Many parts of the U.S. may be getting warmer, according to a new, interactive Department of Agriculture map that shows the best places in the country to grow different plants.
The “Plant Hardiness Zone Map,” an update of a 1990 static version, shifts temperatures up one 5-degree increment across much of the country, reflecting newer and more complete data, the USDA said today.
The map is based on weather-station data from 1976 to 2005, compared with the previous version that used statistics from 1974 to 1986, the USDA said. The guide may help about 80 million U.S. gardeners, businesses including the Home Depot Inc. that stock seeds and implements, as well as crop insurers including Wells Fargo & Co. and Ace Ltd., which have some government-set standards determined by the map.
“The increases in accuracy and detail that this map represents will be extremely useful for gardeners and researchers,” said Catherine Wotecki, the USDA’s undersecretary for research, education and economics.
Scientific data shows that the world is getting warmer, with potentially adverse consequences for farmers worldwide. Kim Kaplan, a USDA spokeswoman, said the map’s trend toward warmer temperatures compared with 1990, especially evident in the Northeast, may be attributed to better data. More research would be needed to prove the U.S. is warming, she said.
Drought in the Great Plains, flooding along the Mississippi River and deep freezes in the South pushed payments by companies including Wells Fargo and Ace to a record $9.1 billion in 2011, according to National Crop Insurance Services. When all claims are settled, the total may top $10 billion, the Overland Park, Kansas-based company said yesterday in a statement.
The trend toward warmer temperatures is “part and parcel of climate change,” David Wolfe, a plant and soil scientist at Cornell University in Ithaca, New York, said by telephone. Winter lows that creep upward, shown on the new map, mean more pests will survive to destroy grains, oilseeds and other crops during growing seasons, he said.
At the same time, warmer weather may create opportunities for other crops. In upstate New York where Wolfe teaches, the local wine industry may be able to diversify its grapes, he said.
Plant hardiness-zone designations represent the average annual extreme minimum temperatures at a given location during a particular time period, the USDA said. Low temperature during the winter is a crucial factor in the survival of plants at specific locations.
The new map is searchable online by zip code and will not be available for sale, the USDA said. It was developed jointly by the USDA’s Agricultural Research Service and Oregon State University’s PRISM Climate Group.