Extreme Outcomes: Prospects for major tipping and socially contingent events and associated economic and social costs

The document assesses 'extreme outcomes'—near-catastrophic climate events and socially contingent responses—that are often underrepresented in economic assessments. It identifies key biogeophysical tipping elements, such as the melting of the Greenland and West Antarctic ice sheets, and evaluates their potential to trigger severe economic losses and social instability. A high-end sea level rise scenario of 1.65m by the 2080s is estimated to cost approximately $1 trillion per year and displace millions. The brief also explores the nexus of climate change, state fragility, and forced migration, particularly in South Asia and Bangladesh, arguing that these 'wicked problems' require multiple lines of evidence and a shift toward building resilience rather than simple prediction.

• Biogeophysical tipping elements that could have serious consequences within 50 to 100 years include the melting of the Greenland and West Antarctic ice caps, Hindu-Kush-Himalaya-Tibetan glaciers, changes in the Atlantic thermohaline circulation (THC) and El Niño/Southern Oscillation (ENSO), Amazon drought, and shifts in the Indian summer monsoon and southwestern North American rainfall.
• A high-end sea level rise (SLR) scenario of 1.65m by the 2080s could result in the loss of nearly 60% of global wetlands and put over 30 million additional people per year at risk from coastal flooding, with undiscounted economic costs reaching approximately $1 trillion per year.
• Current estimates suggest that over 100 million people could seek to move due to climatic risks, potentially as early as the 2050s, building upon an existing base of over 30 million migrants already caused partially by environmental forcing.
• In South Asia, the combination of physical climate impacts, such as the instability of the Indian monsoon and glacial retreat, could interact with security and conflict to create a socially contingent tipping point.
• The inclusion of tipping elements as discontinuities in the PAGE09 integrated assessment model significantly increases the social cost of carbon (SCC); without these discontinuities, the mean SCC value drops from $106 to $79 per tonne of CO2, a 25% decrease.
• In Bangladesh, sea level rise is projected to severely reduce cultivable land and paddy crops; with a rise of 88 cm, cultivable land could drop from 45% to 15%, and the major paddy crop could be reduced from 88% to 12%.
• Climate change and extreme outcomes are characterized as 'wicked' environmental problems because their definition depends on framing, stakeholders hold conflicting views, and there is a limited window for action with strong path-dependence.

APA

Downing, T. E., & Butterfield, R. E. (2012). Extreme Outcomes: Prospects for major tipping and socially contingent events and associated economic and social costs. Stockholm Environment Institute. https://www.sei.org/mediamanager/documents/Publications/SEI-PolicyBriefingNote-ExtremeOutcomes-2012.pdf

Chicago

Downing, Thomas E, and Ruth E Butterfield. Extreme Outcomes: Prospects for major tipping and socially contingent events and associated economic and social costs. Stockholm Environment Institute, 2012. https://www.sei.org/mediamanager/documents/Publications/SEI-PolicyBriefingNote-ExtremeOutcomes-2012.pdf.

Wikipedia

{{cite report |last1=Downing |first1=Thomas E |last2=Butterfield |first2=Ruth E |title=Extreme Outcomes: Prospects for major tipping and socially contingent events and associated economic and social costs |publisher=Stockholm Environment Institute |date=April 2012 |url=https://www.sei.org/mediamanager/documents/Publications/SEI-PolicyBriefingNote-ExtremeOutcomes-2012.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{downing2012extreme, author = {Downing, Thomas E and Butterfield, Ruth E}, title = {{Extreme Outcomes: Prospects for major tipping and socially contingent events and associated economic and social costs}}, institution = {Stockholm Environment Institute}, year = {2012}, month = apr, url = {https://www.sei.org/mediamanager/documents/Publications/SEI-PolicyBriefingNote-ExtremeOutcomes-2012.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }