U.S. Senator Dianne Feinstein wrote a tweet on August 7, claiming that Lake Tahoe, which straddles California and Nevada, was warming faster than the oceans and 14 times faster than the historical average.
Lake Tahoe is warming faster than the oceans, 14 times faster than the historical average. We must #ActOnClimate if we want to save the lake! #TahoeSummit
Lake Tahoe is warming 14 times faster than its historical average.
Fact check: Mostly True.
The UC Davis Tahoe Environmental Research Center posts a public annual report about the state of the lake.
The Tahoe: State of the Lake Report 2016 says: “In the last four years the lake has warmed at an alarming rate of over 0.3°F/year, 15 times faster than the long-term warming rate.”
The 2017 report states: “In the last four years the lake has warmed at an alarming rate of over 0.5°F/year, 14 times faster than the long-term warming rate.”
These two reports seem to support the claim from the senator. However, the most recent report from 2018 states that “in 2017, the volume-averaged temperature increased by only 0.04°F (0.02°C) over the previous year, but bringing it to the warmest value recorded. Since 2012, the average temperature of the lake has warmed by 1.1°F (0.61°C).”
This is a rate of 0.18°F per year. This is not 14 times faster than the long-term warming rate.
The statement from Senator Feinstein is thus false for the year 2018, but is true for 2016 and 2017, according to the UC Davis Tahoe Environmental Research Center report.