Environmental Engineering Reference
In-Depth Information
Table 9.1
Biologic indicators of climate change
Plants now bloom an average of 5.2 days earlier each decade.
The density of vegetation has increased in the United States because of
both warming and increased rainfall.
As permafrost has melted, arctic shrubs in Alaska have invaded
previously shrub-free areas. In Antarctica, mosses now colonize formerly
bare ground.
The ranges of migratory plants and animals have shifted an average of
3.6 miles per decade toward the poles (2,000 feet per year).
The tree line in Siberia is moving north. Conifers now grow where no
living tree has grown in 1,000 years. Tree lines in Europe and New
Zealand have climbed to higher altitudes.
Plants in Europe and North America now unfold their leaves and fl ower
up to three days earlier than in previous decades. Trees are leafi ng earlier
throughout Europe, and fall colors appear later.
Marine mammals are being pushed northward as warmth-loving fi sh
invade their feeding grounds in the northern Bering Sea.
Warm-water fi sh are fl ourishing, but cold-adapted species are in decline.
Over the past four decades, the traditional mid-February to April maple
sugaring season in northern New England has slowly gotten shorter. It
now starts a week early and ends ten days early. Maple trees are moving
northward to Canada, being replaced by oaks.
Mosquito-borne diseases have moved northward in Asia and Latin
America over the past decade.
Thirty-nine butterfl y species in North America have shifted their range
northward by 124 miles since 1975 (4.6 miles per year).
The Audubon Society has reported a striking northward movement by
most species of birds. The wild turkey has moved 400 miles north, the
boreal chickadee 280 miles.
Robins are building nests 240 miles north of the Arctic Circle.
Barn owls, fi nches, dolphins, and hornets are arriving in Arctic villages
where the natives have no words in their language to name these
creatures—and no barns.
Red foxes have moved north in Canada as Arctic foxes have retreated.
In the Yukon, squirrels are mating and giving birth eighteen days earlier
than their great-grandmothers because the amount of their main food
(spruce cones) is increasing because of lengthened summers.
