Understanding Long-Term Climate Changes for Kansas City, Missouri

INTRODUCTION Weather conditions in Kansas City, Missouri will change as greenhouse gas concentration continues to increase. This report will assist the planning efforts of city officials and staff or other individuals considering the potential impact of climate change on the area. It contains summary information of the local weather response expected under different possible levels of greenhouse gases in the future. The Kansas City Climate Change Story As pointed out in the National Climate Assessment, climate change will tend to amplify existing climate-related risks to people, ecosystems, and infrastructure in the Midwest. Analysis in this report indicates Kansas City can expect to see changes consistent with those expected regionally. While the recent change in temperatures observed in Kansas City is relatively modest, temperature is projected to increase substantially over the remainder of this century. Temperature will increase in all seasons, summers will accumulate more cooling degree-days and winters will accumulate fewer heating degree-days. Heat waves will become more frequent and summer nights will become hotter. Recent and projected increases in precipitation for Kansas City are substantial, with seasonal rainfall increases clear for both spring and fall. In addition, rainfall increase is clear for extreme events including annual maximum of daily, 5-day, and 15-day precipitation. These projected changes in temperature and precipitation extremes can be expected to increase demand for summertime cooling, degrade local air quality, and place additional stress on water supply systems, wastewater and stormwater management systems, and flood control efforts. METHOD This climate change assessment for Kansas City utilizes the same database of projected climate variables used to develop insights into national and regional climate change and associated impacts reported in the third U. S. National Climate Assessment (NCA; Melillo and Coauthors, 2014). The NCA and other assessments explore a variety of potential future climates that each correspond to as many as eight, well-established scenarios of global human greenhouse gas (GHG) emissions adopted by the Intergovernmental Panel on Climate Change (IPCC; Nakicenovic and Coauthors, 2000), a program of the World Meteorological Organization and the United Nations Environment Program. While useful for discerning trends over broad areas, these national and global assessments simply cannot provide the localized information for planning or similar local activities of interest to the tens of thousands of municipalities in the United States.

In part to simplify the process, this report provides an assessment of change in local climate conditions through the end of the 21st century for just two emissions scenarios developed for the IPCC and summarized in the NCA. A1FI is a high emissions scenario in which the rate of GHG emissions continues to increase in a manner consistent with that seen for the last two decades. A1B is a moderate emissions scenario in which the rate of increase GHG emissions slows due to a variety of mitigation efforts. 1

Understanding Long-Term Climate Changes for Kansas City, Missouri: A Climate Assessment

While A1FI might be considered “business as usual,” voluntary commitments made at the Conference of Parties (COP) in Paris in December of 2015, would put the world on a path closer to A1B, and the agreement to limit warming to +2C (+3.4°F) would be below A1B. This discussion serves to underscore one of the major sources of uncertainty in climate projections, the rate at which GHG (especially from fossil fuels) will be emitted. (More detailed descriptions of handling of uncertainty are provided in Appendix A.) Any changes observed over the last three or four decades, a period when the climate signal associated with increase concentrations of GHG began to emerge from the noise created by weather variability, provide a context within which projected change can be evaluated. When broad spatial patterns of change occur, many municipalities within the same region will experience a common direction of change (warmer vs. cooler, wetter vs. dryer). When local change is significantly different from regional change, the likelihood that local change will continue should be assigned less confidence unless a factor explaining trend differences is determined. Some examples include urbanization, deforestation, and switch from grassland to cropland. Confidence in the direction and rate of projected climate change is important when including consideration of future climate in planning or other decision making activities. ClimateLOOK™ reports, therefore, include a discussion of the level of agreement of climate projections generated for a location of interest to regional trends observed over the previous 40 years (1976-2015). When the direction of projected regional trend differs from that of any observed regional trend, the projected trend is characterized as being in “poor agreement.” Conversely, when the projected regional trend agrees with direction, but not the rate, of the observed trend (differ by more than 20 percent) the projected trend is characterized as only being in “good agreement.” Finally, when the projected regional trend agrees with rate and direction of any observed regional trend, the projected trend is characterized as being in “very good agreement.” Users are cautioned that any trend labeled in this report as being in “poor agreement” with the regional observed trend, as described above, are highly suspect. Users should always apply professional judgment and awareness of sensitivity of potential decisions or applications of the results of this report when determining the usefulness of the analysis it contains.

