Observed Climate Change in Wisconsin

By | July 25, 2008


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[Illustrations, footnotes and references available in PDF version]


In April 2007, Wisconsin Governor Jim Doyle signed Executive Order 191 creating the Governor’s Task Force on Global Warming and tasked it with developing a plan of action to reduce Wisconsin’s greenhouse gas emissions. Citing that “the failure to reduce greenhouse gas emissions could raise Wisconsin temperatures, increase the severity of droughts, further reduce water levels in Lake Michigan, destroy wetlands, harm croplands and forests, and harm public health, among other damaging effects,” the Governor defined the Task Force’s mission as:

  1. Present viable, actionable policy recommendations to the Governor to reduce greenhouse gas emissions in Wisconsin and make Wisconsin a leader in implementation of global warming solutions; and
  2. Advise the Governor on ongoing opportunities to address global warming locally while growing our state’s economy, creating new jobs, and utilizing an appropriate mix of fuels and technologies in Wisconsin’s energy and transportation portfolios; and
  3. Identify specific short term and long term goals for reductions in greenhouse gas emissions in Wisconsin that are, at a minimum consistent with the Wisconsin’s proportionate share of the reductions that are needed to occur worldwide to minimize the impacts of global warming;

Conspicuously missing from the Task Force’s objectives, however, are three major areas of importance: 1) a careful review of the state’s climate history and its impacts with regard to how the state’s climate has changed and whether or not the changes bear any resemblance of changes expected from human-caused “global warming,” 2) a quantification of the impacts of the state’s emissions reductions efforts on the course of future climate change, either globally, regionally, or locally, and 3) an assessment of the impacts of any proposed greenhouse gas reduction measures on the state’s economy.

In this report, we provide the analyses that should have been required of the Task Force. We find that there has been little “global warming”-related change to Wisconsin’s climate and what changes have occurred have been well adapted to by its residents. We demonstrate how fruitless any efforts at greenhouse emissions limitations will be on the climate. In fact, we find that even a complete cessation of all carbon dioxide emissions originating in Wisconsin would be subsumed by global greenhouse gas emissions increases (primarily from China and India) in only six week’s time and would produce no detectable or scientifically meaningful impact on local, regional, or global climate. Unfortunately, the same cannot be said for the economic consequences of greenhouse gas emissions’ legislation—they have been recently estimated to be large, and negative, for the citizens of Wisconsin.
Observed climate change in Wisconsin

Annual temperature: The historical time series of statewide annual temperatures in Wisconsin begins in 1895. Over the entire record, there has been an overall warming trend of about 1ºF/100yr. Despite this slight long-term rise however, the record is largely dominated shorter term variability—that is, the variations in temperature from year-to-year and decade-to-decade are as large, or larger, than the overall 113-year trend. For example, the run of recent warm years since 1998 comes on the heels of a period of steady to slightly falling temperatures that extended from the early 1930s through the mid-1990s. Previous to then, temperatures warmed rapidly from the 1910s through the 1930s. The highest annual average statewide temperature in Wisconsin was recorded in 1931.

Wisconsin statewide annual temperatures, 1895-2007

Figure 1. Annual statewide average temperature history for Wisconsin, 1895-2007 (available from the National Climatic Data Center, http://www.ncdc.noaa.gov/oa/climate/research/cag3/wi.html).

Seasonal temperatures: When Wisconsin’s temperature history is broken down into the four seasons of the year, it can be seen that most of the annual warming has occurred in the winter and spring. In fact, there has been no long-term change in the state’s average summer or fall temperatures during the past 113 years. Again, even in the winter and spring, year-to-year and/or decade-to-decade variability is more strongly evident than is the overall change. Aside from the warm winters of 1998 and 2002, temperatures in recent years do not appear out of the ordinary when compared with the observed temperature history. There is little evidence of unprecedented “climate change” to be found in Wisconsin’s temperature observed temperature history.

