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The water in Lake Tahoe is warmer than ever, a new study has found, and that's a big concern for scientists concerned about the effects of global warming.

The study by the Tahoe Environmental Research Center at UC Davis, released Thursday, found that surface water temperatures in July 2017 reached as high as 68.4 degrees — the warmest on record. More alarmingly, the temperature is more than six degrees warmer than the previous year.

The warming trend is expected to continue. As the report states: "The initial results are showing that the Lake Tahoe basin will be considerably warmer in the future." That's due in part to a decrease in snow — though still lots of precipitation — to cool the lake water.

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The Tahoe Basin will also continue to warm and dry up in the next few decades. That could have serious side effects; drying soil means trees will be more vulnerable to insect attacks and disease, as well as wildfire.

By the end of the century, the temperature of the Tahoe Basin is predicted to increase seven to nine degrees, upping the temperature of the lake water even more. That increase "is certainly big," Geoffrey Schladow, director of the UC Davis Tahoe Environmental Research Center and author of the report, told the Reno Gazette Journal. Rising water temperatures, coupled with rising average air temperatures in Tahoe City, could spell big problems for Tahoe's future.

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And rising temperatures aren't the only major concern. The clarity of the lake also reached a historic low level at an average of just 59.7 feet. According to researchers, there are two causes for this: the five-year drought, which limited precipitation and snow, and the record high precipitation California experienced in 2017. As a result, more sediment fell into the lake than the five preceding years combined.

"While 2017 may be viewed as an anomalous year," Schladow told the Gazette Journal, "it has reinforced the fact that progress toward environmental restoration of Lake Tahoe will be punctuated by extreme years in future decades."

Read the full report here.

Alyssa Pereira is an SFGATE staff writer. Email her at apereira@sfchronicle.com or find her on Twitter at @alyspereira.