CLIMATE OF THE KANSAS CITY AREA Historically, Kansas City lies in a humid continental climate zone, described as temperate with extremes of heat, cold, and precipitation. The Kansas City climate station used in this assessment, as well as the NCA, is located at the Charles B. Wheeler Downtown Airport (Figure 1), and has a period of record from 1893 to present. Since record keeping began at that station, Kansas City has experienced high and low average annual temperatures of 65.1°F and 45.8°F. Annual rainfall is 34.8" and snowfall is 16.2". Monthly temperature reaches peak value in July with average high temperature of 89.2°F. The annual low occurs in January with average minimum of 20.3°F. Rainfall is largest in June with an average of 4.9". The least precipitation occurs in February with an average of 1.3".

Figure 1: Location of the Global Historical Climatology Network Station [USW00013988] that provided historical observations used in the NCA and reported in this report. (Google Maps)

 USW00013988

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Understanding Long-Term Climate Changes for Kansas City, Missouri: A Climate Assessment

Figure 2: U.S. Climate Divisions (NOAA2016a). Extreme daily conditions are inherent in the climate of Kansas City and the surrounding region (referred to as Missouri Climate Division 1; Figure 2). The highest and lowest recorded temperatures differ by over 130° F, with the annual record maximum and minimum temperatures of 112° F and -22° F. The maximum daily rainfall and snowfall are 8.1" and 20.5" (More information on observed trends in the regional precipitation is reported in NOAA Atlas 14 [NOAA 2016b]). Observed regional changes in temperature and precipitation for the 40-year period 1976 ‒ 2015 (Figures 3 and 4) are summarized below:  Annual temperature has increased in Missouri by 0.3°F per decade, with the average annual statewide temperature increasing from 53.6°F to 55.8°F (Figure 3a).  Annual temperature has increased in Missouri Climate Division 1, by 0.3°F per decade, with the average annual temperature increasing from 52.0°F to 54.2°F (Figure 3b).  Annual precipitation has increased in Missouri by 0.54" per decade. Based upon the trend, the average annual statewide precipitation has increased from 40.1" to 44.5" (Figure 4a).  Annual precipitation has increased in Missouri Climate Division 1 by 0.25" per decade, with average annual precipitation increasing from 37.5" to 40.0" (Figure 4b).

Figure 3a: Recent change in annual temperature for Missouri statewide (Figure source: NOAA National Centers for Environmental Information, Climate At A Glance).

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Understanding Long-Term Climate Changes for Kansas City, Missouri: A Climate Assessment

Figure 3b: Recent observed trends in annual temperature for Missouri Climate Division 1, Northwest Prairie (Fig. 3b; top panel) (Figure source: NOAA National Centers for Environmental Information, Climate At A Glance).

Figure 4a and 4b: Recent observed trends in annual precipitation for Missouri statewide (Fig. 4a; middle panel) and Missouri Climate Division 1, Northwest Prairie (Fig. 4b; bottom panel) (Figure source: NOAA National Centers for Environmental Information, Climate At A Glance).

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Understanding Long-Term Climate Changes for Kansas City, Missouri: A Climate Assessment

Figure 5. Projected trends in annual average temperature. Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column— observed; blue columns—moderate emissions scenario; red columns— high emissions scenario).

