GLOBAL CLIMATE CHANGE AND ILLINOIS

A Publication of the Global Climate Change Program of the Illinois State Water Survey

Miscellaneous Publication 131

October 1991 GLOBAL CLIMATE CHANGE AND ILLINOIS What controls Illinois' climate? is cool to the north and warm to the south. This The climate of Illinois is greatly affected by affects air masses and leads to the development the state's position in the middle of the North of major cyclonic storms over North America. American continent, the third largest land mass Mountains are the second climatic factor. on earth. The mountains in the western part of Even the hills of extreme southern Illinois affect the continent are a formidable barrier to the the region's local climate, making it somewhat prevailing westerly winds that circle the globe. cooler and rainier in the summer. But flat lands in the central United States permit The oceans and their accompanying cold air movement across the Midwest from both the and warm currents are the third major climatic factor. The North Pacific Drift affects the continent's West Coast, the Gulf Stream affects the East Coast, and the Gulf of Mexico affects the central and eastern United States and Illinois in particular. The Great Lakes also affect the surrounding climates, including that of north­ eastern Illinois. Storms are a very active climatic control in Illinois. They result from major temperature and pressure differences in air masses that collide and produce much of our cloudiness and pre­ cipitation. Illinois storms include major winter cyclones and thunderstorms. Air pressure over the continent and the frozen lakes of northern Canada and the warm adjacent oceans is the fifth climatic factor. Gulf of Mexico. The shape, size, and surface Pressure distribution varies considerably due to topography of North America set the stage for major temperature differences over the conti­ Illinois' climate. nent and the oceans. These differences create Up to six natural factors can interact to the wind and air-mass patterns over Illinois and produce the climate, and five of them affect the all of North America. Illinois climate. The most significant is solar en­ Warm, moist air from the south typically ergy. The considerable north-south length of meets cold, dry air from the north somewhere Illinois brings about differential heating, with over the central United States—often in Illinois. more warming in the south. The same differen­ These continual air movements provide Illinois tial heating characterizes the entire continent: it with an exceptional variety of weather extremes. 2 Weather events typical of Illinois' continental climate include droughts, floods, and every known form of severe weather. These extremes alternate with calm periods that may be sunny or cloudy. In recent decades we have discovered that major urban areas like Chicago and St. Louis also exert controls on the local climate. For example, the climates in and around large urban areas are warmer, windier, cloudier, and rainier than rural climates.

