Global Warming Blamed for California's Worst Drought in 500 Years
In more grim news for California, snowpack levels in Sierra Nevada mountains which contribute to the water supply of the state, were at their lowest in five centuries past winter a new study claims.
Researchers compared historic precipitation levels in the rings of blue oak trees to arrive at their conclusion. They first collected data from 1,500 blue oak trees at 33 sites. They then used archival data available data for the period 1930-1980. A comparison of both data sets with present data showed a correlation which researchers utilized to obtain historical figures from the year 1,500.
Blue oaks are a good indicator as they are sensitive to winter precipitation given that California has a Mediterranean climate with wet winters and dry summers. The state is in its fourth year of drought, which has been worsened by anthropogenic activities, NBC News reports.
Researchers wrote in the journal Nature Climate Change that snow water equivalent in April this year was at only 5% of its historical 50-year average.
According to The New York Times, the snowmelt from the mountains meets a third of the state's drinking water besides water for electricity generation and fighting fires.
"Our study really points to the extreme character of the 2014-15 winter. This is not just unprecedented over 80 years - it's unprecedented over 500 years. We should be prepared for this type of snow drought to occur much more frequently because of rising temperatures," said Valerie Trouet, an associate professor at University of Arizona, while adding anthropogenic warming is making the drought more severe.
