Four Corners Drought in 2018 Tied to Human-Caused Climate Change
The 2018 water year centered around an intense drought that stuck to the Four Corners. Weak snowpack, unfilled reservoirs and large wildfires arrived with the record-breaking hot and dry weather.
Two years later, a study published in January found that drought was directly tied to the effects of human-caused climate change.
Researchers at the University of California, Santa Barbara looked at how just an increase in temperature is enough for disastrous effects to appear in the region. Emily Williams, the study’s lead author, says one effect was the increase in hotter air sapping moisture from the ground.
“If it can hold more water, that water has to come from somewhere,” Williams said, a Ph.D. candidate in geography at the university. “In this case, it’s from the soil.”
Williams worked alongside her colleagues at UCSB, Chris Funk and Shraddhanand Shukla, and Daniel McEvoy at the Western Regional Climate Center in Reno.
The U.S. Southwest is heating up faster than the global average, Williams said. The Four Corners recorded a difference of 2 degrees Celsius above pre-industrial levels in 2018.
The study shows the Four Corners’ potential for evaporation grew as much as 80 percent under the increased heat - the effects of which are expected to worsen with climate change.
“Everything points to the fact that in these semi-arid environments we’re going to be seeing more and more pronounced impacts,” Williams said.
Williams joined KSJD’s Daniel Rayzel on Morning Edition to share more from the study.
On the effects of drier air in the Four Corners and elsewhere
There’s a very simple physical relationship between temperature and what we call the atmosphere’s water holding capacity. Warmer air really can hold that much more water. In a dry area - like the Four Corners - during dry conditions, if it can hold more water, that water has to come from somewhere. In this case, it’s from the soil.
The very opposite thing is true in a really tropical environment. If there’s a lot of water available, if the atmosphere can hold that much more water, it means there can be really intense rain and flooding.
On why distinguishing human-caused climate change is necessary
We care about impacts whether it’s related from natural climate variability or human-caused climate change. But the fact of the matter is climate impacts are already here.
I think when people think about climate change they tend to think about coastal areas. But the impacts are also not just on the coast. They are occurring in the Midwest. You have flooding related to human-caused climate change there, and these droughts. To really focus on the fact that this was related to the actions humans have had, it really helps to emphasize that this isn’t this future thing we need to be worrying about. Climate impacts are here and now.
On the future of a warming Four Corners
Looking forward, it’s really hard to say exactly what’s going to happen. We can’t predict when the next drought will be but we know there will be the next one. As we continue down this path, as we keep emitting greenhouse gas emissions, there are certain things we know for certain will happen. And one of those things is that simple physical relationship between temperature and that water holding capacity, the atmosphere. When there are droughts in the future, everything points to the fact that in these semi-arid environments we’re going to be seeing more and more pronounced impacts.
Highlights have been edited for clarity and length.