How does Illinois' current climate rate? Measured over thousands of years, the current Illinois climate is relatively warm. About 160,000 years ago Illinois had a tropical climate with marshes and tropical vegetation. The ice ages of 10,000 to 100,000 years ago brought glaciers and tundralike conditions to Illinois. Much of northern Illinois was once buried under ice a mile thick. Thus, Illinois' past climates, like those around the world, have varied greatly. Our climate is always changing, extreme annual events was a series of record shifting between warmer, colder, wetter, or drier low and high daily temperatures. conditions, with daily and yearly variability in This "noisy" climate of the last 15 years and the weather. the great variability of the Illinois climate from In the last 160 years Illinois' climate has season to season, year to year, decade to decade, shown interesting trends. A relative warming and century to century has made it very difficult trend prevailed from the Civil War era until to detect major, long-term shifts in the climate. 1940, but temperatures have since become It is equally difficult to identify any human cooler. The state's precipitation since the 1940s influences on climate, including those from the shows a "see-saw" trend, with a series of alter­ "greenhouse effect," other than what has been nating wet and dry periods, each ranging from discovered around large urban areas. 5 to 15 years. Beginning in the late 1970s, the Illinois climate has shown a marked trend towards What is the greenhouse effect? greater year-to-year variability with even more The term "greenhouse effect" refers to the extremes. For example, three of the four coldest, presence of certain trace gases in the atmos­ stormiest winters on record in the last century phere, which help keep the earth's temperature occurred in the late 1970s (1976-77, 1978-79, at a "livable" level. These gases are natural parts and 1980-81). Then the state experienced a of the atmosphere, and their warming effect minor drought in 1980-81, followed by the five makes life on earth possible. Therefore, it can be wettest consecutive years on record, 1982-86, said that we live in a "greenhouse" that encircles and then two of the worst summer droughts on the globe to about two to three miles above record, 1988 and 1991. Interspersed with these its surface. 3 indirectly contributes to CO2 buildup since trees and plants absorb major amounts of the gas to grow. Without them, CO2 remains in the atmosphere. Methane, which accounts for 18 per­ cent of the greenhouse gases, is gener­ ated by landfills, wetlands, animals, decaying plants, and underwater bacteria such as in rice paddies. Other major con­ tributors to the greenhouse effect are Carbon dioxide and other gases produced by industry and other nitrous oxide, which is emitted from man-made and natural sources accumulate in the atmosphere. autos, trucks, and chemical fertilizers; These gases act like the glass panes of a greenhouse, letting in the and chlorofluorocarbons (CFCs), which sun's warming rays (1) and trapping the infrared energy that is come from man-made chemicals used in radiated from the warming (2). As a result the air is heated (3). refrigerants, air conditioners, and fast- food containers. The United States con­ The addition of more gases would tend to tributes about 25 percent of all the trace gases raise temperatures even more, causing the released to the atmosphere, and Illinois alone global climate to warm. As trace gases accumu­ contributes 3 to 4 percent of all CO2 emitted. late in the atmosphere, two things happen: they permit sunlight to pass through them and reach How do we estimate the impact the earth, but they also trap some of the sun's warmth, keeping it close to the earth. Like the of the greenhouse effect? air inside a greenhouse on a hot summer day, The greenhouse effect is a well accepted, the earth's atmosphere heats up. At a certain documented process. The concentrations of point, climatic changes will become apparent. trace gases in the atmosphere are increasing, and Excessive buildup of these trace gases is if they continue to accumulate at today's rates chiefly the result of human industry and agricul­ the earth's average surface temperature will ture. Carbon dioxide (CO2) accounts for almost likely increase. But no one can be certain how half of the accumulated trace gases and is a much it will increase, when or how the climate major factor in the global climate. The gas as a whole might react to these increases, or in comes from the burning of fossil fuels (coal, what other ways our climate—and our environ­ gas, and oil) and increasing industrial growth ment—may change as a result of the buildup of and world population, more atmospheric gases. all leading to ever-in­ Scientists can estimate how the greenhouse creasing demands for effect might influence our climate by using energy and natural complex mathematical models of the atmos­ resources. This has phere on supercomputers. These "global climate led to vastly increased models" can calculate temperature, precipita­ consumption of fossil tion, relative humidity, cloudiness, winds, fuels and to the deple­ sunlight, and a host of weather variables at tion of the world's thousands of points on the earth's surface and at forests. For example, many levels rising above the earth. When more the burning of coal trace gases are simulated in these models, they and oil for energy is largely responsible for a 25 indicate that the average global temperature percent increase in atmospheric concentrations would be 3 to 4°C (5 to 8°F) higher than today's of CO2 in the last century. Deforestation also temperatures.