Wisconsin seasonal temperatures, 1895-2007

Figure 2. Seasonal statewide average temperature history of Wisconsin. (source: National Climatic Data Center, http://www.ncdc.noaa.gov/oa/climate/research/cag3/wi.html)

Precipitation: Averaged across the state of Wisconsin for each of the past 113 years, the statewide annual total precipitation averages 31.4 inches per year. Wisconsin’s annual precipitation is quite variable from year to year, and has varied from as much as 41.86 inches falling in 1938 to a little as 20.93 inches in 1976. The precipitation history of Wisconsin shows that since widespread record keeping began in 1895, there has been an increase in the state’s average annual precipitation of about 7 percent. There is no indication, however, that either the frequency or severity of wet years or dry years have increased.

Wisconsin annual precipitation, 1895-2007

Figure 3. Statewide average precipitation history of Wisconsin. There has been about a 7% increase in the statewide annual average precipitation from 1895 through 2007 (source: National Climatic Data Center, http://www.ncdc.noaa.gov/oa/climate/research/cag3/wi.html).

Drought: Since 1895, there has been an overall trend towards slightly wetter conditions across Wisconsin, as the increases in precipitation have made up for any increases in evaporative loss that may have occurred as a result of the state’s slightly warming temperatures. It is clearly evident from the history of the Palmer Drought Severity Index—a standard measure of moisture conditions that takes into account both inputs from precipitation and losses from evaporation—that there has been an overall decrease in the frequency of extreme drought conditions across the state. Of the eight statewide averaged extreme drought events experienced since 1895, seven of them occurred prior to 1980. Also evident from the state’s drought history is the fact that annual and decadal variations play a large role in the pattern of long-term moisture status across the state and both dry periods and wet periods occur with regularity in the natural climate of Wisconsin.

Wisconsin drought severity, 1895-2007
Palmer drought severity index

Figure 4. Monthly statewide average values of the Palmer Drought Severity Index (PDSI) for the state of Wisconsin, 1895-2007 (data from the National Climate Data Center, www.ncdc.noaa.gov)

Paleodrought: The role of natural climate variability is even more on display when we investigate the very long-term moisture records for the state. We find that the droughts experienced during the past century in Wisconsin pale in comparison to the long lasting and severe dry conditions that have occurred there in the more distant past.

The character of past climates can be judged from analysis of climate-sensitive proxies such as tree-rings. Using precipitation information about past precipitation contained in tree rings, Dr. Edward Cook and colleagues have been able to reconstruct a summertime moisture record for Wisconisn that extends back in time more than 700 years.

Interestingly, while there has been a slight trend towards generally wetter conditions across the past seven centuries in Wisconsin (as shown in Figure 5), what is more evident in the paleoreconstruction of moisture levels is the large and persistent swings from dry conditions to wet conditions and then back again. It appears that the precipitation climate of Wisconsin has become more stable (less variable) over the course of the past 700 years—with recent wet periods not being as wet and persistent, and recent dry periods not being as dry and persistent as periods were in the past.

Importantly, the paleo-climate record give us clear indication that both droughts and wet periods are a natural part of the Wisconisn’s climate system and thus neither should not be used as an example of events that are uniquely caused by anthropogenic climate change. Instead, they have been far worse in the past, long before any possible human influences.

Wisconsin’s reconstructed paleo-drought severity

Figure 5. The reconstructed summer (June, July, August) Palmer Drought Severity Index (PDSI) for central Wisconsin from 1250 A.D. to 2003 A.D. depicted as a 20-yr lowpass filter. (National Climate Data Center, http://www.ncdc.noaa.gov/paleo/pdsi.html)

Crop Yields: In Wisconsin, the annual yields from the state’s major cash crops such as corn and soybeans have risen dramatically during the past 50 years (USDA), while the climate there has changed relatively little. This is strong indication that factors other than climate and climate change are largely responsible for the rapid yield rise.

Wisconsin Crop Yields, 1950-2007

Figure 6. History of crop yields (1950-2007) of two of the state’s economically significant crops, corn (top), and soybeans (bottom). There is no indication that long-term climate changes are negatively impacting crop yields.

