It’s no secret, especially among climatologists, that we’re getting a lot less snow now than we used to.

Researchers at Dartmouth College in New Hampshire have been poring over 100 years of available snow data across the globe — which includes everything from simple measurements with yardsticks to sophisticated calculations using automated sensors and satellite photos — to quantify just how much of a decline there’s been, and now they have some early results.

In a study published in the Bulletin of the American Meteorological Society in November that’s focused on the Western United States, researchers found declines as big as 30% over the past century, which are directly linked to proceeding summertime droughts and consistent with climate change caused by human activity such as the burning of fossil fuels.

“Snow losses are huge,” said Justin Mankin, one of the study’s authors. “That 30% reduction we’ve seen so far is the equivalent to losing Lake Mead, the largest reservoir we have in the United States, the one that sits behind Hoover Dam.”

Snow is critical to the water supply in Western States where summers are arid and snow melt accounts for about 70% of the annual water supply, acting as a reservoir that fills rivers and streams in the spring and summer.

Water shortages, droughts and wildfires are projected to hit the West hard and more frequently as a result, but climate scientists say New York and the surrounding region have also seen a steep drop-off in snowfall.

“Most places are 10 to 15 inches behind,” said Mark Wysocki, a climatologist at Cornell University who was not affiliated with the study. “I think people are going to be very disappointed up here in the Northeast with winters. That doesn’t mean we can’t get a blizzard. It's just that we won’t get as many of them.”

That may be bad news for skiers and snow lovers, but Gottlieb said less snow has serious health and environmental impacts. Reductions in snowfall directly affects agriculture and the production of hydroelectric power.

David Robinson, a climatologist at Rutgers University who reviewed the study, said snow usually accounts for 20% of the New York metropolitan area’s total annual precipitation. When it doesn’t snow, the precipitation often comes in the form of rain or ice, which will make short-term flash floods more frequent.

New York state is already receiving more total precipitation than usual despite the decrease in snowfall, according to Wysocki.

The lack of snow and colder temperatures also pose a threat to trees. Insects typically die off in the winter, but as the climate warms, they are thriving year round and increasing in number.

“As you get more of these insects, they just spread from tree to tree, area to area,” Wysocki said. “They can devastate a forest within two to three years. They’re actually taking the nutrients away from the tree, and the tree starts to die a very slow death. It’s hard to bring it back to life.”

In Tompkins County, New York, where Wysocki resides, forests have had to be cut down because trees have died from insect infestation, he said. It’s the only way to stop it from spreading.

The change will also threaten food supplies and human health, including an increase in insect-born diseases such as Lyme and West Nile virus.

The Dartmouth researchers will continue analyzing the remaining data from other parts of the Earth. Modeling the decline in snowfall and measuring its impacts is essential, Robinson said, for predicting the planet’s future climate and mitigating the effects of climate change.

“Climate models are our crystal balls,” Robinson said. “There’s no point on the thermometer that’s more important than freezing point because it makes all the difference whether your water is going to be in liquid or frozen form. All you have to do is push that temperature above the freezing mark, and you’ll no longer see as much snow.”