A host of environmental pressures are exacerbated by global warming, scientists say, ranging from more weeds and pests to reduced winter chill periods. That could threaten the viability of berry production generally, while all but wiping out cranberry and Concord grape production in the region's southernmost states. The report warns that as temperatures rise and growing seasons lengthen, the minimum chilling requirement needed for fruiting buds to mature may not be met, causing a precipitous drop in fruit yield as far north as Massachusetts.
Peter Beaton, a third-generation cranberry grower here in Wareham, Mass., near the Cape Cod Canal, has seen growing effects from what he concludes is a warming climate since the 1970s.
"Quite often, when you would get into late October or the first of November, there would be an inch or two of ice on the bogs when it was time to harvest the cranberries. And that was not a rare occurrence – that was a common occurrence," says Mr. Beaton, outgoing president of the Cape Cod Cranberry Growers Association (CCCGA). He can't recall a time once during the past 10 years when the cranberry harvest was delayed because of ice. The CCCGA, founded in 1888, represents 87 percent of the cranberry growers in Massachusetts.
Cranberry growers can flood bogs to shield their crop from winter frosts and summer heat, thereby protecting the cranberries from temperature extremes. Other berry growers cannot resort to such tactics, as most berries cannot survive submerged for very long.
A sharp frost in late April 2007 ravaged grape and blueberry blossoms that had emerged during an unusually warm period, killing up to 90 percent of the blossoms from Missouri to Alabama and the Carolinas. This type of stop-and-go winter is exactly what people in New England's lucrative berry industry are concerned will become more frequent.
Some researchers are less concerned about temperatures being cold enough to mature fruit than they are with erratic weather patterns brought on by climate change. More frequent droughts and floods, as well as salt-water incursion from hurricanes and rising sea levels pose serious risks.