Rising air temperatures mean we need to prepare now for a future with less water in Utah’s rivers.
It is undeniable that Utah’s temperatures have risen dramatically over the last 30+ years. This temperature increase creates a cascade of impacts to Utah’s watersheds and will have major economic impacts on every Utah resident. We stand at a crossroads — we can continue to ignore the effects of the changing climate or we can adapt to this reality.
Utah is unprepared for the effects that warmer temperatures are having on every watershed and every aspect of the state’s economy—from healthcare to recreation. A study by NRDC ranked Utah as one of the 7 least-prepared states for the challenges of the 21st Century. We can mitigate the damage, but only if we are proactive.
Over 80% of the Wasatch Front’s water comes from snowmelt runoff. Increasing air temperatures will result in more rain and less snow. This, in turn, threatens our snowpack, which will have massive consequences on our ecosystems and economy.
Climate models indicate there may be a 5-15% increase in precipitation levels in Northern Utah, but rising temperatures mean this will occur more frequently as rain—leading to less snow accumulation and an earlier snowmelt. Because the snowpack is instrumental in holding water and preventing loss through runoff, less total snow and earlier snow melting could lead to droughts and shortages.
An analysis of snowpack between 1979 and 2008 in both the Ben Lomond watershed and in the Oquirrh Mountains made some startling estimations. One study estimated there would be an 8 – 10% decrease in snow with each 1°C in warming of the air mass above the surface (the troposphere).
How warm will Utah get?
Over the past 100 years, the Earth’s average temperature has increased 1.3°F. Utah’s distance from the ocean’s cooling effects has lead to more dramatic temperature increases over the same period—about 2.7°F.
It has been estimated that by 2050, air temperatures in Utah will be ~3°F higher in winter and ~3.6°F higher in the summer compared to current temperatures. By the year 2100, average Utah air temperatures may increase by ~6°F in winter and by ~8°F in summer above today’s temperatures. The effects of such drastic temperature increases could be catastrophic—especially if we ignore the issue.
What’s the big deal about a few degrees?
A few degrees warmer might seem like a small change, but it could have huge repercussions—particularly by increasing the frequency and severity of extreme weather events like droughts, floods and heat waves. As you can see in the graphic below, an increase of just 3°F in the average air temperature skyrockets the odds of having a drought by 2,500% (or one drought for every three years). Apply this same concept to floods, heat waves and wildfires, and it becomes clear we need to think carefully about how to prepare for more risk.
Today, the Colorado River Basin provides water to over 30 million people, and over 80% of that water comes from snowmelt in headwater states, including Utah. This means Utah’s snowpack is critical not just to Utahns, but also to Westerners from outside our borders. Increased air temperatures are expected to lower Colorado River stream-flow by 9-30% in coming decades according to a number of studies.
That’s why new diversions like the Lake Powell Pipeline must be carefully scrutinized by all Colorado River Basin residents and Utahns should be wary of claims by water project salesmen that the Pipeline has no risk.
The American Southwest could see a long-term drying period with lower precipitation levels—something that historically occurred only once every hundred years and is now predicted to become more frequent. Coined a ‘megadrought,’ this could be particularly difficult for Southern Utah, where streams already are under great duress during summer months.
It’s time to act
Utah is already the second most arid state in the nation, and as temperatures continue to increase we can expect less snow at the end of each winter. That makes it hard to imagine why some Utah water suppliers are years behind the rest of the West in determining the impacts of the decreasing snowpack. These agencies need to estimate how much less water they will receive in coming years as a function of these losses, and make up time to develop a better plan for mitigating the damage caused by climate change.