Overview
I'm currently a postdoc on the ECCLES project led by Prof. Peter Cox studying connections between emergent constraints and early-warning signals used to detect the approach of a tipping point. A system is often described to pass a tipping point when gradual changes made to input levels or rates cause the output to suddenly change state. Whilst Emergent Constraints are a method for reducing uncertainties in climate change projections. Other current work involves studying the possibility of briefly overshooting tipping thresholds, and the stability of methane hydrates in the sediment beneath the ocean floor.
In my previous postdoc position, supervised by Prof. Tim Lenton and Dr. Anna Harper, I studied potential tipping points in UK ecosystem services from future land-use and climate change projections. This project involved used the Joint UK Land Environment Simulator (JULES) a land-surface model to look for tipping events in carbon stocks, greenhouse gas emissions and frehwater fluxes.
During my PhD (also here at Exeter) I studied the underlying dynamics behind tipping points, supervised by Prof. Jan Sieber and Prof. Peter Cox. In particular my work studied a more recent concept of tipping known as rate-induced tipping. For classical tipping events such as a slow passage through a fold bifurcation, so-called early-warning indicators (increase in autocorrelation and variance) have been developed to detect the approach of a tipping point. However, for rate-induced tipping the dynamics are different and thus it is unclear if these early-warning indicators can still be used for rate-induced tipping events. However, we were able to show that there exists both a delay in the time of tipping from when one would expect to see tipping and in the early-warning indicators. Furthermore, these delays are consistent such that we conclude that early-warning indicators can be used for rate-induced tipping events.
Publications
Copyright Notice: Any articles made available for download are for personal use only. Any other use requires prior permission of the author and the copyright holder.
| 2024 | 2023 | 2022 | 2021 | 2020 | 2019 | 2017 | 2016 |
2024
- Huntingford C, Cox PM, Ritchie PDL, Clarke JJ, Parry IM, Williamson MS. (2024) Acceleration of daily land temperature extremes and correlations with surface energy fluxes, npj Climate and Atmospheric Science, volume 7, no. 1, article no. 84, DOI:10.1038/s41612-024-00626-0. [PDF]
- Ritchie P, Lux-Gottschalk K. (2024) Uncertainty quantification for overshoots of tipping thresholds, DOI:10.5194/egusphere-egu24-8618. [PDF]
- Lenton T, Ritchie P, Boulton C. (2024) Are early warning signals present for climate tipping points detected in CMIP6?  , DOI:10.5194/egusphere-egu24-11464. [PDF]
- Parry I, Ritchie P, Cox P. (2024) Analysing the impact of solar radiation management on the terrestrial biosphere in CMIP6 models, DOI:10.5194/egusphere-egu24-15841. [PDF]
2023
- Ritchie PDL, Abrams JF, Armstrong McKay DI, Cox PM, Lenton TM. (2023) Tipping points: Both problem and solution, One Earth, volume 6, no. 12, pages 1610-1613, DOI:10.1016/j.oneear.2023.11.016. [PDF]
- Dakos V, Boulton CA, Buxton JE, Abrams JF, Armstrong McKay DI, Bathiany S, Blaschke L, Boers N, Dylewsky D, López-Martínez C. (2023) Supplementary material to "Tipping Point Detection and Early-Warnings in climate, ecological, and human systems", DOI:10.5194/egusphere-2023-1773-supplement. [PDF]
