacturing.
These examples demonstrate that accounting methodology influences how climate responsibility is distributed. Production-based, consumption-based, and total-contribution frameworks each illuminate different dimensions of the global climate system.
Rather than viewing these approaches as competing methodologies, they should be regarded as complementary analytical tools. The Per Capita Total Contribution (PCTC) framework asks, What is a nation’s or individual’s total contribution to climate change? The consumption-based framework asks, What emissions are required to sustain the average resident’s lifestyle? Together, they provide a more complete understanding of climate responsibility than either approach can achieve alone, revealing both the systemic impacts of resource production and the powerful role of consumer demand in shaping the global climate.