Climate Indicator (Annual Average For Period) 1976 - 2015 2021 - 2060 2061 - 2100 Observed A1FI (High) A1B (Mod) A1FI (High) A1B (Mod) Temperature (oF) 56.5 ((High)(High)60.3 60.3 64.4 1!1B 63.4(Mod) Heat Wave Daytime Temperature (oF) 100.3 105.3 103.5 111.4 107.5 Heat Wave Nighttime Temperature (oF) 79.8 83.9 83.4 90.2 87.2 Number of Days Max. Temp. > 105 oF 0.7 6.3 3.6 21.9 9.8 Number of Days Min. Temp. > 70 oF 36.4 84.4 77.0 114.9 99.7 Cold Wave Nighttime Temperature (oF) 1.4 5.6 5.0 10.8 10.8 Number of Freeze - Thaw Cycles 4.4 3.8 3.3 2.9 2.9 Cooling Degree Days 1662.8 2414.3 2287.0 3270.0 2846.2 Heating Degree Days 4790.3 4137.1 4015.3 3496.4 3420.6 Spring Frost April 02 April 01 March 26 March 24 March 16 Fall Frost October 31 November 07 November November 16 November 10 Frost Free Days 212.5 219.7 224.505 237.0 238.4 Table 1: Average annual values for temperature related climate indicators Projected Climate Change for Kansas City through 2100 Over the coming century, climate change is projected to affect the state of Missouri, and the Midwest as a whole, by increasing annual temperature and rainfall (NCA 2014). Kansas City is projected to also experience increases in temperature and precipitation, though these changes may differ in detail from regional and statewide changes expected. Temperature Kansas City is projected to experience an increase in annual average temperature of 4°F by mid-century (2021-2060) compared to that observed during the last four decades (1976 ‒ 2015), regardless as to which emissions pathway tends to be more representative of actual emissions (Figure 5, Table 1). The increase is projected to be roughly 7°F by the end of the century (2061 ‒ 2100) if moderate emissions reductions are achieved or as high as 8°F if the rate of increase in emissions seen recently continues. The direction of trend in projected temperature agrees with the increase observable over the last 40 years. The rate of increase in temperature would, however, need to accelerate relative to the observed trend, and so the projected trend is only in “good agreement” with the observed record (Figure 3). Highlights drawn from the summary of relevant climate indicators related to temperature presented in Table 1 include:  Heat waves are projected to increase, on average, by 5°F by mid-century and by 11°F by 2061 ‒ 2100. The worst of the events could be avoided by the end of the century, if the emissions reductions represented in the moderate scenario occur, as the maximum temperatures projected at those emission levels are projected to rise by 7°F (Figure 6).  The number of hot days, when temperatures exceed 105°F, is projected to increase in frequency from less than once per

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Understanding Long-Term Climate Changes for Kansas City, Missouri: A Climate Assessment

Figure 6. Projected trends in annual maximum of 3-day maximum temperatures indicating severity of heat waves. Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column— observed; blue columns— moderate emissions scenario; red columns—high emissions scenario).

Figure 7. Projected trends in annual number of days with maximum temperature exceeding 105°F indicating frequency of heat waves. Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column—observed; blue columns—moderate emissions scenario; red columns—high emissions scenario).

year to more than 5 times per year by mid-century and 21 times a year by the end of the century. The frequency of these events under the moderate emissions scenario is projected to increase less dramatically, to 3 times per year by mid-century and 9 times a year by the end of the century (Figures 7).  Hot nights, associated with heat waves, are projected to increase in temperature and frequency. The maximum average overnight lows are projected to increase by 4°F by mid-century and 10°F by the end of the century under the high emissions scenario. Hot nights in the moderate emissions scenario would be somewhat cooler, but average overnight temperatures associated with heat waves are still projected to increase by 9°F by the end of the century. The frequency of overnight lows above 70°F, when air conditioning is often employed, can be expected to double by the end of the century under both emission scenarios (Figures 8 and 9).  The coldest nights are projected to become milder by 4°F by mid-century and 9°F by the end of the century under regardless of which emissions pathway to be more representative of actual emissions (Figure 10).  Freeze-thaw cycles, however, do not change markedly, though they occur over a shorter cold season (Figure 11).  The cooling and heating degree days increase and decrease, respectively. Heating degree days are projected to decrease from 4800 to 3500 by the end of the century under the high emissions scenario (Figure 12). Cooling degree days, however, are projected to increase from about 1600 to roughly 3270 in the high emissions scenario (Figure 13) by end of the century.  The frost-free period, under the high emissions scenario, is projected to increase in length from 212 days to nearly 220 days by mid-century and to over 237 days in by centuries end. However, year-to-year variability is large (Table 1).

