Patrick M. Reed

Professor

Patrick Reed is a professor of engineering. He is senior author on a study published last month about drivers of the water shortage in the Colorado West Slope river basins. The study found a potential 50% drop in the West Slope basin’s inflows to Lake Powell over the next several decades. 

Reed says:

“Although Lake Powell’s storage hitting a record low elevation brings a lot of attention, the issues driving the system to this record represent years in the making. You have a complex mixture of drought drivers and human use uncertainties that have to be navigated as we move forward.

“The record low elevation in Lake Powell emphasizes the need to carefully understand at the user level how water rights, demands, and drought interact to shape water shortages. This will be critical information for formulating effective near-term to long-term management responses.”

Flavio Lehner

Climate scientist and associate professor of earth and atmospheric science

Flavio Lehner is a climate scientist and associate professor. He has monitored water supply in the Southwest for about a decade.

Lehner says: 

 

“A crisis in the making. What sounds cliché is for once very true when it comes to the current water scarcity in the Colorado River, the major water artery of the Southwest serving 40 million people and supporting a large agricultural and energy production enterprise. There is on the one hand the human water consumption, which, despite having stabilized recently, has outpaced the amount of water the river typically delivers each year. Then, there’s human-made climate change, which has raised temperatures, leading to more water being lost to evaporation.

 

“But the elephant in the room remains the question of what is happening to precipitation? The Colorado River Basin has seen a steady decline in precipitation since the 1980s, which is really what set the pace for the water scarcity now making headlines. For a long time - and counter to the clear story of fossil fuel-driven warming - it was unclear whether the reduction in precipitation itself is influenced by climate change. Too variable and complex are the processes shaping multi-decadal precipitation trends in the region.

 

“I’m involved in new research suggesting the precipitation decline itself might have a human fingerprint. The combination of greenhouse gases and aerosol emissions (think air pollution) over the past 2-3 decades appear to have systematically shifted weather patterns such that they deliver less precipitation to the Southwest. Combine this with the human water consumption and growing evaporative losses and the current water crisis suddenly appears much more inevitable than previously assumed. 

 

The Pacific Ocean is the pacemaker of North American’s weather. As big population centers, especially in Asia, clean up their air, the precipitation-suppressing weather patterns should wane, yet humans are clearly continuing to emit greenhouse gases, which all but guarantees continued water scarcity in the Southwest.”