Tracing the True Drivers of Transport Emissions

Transport is essential for connecting industries to raw materials, production sites, and final consumers. Almost every sector relies on transport to move intermediate and final goods, often across multiple borders. This means that transport emissions in one region may be generated in response to consumption or production taking place elsewhere.

Decarbonization strategies should therefore extend beyond the transport sector, focusing on the sectors and regions that create the demand for transport services. Targeting these drivers can unlock broader and possibly more cost-effective reductions in emissions.

The Environmentally Extended Multiregional Input–Output Tables provide a practical approach to uncover these linkages. By integrating environmental accounts with core multiregional input–output tables, they trace not only the direct emissions of each sector but also the indirect emissions embedded in the inputs they consume. In the transport sector context, this approach captures demand-driven emissions or the indirect (Scope 3) emissions that result from each sector’s use of transport services. Transport emissions therefore are attributed not only to where they occur but also to the industries and regions generating demand.

Building on this framework, the Leontief model may be used with the Environmentally Extended Multiregional Input–Output Tables to quantify the emissions embodied in both the production and consumption of goods and services. Applied to transport, this model quantifies demand-driven emissions by region and economic sector—showing shared responsibility for these emissions across the production system.

From a sectoral perspective, transport supports nearly all economic activity. Beyond the emissions generated by the sector’s own operations, demand from other sectors accounts for almost two-thirds of total transport emissions. Manufacturing and services each contribute about 32% of transport-related emissions, followed by construction (17%) (Figure 1)^[1].

Figure 1: Transport-Generated Emissions by Transport Subsectors (Exporting Sectors) Arising from Demand of Other Economic Sectors (Importing Sectors), 2023 (GgCO₂e)

Source: Authors’ analysis using ADB’s Environmentally Extended Multiregional Input–Output Tables. 

The scale of these contributions reflects transport’s central role in sustaining production and services. Manufacturing depends on logistics networks to move raw materials, components, and intermediate goods. In services, emissions are largely driven by public administration and defense, and trade—all of which depend on transportation as the backbone of their operations. Construction projects also rely heavily on transport for moving equipment and materials, where delays or inefficiencies can amplify both costs and emissions across supply chains.

Regional analysis of transport emissions driven by demand from all other sectors identifies Asia and the Pacific as the largest contributor, accounting for nearly half (48%) of global transport-related emissions. Even when domestic demand is excluded, the region still leads with a 36% share of emissions arising from demand for its transport services (Figure 2)^[2].

Figure 2. Transport-Generated Emissions by Exporting regions and importing regions, 2023 (GgCO₂e) 

Source: Authors’ analysis using ADB’s Environmentally Extended Multiregional Input–Output Tables. 

This pattern underscores Asia’s role as the world’s production hub, where energy-intensive manufacturing, rapid urbanization, and growing freight activity drive heavy reliance on transport. Emissions from its transport service exports now surpass those from imports, reflecting the region’s industrial base serving global demand, fueled by lower labor costs, economies of scale, and specialized inputs. Advances in transport and logistics have weakened the link between production and the physical location of inputs, expanding markets, encouraging cross-border supply chains, and enabling a relocation of manufacturing activities toward economies with comparative advantage. Ultimately, decarbonizing transport demands shared responsibility and coordinated action across regions.

To meet net-zero goals, transport cannot be treated in isolation. The sector’s emissions are influenced not only by the energy used in vehicles but also by the economic activities that depend on them. Long-distance freight, energy-intensive manufacturing, and expanding urban demand all reinforce transport’s role as a major source of emissions, highlighting the need for a coordinated and cross-sectoral approach.

Analysis using the Environmentally Extended Multiregional Input–Output Tables shows interdependencies across global value chains, tracing how transport connects sectors and regions. It shows that decarbonization strategies can extend beyond improving transport technologies, infrastructure, and user habits to also consider the sectors whose demand drives transport emissions. In Asia, aligning trade, industry, and construction policies with transport decarbonization efforts—while strengthening monitoring systems and integrating environmental criteria into supply chain management—can help achieve sustainable, low-carbon growth.

^[1] Values are calculated using the Environmentally Extended Multiregional Input–Output Tables, which link emissions inventories (classified under IPCC categories) to corresponding economic sectors. Emission intensities were first derived by dividing transport-related emissions (civil aviation, road transportation excluding resuspension, railways, water-borne navigation, and other transportation) by sectoral economic output from the ADB MRIO. Using the Leontief model, total emissions were then expressed as a function of final demand and intersectoral linkages, captured through the Leontief inverse. From this framework, the transport sector rows (inland, water and air transport, and supporting activities) were isolated to estimate how much of their emissions were attributable to demand from all other economic sectors. To emphasize these cross-sectoral linkages, the figure excludes emissions driven by the transport sector’s own demand.

^[2] Values for Figure 2 are calculated using the same methodology as Figure 1. To emphasize the cross-regional linkages, the figure excludes emissions driven by each region's own demand of transport services.

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