- Dakos V, Boulton CA, Buxton JE, Abrams JF, Armstrong McKay DI, Bathiany S, Blaschke L, Boers N, Dylewsky D, López-Martínez C. (2023) Tipping Point Detection and Early-Warnings in climate, ecological, and human systems, DOI:10.5194/egusphere-2023-1773. [PDF]
- Ritchie PDL, Alkhayuon H, Cox PM, Wieczorek S. (2023) Rate-induced tipping in natural and human systems, Earth System Dynamics, volume 14, no. 3, pages 669-683, DOI:10.5194/esd-14-669-2023. [PDF]
- Huntingford C, Cox PM, Williamson MS, Clarke JJ, Ritchie PDL. (2023) Emergent constraints for the climate system as effective parameters of bulk differential equations, Earth System Dynamics, volume 14, no. 2, pages 433-442, DOI:10.5194/esd-14-433-2023. [PDF]
- Huntingford C, Cox P, Rithie P, Clarke J, Williamson M. (2023) Acceleration of Daily Land Temperature Extremes and Link to Land Forcing, DOI:10.5194/egusphere-egu23-17519. [PDF]
- Clarke J, Cox P, Ritchie P, Huntingford C. (2023) Spatial Early Warning Signals for Rapidly Forced Systems, DOI:10.5194/egusphere-egu23-12923. [PDF]
- Ritchie P, Alkhayuon H, Cox P, Wieczorek S. (2023) When to Expect Rate-Induced Tipping in Natural and Human Systems, DOI:10.5194/egusphere-egu23-8105. [PDF]
- Cox P, Williamson M, Clarke J, Huntingford C, Ritchie P. (2023) The paradox of the darkening planet and the Earth’s climate sensitivity, DOI:10.5194/egusphere-egu23-7393. [PDF]
- Parry I, Ritchie P, Cox P. (2023) Evidence of localised Amazon rainforest dieback in CMIP6 models, DOI:10.5194/egusphere-egu23-17341. [PDF]
- Clarke JJ, Huntingford C, Ritchie PDL, Cox PM. (2023) Seeking more robust early warning signals for climate tipping points: the Ratio of Spectra method (ROSA), Environmental Research Letters, DOI:10.1088/1748-9326/acbc8d. [PDF]
2022
- Wunderling N, Winkelmann R, Rockström J, Loriani S, Armstrong McKay DI, Ritchie PDL, Sakschewski B, Donges JF. (2022) Global warming overshoots increase risks of climate tipping cascades in a network model, Nature Climate Change, volume 13, no. 1, pages 75-82, DOI:10.1038/s41558-022-01545-9. [PDF]
- Parry IM, Ritchie PDL, Cox PM. (2022) Evidence of localised Amazon rainforest dieback in CMIP6 models, Earth System Dynamics, volume 13, no. 4, pages 1667-1675, DOI:10.5194/esd-13-1667-2022. [PDF]
- Ritchie P, Alkhayuon H, Cox P, Wieczorek S. (2022) Rate-induced tipping in natural and human systems, DOI:10.5194/egusphere-2022-1176. [PDF]
- Huntingford C, Cox PM, Williamson MS, Clarke JJ, Ritchie PDL. (2022) Emergent constraints for the climate system as effective parameters of bulk differential equations, DOI:10.5194/esd-2022-43. [PDF]
- Ritchie PDL, Parry I, Clarke JJ, Huntingford C, Cox PM. (2022) Increases in the temperature seasonal cycle indicate long-term drying trends in Amazonia, Communications Earth & Environment, volume 3, no. 1, article no. 199, DOI:10.1038/s43247-022-00528-0. [PDF]
- Wunderling N, Winkelmann R, Rockström J, Loriani S, Armstrong-McKay D, Ritchie P, Sakschewski B, Donges J. (2022) Global warming overshoots increase risk of triggering climate tipping points and cascades, DOI:10.21203/rs.3.rs-1418830/v1.
- Parry I, Ritchie P, Cox P. (2022) Evidence of Amazon rainforest dieback in CMIP6 models, DOI:10.48550/arxiv.2203.11744.