Crop yields increase primarily as a result of technology—better fertilizer, more resistant crop varieties, improved tilling practices, modern equipment, and so on. The level of atmospheric carbon dioxide, a constituent that has proven benefits for plants, has increased as well. The relative influence of weather is minimal compared with those advances. Temperature and precipitation show only weak or non-existent long-term trends; they are instead responsible for some of the year-to-year variation in crops yields about the long-term upward trend. Even under the worst of circumstances, minimum crop yields continue to increase. Through the use of technology, farmers are adapting to the climate conditions that traditionally dictate what they do and how they do it and producing more output than ever before. There is no reason to think that such adaptations and advances will not continue into the future. Thus, projections of negative impacts to Wisconsin’s agriculture that may result from climate change are largely pessimistic and unfounded.

The Great Lakes: There is much concern that future climate change will negatively impact the Great Lakes, in particular, Lake Superior and Lake Michigan upon which Wisconsin shares a shoreline. The primary concern is that warmer summers and less precipitation will act together to lower the lake levels, and in doing so harm wetlands and adversely impact other lake ecosystems and human activities on the lakes. Indeed, in recent years the water level in both Lake Superior and Lake Michigan have been low and the long-term trend has been towards less water.

However, blaming climate change on the lake level trends doesn’t make much sense. As we have seen, the summer temperatures across Wisconsin exhibit no long-term trend (Figure 2) and the annual precipitation across Wisconsin has been increasing (Figure 3). These trends hardly support a climate pressure to lower lake levels.

A recent paper appearing in the scientific journal Hydrology and Earth System Sciences demonstrates this point further. Two hydrologic engineers examined the hydrology of the Great Lakes, including a 70-year history of total precipitation, temperature and streamflow into and through the lakes (McBean and Motiee, 2008). They found statistically significant increases in precipitation over four of the five lakes, no significant increases in temperatures over any lake, and generally increases in streamflow through the lakes. These findings indicate that the observed hydroclimate of the Great Lakes over the past 70 years has not followed the pattern predicted by climate models to occur with an increasing greenhouse effect.

One explanation for the lowering of the water levels in Lake Michigan, despite increases in precipitation, is that there has been an increase in the flow out of the Lake Michigan and Lake Huron. The causes of the increased flow rate may be 1) a result of erosion of the St. Clair River channel as a result of historical dredging operations, 2) increased shoreline protection measures which have reduced the natural flow suppressing sand supply, and/or 3) a change in the geometry and position of the main flow channel through Lake Huron (Baird, 2005). None of the explanations is the result of changes in the region’s climate.

Heatwaves: The population of Wisconsin has likely become less sensitive to the impacts of excessive heat events over the course of the past 30-40 years. This is true in most major cities across the United States—a result of the increased availability and use of air-conditioning and the implementation of social programs aimed at caring for high-risk individuals—despite rising urban temperatures.

Heat-related mortality trends across the U.S.

Figure 7. Annual heat-related mortality rates (excess deaths per standard million population). Each histogram bar indicates a different decade (from left to right, 1970s, 1980s, 1990s). (Source: Davis et al., 2003b).

A number of studies have shown that during the several decades, the population in major U.S. cities has grown better adapted, and thus less sensitive, to the effects of excessive heat events (Davis et al., 2003a, 2003b). Each of the bars of the illustration above represents the annual number of heat-related deaths in 28 major cities across the United States. There should be three bars for each city, representing, from left to right, the decades of the 1970s, 1980s and 1990. For nearly all cities, the number of heat-related deaths is declining (the bars are get smaller). And although there are no cities from Wisconsin that were directly included in the Davis et al. studies, in most cities in states in the upper Midwestern United States that were part of the investigation, there has been a significant decline in heat-related mortality over time (see for instance, the nearby cities of Detroit (DET in the figure above), Minneapolis (MIN) and Chicago (CHI)). All the surrounding cities show that the heat-related mortality in the 1990s was significantly less, on a per capita basis, than the heat-related mortality in the 1960s and 1970s—meaning that the population of those cities has become better adapted to heat waves. This is likely to be the case in Wisconsin cities as well, as these cities share characteristics of the climate of those of the cities noted above. This adaptation is most likely a result of improvements in medical technology, access to air-conditioned homes, cars, and offices, increased public awareness of potentially dangerous weather situations, and proactive responses of municipalities during extreme weather events.

The pattern of the distribution of heat-related mortality shows that in locations where extremely high temperatures are more commonplace, such as along the southern tier states, the prevalence of heat-related mortality is much lower than in the regions of the country where extremely high temperatures are somewhat rarer (e.g. the northeastern U.S.). This provides another demonstration that populations adapt to their prevailing climate conditions. Contrary to pessimistic projections of increasing heat-related mortality, if temperatures warm in the future and excessive heat events become more common, there is every reason to expect that adaptations will take place to lessen their impact on the general population.

Vector-borne diseases: Malaria, dengue fever, and West Nile Virus, which have been erroneously predicted to spread owing to “global warming,” are not tropical diseases. Climate change will accordingly have a negligible effect on their transmission rates. These diseases are readily controlled by well-known public health policies.

Malaria epidemics occurred as far north as Archangel, Russia, in the 1920s, and in the Netherlands. Malaria was common in most of the United States until the 1950s (Reiter, 1996). In the late 1800s, when the United States was colder than today, malaria was endemic east of the Rocky Mountains—a region stretching from the Gulf Coast all the way up into northern Minnesota, including all if Wisconsin.

In 1878, 100,000 Americans were infected with malaria, and some 25,000 died. Malaria was eradicated from the United States in the 1950s not because of climate change (it was warmer in the 1950s than in the 1880s), but because of technological advances. Air-conditioning, the use of screen doors and windows, and the elimination of urban overpopulation brought about by the development of suburbs and automobile commuting were largely responsible for the decline in malaria (Reiter, 1996).

Malaria occurrence in the United States, 1880s

Figure 8. In the late 19th century malaria was endemic in shaded regions, including the entire state of Wisconsin. (Source: Reiter, 2001)

The effect of technology is also clear from statistics on dengue fever outbreaks, another mosquito-borne disease. In 1995, a dengue pandemic hit the Caribbean and Mexico. More than 2,000 cases were reported in the Mexican border town of Reynosa. But in the town of Hidalgo, Texas, located just across the river, there were only seven reported cases (Reiter, 1996). This is just not an isolated example. Data collected over the past decade have shown a similarly large disparity between incidence of disease in northern Mexico and in the southwestern United States, though there is very little climate difference.

Another “tropical” disease that is often wrongly linked to climate change is the West Nile Virus. The claim is often made that a warming climate is allowing the mosquitoes that carry West Nile Virus to spread into Wisconsin. This reasoning is incorrect. West Nile Virus, a mosquito-borne infection, was introduced to the United States through the port of New York in summer 1999. Since its introduction, it has spread rapidly, reaching the West Coast by 2002. Incidence has now been documented in every state as well as most provinces of Canada.

Spread of the West Nile Virus across the United States after its Introduction in New York City in 1999

Figure 9. Spread of the occurrence of the West Nile Virus from its introduction to the United States in 1999 through 2007. By 2003, virtually every state in the country had reported the presence of virus. (source: http://www.cdc.gov/ncidod/dvbid/westnile/Mapsactivity/surv&control07Maps.htm).

The rapid spread of West Nile Virus across the U.S. and Canada is not a sign that temperatures are progressively warming. Rather, it is a sign that the existing environment is primed for the virus. In the infected territories, mean temperature has a range more than 40ºF. The virus can thrive from the tropics to the tundra of the Arctic – anywhere with a resident mosquito population. The already-resident mosquito populations of Wisconsin are appropriate hosts for the West Nile virus—as they are in every other state.

Impacts of climate-mitigation measures in the state of Wisconsin

Globally, in 2004, humankind emitted 27,186 million metric tons of carbon dioxide (mmtCO2), of which emissions from Wisconsin accounted for 108.8 mmtCO2, or a mere 0.4% (EIA, 2007a,b). The proportion of manmade CO2 emissions from Wisconsin will decrease over the 21st century as the rapid demand for power in developing countries such as China and India rapidly outpaces the growth of Wisconsin’s CO2 emissions (EIA, 2007a).

During the past 5 years, global emissions of CO2 from human activity have increased at an average rate of 3.5%/yr (EIA, 2007a), meaning that the annual increase of anthropogenic global CO2 emissions is more than 8 times greater than Wisconsin’s total emissions. This means that even a complete cessation of all CO2 emissions in Wisconsin will be completely subsumed by global emissions growth in just six week’s time! In fact, China alone adds about four Wisconsin’s-worth of new emissions to its emissions’ total each and every year. Clearly, given the magnitude of the global emissions and global emission growth, regulations prescribing a complete cessation – let alone a small reduction – of Wisconsin’s CO2 emissions will have absolutely no effect on global climate, temperature or sea level.

Wigley (1998) examined the climate impact of adherence to the emissions controls agreed under the Kyoto Protocol by participating nations, and found that, if all developed countries meet their commitments in 2010 and maintain them through 2100, with a mid-range sensitivity of surface temperature to changes in CO2, the amount of warming “saved” by the Kyoto Protocol would be 0.07°C by 2050 and 0.15°C by 2100. The global sea level rise “saved” would be 2.6 cm, or one inch. Even a complete cessation of CO2 emissions in Wisconsin is only a tiny fraction of the worldwide reductions assumed in Dr. Wigley’s global analysis, so its impact on future trends in global temperature and sea level will be only a minuscule fraction of the negligible effects calculated by Dr. Wigley.

To demonstrate the futility of emissions regulations in Wisconsin, we apply Dr. Wigley’s results to the state, assuming that the ratio of U.S. CO2 emissions to those of the developed countries which have agreed to limits under the Kyoto Protocol remains constant at 39% (25% of global emissions) throughout the 21st century. We also assume that developing countries such as China and India continue to emit at an increasing rate. Consequently, the annual proportion of global CO2 emissions from human activity that is contributed by human activity in the United States will decline. Finally, we assume that the proportion of total U.S. CO2 emissions in Wisconsin – now 1.8% – remains constant throughout the 21st century. With these assumptions, we generate the following table derived from Wigley’s (1998) mid-range emissions scenario (which itself is based upon the IPCC’s scenario “IS92a”):

Table 1
Projected annual CO2 emissions (mmtCO2)

Note: Developed countries’ emissions, according to Wigley’s assumptions, do not change between 2025 and 2050: neither does total U.S or Wisconsin emissions.

In Table 2, we compare the total CO2 emissions saving that would result if Wisconsin’s CO2 emissions were completely halted by 2025 with the emissions savings assumed by Wigley (1998) if all nations met their Kyoto commitments by 2010, and then held their emissions constant throughout the rest of the century. This scenario is “Kyoto Const.”

Table 2
Projected annual CO2 emissions savings (mmtCO2)

Table 3 shows the proportion of the total emissions reductions in Wigley’s (1998) case that would be contributed by a complete halt of all Wisconsin’s CO2 emissions (calculated as column 2 in Table 2 divided by column 3 in Table 2).

Table 3
Wisconsin’ percentage of emissions savings

Using the percentages in Table 3, and assuming that temperature change scales in proportion to CO2 emissions, we calculate the global temperature savings that will result from the complete cessation of anthropogenic CO2 emissions in Wisconsin:

Table 4
Projected global temperature savings (ºC)

Accordingly, a cessation of all of Wisconsin’s CO2 emissions would result in a climatically-irrelevant and undetectable global temperature reduction by the year 2100 of less three thousandths of a degree Celsius. This number is so low that it is effectively equivalent to zero. Results for sea-level rise are also negligible:

Table 5
Projected global sea-level rise savings (cm)

A complete cessation of all anthropogenic emissions from Wisconsin will result in a global sea-level rise savings by the year 2100 of an estimated 0.05 cm, or about two hundredths of an inch. Again, this value is climatically irrelevant and virtually zero.

