Understanding and predicting hydroclimatic extremes in the Anthropocene : a causal, stochastic physics approach
department or school: Forestry, Faculty of
data provider: DSpace
degree campus: UBCV
creator: Kaluarachchi, Samadhee
issued: 2025-10-15T15:17:08Z
issued: 2025
related degree: Master of Science - MSc
degree grantor: University of British Columbia
description: Anthropogenic activities such as climate change and forest harvesting have amplified magnitudes and frequencies of a range of hydroclimatic extremes, with continued increases expected throughout the 21st Century. Extreme events have already caused deaths, adverse health impacts, infrastructure damage, lawsuits, and major economic losses worldwide, underscoring the urgent need for effective risk management. Reliable projections and effective solutions are essential for managing risk, and both depend on a sound understanding of hydroclimatic phenomena. This thesis synthesizes insights from across hydroclimatology literature to argue that a causal, stochastic approach is the most reliable framework for understanding extremes. Stochastic physics embeds physical understanding within probabilistic distributions, accounting for the phenomenon’s natural and anthropogenic controls. It allows for identification of change between a system’s natural and anthropogenically influenced states, especially large frequency changes which surpass those of magnitude. A review of changing hydroclimatic regimes, core stochastic physics principles, and finance literature on system fragility suggests that such large frequency changes under anthropogenic influence may stem, at least in part, from natural regimes which are inherently sensitive (or fragile) to disturbance. The strengths of a causal, stochastic approach are highlighted with a forest hydrology example, where the question of whether forests mitigate large floods remains a decades-long scientific controversy. The traditional deterministic approach uses regression analysis to compare floods between control (e.g., forested) and treatment (e.g., harvested) catchments to study the effects of changing forest cover. This approach evokes less relevant research questions, an improper hypothesis, and a non-causal experiment, indicating low rigour in its conclusions. In contrast, a causal, stochastic approach using probabilistic concepts to …
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/92607
note: UNDERSTANDING AND PREDICTING HYDROCLIMATIC EXTREMES IN THE ANTHROPOCENE: A CAUSAL, STOCHASTIC PHYSICS APPROACH by Samadhee Kaluarachchi B.Sc. (Hons), The University of British Columbia, 2023 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE in THE FACULTY OF GRADUATE AND POSTDOCTORAL STUDIES (Forestry) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) October 2025 © Samadhee Kaluarachchi, 2025 ii The following individuals certify that they have read, and recommend to the Faculty of Graduate and Postdoctoral Studies for acceptance, the thesis entitled: Understanding and predicting hydroclimatic extremes in the Anthropocene: A causal, stochastic physics approach submitted by Samadhee Kaluarachchi in partial fulfilment of the requirements for the degree of Master of Science in Forestry Examining Committee: Dr. Younes Alila, Professor, Department of Forest Resources Management, UBC Supervisor Dr. Bianca Eskelson, Professor, Department of Forest Resources Management, UBC Supervisory Committee Member Dr. Scott McDougall, Associate Professor, Department of Earth, Ocean and Atmospheric Sciences, UBC Additional Examiner Additional Committee Members: Dr. Cindy Prescott, Professor Emerita, Department of Forest and Conservation Sciences, UBC Supervisory Committee Member iii Abstract Anthropogenic activities such as climate change and forest harvesting have amplified magnitudes and frequencies of a range of hydroclimatic extremes, with continued increases expected throughout the 21st Century. Extreme events have already caused deaths, adverse health impacts, infrastructure damage, lawsuits, and major economic losses worldwide, underscoring the urgent need for effective risk management. Reliable projections and effective solutions are essential for managing risk, and both depend on a sound understanding of hydroclimatic phenomena. This thesis synthesizes insights from across hydroclimatology literature to argue that a causal, stochasti…
has type: Thesis/Dissertation
date issued: 2025-11
is shown at: 10.14288/1.0450434
language: eng
degree discipline: Forestry
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Alila, Younes, 1962-
type: Text
identifier URI: http://hdl.handle.net/2429/92607