3.1 2.a - Changing emissions in the United Kingdom and China

Why industrialisation increased emissions

Industrialisation increases the energy and materials used to make goods, move people and build settlements. When that expansion relies on fossil fuels, carbon stored underground for millions of years is transferred rapidly to the atmosphere. Coal powered early factories and electricity systems; oil enabled large-scale road transport, aviation and shipping; gas supplied electricity, industry and heating. Rising populations and consumption increased demand, although access and consumption remained highly unequal.

The mechanism is not simply “more factories”. Emissions depend on how much energy is required per unit of output and how much carbon is released per unit of energy. Efficient machinery can reduce energy intensity, while changing from coal to lower-carbon electricity can reduce carbon intensity. Total emissions may still rise if the expansion of output outweighs those improvements. Conversely, economic growth and territorial emissions can move in different directions if energy and production systems change sufficiently.

Other activities add different gases. Cement manufacture releases carbon dioxide when limestone is processed as well as through fuel use. Livestock and rice cultivation can release methane; fertiliser use can increase nitrous oxide emissions; landfill and fossil-fuel leakage also release methane. Deforestation removes carbon stored in vegetation and can weaken future uptake. These mechanisms explain why a complete inventory must extend beyond electricity generation.

A carbon dioxide equivalent expresses different gases using a common warming metric over a stated period. It allows gases to be added, but the result depends on the chosen metric and time horizon. Emissions are a flow per year, whereas atmospheric concentration is a stock. Reducing annual additions does not necessarily reduce the atmospheric stock if additions still exceed removal. IPCC AR6 Working Group III Chapter 2 assesses emissions trends and drivers, 2022.

Comparing national contributions

Different emissions measures answer different geographical questions. Annual territorial emissions show releases within a country's borders during one year. They help identify where production takes place and where domestic policy can act directly. Per-capita emissions divide the total by population, giving an average contribution per person rather than an individual footprint. A national average conceals inequalities between households and regions.

Cumulative emissions add releases over a period. They matter because much emitted carbon dioxide remains within the climate system for a long time, so early industrialisation contributes to present warming. The start date, gas and treatment of land use must be stated. A country with a small current share can still have a substantial historical contribution.

Consumption-based accounting reallocates emissions embodied in traded goods to the final consumers. Subtract domestic emissions embodied in exports, then add overseas emissions embodied in imports.

Worked example — a net importer of embodied emissions

Illustrative dataset: territorial emissions are 100 units, of which 30 produce exports; imports embody 50 units emitted overseas.

The footprint exceeds the territorial total by 20 units because embodied imports exceed embodied exports. Physical emissions are reallocated, not created by the accounting.

Worked example — a net exporter of embodied emissions

Illustrative dataset: another economy emits 160 territorial units, with 70 embodied in exports and 25 embodied in imports.

Its footprint is 45 units below its territorial emissions because more production emissions serve overseas consumers than arrive in imports.

The balance has changed as industrial production and consumption expanded in emerging economies. Global supply chains mean some emissions produced in China support consumption elsewhere, but not all Chinese emissions are export-related. Domestic investment, transport and household demand also matter. Equally, UK territorial reductions cannot all be dismissed as relocation: cleaner electricity and efficiency change real production emissions. A defensible comparison separates these effects.

Before comparing numbers, check year, gases, land-use inclusion, territorial or consumption boundary, and total or per-capita units. Mixing fossil carbon dioxide for one country with all-gas totals for another creates an apparent comparison that has no consistent meaning.