The evidence of a warming planet is all around us.
One place that makes this startlingly clear is California's Sierra Nevada mountain range, where the current snowpack is at the lowest it has been for 500 years, according to a study published online Monday in the journal Nature Climate Change.
The shrinking snow levels, linked to the state's devastating drought, will likely take a toll on the water supplies of farms and cities, reduce the amount of hydroelectric power available, and make wildfires more likely, according to the study's researchers.
Here are some photos that reveal the extent of the problem in stark but stunning beauty.
California is in the midst of a record drought that started in 2012, causing authorities to restrict water use across the state for the first time. The drought's severity is especially clear in the Sierra Nevada (pictured here), where the snowpack April 1 was just 5% of its historical average.
California gets 80% of its precipitation during winter, and the Sierra Nevada snowpack plays a vital role, providing 30% of the state's water supply.
In the new study, scientists pieced together the April 1 snowpack conditions over the entire 400-mile Sierra Nevada range for the past 500 years. They chose April because that's when snow in the Sierra starts to melt due to increased rain and higher temperatures.
To determine historical snow levels, the researchers analyzed data from tree rings in the blue oak (pictured below), a tree that is sensitive to changes in winter rain and snowfall.
This image shows the Sierra Nevada snowpack in March 2010 (left) vs. March 2015 (right), an ominous sign of rising temperatures.
The results of the new study show that this year's snowpack is "unprecedented in the context of the past 500 years," the researchers write. There is a possibility that a few years — primarily in the 16th century — may have had less snow, but the odds are extremely low.
The study suggests that the record-low snowpack is the most severe at lower elevations because warmer temperatures have a greater effect at these low altitudes. Scientists say this kind of warming will make severe droughts more likely, cause snow to melt earlier in spring, and decrease the amount of snowfall relative to rainfall — all of which could bode ill for California's water supply.