After learning about the retreating glaciers and melting of snow cover in this weeks Module, I was interested to learn more about recent observations of melting. Learning about the use of tree rings to reconstruct climate records for example, is an interesting proxy technique explained in the module. Temperature, seasonal, and precipitation records are preserved in tree rings and are powerful indicators of paleoclimate.

In a New York Times article from September of 2015, author Nicholas Fleur explains how the once snow covered Sierra Nevada in California, was seeing its lowest levels of cover in the last 500 years. Nature Climate Change, a science journal published an article using tree-ring data from centuries old blue oak trees as context for the mountain range’s diminished snowfall. According to this study, “the snowpack levels were just 5% of their 50-year old historical average.” This study is unique because it is the first to create a model that describes temperature and precipitation levels that go back centuries before researchers manually started measuring snow levels each year.

The importance of this study for people living in California however goes far beyond my fascination with proxy techniques. Snowmelt from the Sierra Nevada is responsible for filling not only reservoirs that provide a third of all the drinking water for the state of California, but also reservoirs that provide water necessary to fight wildfires and generate electricity. The data compiled in this study was a mix between temperatures found in tree ring data from 1,500 blue oaks from 33 sites and precipitation data that covered a period of time from 1500 to 1980. In conclusion, the study found that the snowpack levels as low as this year’s (2015) were a once in 1,000 years occurrence.

What this means for the future of California is still widely unknown, but the study conducted using tree rings will provide data to help predict the future for California as well as give other scientists a foundation to use their techniques to help create models for past climate data as well.

Fleur, Nicholas. Study Finds Snowpack in California’s Sierra Nevada to Be Lowest in 500 Years. New York Times. 14 September 2015. http://www.nytimes.com/2015/09/15/science/california-snow-report.html