Data from the Coupled Model Intercomparison Project (CMIP) examined the potential climate impact on Colorado River flows through 2050. With current operating guidelines expiring in 2026, this study will help lawmakers develop a long-term plan for water use.

 

The study shows the importance of precipitation variability and how to best understand past, present, and future changes from "natural, unforced variability or in response to changes in radiative forcing in a multi-model context." Further, while past studies had found that from 2000 through 2021 marked the driest period over the last 1,200 years. However, according to studies by the University of Colorado and the University of Hawaii, that has likely changed as the region may be due for an upswing in precipitation as during that time there were about 12.5 million acre-feet of water that could uptick to 13.5 million acre-feet.

CMIP agrees with this research as precipitation in the upper Colorado River basin is expected to increase by 5% to 7% between 2026 and 2050. With that, the study shows that an increase in rainfall is projected to counteract some flow reductions caused by basin-wide warming. Further, there appears to be potential variance in precipitation at Lees Ferry - the place where visitors can drive up to the water's edge - ranging between a 25% dip and a 40% increase.

The report indicates that water resource recovery is achievable when flows are modeled based on drought conditions similar to those from 2000 to 2020. However, landscape architects should be aware of the ongoing risk of further declines in river flows, particularly if temperature increases are not balanced by corresponding gains in precipitation.