In 1965 the U.S. Department of Agriculture planted lilacs in some 70 locations in the northeast, and noted when they first bloomed. Figuring that the onset of spring was signalled by the lilacs blooming, the USDA was trying to help determine the best time for planting crops, like corn. But what they now have is a record of when lilacs bloomed in the past 44 years. And they are blooming as much as two weeks earlier now than in 1965.
Other evidence of early spring (and summer) onset is discussed in new books by Amy Seidl (Early Spring) and Stephan Farris (Forecast) but almost anyone in agriculture or forestry, etc. from wineries in California to corn growers in Iowa to maple sugar producers in New England can tell you this has been happening, and it's starting to have an impact. Sugar maples in New England (above right), for example, are dying and may soon be virtually extinct. The rippling effect of climate change--from northern species dying out to disease-carrying insects moving north--is just beginning. For now, some of it is pleasant, as April becomes the new May. But it's already starting to change lives and livelihoods, and a sane society would have noticed that by now.