The Press and Pulse of Climate Change: Extreme Events in the Colorado River Basin

Abstract

Extremes in temperature and precipitation are associated with damaging floods, prolonged drought, destructive wildfires, agricultural challenges, compromised human health, vulnerable infrastructure, and threatened ecosystems and species. Often, the steady and progressive trends (or presses) of rising global temperature are the central focus in how climate impacts are described. However, observations of extreme weather events (or pulses) increasingly show that the intensity, duration and/or frequency of acute events are also changing, resulting in greater impacts on communities and the environment. Describing how the influence of extreme events may shape water management in the Colorado River Basin in clear terms is critical to sound future planning and efforts to manage risk. Three scenario planning workshops in 2019 and 2020 were held as part of a Colorado River Conversations series, identifying potential impacts from multiple intersecting extreme events. Water managers identified climate‐related events of concern in the Colorado River Basin that necessitate greater attention and adaptive responses. To support efforts to include consideration of climate‐change‐driven extremes in water management and planning, we explore the current state of knowledge at the confluence of long‐term climate shifts and extreme weather in the Colorado River Basin related to the events of concern that were identified by scenario planning participants.

A survey of blow fly (Diptera: Calliphoridae) populations in Phoenix, Arizona

“…While the most extreme effects may be seen in the desert, Arizona is a highly diverse state, and temperatures are rising across its deserts, mountains, rivers, and forests. Concurrently, the late summer monsoons that typically bring relief to these regions are often delayed or even entirely absent (McCoy et al, 2022), resulting in increased duration of these extreme temperatures. Blow flies are already the product of extreme specialization as a result of their exploitation of a highly competitive resource, but in the desert they must also confront temperatures that approach the very limits of their survival.…”

Stakeholder-Informed Hydroclimate Scenario Modeling in the Lower Santa Cruz River Basin for Water Resource Management

“…It is useful to identify riparianrelated areas likely to experience the highest degree of impacts and assessment of changes in precipitation and temperature that can affect environmental habitat suitability for species across the study region. This approach can be applied to environmental management and planning efforts in other areas in which wet/dry seasonality and/or highly variable rainfall and streamflow strongly influence environmental functions [6,66].…”

Featured Collection introduction: Severe sustained drought revisited managing the Colorado River system in times of water shortage 25 years later—Part II

“…The call for papers for the JAWRA Featured Collection: Severe Sustained Drought Revisited: Managing the Colorado River System in Times of Water Shortage 25 Years Later led to more insights than could fit into a single issue. This second set of articles highlights the work done by Salehabadi et al (2022) on three historically based drought scenarios, McCoy et al (2022) on explaining seven climate‐related extreme events of greatest interest to water managers, Colby and Hansen (2022) on urban water demand management and policies for improving water supply reliability, Garcia‐Hernandez et al (2022) on water quality in the Colorado River Delta, and Ayres et al (2022) on economic losses from reducing inflows into the Salton Sea. These papers, alongside the first set of articles (see overview in Frisvold et al, 2022), continue to illustrate the range of challenges and the expertise applied to them in thoughtful, innovative, and multi‐disciplinary ways.…”

“…The article cites a few analyses that find some programs are not especially cost‐effective (i.e., they achieve minimal reductions in water demand per program dollar spent) and includes an appendix that briefly describes programs that different cities have adopted to reduce urban water use. As with the McCoy et al (2022) article, this article will be highly useful to urban water managers and other regional stakeholders. Water managers can see what other cities are doing, what the current literature says about the performance of different programs, and what methods could be used to evaluate their own programs.…”

“…The article by McCoy et al (2022) builds on three scenario planning workshops held as part of a Colorado River Conversations series (https://ccass.arizo na.edu/color ado-river -conve rsati ons-project). At these workshops, water managers identified the most concerning climaterelated extreme events.…”