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Understanding Long-Term Climate Changes for Kansas City, Missouri: A Climate Assessment

Figure 8. Projected trends in annual maximum of 3-day minimum temperatures indicating severity of hot nights associated with heat waves. Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column— observed; blue columns—moderate emissions scenario; red columns— high emissions scenario).

Figure 9. Projected trends in annual number of days with minimum temperature exceeding 70°F indicating frequency of hot nights associated with heat waves. Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column—observed; blue columns—moderate emissions scenario; red columns—high emissions scenario).

Figure 10. Projected trends in annual minimum of 3-day minimum temperatures indate severity of cold snaps. Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column—observed; blue columns—moderate emissions scenario; red columns—high emissions scenario).

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Understanding Long-Term Climate Changes for Kansas City, Missouri: A Climate Assessment

Figure 11. Projected trends in annual number of freeze-thaw cycles per year. Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column—observed; blue columns—moderate emissions scenario; red columns—high emissions scenario).

Figure 12. Projected trends in annual Heating Degree Days (HDD) indicating possible energy demand for heating. Annual sum of 65 OF minus average daily temperature (Days with average temperature >65 OF are assigned a value of 0.) Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column—observed; blue columns—moderate emissions scenario; red columns—high emissions scenario).

Figure 13. Projected trends in annual Cooling Degree Days (CDD) reflecting possible energy demand for cooling. Annual sum of average daily temperature minus 65 OF. (Days with average temperature <65 OF are assigned a value of 0.) Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column—observed; blue columns—moderate emissions scenario; red columns—high emissions scenario).

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Understanding Long-Term Climate Changes for Kansas City, Missouri: A Climate Assessment

Figure 14. Projected trends in annual average precipitation. Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column— observed; blue columns—moderate emissions scenario; red columns— high emissions scenario).

Climate Indicator (Annual Average For Period) 1976 - 2015 2021 - 2060 2061 - 2100 Observed A1FI (High) A1B (Mod) A1FI (High) A1B (Mod) Precipitation (inches)1 38.8 40.2 (Mod)40.2 44.6 1!1B (Mod41.1) Maximum 1-day Precipitation (inches) 3.4 3.5 3.5 4.0 3.7 Maximum 5-day Precipitation (inches) 5.5 6.2 5.9 7.0 6.1 Maximum 15-day Precipitation (inches) 7.5 8.8 8.4 10.4 8.9 Number of Days > 1.50" 5.0 5.6 5.3 9.3 8.3 Number of Days > 4.00" 0.3 0.4 0.3 0.6 0.4 Maximum Consecutive Dry Days 30.9 33.0 32.2 39.5 42.8 Table 2: Average annual values for precipitation related climate indicators.

Precipitation Kansas City is projected to experience an increase in annual average precipitation of roughly 1.5” (roughly 4 percent) by mid- century (2021-2060) compared to that observed during the last four decades (1976 ‒ 2015), regardless as to which emissions pathway tends to be more representative of actual emissions (Figure 14, Table 2). The increase is projected to be over 2” (roughly 6 percent) by the end of the century (2061 ‒ 2100) if moderate emissions reductions are achieved or as high as 6 inches (roughly 15 percent), if the rate of increase in emissions seen recently continues (Table 2). These projected precipitation increases are consistent with recent trends at both the local and regional level, and are thus considered to be in “very good agreement.” Furthermore, this increase in precipitation can be expected to occur through an increase in the number of extreme events discussed in Table 2 are summarized below (For a more in depth discussion of the implications for engineering practice of some of these indicators of change in precipitation see Olson and Coauthors, 2015):  Extreme rainfall amounts are projected to increase for the annual maximum of 1-day, 5-day, and 15-day rainfall (Figures 15, 16, and 17). The increase in annual maximum 1-day, 5-day and, 15-day rainfall, respectively, for the high emissions scenario is 3, 13, and 17 percent by mid-century and 18, 27, and 39 percent by the end of the century. Projected increases under the moderate emissions scenario is 3, 7, and 12 percent by mid-century and 9, 11, and 19 percent by the end of the century.  Number of excessive rainfall days, with rainfall exceeding 1.5" and 4.00", is projected to increase substantially (Figures 18 and 19). The average number of days per year exceeding 1.5" for the high emissions scenario is projected to increase by 12 percent by mid-century and nearly double by the end of the century. Projections for the moderate emissions scenario increase from by 6 percent by mid-century and 66 percent by the end of the century. The reduction in return interval for