- Wunderling N, Winkelmann R, Rockström J, Loriani S, McKay DA, Ritchie P, Sakschewski B, Donges JF. (2022) Tipping risks due to temperature overshoots within the Paris range, DOI:10.5194/egusphere-egu22-4425. [PDF]
- Clarke J, Huntingford C, Ritchie P, Cox P. (2022) Early Warning Signals For Climate Tipping Points: Beyond White Noise, DOI:10.5194/egusphere-egu22-10031. [PDF]
- Parry I, Ritchie P, Cox P. (2022) Evidence of Amazon rainforest dieback in CMIP6 models, DOI:10.5194/egusphere-2022-82. [PDF]
2021
- Clarke J, Huntingford C, Ritchie P, Cox P. (2021) The compost bomb instability in the continuum limit, The European Physical Journal Special Topics, volume 230, no. 16-17, pages 3335-3341, DOI:10.1140/epjs/s11734-021-00013-3. [PDF]
- Ritchie PDL, Clarke JJ, Cox PM, Huntingford C. (2021) Overshooting tipping point thresholds in a changing climate, Nature, volume 592, no. 7855, pages 517-523, DOI:10.1038/s41586-021-03263-2. [PDF]
2020
- Boulton CA, Ritchie PDL, Lenton TM. (2020) Abrupt changes in Great Britain vegetation carbon projected under climate change, Global Change Biology, volume 26, no. 8, pages 4436-4448, DOI:10.1111/gcb.15144. [PDF]
- Clarke J, Ritchie P, Cox P. (2020) Conditions for the Compost Bomb Instability, DOI:10.5194/egusphere-egu2020-9929. [PDF]
- Ritchie P, Cox P, Sieber J. (2020) How fast to turn around: preventing tipping after a system has crossed a climate tipping threshold, DOI:10.5194/egusphere-egu2020-5555. [PDF]
- Ritchie P, Smith G, Davis K, Fezzi C, Halleck-Vega S, Harper A, Boulton C, Binner A, Day B, Gallego-Sala A. (2020) Shifts in national land use and food production in Great Britain after a climate tipping point, Nature Food, volume 1, pages 76-83, DOI:10.1038/s43016-019-0011-3. [PDF]
2019
- Ritchie PDL, Harper AB, Smith GS, Kahana R, Kendon EJ, Lewis H, Fezzi C, Halleck-Vega S, Boulton CA, Bateman IJ. (2019) Large changes in Great Britain’s vegetation and agricultural land-use predicted under unmitigated climate change, Environmental Research Letters, volume 14, no. 11, pages 114012-114012, DOI:10.1088/1748-9326/ab492b. [PDF]
- Ritchie P, Karabacak Ö, Sieber J. (2019) Inverse-square law between time and amplitude for crossing tipping thresholds, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, volume 475, no. 2222, DOI:10.1098/rspa.2018.0504.
2017
- Ritchie P, Sieber J. (2017) Probability of noise- and rate-induced tipping, Physical Review E, volume 95, no. 5, DOI:10.1103/PhysRevE.95.052209.
2016
- Ritchie P, Sieber J. (2016) Early-warning indicators for rate-induced tipping, Chaos, volume 26, no. 9, DOI:10.1063/1.4963012.
Further information
Conferences and Presentations
Challenges of Predicting Critical Transitions in Natural Systems, Exeter, December 2023
SIAM Conference on Applied Dynamical Systems, Portland, USA, May 2023
EGU General Assembly, Lead convener, Vienna, Austria, April 2023
EGU General Assembly, Vienna, Austria, April 2023
Invited One World Mathematics of Climate seminar, Online, April 2023
Joint TiPES/CriticalEarth Conference, Munich, Germany, February 2023
OptimESM kick-off meeting, Online, February 2023
TiPES Conference, Dartington Hall, September 2022
GAMM Conference, Aachen, Germany, August 2022
SIAM Mathematics of Planet Earth, Online, July 2022
Tipping Points Reading Group, March 2022
Sky news appearance for Nature paper, April 2021
Invited Applied Mathematics Seminar to Universiry College Cork, Online, February 2021
Emergent Constraints & Tipping Points workshop, Online, November 2020
TiPES Webinar, Online, July 2020
EGU2020: Sharing Geoscience Online, Online, May 2020
CMIP6 Analysis Workshop, Online, April 2020
Tipping Points Reading Group, January 2020
Valuing Nature Conference, London, October 2019
European Climate Change Adaptation (ECCA) Conference, Lisbon, Portugal, May 2019
CRITICS Summer Meeting, Cork, Ireland, August 2018
JULES users Reading Group, March 2018
LWEC Conference, January 2018, Poster
Met Office visit, December 2017
Valuing Nature Conference, Edinburgh, October 2017, Poster
Tipping Points Reading Group, September 2017
CRITICS Summer meeting, Valladolid, Spain, September 2017
Dynamics Days Europe, Szeged, Hungary, June 2017
SIAM Conference on Applications of Dynamical Systems, Snowbird , USA, May 2017
Tipping Points Reading Group, August 2016
Climate Tipping Points Workshop, Dartington Hall, April 2016
Dynamical Systems Reading Group, November 2015
Dynamics Days Conference, Exeter, September 2015, Poster
Equadiff Conference, Lyon, France, July 2015
SIAM Conference on Applications of Dynamical Systems, Snowbird, USA, May 2015
Dynamical Systems Reading Group, May 2014
ICMS Tipping Points Worshop, September 2013, Poster
Emergent Constraints & Tipping Points workshop
In November 2020 we hosted an online collaborative workshop to bring together Climate Scientists, Mathematicians and Ecologists to answer key questions around the relationships between the variability and sensitivity of the Earth System and its subcomponents. The first part of the workshop discussed proposed emergent constraints on future projections, many of which are based-on assumed relationships between sensitivity and variability. The second part of the workshop examined potential climate tipping points, in both observational data and climate model projections. The programme is given below and recordings of the presentations can be found using the links attached to the talk titles:
Emergent Constraints Presentations
Monday 23rd November
16:00 – 16:15: Peter Cox & Mark Williamson: Welcome and introduction to the workshop
16:15 – 16:45: Manuel Schlund: Emergent constraints on ECS and carbon cycle feedbacks in CMIP6
16:45 – 17:00: James Annan: What can we learn about climate sensitivity from interannual variability?
