Climate Rules

less snow

What we eat, how we dress, where we work and play, our forests, streams, lakes and landscapes are all influenced by climate. Now the rules are changing at Lake Tahoe and around the world.

What's Happening to the Lake?

Expected impact of climate change on Lake Tahoe

The 21st century climate expectations:

  1. Snow declining as a fraction of total precipitation
  2. Extended droughts
  3. Increased algal growth
  4. Increased threat from aquatic invasive species
  5. More extreme streamflow events
  6. Increased tree mortality
  7. Future impacts on clarity
  8. Reduced deep lake mixing

Evidence of Climate Change

Continuous monitoring of Lake Tahoe since 1968 provides a unique record of change for one of the world’s most beautiful yet vulnerable lakes. Combined change with more than one hundred years of meteorological data, it is possible to look for the impacts of the changing climate on the state of the lake.

Warming Air Temperature - Over the last 100 years, the average daily minimum temperature has risen 4.2 °F — now above freezing. The average daily maximum temperature has risen 2 °F.

Declining Snow - As a percentage of total precipitation, snowfall has declined since 1910. In 2015, the snowfall in Tahoe City was only 5.4% of the total precipitation, the lowest on record.

Warming Water Temperatures - Since 1970, the average water temperature has increased by 1.4 °F. Since 2012, Lake Tahoe has warmed at a record rate of 0.3 °F/year.

Less Mixing - Each winter, surface waters cool and sink, transporting life-sustaining oxygen downward. The colder and longer the winter, the more the lake mixes. In 2016, water mixed to a depth of only 262 ft.

Solutions

1.   Slow the rate of oxygen depletion by reducing nutrient inputs

2.   Sequester nutrients and sediments in floodplains away from the lake

3.   Accelerate the pace of clarity recovery