Editing IPCC:AR6/WGIII/Chapter-10 (section)

== Executive Summary ==

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'''Meeting climate mitigation goals would require transformative changes in the transport sector (''' '''''high confidence''''' ''').''' In 2019, direct greenhouse gas (GHG) emissions from the transport sector were 8.7 GtCO 2 -eq (up from 5.0 GtCO 2 -eq in 1990) and accounted for 23% of global energy-related CO 2 emissions. 70% of direct transport emissions came from road vehicles, while 1%, 11%, and 12% came from rail, shipping, and aviation, respectively. Emissions from shipping and aviation continue to grow rapidly. Transport-related emissions in developing regions of the world have increased more rapidly than in Europe or North America, a trend that is likely to continue in coming decades ( ''high confidence'' ). {10.1, 10.5, 10.6}

'''Since the IPCC’s Fifth Assessment Report (AR5) there has been a growing awareness of the need for demand management solutions combined with new technologies, such as the rapidly growing use of electromobility for land transport and the emerging options in advanced biofuels and hydrogen-based fuels for shipping and aviation.''' There is a growing need for systemic infrastructure changes that enable behavioural modifications and reductions in demand for transport services that can in turn reduce energy demand. The response to the COVID-19 pandemic has also shown that behavioural interventions can reduce transport-related GHG emissions. For example, COVID-19-based lockdowns have confirmed the transformative value of telecommuting replacing significant numbers of work and personal journeys as well as promoting local active transport. There are growing opportunities to implement strategies that drive behavioural change and support the adoption of new transport technology options. {Chapter 5, 10.2, 10.3, 10.4, 10.8}

'''Changes in urban form, behaviour programmes, the circular economy, the shared economy, and digitalisation trends can support systemic changes that lead to reductions in demand for transport services or expand the use of more efficient transport modes (''' '''''high confidence''''' ''').''' Cities can reduce their transport-related fuel consumption by around 25% through combinations of more compact land use and the provision of less car-dependent transport infrastructure. Appropriate infrastructure, including protected pedestrian and bike pathways, can also support much greater localised active travel. [[#footnote-001|1]] Transport demand management incentives are expected to be necessary to support these systemic changes ( ''high confidence'' ). There is mixed evidence of the effect of circular economy initiatives, shared economy initiatives, and digitalisation on demand for transport services. For example, while dematerialisation can reduce the amount of material that needs to be transported to manufacturing facilities, an increase in online shopping with priority delivery can increase demand for freight transport. Similarly, while teleworking could reduce travel demand, increased ridesharing could increase vehicle-km travelled. {Chapter 1, Chapter 5, 10.2, 10.8}

'''Battery electric vehicles (BEVs) have lower lifecycle greenhouse gas emissions than internal combustion engine vehicles (ICEVs) when BEVs are charged with low-carbon electricity (''' '''''high confidence''''' ''').''' Electromobility is being rapidly implemented in micromobility (e-autorickshaws, e-scooters, e-bikes), in transit systems, especially buses, and, to a lesser degree, in the electrification of personal vehicles. BEVs could also have the added benefit of supporting grid operations. The commercial availability of mature lithium-ion batteries (LIBs) has underpinned this growth in electromobility.

As global battery production increases, unit costs are declining. Further efforts to reduce the GHG footprint of battery production, however, are essential for maximising the mitigation potential of BEVs. The continued growth of electromobility for land transport would require investments in electric charging and related grid infrastructure ( ''high confidence'' ). Electromobility powered by low-carbon electricity has the potential to rapidly reduce transport GHG and can be applied with multiple co-benefits in the developing world’s growing cities ( ''high confidence'' ). {10.3, 10.4, 10.8}

'''Land-based, long-range, heavy-duty trucks can be decarbonised through battery electric haulage (including the use of electric road systems), complemented by hydrogen- and biofuel-based fuels in some contexts (''' '''''medium confidence''''' '''). These same technologies and expanded use of available electric rail systems can support rail decarbonisation (''' '''''medium confidence''''' ''').''' Initial deployments of battery electric, hydrogen- and bio-based haulage are underway, and commercial operations of some of these technologies are considered feasible by 2030 ( ''medium confidence'' ). These technologies nevertheless face challenges regarding driving range, capital and operating costs, and infrastructure availability. In particular, fuel cell durability, high energy consumption, and costs continue to challenge the commercialisation of hydrogen-based fuel cell vehicles. Increased capacity for low-carbon hydrogen production would also be essential for hydrogen-based fuels to serve as an emissions reduction strategy ( ''high confidence'' ). {10.3, 10.4, 10.8}

'''Decarbonisation options for shipping and aviation still require R&amp;D, though advanced biofuels, ammonia, and synthetic fuels are emerging as viable options (''' '''''medium confidence''''' ''').''' Increased efficiency has been insufficient to limit the emissions from shipping and aviation, and natural gas-based fuels are likely inadequate to meet stringent decarbonisation goals for these segments ( ''high confidence'' ). High energy density, low-carbon fuels are required, but they have not yet reached commercial scale. Advanced biofuels could provide low-carbon jet fuel ( ''medium confidence'' ). The production of synthetic fuels using low-carbon hydrogen with CO 2 captured through direct air capture (DAC) or bioenergy with carbon capture and storage (BECCS) could provide jet and marine fuels but these options still require demonstration at scale ( ''low confidence'' ). Ammonia produced with low-carbon hydrogen could also serve as a marine fuel ( ''medium confidence'' ). Deployment of these fuels requires reductions in production costs. {10.2, 10.3, 10.4, 10.5, 10.6, 10.8}

