Polar Vortex Chills Parks
Hundreds of millions of people across North America learned the hard way about a new weather phenomenon this winter — the polar vortex. No matter that the term has been in scientific use for almost 75 years, weather forecasters gushed about the polar vortex as if it had just been discovered hiding somewhere around the North Pole and then unexpectedly and malevolently snuck south this winter to make our lives miserable. However, people everywhere got a quick education on what a polar vortex can do when the temperatures plunged below zero into bone-chilling, record-setting cold throughout much of the nation.
Some meteorologists dispute the assumption that the polar vortex was the root cause of our exceptionally harsh winter. They agree that a polar vortex is a well-known weather pattern that is produced by a swirling mass of high-level cold air that hovers over each of the poles year round, but they don’t believe that a polar vortex pattern in and of itself caused the bitter cold. The deep freeze, according to them, was kickstarted by changes in the jet stream, which dipped far to the south this winter and caused a colossal breakaway of frigid artic air to blast through much of the heartland of the U.S. and even affect areas in the Deep South. This was why, paradoxically, temperatures in Alaska were the warmest on record, confusing plants and wildlife and shattering records for the highest wintertime temperatures ever recorded for the state.
There is no question that parks across America took a big hit from the polar vortex this winter. Some effects were obvious and immediate: frozen pipes, closed parks, greatly increased snow-plowing duties and just miserable conditions for workers and the public alike. In Chicago, the Chicago Park District reported that the ground froze deeper than in previous years, and that deep freeze may likely push back ballfield prep dates, planting of landscape beds and mowing schedules. They expect to see significant salt damage to landscaped areas and increased plant death as well. No shrinking violets themselves, the Chicago Park District staff hacked ice from Lake Michigan in early March to keep the water open for this year’s Polar Plunge, which was a huge success because of the participation of Jimmy Fallon and Mayor Rahm Emanuel and their support for the Special Olympics, which this event benefits.
From a conservation perspective, such bitter cold is very hard on wildlife that is not prepared and adapted to the conditions. Certain bird species are especially susceptible. Songbirds and waterfowl that didn’t migrate far enough to the south were caught unawares and suffered grievously when they lost open water and food sources. Previous cold waves have been especially hard on bluebirds, bobwhite quail and great blue herons, for example, which tend to stay in their breeding ranges when winter weather is mild instead of dispersing or migrating to the south ahead of frozen conditions. Wildlife, like people, can become habituated to a string of mild winters. When the cold came this year, its effects were more pronounced because of the much warmer than average winter temperatures in recent years. Unfortunately, the beneficial impacts that very cold weather could have on some invasive species has not affected the Burmese pythons that have invaded Everglades National Park and which are moving northward. Nor is there much hope that the cold will knock back the growing infestation of brown marmorated stinkbugs. Too bad — the stinkbugs and pythons are here to stay.
Plants took a big hit this winter as well, especially ornamentals and landscape plants. Many horticulturalists say the effects of the freeze won’t be fully known for several months and will become more apparent when plants and trees die off because they weren’t able to store energy and withstand the harsh extremes. Nonetheless, there may be a few unexpected silver linings from the big freeze.
Dave Nolin, director of conservation for Five Rivers MetroParks in central Ohio, says there is hope that the several nights of extremely cold weather they experienced in the Columbus region — minus 9 degrees Fahrenheit — might kill the larvae of emerald ash borers, an invasive insect species that has devastated forests in the mid-Atlantic and Northeast after its discovery in Michigan in 2001.
Since ash tree species are one of the most important colonizing trees in central Ohio, the parks became dominated by colonizing ash trees rather than oaks and hickories, which don’t spread as well as pioneering species. These trees are now under relentless attack by the emerald ash borer, whose larvae feed under the bark of ash trees and eventually weaken and kill the host trees. More than 90 percent of the ash trees in Five Rivers parks are now dead as a result of emerald ash borer infestation. However, the U.S. Forest Service says that when temperatures reach 0 degrees, 5 percent of larvae die. At -10 degrees, 34 percent die, and at -20 degrees, 79 percent die. Nolin hopes that there might be one benefit from the bitter winter cold if the larval populations of emerald ash borers are knocked back to more manageable levels. Similar impacts may have occurred to larval populations of the hemlock woolly adelgid, which is decimating northern hemlock forests, and also the gypsy moth, an invasive pest long established through much of the United States.
One of the more significant effects of the polar vortex this past winter may not necessarily have anything to do with impacts to the land or to natural resources. Rather, it may be the effect it had on public perceptions of extreme weather events. Many people might think popular opinion would swing strongly toward the perception that the harsh winter and extreme cold weather are proof that climate change (often thought of as “global warming”) is not happening. In fact, just the reverse appears to be true. A recent study published in the journal Climatic Change described the results of a public survey about perceptions of climate change conducted in Britain just after the record-setting cold winters of 2009–10 and 2010–11. Paradoxically, three times as many people surveyed believed that climate change had something to do with the extremely harsh winters that had just occurred — the coldest temperatures in 350 years — than believed that the extreme cold was a sign that climate change wasn’t occurring. This is a remarkable finding open to several interpretations, but the authors point toward the strongest conclusion being that people are seeing and experiencing much different weather than might be expected, which is changing their perceptions about climate change.
If the public is to understand the true impacts of climate change on parks, both causes and effects, then part of our task as stewards of natural resources is to combat the perception that a single extreme weather event, or even several extreme weather events, is a direct result of climate change. Parks and recreation have a growing stake in developing successful adaptation and mitigation strategies to meet the challenges of a changing climate, not the least of which is improving the public’s understanding of why an effective response to climate change is critical for the future of parks and recreation. One somwehat unanticipated effect of the polar vortex is that it has made a much larger segment of the public aware of the importance of global weather patterns. This alone is an important step to creating understanding of what a changing climate will mean to public parks and outdoor recreation.
Richard J. Dolesh is NRPA’s Vice President of Conservation and Parks.