Climate change is happening now, scientists are telling us.
Presented here are five instances where studies have documented the changes being wrought in Wisconsin by the warming planet.
These are scientific, often peer-reviewed studies, of the birds that trill in our backyards, the lake ice upon which we plop our ice-fishing buckets, the aspen trees that grace our parks.
While some may still debate global warming, scientists pondering the data say without a doubt that climate change is already upon us, that it has been happening for some time, and that it is altering the landscape and changing life's intricate mechanisms.
In fact, Don Waller, a UW-Madison botanist, is convinced that the stories being told us by science are the very earliest and subtle chapters of a work that will eventually describe a profoundly altered world.
"There is more going on," Waller said, "than we have even the slightest inkling of right now."
Bugs
Goldenrod aphids in northern Wisconsin produce more winged offspring in response to predators if the carbon dioxide level is high, research published in the journal Ecology showed.
The science, conducted by former UW-Madison entomologist Edward Mondor, shows that changes in climate are likely affecting the numbers of such insect pests and relationships between those insects and the predators that normally keep them in check.
Ice
It doesn't take a scientist to know that something is up with the ice on Madison's lakes. UW-Madison limnologist John Magnuson studied 150 years of ice records on 39 bodies of water across the Northern Hemisphere, including lakes Mendota and Monona. Magnuson found that the lakes are freezing 8.7 days later and the ice is breaking up 9.8 days earlier than 150 years ago.
Birds and flowers
Analyzing 61 years' worth of springtime data on blooming plants and migrating birds at her family's famous farm, plant ecologist Nina Leopold Bradley found that a third of the events recorded are occurring earlier. Forest phlox, for example, is blooming in late April instead of early May.
And birds such as this rose- breasted grosbeak are arriving up to 20 days earlier in the spring.
Trees
One of the confusing things about climate change is that some species suffer while others benefit.
UW-Madison botanist Don Waller and colleagues have studied growth patterns of more than 900 aspen trees in southwestern Wisconsin. Those studies show aspen growth has increased more than 30 percent over 70 years. The growth, Waller said, corresponds with increasing levels of carbon dioxide, a greenhouse gas.
Lakes and rivers
The levels of lakes and the flow of rivers and streams in Wisconsin are changing.
Researchers have found greater fluctuation of water levels. Currently, water levels in some central Wisconsin lakes are at 50-year lows. John Lenters, a UW-Madison climatologist, studied data on Great Lakes levels for 139 years and found the annual rising and falling of the lakes has gotten earlier by about a month. Similar changes have been observed on the Upper Mississippi.Wisconsin State Journal