'''Scenarios from bottom-up and top-down models indicate that without intervention, CO''' 2 '''emissions from transport could grow in the range of 16% and 50% by 2050 (''' '''''medium confidence''''' ''').''' The scenarios literature projects continued growth in demand for freight and passenger services, particularly in developing countries in Africa and Asia ( ''high confidence'' ). This growth is projected to take place across all transport modes. Increases in demand notwithstanding, scenarios that limit warming to 1.5°C with no or limited overshoot suggest that a 59% reduction (42–68% interquartile range) in transport-related CO 2 emissions by 2050, compared to modelled 2020 levels is required. While many global scenarios place greater reliance on emissions reduction in sectors other than transport, a quarter of the 1.5°C degree scenarios describe transport-related CO 2 emissions reductions in excess of 68% (relative to modelled 2020 levels) ( ''medium confidence'' ). Illustrative mitigation pathways 1.5 renewables (REN) and 1.5 low demand (LD) describe emission reductions of 80% and 90% in the transport sector, respectively, by 2050. Transport-related emission reductions, however, may not happen uniformly across regions. For example, transport emissions from the Developed Countries and Eastern European and West-Central Asian countries decrease from 2020 levels by 2050 across all scenarios compatible with a 1.5°C goal (C1–C2 group), but could increase in Africa, Asia and Pacific, Latin America and Caribbean, and the Middle East in some of these scenarios. [[#footnote-000|2]] {10.7}

The scenarios literature indicates that fuel and technology shifts are crucial to reducing carbon emissions to meet temperature goals. In general terms, electrification tends to play the key role in land-based transport, but biofuels and hydrogen (and derivatives) could play a role in decarbonisation of freight in some contexts ( ''high confidence'' ). Biofuels and hydrogen (and derivatives) are likely more prominent in shipping and aviation ( ''high confidence'' ). The shifts towards these alternative fuels must occur alongside shifts towards clean technologies in other sectors ( ''high confidence'' ). {10.7}

'''There is a growing awareness of the need to plan for the significant expansion of low-carbon energy infrastructure, including low-carbon power generation and hydrogen production, to support emissions reductions in the transport sector (''' '''''high confidence''''' ''').''' Integrated energy planning and operations that take into account energy demand and system constraints across all sectors (transport, buildings, and industry) offer the opportunity to leverage sectoral synergies and avoid inefficient allocation of energy resources. Integrated planning of transport and power infrastructure would be particularly useful in developing countries where ‘greenfield’ development doesn’t suffer from constraints imposed by legacy systems. {10.3, 10.4, 10.8}

'''The deployment of low-carbon aviation and shipping fuels that support decarbonisation of the transport sector could require changes to national and international governance structures (''' '''''medium confidence''''' ''').''' Currently, the Paris Agreement does not specifically cover emissions from international shipping and aviation. Instead, accounting for emissions from international transport in the Nationally Determined Contributions is at the discretion of each country. While the International Civil Aviation Organization (ICAO) and International Maritime Organization (IMO) have established emissions reductions targets, only strategies to improve fuel efficiency and reduce demand have been pursued, and there has been minimal commitment to new technologies. Some authors in the literature have argued that including international shipping and aviation under the Paris Agreement could spur stronger decarbonisation efforts in these segments. {10.5, 10.6, 10.7}

'''There are growing concerns about resource availability, labour rights, non-climate environmental impacts, and costs of critical minerals needed for LIBs (''' '''''medium confidence''''' ''').''' Emerging national strategies on critical minerals and the requirements from major vehicle manufacturers are leading to new, more geographically diverse mines. The standardisation of battery modules and packaging within and across vehicle platforms, as well as increased focus on design for recyclability, are important. Given the high degree of potential recyclability of LIBs, a nearly closed-loop system in the future could mitigate concerns about critical mineral issues ( ''medium confidence'' ). {10.3, 10.8}

'''Legislated climate strategies are emerging at all levels of government and, together with pledges for personal choices, could spur the deployment of demand- and supply-side transport mitigation strategies (''' '''''medium confidence''''' ''').''' At the local level , legislation can support local transport plans that include commitments or pledges from local institutions to encourage behaviour change by adopting an organisational culture that motivates sustainable behaviour, with inputs from the creative arts. Such institution-led mechanisms could include bike-to-work campaigns, free transport passes, parking charges, or eliminating car benefits. Community-based solutions like solar sharing, community charging, and mobility as a service can generate new opportunities to facilitate low-carbon transport futures. At the regional and national levels, legislation can include vehicle and fuel efficiency standards, R&amp;D support, and large-scale investments in low-carbon transport infrastructure. {10.8, Chapter 15}

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