Keynote 2: Tipping positive change to avoid climate tipping points - Prof. Tim Lenton

Transcript

1. Tipping positive change to avoid climate tipping points Tim Lenton t.m.lenton@exeter.ac.uk
2. Passing a tipping point Thanks to Chris Boulton for the animation
3. Already at ~1.4°C of global warming, warmwater coral reefs are crossing their tipping point and experiencing unprecedented dieback.
4. Lenton et al. (2019) Nature
5. Early warning signals in observational data Central western Greenland Ice Sheet Atlantic Meridional Overturning Circulation Boers et al. (2025) Nature Geoscience Amazon Rainforest
6. Tipping point risks increase with warming Global Tipping Points Report 2025 & Armstrong McKay, et al. (2022) Science
7. Atlantic Meridional Overturning Circulation (AMOC)
8. AMOC tipping point in a 2°C warmer world van Westen & Baatsen (2025) GRL
9. Unsustainable state Sustainable state
12. Norwegian car sales 100% 90% 80% Market share 70% 60% 50% 40% 30% 20% 10% 0% 1990 1995 2000 2005 2010 2015 2020 Year Battery Electric Plugin Hybrid Non-plugin Hybrid Diesel Petrol
13. Members of A-Ha with Harald Røstvik and Frederic Hauge Credit: William Mikkelsen / Harald N. Røstvik files
14. Early opportunity signals prior to tipping Mercure et al. (2025) Nature Communications
16. EV cars cheaper than petrol cars in many markets Cascade of positive tipping points Electric vehicles cheaper than petrol cars in major economies Electric vehicle support policies in major economies Petrol cars still cheaper EV light trucks cheaper than diesel EV & battery deployment up; costs down Diesel trucks still cheaper Renewables + battery storage cheaper than coal power Petrol cars cheaper than electric vehicles Coal still cheaper Oil firms commit fully to diversifying investments Oil firms still hedging their bets Sharpe & Lenton (2021) Climate Policy
17. UK electricity production Updated from Sharpe & Lenton (2021) Climate Policy
19. Credit: Russell Watkins / DFID
20. We've identified the 10 most viable positive tipping points: Global Tipping Points Report 2025
21. Nijsse et al. (in review)
22. Yellowstone wolf reintroduction North Sea fish stock recovery Baltic sea potential recovery UK, Netherlands shallow lake recovery Netherlands seagrass, mussel bed restoration Pacific kelp forests sea otter recovery Rajasthan community groundwater management Florida saltmarsh restoration Philippines, Kenya marine reserves Indonesia mangrove restoration Pacific islands locally managed marine areas Kenya, Uganda smallholder tree planting Tanzania community forest management Amazon rainforest potential regeneration Lenton (2026) Nature Sustainability
23. The International Small-group Tree planting initiative (TIST) Credit: TIST
24. Credit: TIST
25. MOVING FROM CATASTROPHE TO PROSPERITY - Limiting overshoot of 1.5 °C global warming is the - only way to avoid catastrophic risks from Earth system tipping points With collective action and policies to phase-out fossil fuels and regenerate nature we can turn from facing existential tipping point risks to seizing positive tipping point opportunities
26. GLOBAL TIPPING POINTS REPORT 2025 global-tipping-points.org