The Trillion Dollar Question

This research paper by the World Resources Institute attempts to quantify and distinguish between public and private capital investment in global transport to help shift funding toward sustainable, low-carbon systems.

• Global annual capital investment in transport is estimated to be between US$1.4 trillion and US$2.1 trillion, with private investment accounting for approximately 58% of the total.
• The distribution of investment varies by income level: private investment is nearly double that of the public sector in high-income countries, where 75% of all investment occurs, while public investment is slightly larger in middle- and low-income countries.
• Public investment in transport ranges from US$569 billion to US$905 billion annually and is primarily composed of domestic budget expenditures; in 2010, only 2% was international (mostly ODA) and less than 0.5% came from climate-focused institutions.
• Private investment in transport, estimated between US$814 billion and US$1.2 trillion per year, has seen significant growth in the developing world, with World Bank data showing a 400% increase in private participation in transport projects from 1990 to 2012.
• The paper concludes that shifting investment toward sustainable, low-carbon transport, particularly in rapidly urbanizing and motorizing countries, will require leveraging public finance and creating a secure investment climate for private capital.

APA

World Resources Institute (n.d.). The Trillion Dollar Question. https://www.wri.org/research/trillion-dollar-question

Chicago

World Resources Institute. The Trillion Dollar Question. n.d. https://www.wri.org/research/trillion-dollar-question.

Wikipedia

{{cite report |author=World Resources Institute |title=The Trillion Dollar Question |url=https://www.wri.org/research/trillion-dollar-question |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{worldresourcesinstitutendtrillion, author = {{World Resources Institute}}, title = {{The Trillion Dollar Question}}, institution = {World Resources Institute}, url = {https://www.wri.org/research/trillion-dollar-question}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }