By the numbers: climate change in Wisconsin and the Midwest

Photo by Rick Chamberlin

When you have mastered numbers, you will in fact no longer be reading numbers, any more than you read words when reading books. You will be reading meanings.”

-W. E. B. Du Bois

The word “chronicle” implies words and lots of them, and it is my intention to keep Climate Chronicle firmly grounded in that realm. But even a dyed-in-the-wool wordie like me knows that there are times when only numbers will do. This weekend we celebrate some numbers in the form of a date: 7/4/1776. Wouldn’t it be grand if our nation was someday able to celebrate the date of our independence from fossil fuels? And wouldn’t it be great if that date came in our lifetime?

That day will only come if we are able to get our heads around the problem and truly understand the effect that our addiction to oil and coal (and to a lesser extent natural gas) has had, is having and is likely to have on the lands we love and for which our ancestors fought so hard. A picture may be worth a thousand words, but you need numbers (or some concept of them) to even say that. So consider what follows to be a kind of picture painted by numbers, a picture which tells the story of climate change in Wisconsin and the Midwest. Despite all those numbers, there is a definite narrative arc to this story. If it is difficult to imagine a happy ending, well, at least I try to show that it doesn’t necessarily have to end like Hamlet does.

The index below is by no means exhaustive. Except for the first five items, which provide some necessary context, the facts presented are specific to the Midwest† and Wisconsin. Unless otherwise noted, the data is from one of three sources:

So without further ado, and with a nod to co-founder Bill McKibben, who during his tenure at Harper’s Magazine created the useful and popular Harper’s Index, I give you…

Wisconsin & Midwest climate change by the numbers

Approximate number of years since the atmospheric carbon dioxide (CO2) level has been as high as it is today (UCS): 800,000

The highest level of CO2 in the Earth’s atmosphere, in parts per million, in the 420,000 years leading up to the Industrial Revolution (UWSG): 280

Parts per million of CO2 in the atmosphere above which the nation’s leading climate scientist James Hansen says is “not compatible with the planet on which civilization developed or to which life on earth is adapted” (James Hansen): 350

Level of CO2, expressed in parts per million, in the Earth’s atmosphere today (NOAA): 392.94

Number of years that carbon dioxide added to the atmosphere today remains in the atmosphere (UWSG): 50-100

Percent of U.S. global warming emissions attributable to Wisconsin (UCS): 2

Percent of Wisconsin’s global warming emissions generated by energy use (UCS): 85

Percent generated by agriculture (UCS): 8

Percent by which Wisconsin’s CO2 emissions grew between 1990 and 2004 (WERPC): 25

Number of degrees Fahrenheit Wisconsin’s average annual temperature has risen in the last 50 years (UCS): 1-2

Number of degrees F average annual temperatures in the Midwest have risen since 1980 (UCS): 2.6

Number of months (average) Lake Mendota in south central Wisconsin remained ice covered 150 years ago (UWSG): 4

Number of months (average) Lake Mendota remains ice covered today (UWSG): 3

Amount that winter tourists spend in Wisconsin each year (WERPC): $2,000,000,000

Approximate number of degrees F mean temperatures have risen in the Upper Great Lakes in the last 50 years (UCS): 4

Number of deaths in Chicago attributed to 1995 heat wave* (UCS): 700

Number of days per summer with highs over 90 degrees F that Milwaukee is likely to experience near the end of the century if current pollution trends continue (UCS): 55

Number of days over 100 degrees (UCS): 22

Percent by which Wisconsin winters and springs would be wetter by then (UCS): 25

Percent by which summer rains would decrease (UCS): 10

Percent increase in heavy rainfall events in the Midwest in the last 50 years (UCS): 100

Approximate percent of this increase that occurred in the last 30 years (UCS): 66

Number of inches of rain that fell on Ontario, Wisconsin in a single day in June of 2008 (UCS): 6

Number of Wisconsin counties declared federal disaster areas that summer due to flooding and other storm damage (UCS): 29

Amount lost from ruined crops, lower crop yields and delayed plantings because of that heavy rainfall event (UCS): $150,000,000

