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.

Back to top

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.

Back to top