Risk-Based Reanalysis of the Effects of Climate Change on U.S. Cold-water Habitat

Abstract

A probabilistic risk assessment was conducted for the effects of future climate change on U.S. cold-water habitat. Damage functions for the loss of current cold-water fish habitat in the United States and the Rocky Mountain region were integrated with probability distributions for U.S. June/July/August (JJA) temperature change using Monte Carlo techniques. Damage functions indicated temperature thresholds for incipient losses (≥5%) of cold-water habitat in the United States and the Rocky Mountains of 0.6 and 0.4 ∘C, respectively. Median impacts associated with different temperature distributions suggested habitat loss in 2025, 2050, and 2100 of approximately 10, 20, and 30%, respectively, for the United States and 20, 35, and 50%, respectively, in the Rocky Mountains. However, 2100 losses in excess of 60% and 90% were possible for the United States and the Rocky Mountains, respectively, albeit at low probabilities. The implementation of constraints on greenhouse gas emissions conforming to the WRE750/550/350 stabilization scenarios had little effect on reducing habitat loss out to 2050, but median effects in 2100 were reduced by up to 20, 30, and 60%, respectively. Increased focus on probabilistic risk assessment may be a profitable mechanism for enhancing understanding and communication of climate change impacts and, subsequently, risk management.