4 What could happen to our climate? It is widely expected that global warming with surface temperatures 5 to 8°F higher will also change the wind patterns and ocean cur­ rents that determine climate. Global precipita­ tion will generally increase, but when and where it falls will change. The frequency of extreme weather events such as droughts, hurricanes, and extremely hot days would also change in the mid-latitudes where Illinois is located. Studies of the potential effects of such Although they are the best tools we have for climate change reveal that all facets of agricul­ predicting climate change, these climate models ture, natural ecosystems, energy consumption, are not without problems. They can simulate industry, transportation, and population distribu­ large-scale climate features, but they do not yet tion would be somehow affected. An expected adequately represent regional features needed rise in sea level would threaten coastal develop­ for making detailed climate projections. ment and wetlands. Storm and flood damage to Most scientists agree that a rise in tempera­ natural environments and to man-made struc­ tures will occur within the next century because tures would increase. Expansion of grasslands of the added greenhouse effect. While this may and deserts, the decline of forest ecosystems, not seem significant, consider this: in the ice age more forest fires, and species losses could ac­ that ended 12,000 years ago, it was only about company the warming. 9°F colder than today's average temperature. Some irrigation and hydro­ However, the global temperature increases that electric projects would ended that ice age averaged only a few degrees receive inadequate rainfall, over a thousand years. If the global models are while others would overfill. correct and trace gases continue to build up, we Most current estimates could experience the same temperature change suggest that important agri­ in less than a hundred years. cultural areas in the mid- When estimating how additional heating western and southeastern could change the climate, we must project how United States would be much the greenhouse gases will increase in the warmer and drier during future. For example, to estimate how much the growing season. CO2 will be added to the atmosphere, we must Changes in agricultural estimate such difficult factors as the amount of production and irrigation fuel emissions and the size of the populations usage are likely to result using the fuel. We must also estimate how much from higher temperatures, lower soil moisture, added CO2 will be taken up by the oceans, longer growing seasons, and modified rainfall which is a major unknown. Thus, projecting patterns. future gas levels is difficult and controversial, The greenhouse effect will not exert the but nonetheless critical. Only after making same influence everywhere. The climate effects those determinations can scientists debate the will be greatest at the North and South Poles, effects of these gases on the earth's climate. least at the Equator. Some areas will actually benefit from a climate change, but Illinois is not one of them.

