Climate Science

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.

Meteorological conditions such as air temperature, wind speed, and solar radiation affect physical lake processes including depth of mixing and currents within the lake. This information is critical for water quality modeling. Analyses of long-term air and lake temperature data are providing evidence of global climate change and warming in the Tahoe Basin. With support of the local basin agencies and the National Science Foundation, the UC Davis Tahoe Environmental Research Center (TERC) and its precursors has conducted continuous monitoring of Lake Tahoe since 1968, amassing a unique record of change for one of the world’s most beautiful yet vulnerable lakes. In collaboration with government research agencies, such as the US Geological Survey and NASA/JPL, we have also compiled time series information on the basin’s streams, and on the spatial complexities of the lake’s surface temperatures. Combined with the more than one hundred years of meteorological data that exist for the Tahoe basin, it is now possible to examine this record to look for the impacts of the changing climate on the state of the lake.

This data record has also allowed for the development and calibration of models to look at what the future impacts of climate change are likely to be in the Tahoe basin. The 21st century climate is expected to impact the air temperature, amount and type of precipitation, stream discharge, sediment and nutrient loading, lake temperature, lake mixing, water quality, biodiversity and aquatic invasive species. Awareness of these impacts, and the range of approaches to mitigate or minimize them, is essential for resource management agencies in the Tahoe basin, for decision-makers at all levels of government, and for those living in the Tahoe basin.

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

Related Research Projects

CAAP
Meteorology
Atmospheric Deposition
Modeling Climate Change Impacts