May 13--ROCK COUNTY

Farmer David Arndt knows the value of rain. Some of his corn crop shriveled and died during a searing drought in the summer of 1976. Almost 30 years ago, Arndt started installing irrigation as insurance against dry spells on his 2,500 acres. Last fall, his fertile fields in La Prairie Township produced a record average of 211 bushels of corn per acre. "It was our best year ever," he says, explaining how the right amount of water, good management and seed corn with hardy genetics combined for a bumper crop. Arndt and other Rock County farmers raise 240,000 acres of corn and soybeans annually. They know from hard experience that drought, extreme heat and flooding are wild cards in the growing game.

And they pride themselves on their abilities to learn and adapt. But what will happen to future generations of local farmers if drought, heat and flooding grow more severe and occur more often? If predictions about global warming come true, a new climate in Wisconsin will pose huge challenges for everyone, especially farmers. On a recent morning, Arndt concentrated on planting a new crop of field corn. He expressed concern about the impact of global warming but said no one knows for sure how it could play out in Rock County. He has no doubt that global warming is happening. But he expresses the optimism that allows farmers to put seeds in the ground every spring.

"We will deal with whatever is thrown at us," he says. Mother Nature just may be preparing to toss a giant curve ball. Rising temperatures Scientists confirm that climate changes already are happening. -- Winters are getting shorter. -- Annual average temperatures are growing warmer. -- Extreme heat events are occurring more often. -- The duration of ice cover on lakes is decreasing as air and water temperatures rise. -- Heavy bouts of precipitation, both rain and snow, are becoming more common. But that's only the beginning. If nothing is done to slow the rate of global warming, scientists predict a Wisconsin with temperatures that may rise 5 degrees to 20 degrees higher in summer and 5 degrees to 12 degrees higher in winter.

As a result, summers in the state may feel more like current-day Illinois by 2030 and like Arkansas in 2095. Winters also will be milder, such as those in Iowa. Steve Vavrus is trying to figure out how climate change might affect Wisconsin in the middle to later part of this century. The UW-Madison scientist at the Center for Climactic Research is studying various computer-climate models. He already has dramatic findings, which he calls "pretty reliable." According to Vavrus: -- Extreme cold waves in winter would disappear. We would no longer have old-fashioned winters, when the mercury plunges below zero for days.

-- On the flip side, the number of extremely hot days would increase by up to 12 days in summer. "These are days when temperatures rise to roughly 95 degrees or more," Vavrus says. "It is the kind of heat that kills people and puts a big demand on electricity." --In addition, severe storms that dump 2 inches to 3 inches of rain would be more common. "It is a paradox," Vavrus says. "We will see heavier rainfall in the future, but there will be longer stretches of dry weather, which is a double whammy for agriculture." He does not know if the changes would occur gradually or if they would happen in big leaps, "but it is looking like the climate will be noticeably different by the end of the century." Vavrus expects to report his findings within the next year.

"The fact that global warming is occurring is irrefutable," Vavrus says. "But what impact it will have is open to interpretation." Growing awareness John J. Magnuson is fielding a flurry of phone calls at his Madison office. The UW-Madison scientist is supposed to be retired. But get in line if you want to talk to him. He is a nationally known expert on climate change. With feature films, glossy magazines and television shows pouring forth climate-change stories, experts such as Magnuson are in demand. "It is a sea change," the professor emeritus of zoology and limnology says. In nautical terms, that means a turnaround in the direction of wind and waves.

In global-warming terms, that means people are now asking questions about the future. "Those of us who have been working on climate issues for 10 to 12 years see the difference," he says. In part, Magnuson credits the Intergovernmental Panel on Climate Change for the turnaround in awareness. The international body of scientists has met three times, issuing highly publicized reports, most recently on May 4. In February, thousands of scientific experts around the world concluded that rising average temperatures are almost certainly the result of human activity, primarily the burning of fossil fuels to produce electricity and drive cars.

These activities emit gases, mostly carbon dioxide, which blanket the planet and trap heat. In April, the panel on climate change declared that global warming has begun to change life on Earth-from plankton in the oceans to polar bears in the Arctic. In addition, it said many animal and plant species have begun dying off or changing sooner than predicted, based on the review of hundreds of research studies. The reports have helped push what had been a slowly simmering concern in many parts of the country to the forefront. Just as changes are occurring around the world, Magnuson assures they are also taking place in Rock and Walworth counties.

"It's global," he says. "It's also local." Magnuson sees some of the hardest evidence of global warming outside his office window on Lake Mendota, where the duration of ice cover has declined almost a month in the last 150 years. In 2000, the UW limnologist led a team that studied freeze- and break-up dates on lakes and rivers spanning the Northern Hemisphere from 1846 to 1995. Among them was Walworth County's Geneva Lake, which also is frozen about a month less each winter. "The duration of ice on lakes is a miner's canary," Magnuson says. "The rate of ice loss has increased dramatically in the last 30 years, which corresponds to the rapid rate of warming of the Earth." Scientists say the average global temperature has increased 1.5 degrees in the 20th century, and it has heated up more intensely during the last two decades.

