This report is unique in drawing on a series of case studies to explore 10 transboundary climate risks of global importance. The assessments take a deep dive into how transboundary climate risks impact local livelihoods, and critical sectors such as finance, health and global supply chains (e.g. agricultural commodities and manufacturing components). Each chapter explores, for a given transboundary climate risk, its likelihood in a changing climate, its impacts across different distances and time scales, and its method of transmission, as well as provides readers with an in-depth analysis of a representative real-world case study.

This report by Adaptation Without Borders rings the alarm bell on transboundary climate risks. It is the first collection of evidence on risks that undermine effective responses to climate change, yet that remain largely unrecognized: a “blind spot” in both climate policies and solutions. It brings together the best available knowledge, drawing on a wealth of case studies.
Key messages

Transboundary climate risks, which are triggered by a climate hazard in one country, cross borders, continents and oceans to affect communities on the other side of the world. So do the consequences of some adaptation actions.
In a world that is increasingly interconnected, these risks are transmitted through shared natural resources and ecosystems, trade links, finance and human mobility.
Transboundary climate risks are expected to increase as global warming accelerates to threaten entire societies and economies.
No country is immune: transboundary climate risks can affect any country, at any time, regardless of its level of development. They combine with non-climate drivers such as poverty and conflict to undermine our collective wellbeing.
Transboundary climate risks have the greatest impact on the poorest and most vulnerable people, exacerbat-ing inequities and the root causes of their vulnerability.
Evidence shows that transboundary climate risks are a global concern, yet the international, regional and local mechanisms to adapt to climate change are not yet equipped to meet this common challenge.
The authors argue that a global response to transboundary climate risks is necessary to build collective resilience to climate change.

The report is structured as follows:

Part I: The state of knowledge on transboundary climate risks (p.17-28)
Part II: Assessing 10 globally significant transboundary climate risks (p. 29-96)
Part III: The solution space to managing transboundary climate risks (p. 97-113)