5 What could happen in Illinois? plant growth are enhanced but plant transpira­ Changes in weather patterns and the hydro- tion is reduced. The changes would modify logic cycle brought on by climate change would vegetation patterns which, in turn, would alter have enormous implications for Illinois, affect­ the soil's ability to hold moisture, further chang­ ing nearly every activity in the state. This is ing runoff and water distribution. what could happen: If Illinois agriculture continues to rely on Climate. It is widely expected corn and soybean production, hardier species that a global climate change will be required. But they would be unlikely to from added trace gases will match today's yields. It may be that cultivation mean a warmer climate for of some crops will move to the more northern Illinois within the next 50 latitudes of the United States—or even into years. Winters will be warmer southern Canada. Illinois agriculture would and so will summers, which most likely shift to more drought-resistant crops will have more 90°F+ days. Future average sum­ such as wheat. These changes will certainly mers will resemble the hot and dry summers of impact the state's current position as an 1988 and 1991. The amount of precipitation agricultural leader. may be slightly higher, but the seasonal amounts Energy. Energy users and pro­ will shift: there will be less in the summer and ducers are likely to face mixed more in the winter and spring. In addition, sci­ consequences. A longer summer entists now believe that even small global with many more 90°F+ days will weather shifts could translate into more fre­ mean a greater demand for air quent, extreme weather conditions. This means conditioning. Conversely, milder, that Illinois will experience more severe storms shorter winters will mean a and higher winds. falling demand for winter heating. These Water resources. Illinois hy- changes in energy demand will require utilities drologic cycle will be changed to alter their production patterns. Utilities mat as runoff patterns and river depend on reservoir or lake water for cooling flows are altered, and quantities will also have to contend with less water and and locations of ground water higher surface water temperatures. change. A 2°F increase in the Transportation. As recent state's annual temperature droughts illustrated, less water in coupled with a 10 percent decrease in its pre­ the state's hydrologic system cipitation would cause a 25 percent reduction in means more frequent low flows the average annual runoff into river basins in in major streams and rivers. The some areas. In other areas, the wanner weather transport of bulk commodities could alter spring runoff patterns by causing an such as grains, petroleum, and earlier snowmelt, thus drastically intensifying coal on the Midwest's complex barge system flood conditions. may have to be greatly curtailed. This could Agriculture. Higher tempera­ mean more business for the region's railroads tures, lower soil moisture, and Great Lakes shipping. longer growing seasons, modi­ Natural resources. All natural fied summer rainfall patterns, resources in Illinois will be and increased CO2 concentra­ affected by a significant climate tions would mean an increased change. The rapid shift in climate need for water, leading to more of the magnitude suspected in 50 irrigation and shifts in crop production. As CO2 to 100 years could be devastating concentrations increase, photosynthesis and to many plant species that simply 6 could not adjust in time. For example, trees such precipitation, winds, storms, and much more. as birches could not survive in the new warmer, And the Survey is our state's record-keeper for drier climate and would likely disappear. Many weather observations that date back to the early wetlands and the life that thrives in and around 1800s. Altogether this information constitutes a them would also disappear. Entire ecosystems valuable historic climate database needed to would change. assess our climate and how it is changing. Society. People will also have The Water Survey's Global Climate Change to adapt—particularly those in Program coordinates research expertise and urban areas—or move to more resources for a statewide approach to the possi­ northerly climes. More than 80 bility of climate change and how it will affect percent of Dlinoisans live in Illinois. Some research projects focus on the communities of 100,000 or atmospheric processes involved in global cli­ more, including 7 million in the mate change, others focus on how change will Chicago metropolitan area. A projected increase affect Illinois. Still other projects are studying in summer temperatures of 5 to 8°F, coupled past data to help determine the beginning of with temperatures above 90°F on two-thirds of climate change. all summer days, will make living and working Because Illinois' climate varies so much in our metropolitan areas much more difficult, from year to year, better monitoring systems are costly, and generally less pleasant essential to detect change. But this is difficult Business and industry. because short-term fluctuations mask the long- Efforts to lessen die climate term trends that might indicate climate change changes or curb the greenhouse due to global warming. Also, the climate is not effect through fuel conservation stable—it has always shifted and fluctuated over and reductions of trace gas decades and centuries. Thus, Water Survey emissions will influence all scientists are experimenting with entirely new activities that emit trace gases, monitoring techniques, such as measuring including industry and transportation. ground-water temperatures deep below the Regulations on the burning of fossil fuels and earth's surface, which may detect trends diffi­ releases of CFCs and nitrous oxides will cer­ cult to find in air temperatures. tainly be enacted as the climate changes. Adap­ And as part of the Water Survey's public tation to the climate changes may or may not service mission to the state, scientists will also be acceptable. concentrate on the impacts of climate change on the people of Illinois. If CO2 emissions The Water Survey's Global must be reduced, Illinois industry and transpor­ tation would be greatly affected. If global Climate Change Program warming occurs, our lives would change: life in The issue of climate change is critical to the our cities could become very difficult, and life and economy of Illinois. In response to the agriculture and energy production would also serious questions it raises for us, the Illinois change drastically. State Water Survey has established the Global Our water resources are the key. What Climate Change Program. would Chicago be like if Lake Michigan were to As the primary agency in Illinois concerned shrink because water levels dropped 9 feet? with water and weather resources, the Water How would 50 percent less flow in the Illinois Survey has a long history of expertise in climate or Mississippi Rivers affect agriculture and our research. For more than a century, the Survey historic riverside cities? The water resources has helped maintain climate monitoring stations contained in our rivers and lakes and in our vast throughout the state, measuring temperature, subsurface aquifers are essential to Illinois. 7 Commercial shipping, water supplies, recrea­ tion, industry, and agriculture could all be very different only five decades from now. The Global Climate Change Program at the Illinois State Water Survey will serve as a clearinghouse for scientific information. Mem­ bers of the public, Illinois water resource man­ agers, educators, government policy makers, and those involved in industry and agriculture are invited to contact the Water Survey for more information.

Global Climate Change Program Stanley A. Changnon, Head

Illinois State Water Survey 2204 Griffith Drive Champaign, Illinois 61820-7495 Telephone (217) 333-2210 Telefax (217) 333-6540 A Division of the Illinois Department of Energy and Natural Resources

The Illinois State Water Survey was founded in 1895. It is the primary agency in Illinois concerned with water and atmospheric resources. Research and service programs encompass the assessment and evaluation of ground, surface, and atmospheric water resources as to quantity, quality, and use. Scientific research anticipates and reacts to practical problems in the state of Illinois. Much of the Survey's work is facilitated by an extensive database collected and developed over the course of a century.

Produced by the Illinois State Water Survey Office of Publications Services under the scientific guidance of Stanley A. Changnon.

Printed on recycled paper

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