The Trillion Dollar Question

The paper estimates annual global transport capital investment between $1.4 trillion and $2.1 trillion, noting that private investment accounts for approximately 58% of the total. It highlights a disparity in investment sources between high-income countries, where private investment dominates, and middle- and low-income countries, where public investment is slightly more prevalent. The authors argue that leveraging private investment and public resources is essential for transitioning to low-carbon transport, particularly in rapidly urbanizing developing nations.

• Annual global capital investment in transport, excluding consumer spending, is estimated to be between US$1.4 trillion and US$2.1 trillion.
• Private investment makes up the majority of global transport investment at approximately 58%, with estimated annual flows between US$814 billion and US$1.2 trillion.
• Public investment in transport ranges from US$569 billion to US$905 billion annually and consists almost entirely of domestic budget expenditures, with only 2 percent being international (mostly ODA) and less than 0.5 percent coming from climate-focused sources as of 2010.
• Investment patterns vary by economic status: private investment is nearly double that of the public sector in high-income countries, where 75% of all investment occurs, whereas the public share is slightly larger in middle- and low-income countries.
• Private participation in transport projects in the developing world grew by 400% between 1990 and 2012, and leveraging this private investment is seen as essential for transitioning to low-carbon transport in these regions.

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} }