Worst-case climate change

The report argues that prudent risk management requires consideration of bad-to-worst-case scenarios. The COVID-19 pandemic has underlined the need to consider and prepare for infrequent, high-impact global risks, and their systemic dangers. Climate change is a similar risk, and it is mismatched to current risk management practices. It argues that catastrophic climate change scenarios need to be explored better to prepare for and manage the risk.

Understanding extreme climate change dynamics and impacts in the long term

The report argues that potential long-term states of the Earth system under extreme climate change, such as different “Hothouse Earth” scenarios, are poorly understood. It suggests that it is vital to map such scenarios and explore the risk of irreversible large-scale, abrupt transitions. Each Intergovernmental Panel on Climate Change (IPCC) assessment found greater risks occurring at lower increases in global mean temperatures.

Exploring climate-triggered pathways to mass morbidity and mortality

The report suggests that it is important to understand the mechanisms that could result in human mass mortality and morbidity due to climate change. The likelihood of extreme climate change is largely unknown and underplayed, and nonlinear climate damages could result in even larger risks than currently known. The report argues that too much is at stake to refrain from examining high-impact low-likelihood scenarios.

Investigating social fragility: Vulnerabilities, risk cascades, and risk responses

The report argues that understanding human societies’ vulnerabilities to climate-triggered risk cascades could help to prepare for and manage these risks. These cascades could arise from climate-induced conflicts, political instability, and systemic financial risks. The report suggests that it is necessary to understand these risks to improve resilience and inform policies, including emergency responses.

Synthesising the research findings into “integrated catastrophe assessments”

The report outlines a proposed research agenda covering four main questions:

1) What is the potential for climate change to drive mass extinction events?

2) What are the mechanisms that could result in human mass mortality and morbidity?

3) What are human societies’ vulnerabilities to climate-triggered risk cascades, such as from conflict, political instability, and systemic financial risk?

4) How can these multiple strands of evidence be usefully synthesised into an “integrated catastrophe assessment”?

The report suggests that understanding bad-to-worst-case scenarios is vital to robust decision-making, from preparation to consideration of emergency responses. The proposed research agenda aims to direct exploration of the worst risks associated with anthropogenic climate change.

An IPCC special report on catastrophic climate change

The report argues that the Intergovernmental Panel on Climate Change (IPCC) has yet to give focused attention to catastrophic climate change. The report suggests that a special report on catastrophic climate change could help trigger further research and help bring into focus how much is at stake in a worst-case scenario.

Effective communication of research results

Finally, the report suggests that effective communication of research results will be key to trigger action. The role of emotions is complex, and it is strategic to adjust messages for specific audiences. The report highlights the importance of avoiding political bundling, selecting trusted messengers, and choosing effective frames to ensure a useful and accurate civic discussion.