Rate-Induced Tipping to Metastable Zombie Fires
arXiv:2210.02376 · doi:10.1098/rspa.2022.0647
Abstract
Zombie fires in peatlands disappear from the surface, smoulder underground during the winter, and `come back to life' in the spring. They can release hundreds of megatonnes of carbon into the atmosphere per year and are believed to be caused by surface wildfires. Here, we propose rate-induced tipping (R-tipping) to a subsurface hot metastable state in bioactive peat soils as a main cause of Zombie fires. Our hypothesis is based on a conceptual soil-carbon model subjected to realistic changes in weather and climate patterns, including global warming scenarios and summer heatwaves. Mathematically speaking, R-tipping to the hot metastable state is a nonautonomous instability, due to crossing an elusive quasithreshold, in a multiple-timescale dynamical system. To explain this instability, we provide a framework combining a special compactification technique with concepts from geometric singular perturbation theory. This framework allows us to reduce an R-tipping problem due to crossing a quasithreshold to a heteroclinic orbit problem in a singular limit. We identify generic cases of tracking-tipping transitions via: (i) unfolding of a codimension-two heteroclinic folded saddle-node type-I singularity for global warming, and (ii) analysis of a codimension-one saddle-to-saddle hetroclinic orbit for summer heatwaves, in turn revealing new types of excitability quasithresholds.
arXiv comment35 pages, 15 figures
References in corpus (9)
- Tipping points in open systems: bifurcation, noise-induced and rate-dependent examples in the climate system
- A mathematical framework for critical transitions: bifurcations, fast-slow systems and stochastic dynamics
- Parameter shifts for nonautonomous systems in low dimension: Bifurcation- and Rate-induced tipping
- When very slow is too fast -- collapse of a predator-prey system
- Probability of noise- and rate-induced tipping
- Adapting to a Changing Environment: Non-obvious Thresholds in Multi-Scale Systems
- Compactification for Asymptotically Autonomous Dynamical Systems: Theory, Applications and Invariant Manifolds
- Rate and Noise-Induced Tipping Working in Concert
- Rate-Induced Tipping to Metastable Zombie Fires