IPCC Working Group III Report: What Do Scientists Tell Us About Transportation?

In early April, the Report of the IPCC's Third Working Group focusing on scenarios for reducing greenhouse gas emissions to limit climate change—in other words, possible courses of action. Hélène Chauviré and Louise Badoche of Carbone 4 recently provided a summary of the key points ^[1].

This document extremely dense, Since the full report is a 3,000-page compilation of no fewer than 18,000 studies, it covers all areas of action, including, among other things, a sector-based approach. Here, we propose to provide a Focus on the topic of transportation ^[2]. The summary for policymakers is available here.

The Current Situation and Outlook

Currently, humanity emits approximately 56 GtCO2e per year of which approximately 15% (8.7 GtCO2e) is attributable to direct emissions from the transportation sector, and even more so if we include indirect emissions related, for example, to the production of the various energy sources used for transportation.

The IPCC proposes Various decarbonization scenarios enabling net-zero CO2e emissions to be achieved by various dates. The first conclusion that can be drawn from the report is that, across all of these scenarios, Transportation emissions are set to decrease dramatically.

The graph above shows (on the left) the breakdown of emissions in 2019 by sector and (on the right) that same breakdown at the point when net-zero is achieved in each scenario. We can see that in all scenarios, the share of transportation—shown in purple—decreases sharply.

This massive reduction in emissions to achieve net-zero should be viewed in the context of the trend over the past few decades, which has seen the Transportation emissions have increased by more than 70% since 1990. Without action, emissions could even continue to increase from 16% to 50% by 2050 ^[3].

With 70% of emissions coming from road transport, 11% from maritime and inland waterway transport, and 12% from aviation ^[3], This applies to all modes of transportation.

What are the possible courses of action?

In its technical summary, the IPCC outlines several avenues for action. Among these, it notes that the adoption of new technologies lower carbon emissions go hand in hand with a infrastructure investment in both transportation and energy production (i.e., electricity or low-carbon hydrogen). Several conclusions are highlighted, including:

On the road, battery electric vehicles (BEVs) are emerging as a key driver. Among other things, the IPCC emphasizes the need to invest in charging networks and infrastructure. The potential co-benefits, including in developing countries, are also highlighted. Nevertheless, the IPCC warns of the risks associated with battery production (including resource availability, human rights, non-climate environmental impacts, and the cost of raw materials).
For road freight transport, the IPCC also highlights the use of battery-powered vehicles (including electric road systems) as promising, supplemented in certain contexts by hydrogen and biofuels. The IPCC notes, however, that the limited availability of low-carbon hydrogen currently poses a constraint.
For the maritime and aviation sectors, The IPCC specifies that decarbonization options still require R&D, although advanced biofuels, ammonia, and synthetic fuels appear to be viable options. The IPCC also highlights the challenges of reducing the costs of these fuels
The Decline in Transportation Demand, is also highlighted by the IPCC, which emphasizes behavioral aspects as a means of leveraging this factor. Although the report’s transportation section does not directly use the term, it is indeed moderation as discussed by the IPCC.

In more quantitative terms, the IPCC proposes a Estimation of permitted emission reductions for certain mitigation options which he compares with options in other sectors. It is clear that the transportation sector stands out because a A large number of initiatives are directly profitable From an economic standpoint, without even considering the carbon footprint: for example, cycling instead of driving is directly less expensive for the user.

Conclusion: More than just a document to summarize—it’s a gold mine waiting to be tapped

The few conclusions presented above may seem obvious and predictable to some of the most knowledgeable readers of Carbone 4’s Mobility Insights. Indeed, it is difficult to go beyond the obvious (and yet fundamentally important) when summarizing several hundred pages of scientific research in just a few lines.

We strongly encourage you to delve into the details of the IPCC report if you wish to explore a particular topic in greater depth—whether it be decarbonization scenarios for different modes of transport, the maturity of new fuels, the emission factors of various technologies, maritime freight in the Arctic, the impact of contrails, or even the governance issues surrounding the International Maritime Organization (IMO), the IPCC’s Third Assessment Report is packed with precise, science-based analyses.

Glossary:

GHG: Greenhouse Gases
IPCC: Intergovernmental Panel on Climate Change
GHG: Greenhouse Gases
IMP: Illustrative Mitigation Pathways: a mitigation scenario proposed by the IPCC within the framework of Working Group III
SPM: Summary for Policy Makers: Summary for Decision-Makers

Carbon 4

The information presented here is drawn primarily from the Summary for Policymakers and the Technical Summary.

Technical Summary, 1 TS. 5.3 Transportation, pages 67 and 68

The graph takes into account the monetary costs discounted over the lifetime of the project, without accounting for externalities.