Ed Hopkins of the State Climatology Office says the current statewide average has climbed 0.7 degrees Fahrenheit in the last century. In Beloit, long-term weather records show the annual temperature rose by about 0.6 degrees Fahrenheit. The changes may seem small. But they are big jumps in the climate world. "It was roughly only 9 degrees cooler in the last Ice Age, when we were under a mile of ice," says Richard Lindroth, ecology professor at UW-Madison. "This is a very serious issue." Natural world changing Bird expert Lee Johnson paused earlier this spring to notice the arrival of the eastern phoebe.

When Johnson started bird watching in the 1940s, he considered it normal to see the first phoebe migrate from its wintering grounds about April 4. Now, he sees the bird by mid-March. "They are returning sooner because it is warmer, and the insects are out," he says. "It seems to relate to global warming." The founder of the Sand Bluff Bird Observatory in Winnebago County, Ill., just south of Rock County, has records for some 300,000 birds caught in mist nets at the observatory during more than 40 years. In the last 20 years, Johnson has observed changes that mirror studies around the world that show the climate is changing.

He is catching more southern birds in his bird-banding operations, and he is seeing fewer northern birds that used to come south for the winter. Birds are not the only species expanding their ranges because of warmer weather. Phil Pellitteri has been an entomologist for 30 years. In the last decade, the UW Extension expert has seen bugs in southern Wisconsin that normally would not crawl or fly outside of central Illinois. They are surviving because winters are not as severe. Among them is the gypsy moth. "At 25 degrees below zero, gypsy moth eggs die," Pellitteri says. "When we have milder winters, these kinds of things migrate north." Rock County UW Extension crops and soils educator Jim Stute says destructive soybean aphids and bean leaf beetles are now wintering in the county.

Both pests are new to Wisconsin since 2000, and the bean leaf beetle is still confined to southern-tier counties. Tom Klubertanz, associate professor in the biological sciences at UW-Rock County, has done research on climate change and the control of soybean pests. With higher temperatures and drier conditions, pests such as two-spotted spider mites and bean leaf beetles in soybeans increase their populations more rapidly, he says. He points to the 1988 severe drought across the Midwest, when a massive outbreak of spider mites infected soybeans and corn. "As the drought spread west, pesticide companies were unable to keep up with the demand for their products," Klubertanz says.

"Climate change may permanently place us at higher risk for outbreaks of certain pest species and may therefore increase production costs." What about fish? Anglers look forward to the opening day of fishing season with the same excitement that deer hunters trek to the woods. But some favorite fish may not be there in the years ahead, if climate change continues on an unaltered course. People who study inland lakes say coldwater species such as lake trout, brook trout and whitefish may decline dramatically. Cool-water fish such as muskies and walleyes and warm-water species including bluegills and smallmouth bass will expand their ran es northward.

So far, Rock County's waterways are stable. "I don't believe we have seen any changes in our species compositions that indicate strong trends toward global warming," says Don Bush, regional fisheries expert. "We haven't noticed things like streams no longer being able to support trout, for example, because the water has gotten too warm." He adds a caveat. "That is not to say it is not happening. It's just that the impacts of soil erosion, exotics, grazing, non-point pollution, manure spills and constructions, are far more active than temperature change." Possible health risks The assessment from Jonathan Patz is grim: Global warming could bring a wave of human health risks, including more widespread outbreaks of waterborne diseases such as cryptosporidiosis.

The associate professor at UW-Madison has studied rainfall and runoff and their relationships to waterborne illness in the United States. He found that heavy rainfall-like the kind predicted as a result of climate change-preceded two-thirds of reported waterborne disease outbreaks in a 50-year period. The largest ever occurred in Milwaukee in 1993. Heavy rainfall and runoff overwhelmed the water treatment plant, and an estimated 403,000 cases of intestinal illness and 54 deaths occurred. Patz points to the possibility of other problems: -- More days with high heat may worsen the formation of dangerous levels of ozone.

Ozone and other air pollutants generated by coal-fired power plants are likely to aggravate asthma and other respiratory diseases. "By 2050 just from warming temperatures alone, we may see 68 percent more red-ozone alert days, which means it is hazardous for anyone with respiratory problems to go outside," Patz says. -- Health risks associated with extreme heat are likely to increase, especially for the elderly and the poor. And more frequent heat waves will likely cause more heat-related deaths. He recalls the heat wave of 1995, when 600 heat-related deaths occurre in Chicago over five days.

"People are aware of global warming, but I don't know if they know about all the ways that climate change can affect our health," Patz says. "I have been working in environmental health for a long time, and I think it is a major problem." Statistics tell story David Travis of UW-Whitewater tells his students all the time not to confuse weather variations with global climate changes. But he has no doubt the world is getting warmer. The climate scientist says it is clear in the statistics. Last year was the warmest in the continental United States in the past 112 years, capping a nine-year warming streak unprecedented in the historical record.

Average temperatures for all 48 contiguous states were above or well above average. "I'm convinced the biggest problem people have with greenhouse gases is they cannot see or smell them," Travis says. "If we could colorize them and add a smell to them, people would see the increase and would want to do something about it."