Number of feet Lake Michigan water levels are projected to decline in summer (due to increased evaporation caused by higher temperatures) and winter (due to a decrease in lake ice) toward the end of the century if emissions continue at current levels (UCS): 1-2

Year in which Lake Superior broke an 81-year-old record low for one month when it dropped more than two feet below its historic average September water level (UWSG): 2007

Percent increase in rainfall needed for each degree rise in temperature to maintain existing water levels in our lakes (UWSG): 10

Number of degrees F average summer temperatures are projected to increase by the end of the century if emissions continue at current levels (UWSG): 8-18

Number of degrees F average winter temperatures are projected to increase by the end of the century (UWSG): 6-11

Percent by which yields of Wisconsin corn and soybeans fell from their average annual yields for the period 1978-1997, during the 1988 heat wave (UCS): 65

Percent of crops in Wisconsin that have access to irrigation (UCS): 3-4

Degrees F at which corn crops can fail (UCS): 95

Degrees F at which milk production in dairy cattle decline, depending on humidity (UCS): 75-80

Amount Wisconsin dairy farmers already lose annually from heat stress to their cattle (WERPC): $60,000,000

Number of heavy rainfall events in southeastern Wisconsin in the 20th century matching the hypothetical “once-in-500-years” standard (UWSG): 4

Number of those events that occurred since 1970 (UWSG): 3

Average number of gallons of raw sewage that spilled into Lake Michigan each year from metropolitan Milwaukee because of heavy rainfall events in 1999 (UCS): 9,000,000,000

Average number of gallons of raw sewage that spilled into Lake Michigan from metro Milwaukee after the city spent $4 billion to upgrade its sewage and storm water system (UCS): 1,500,000,000

Top-end estimate of number of gallons of oil that have leaked into the Gulf of Mexico from the blown Deepwater Horizon rig as of June 23, according to FOXNews:  127,000,000

Tons of carbon dioxide that would be kept out of the atmosphere each year if Madison residents replaced even 20 percent of their trips with bicycling (UWSG): 17,000

Number of acute respiratory cases that would be avoided by such a change (UWSG): 14,500

Amount in health care costs that would be saved (UWSG): $40,000,000

Number of work days each year that would be saved (UWSG): 18,000

Number of jobs that would be created by 2012 with a $340 million annual investment in energy efficiency (UCS): 9,000

Amount per year Wisconsin would save by 2012 by making this same investment (UCS): $900,000,000

Amount Wisconsin exports each year to pay for imported fuels including coal, natural gas and petroleum (RENEW Wisconsin): $16,000,000,000

Amount the Midwest could save in 2030 by increasing energy efficiency and conservation, improving vehicle fuel efficiency and reducing miles driven, boosting the use of renewable energy, and increasing agricultural practices (UCS): $11,900,000,000

Number of calls (at least) you could have made to your state or federal elected representatives in the time it took to read this post: 1

*Actual amount is probably far greater because there were no uniform reporting requirements

†The UCS defines the Midwest as the states of Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, Ohio and Wisconsin



  1. Susan McGovern

    Thanks so much for compiling this important information. I am most shocked by the item that our state’s “percent by which….CO2 emissions grew between 1990 and 2004 (WERPC)” was “25,” because 1992 was the year the global environmental summit at Rio de Janiero proposed targeted reductions in CO2 emissions and our state, our country, our planet largely has not followed through. Perhaps in this year we will make a difference, thanks to the RePower American campaign of Al Gore, the wake up call of the Gulf oil spill castastrophe, and the Obama Administration’s commitment to developing renewable, less polluting energy sources.

  2. Are you saying there is no climate variability all this is caused by anthropogenic CO2 emissions?

  3. I share your hope that we will make a difference this year, Susan. We need more families like yours working hard for positive change. Thanks for your careful reading and thoughtful remarks.

  4. Terry: there has always been some natural climate variability. Whether we agree or disagree about the causes of the warming (which seem obvious to me and to the overwhelming majority of climate scientists), hopefully we can agree that the data shows that the impacts are and will be severe, and that we can by our actions steer ourselves toward a less hellish future. Mitigation and adaptation are moral imperatives regardless of the forces driving the warming.