Four ways climate change is transforming our winters

Joe Casola, staff scientist and program director of Science and Impacts, and Dan Huber, science and policy fellow, co-authored this article.

The terms “climate change” and “global warming” might conjure up images of balmy beaches and scalding deserts – a world without winter. But it’s more complicated than that.

As we prepare for the official arrival of the season on Dec. 21, let’s look at a few ways winters in the United States are changing because of global warming, and what we can do to adapt.

1. Snow – The snow season in North America is generally becoming shorter, with the greatest amount of snowfall moving to higher latitudes and elevations. This could have widespread economic consequences.

The draft National Climate Assessment notes that snowpack- and snowmelt-fed rivers in the West have been altered as a result of recent warming, raising the threat of summer droughts in the region. Regions hurt by reduced snowpack may have to expand storage capacity or curtail water use in the summer.

Snowfall is also crucial to the winter sports industries. Due to shorter, drier winters, ski resorts are being forced to devote more money to snowmaking, and snowmobile enthusiasts are driving farther to reach suitable areas.

Some resorts are investing in new, energy-efficient snowmaking equipment, although this can be prohibitively expensive for smaller operations. They’re also trying to expand year-round offerings with attractions like zip lines, treetop obstacle courses, day spas, and concert venues.

2. Christmas Trees – The symbol of holiday tradition for millions, Christmas trees have been suffering the past few years due to a combination of factors influenced by warming.

Climate change is increasing the likelihood of many types of extreme weather, including floods, heat waves and droughts. Those are contributing factors in the deaths of thousands of Christmas trees this year in New Hampshire and Vermont and nearly half the crop last year in Michigan and Wisconsin, where some tree farmers have decided not to replant. Trees are usually harvested 6-10 years after planting, so these impacts will be felt over the next decade.

Tree loss also reduces our ability to mitigate climate change. Trees remove carbon dioxide from the atmosphere and facilitate the storage of carbon in the soil. A Villanova University study says Christmas tree farms are good carbon sinks, with the soil absorbing 10 times as much carbon as the wood itself.

Adaptation may involve switching to different species of trees. Farmers in Oregon are planting non-native species such as Nordmann and Turkish firs, which are resistant to root-rotting bacteria that thrive in warmer winters.

One option to avoid is an artificial tree, many of which are made overseas. The manufacturing and shipping of plastic and metal trees contribute much more to climate change than the cutting of live ones. Plant biologist Clint Springer says a 7-foot cut tree’s impact on climate is 60 percent less than a 7-foot artificial tree used for six years.

3. Maple Syrup – Already at a premium, real maple syrup to top your pancakes could become scarcer because of the trend toward warmer winters and earlier springs. Although production this year rebounded after dropping off in 2012, the risk of warmer winters in the future could make it harder to produce syrup, which could translate into higher prices.

Sap from the sugar maple tree is harvested in the winter and boiled down to make the syrup. Researchers from the U.S. Forest Service and Cornell University say the maple sap season was shorter in 2012 because the freeze-thaw cycle on which it relies was less frequent. The area where maple trees thrive is also shifting northward. In New Hampshire, maple trees appear to be producing sap with relatively low sugar content, requiring more sap to make the same amount of syrup, and climate change is a suspected culprit.

The maple industry is working to meet this challenge. Researchers at the University of Vermont’s Proctor Maple Research Center have developed a new method of collecting sap that involves cutting the top of maple saplings.

4. The Flu – Winter is when people are most likely to get influenza, according to the Centers for Disease Control and Prevention. Now there’s CDC research indicating that a warmer winter may portend an earlier, faster flu outbreak in the following flu season.

For many healthy adults, the flu just means discomfort and missed time at work, but it can be deadly for the elderly or those with certain medical conditions. In response to a relatively warmer winter, it will be more important for a greater portion of the population to receive a seasonal flu vaccine. This will mean shifting resources toward vaccine development, distribution and education.

The wintery examples above illustrate broader points about our changing climate and how we need to adapt: Today’s climate is already different from the climate of the recent past.

Effectively preparing for future climate conditions demands forethought and creativity, not just “business as usual.” And there are no silver bullets for adaptation. Actions will vary by region and by who has to do the adapting. Some plant and animal species might not be able to adapt to the changes fast enough. Some businesses might not either. The amount of adaptation we will need can be lessened if we take action now to reduce emissions of heat-trapping greenhouse gases.