Down To Earth speaks to Kevin Perry from the University of Utah on the Great Salt Lake in the American West
The Great Salt Lake near Salt lake City in Utah, United States. Photo: iStock
The United Nations is holding a global water conference in New York City from March 22-24, 2023. Delegates are currently debating with, talking and listening to each other so that they can decide on concerted action to achieve internationally agreed water-related goals and targets.
Ironically though, the host of the conference, the United States has been witnessing an ecological disaster that now seems to be irreversible. The Great Salt Lake, in the US state of Utah, is the largest saltwater lake in the western hemisphere.
But recent media reports have highlighted the impact of extreme weather as well as anthropogenic effects on the waterbody.
Down To Earth spoke to Kevin Perry, professor of atmospheric sciences at the Department of Atmospheric Sciences, University of Utah. An expert on the waterbody, he spoke about a number of issues concerning it — its current status; similarities and differences between it and the American West's other big ecological disaster of the Colorado river; drought in the region; and finally, the very survival of the Great Salt Lake. Edited excerpts:
Rajat Ghai: For the benefit of our readers, can you explain what has happened at the Lake so far?
Kevin Perry: Great Salt Lake (GSL) is a terminal basin lake that has shrunk dramatically in the last 35 years due to a combination of climate change, drought, and unsustainable water diversion from tributary streams.
The lake elevation has decreased by 17 feet and the surface area of GSL has decreased by more than half, exposing more than 800 square miles of the lakebed to the atmosphere.
Strong winds occasionally generate dust plumes from the exposed lakebed which move into the surrounding communities where more than 2.5 million people reside.
In additon to air quality concerns, the shrinking lake has led to a loss of recreation (all boat marinas are now closed), threats to industry (ski industry, mineral extraction industry), and is on the verge of total ecosystem collapse due to rising salinity levels.
RG: What is the current situation at the lake, given that the American West has received rain and snow this winter due to atmospheric rivers?
KP: Utah has received record snow amounts in the mountains this year and the lake has already risen by 2 feet. The lake will likely rise by an additional two or three feet when the mountain snow melts.
The lake typically loses 2.5 feet of water during the summer due to evaporation. Thus, the net result of the record-breaking snow year is likely to be an increase of 2 to 2.5 feet.
While this is great and will help avoid the ecosystem collapse by reducing the salinity of the lake it cannot make up for over 20 years of water deficits. In fact, the lake has shrunk by 5 feet in the last 4 years so a 2.5 foot gain won't even bring the lake back up to where it was 5 years ago.
What it does is buy us a year or two to implement conservation measures to reduce our overall water usage.
RG: What similarities do you see between the Great Salt Lake and the Colorado River in terms of hydrological disaster?
KP: Unfortunately, the GSL and Colorado River problems are completely different. The shrinkage of the GSL is primarily caused by excessive water diversion. We simply divert 30 per cent excess water from the streams.
Climate change and drought contribute to the shrinkage as well but 2/3 of the water loss is due to decisions we have made on how we use the water.
The situation on the Colorado River is largely being driven by climate change and drought. Computer models indicate that the availability of water in the Colarado River watershed will decrease by 10-15 per cent per decade as the climate warms.
Thus, all of the water users in the desert southwest will need to plan for less water availability in the future. Those same computer models predict a slight increase in precipitation for the GSL watershed. However, any slight increases in precipitation are likely to be compensated for by increases in evaporation.
RG: Is continuous drought now a reality that cannot change in the American West?
KP: The western US is currently in the worst megadrought in the last 2000 years. Megadroughts are periods of more than 20 years with substantially lower-than-normal precipitation.
Tree rings indicate that megadroughts are a naturally-occuring phenomenon in the western US and typically occur once every couple hundred years. This just happens to be the first megadrought since pioneers moved into Utah in the mid 1800s. Megadroughts can last anywhere from 20 to 75 years.
Thus, we are likely to remain in a megadrought for at least another decade (and possibly longer). Once the megadrought ends, precipitation is likely to return to the long-term averages.
However, climate models indicate that we are likely to see more interannual variability and an overall drying trend for most of the west.
RG: Do you see the Great Salt lake becoming the next Aral Sea or Lake Urmia? Or is there still time to save it?
KP: The people of Utah have let their leaders know that saving GSL is a priority. Failure to save the lake will lead to significant economic losses and threats to human health.
The leaders of the state have listened and are committed to making the changes necessary to save the lake. Almost all of the water in the tributary streams originates as snow in the mountains of Utah and the streams primarily stay within the state.
Thus, our leaders have control over the entire watershed. As a result, I am optomistic that we can learn from the history of other shrinking lakes around the world and avoid the same fate.
It will, however, take decades for the lake to fully recover (especially if we remain in a megadrought for an extended period of time).
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