17:00 – 17:15: Rebecca Varney: A spatial emergent constraint on the sensitivity of soil carbon turnover to global warming
17:15 – 17:30: Nick Watkins: On Generalized Langevin Dynamics and the Modelling of Global Mean Temperature
17:30 – 18:00: Break
18:00 – 18:30: Peter Caldwell: Evaluating and combining emergent constraints for climate sensitivity
18:30 – 18:45: Benjamin Sanderson: Addressing structural errors in emergent constraints
18:45 – 19:00: Aurélien Ribes: Making climate projections conditional on historical observations
Tuesday 24th November
16:00 – 16:30: Femke Nijsse: Emergent constraints on transient climate response and equilibrium climate sensitivity from historical warming in CMIP5 and CMIP6 models
16:30 – 16:45: Tim Palmer: Very short-range prediction skill as an emergent constraint
16:45 – 17:00: Kasia Tokarska: Observational and emergent constraints on future warming in CMIP6 models
17:00 – 17:15: Richard Wood: Does recent warming constrain long term climate sensitivity?
17:15 – 17:30: Ryan Padrón: Controls of land carbon sink projections from CMIP6 models
17:30 – 18:00: Break
18:00 – 18:15: Jens Terhaar: Emergent constraints on the Southern Ocean anthropogenic carbon uptake
18:15 – 18:45: Chad Thackeray: Assessing prior emergent constraints on surface albedo feedback in CMIP6
18:45 – 19:00: Nicholas Lutsko: Do Low Cloud-Based Emergent Constraints Fail in CMIP6?
Tipping Points Presentations
Wednesday 25th November
14:00 – 14:30: Marten Scheffer: Lost Attraction: tipping humans
14:30 – 14:45: Joe Clarke: The Compost Bomb in the Continuum Limit
14:45 – 15:00: Eoin O’Sullivan: Non-Obvious Thresholds in the Compost Bomb Model
15:00 – 15:15: Niklas Boers: Precursor signals for abrupt transitions in Earth system dynamics
15:15 – 15:45: Break
15:45 – 16:15: Ulrike Feudel: How to study tipping phenomena in highly multistable systems?
16:15 – 16:45: Ricarda Winkelmann: Beyond gradual change: Tipping points in Antarctica
16:45 – 17:00: Paul Ritchie: Overshooting Tipping Point Thresholds in A Changing Climate
Thursday 26th November
14:00 – 14:30: Peter Ditlevsen: What we learn about tipping points from past climate and models
14:30 – 14:45: Frank Kwasniok: Data-driven modelling and prediction of Atlantic Meridional Overturning Circulation collapse
14:45 – 15:00: Johannes Lohmann: Risk of tipping the overturning circulation due to increasing rates of ice melt
15:00 – 15:15: Hassan Alkhayuon: Phase-sensitive tipping: cyclic ecosystems subject to contemporary climate
15:15 – 15:30: Cris Hasan: Spatiotemporal stability of travelling waves in a Rock-Paper-Scissors model
15:30 – 16:00: Break
16:00 – 16:30: Tim Lenton: Tipping positive change
16:30 – 16:45: Nico Wunderling: Network dynamics of drought-induced tipping cascades in the Amazon rainforest
16:45 – 17:00: Concluding Remarks (Peter Cox)