Even if the entire Western world were to close down its economies completely and revert to the Stone Age, without even the ability to light fires, the growth in emissions from China and India would replace our entire emissions in little more than a decade. In this context, any cuts in emissions from Wisconsin would be extravagantly pointless. Wisconsin’s carbon dioxide emissions, it their sum total, effectively do not impact world climate in any way whatsoever.

Costs of Federal Legislation

And what would be the potential costs to Wisconsin of legislative actions designed to cap greenhouse gas emissions? An analysis was recently completed by the Science Applications International Corporation (SAIC), under contract from the American Council for Capital Formation and the National Association of Manufacturers (ACCF and NAM), using the National Energy Modeling System (NEMS); the same model employed by the US Energy Information Agency to examine the economic impacts.

For a complete description of their findings please visit: http://www.accf.org/pdf/NAM/fullstudy031208.pdf

To summarize, SAIC found that by the year 2020, average annual household income in Wisconsin would decline by $913 to $2,961 and by the year 2030 the decline would increase to between $3,786 and $6,904. The state would stand to lose between 23,000 and 34,000 jobs by 2020 and between 56,000 and 74,000 jobs by 2030. At the same time gas prices could increase by more than $5 a gallon by the year 2030 and the states’ Gross Domestic Product could decline by then by as much as $11.8 billion/yr.

And all this economic hardship would come with absolutely no detectable impact on the course of future climate. This is the epitome of a scenario of all pain and no gain.

Figure 10. The economic impacts in Wisconsin of federal legislation to limit greenhouse gas emissions green. (Source: Science Applications International Corporation, 2008, http://www.instituteforenergyresearch.org/cost-of-climate-change-policies/)

Wisconsin Scientists Reject UN’s Global Warming Claims

At least 590 Wisconsin scientists have petitioned the US government that the UN’s human-caused global warming hypothesis is “without scientific validity and that government action on the basis of this hypothesis would unnecessarily and counterproductively damage both human prosperity and the natural environment of the Earth.”

They are joined by over 31,072 Americans with university degrees in science – including 9,021 PhDs.

The petition and entire list of US signers can be found here:

Names of the Wiscon scientists who signed the petition can be viewed here:


Baird & Associates, 2005. Regime change (man made intervention) and ongoing erosion in the St. Clair River and impacts on Lake Michigan-Huron lake levels. (http://www.georgianbay.ca/pdf/water_levels/10814%20St%5B1%5D.%20Clair%20River%20Report_V5_w%20A%20&%20B.pdf)

Davis, R.E., et al., 2003a. Decadal changes in summer mortality in the U. S. cities. International Journal of Biometeorology, 47, 166-175.

Davis, R.E., et al., 2003b. Changing heat-related mortality in the United States. Environmental Health Perspectives, 111, 1712-1718.

Energy Information Administration, 2007a. International Energy Annual, 2005 (and updates) U.S. Department of Energy, Washington, D.C., http://www.eia.doe.gov/iea/contents.html

Energy Information Administration, 2007b. Emissions of Greenhouse Gases in the United States, 2006 (and updates). U.S. Department of Energy, Washington, D.C., http://www.eia.doe.gov/oiaf/1605/ggrpt/pdf/0573(2006).pdf

Intergovernmental Panel on Climate Change, 2007. Summary for Policymakers, (http://www.ipcc.ch/SPM2feb07.pdf)

McBean, E., and H. Motiee, 2008. Assessment of impact of climate change of water resources: a long term analysis of the Great Lakes of North America. Hydrology and Earth System Sciences, 12, 239-255.

National Climatic Data Center, U.S. National/State/Divisional Data, (www.ncdc.noaa.gov/oa/climate/climatedata.html)

Reiter, P., 1996. Global warming and mosquito-borne disease in the USA. The Lancet, 348, 662.

Wigley, T.M.L., 1998. The Kyoto Protocol: CO2, CH4 and climate implications. Geophysical Research Letters, 25, 2285-2288.