The newest evidence? Today, the U.S. Department of Agriculture unveiled its new, 2012 Plant Hardiness Zone map. The Vermont map confirms what local growers have been saying for years: The Green Mountain State is becoming more temporate and now more resembles the climate of Virginia in the 1960s.
What's worse, if greenhouse gas emissions continue to increase at their present rate, by 2080 Vermont will look and feel more like northern Georgia. The good news? More peach cobbler. The bad news: Say goodbye to real Vermont maple syrup.
According to the USDA, plant hardiness zone designations represent the average annual extreme minimum temperatures at a given location during a particular time period. They do not reflect the coldest it has ever been or ever will be at a specific location, but simply the average lowest winter temperature for the location over a specified time. Low temperature during the winter is a crucial factor in the survival of plants at specific locations.
"Compared to the 1990 version, zone boundaries in this edition of the map have shifted in many areas," according to the USDA press statement. "The new map is generally one 5-degree Fahrenheit half-zone warmer than the previous map throughout much of the United States."
Since 1970, the average temperature in New England has risen 2 degrees Fahrenheit, with average winter temperatures rising twice as fast — 4 degrees between 1970 and 2000. That's according to Alan Betts, an atmospheric researcher from Pittford, Vt.
Precipitation in Vermont has also increased by as much as 20 percent, with more of it arriving as rain and less as snow. Overall, Betts warns Vermonters to expect rainier winters, earlier springs, hotter summers, longer and more persistent droughts, and heavier and more frequent and torrential “extreme” weather events such as Tropical Storm Irene.
Even under the most conservative estimates of future greenhouse gas emissions, Betts predicts that the Green Mountain State will be 3 degrees hotter by 2050 and 5 degrees hotter by century’s end. "If you want to look at what might be the most politically correct thing, you can say something's happening," Vermont gardening expert Charlie Nardozzi tells USA Today. "But the climate is changing. Spring is coming sooner and lasting longer. Fall lasts longer, and overall the weather is so much more erratic now."
To find out what zone your home or business is located in, click here and enter your zip code. For more about the long-term effects of global warming on Vermont, check out this week's cover story here.
Plant Hardiness Zone map courtesy of the USDA