Emissions were not always the mainstay of CO2 monitoring. When records first began at Mauna Loa, US, in 1957, they aimed to track the concentration of atmospheric CO2 as it rose and fell with Earth’s seasons and orbital cycles.
The choice of location, 4000km from the nearest global industrial hub (and the nearest gypsum wallboard plant) in Los Angeles, however, was telling. CO2 had been recognised as a product of burning fuels since the late 18th Century and as a greenhouse gas since 1859. Now, data from Mauna Loa substantiated the climactically consequential matter of industrial emissions: atmospheric CO2 was increasing, by 35% between 1957 and 2025.
Industrial facilities, already subject to direct monitoring and evaluations of their known pollutants like NOx and SO2, first came under supervision for their CO2 emissions in the 1990s. A new rubric, launched by the World Business Council for Sustainable Development and World Resources Institute in 2001, quantified products’ emissions by source, comprising:
Scope 1: Direct emissions from production;
Scope 2: Indirect emissions from production;
Scope 3: Further emissions along the value chain.
These metrics grow successively in their volumes of associated emissions for gypsum wallboard; they may also become harder to quantify.
A fourth ‘scope’ entered unofficial currency in the media after the COP26 Climate Conference in Glasgow, UK, in 2021, namely:
Scope 4: Emissions avoided by using a product.
This begs the question of the basis of comparison. Emissions avoided will vary depending on whether we compare a given product against its next best (lowest-CO2) competitor in its given market or globally – or its respective average or worst alternatives. ‘Competitor’ might be extended to include all classes of alternative across a given application or narrowed according to a product specification. Another possible basis of comparison might simply be ‘doing nothing.’
Scope-sceptics overreach, however, when they say that comparisons are untenable altogether – or will remain so, considering the possibilities of AI and the importance of emissions avoidance in investment decisions. Modelled scenarios about using a product – or not – might soon include detailed market information compatible with something like the EU’s planned European Digital Product Passport. Customers could even input their data to find the exact emissions from their choices, on a price-comparison-site model.
Why stop at present industrial emissions? Why not perhaps cast the net even wider? ‘Scope 5’ is the natural outgrowth of the original three scopes and the new fourth scope. It will take into account the full impacts of the sale of a product – from the future emissions avoided by a company’s reinvestment in research and development, to those resulting from advertising/marketing-driven demand for more, more, more! (pertinent for some consumer goods, if not wallboard). If we imagine tracing the emissions of the entire proceeds of sale, it leads to some interesting places.
One of these might be the personal carbon footprints of company personnel, tied to this source of income. In China, social credit systems have been deployed with mixed success against crises, including the Covid-19 outbreak. If ever they should include emissions, this could be plugged in to corporate reporting. Fake news about a proposed EU personal carbon cap remains under siege on social media; here, though, we are talking about an extra column on the emissions tables of company reports – not new personal restrictions or taxes.
Gypsum wallboard producers acknowledge the value of Scope 5 through their environmental initiatives outside of the value chain, like offsetting their emissions and volunteering their time. For now, the full scope dissolves out of sight into the wider economy.
Scope 1 covers the flue stack; Scope 2 reaches to the end of the power lines and Scope 3 to the rock face at one end and the customer at the other. Scope 4 can serve to ground this in market realities. When all the CO2 is accounted for, Scope 5 offers the possibility of broadening the view in order to control the intertwined impacts of industrial activity.
For now, future-conscious industries could do worse than to consider how their targets look through a new scope, even while continuing to use the existing ones.
A consultation by the Partnership for Carbon Accounting Financials on possible new CO2 accounting methodologies for the finance sector, including Scope 4 emissions, closed on 28 February 2025.
