Colorado River is drying faster than we can imagine threatening over 40M people depending on it: Scientists
The 1,450-mile waterway is losing 9.3% of its flow for every 1-degree-Celsius in temperature, says a new study
A warming climate has been drying up the Colorado river — the lifeline of southwestern America — threatening over 40M people who depend on it, finds a new study.
Currently, seven states depend on the river, supporting more than $1 trillion of economic activity each year. The 1,450-mile waterway has been losing 9.3% of its flow, on average, for every 1-degree-Celsius rise in temperature, the study adds.
"We have wasted nearly 30 years bickering over the science. The science is crystal clear — we must reduce greenhouse gas emissions immediately,” Brad Udall, a senior scientist at Colorado State University and an expert on water supplies in the west who was not involved in the research, told the Guardian.
To arrive at these findings, a team of scientists studied changes in the flow of the river from 1912 to 2017 by modeling historical data on temperature, snow or rainfall and snow cover. Through this, the team could understand how the river has been changing over the years.
Loss of snow cover
Feeding the river is melted snow, which is carried from the Rocky Mountains to the Gulf of California. The river, in turn, nourishes the two largest water reserves, Lake Powell and Lake Mead.
But snow cover on the Colorado basin has been decreasing over the century. High temperatures have resulted in the loss of snow in the Colorado River basin. When there is not enough snow cover, scientists explain, the river will absorb more of the sun’s energy. As a result, the river loses water due to evaporation.
This points to a scenario where the evaporation overtakes snowfall or precipitation — leading to the dwindling flow.
Building on past data, the team also predicted how the river could change in the future. If we do not curb our greenhouse emissions, we could stand to lose 14 to 26% river flow, compared with the average annual flow during the last century.
“This has important implications for water users and managers alike,” Udall said. “More broadly, these results tell us that we need to reduce greenhouse gas emissions as soon as we possibly can," he added.
The study has been published in Science.