1 Annual and Seasonal Accumulation is summed over days during meteorological season. For seasonal average, divide sum by number of days. Days included in each season are: Summer, days 152 - 243; Fall, days 244 - 334; Winter, days 335 - 365 (previous year) and 1 - 59; Spring, days 60 – 151.

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Understanding Long-Term Climate Changes for Kansas City, Missouri: A Climate Assessment

Figure 15. Projected trends in annual average maximum daily precipitation. Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column—observed; blue columns—moderate emissions scenario; red columns—high emissions scenario).

Figure 16. Projected trends in annual average maximum 5-day precipitation. Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column— observed; blue columns—moderate emissions scenario; red columns— high emissions scenario).

Figure 17. Projected trends in annual average maximum 15-day precipitation. Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column— observed; blue columns—moderate emissions scenario; red columns— high emissions scenario).

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Understanding Long-Term Climate Changes for Kansas City, Missouri: A Climate Assessment

Figure 18. Projected trends in annual average number of days when precipitation exceeds 1.5“. Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column—observed; blue columns—moderate emissions scenario; red columns—high emissions scenario).

Figure 19. Projected trends in annual average number of days when precipitation exceeds 4“. Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column—observed; blue columns—moderate emissions scenario; red columns—high emissions scenario).

precipitation exceeding 4.00" for the high emissions scenario decreases from 1-in-3-years to less than 1-in-3-years by mid- century and nearly 1-in-1.5-years by the end of the century. Projections for moderate emissions scenario are similar, with the return interval increasing from 1-in-3-years to more than 1-in-3-years by mid-century and to 1-in-1.5-years in by the end of the century.  Length of annual maximum consecutive dry days is projected to increase but exhibits variation by future period (Figure 20). Recent change is not evident in length of annual maximum consecutive dry days. The increase in annual maximum consecutive dry day length for the high emission scenario is from 31 to 33 by mid-century and to 40 by the end of the century. The projected increase under the moderate emissions scenario is from 31 to 32 by mid-century to 43 in by the end of the century. It should be noted that climate models tend to predict a larger number of days with trace rainfall amounts; hence the modest increase between observed and projected values should be considered a conservative estimate. Trends in Seasonal Temperature and Precipitation While separate examination of average annual changes in temperature and precipitation projected for over the rest of the century is useful, understanding how those changes may play out in tandem seasonally can provide insight into how these two factors may drive changes in important weather extremes. Changes in the likelihood of drought, heat stress, or other impacts related to both temperature and precipitation may be inferred from how these two indicators are projected to behave seasonally

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Understanding Long-Term Climate Changes for Kansas City, Missouri: A Climate Assessment

Figure 20. Projected trends in annual average number of consecutive dry days. Columns show the average by period (left columns, 1976 ‒ 2015; middle columns, 2021 ‒ 2060; right columns, 2061 ‒ 2100) and emissions scenario (black column—observed; blue columns—moderate emissions scenario; red columns—high emissions scenario).

Climate Indicator (Seasonal Average For Period) 1976-2015 2021 - 2060 2061 - 2100 Observed A1FI (High) A1B (Mod) A1FI (High) A1B (Mod) Winter (Dec-Jan-Feb) Temperature (oF) 32.0 36.0 37.0 39.2 1!1B40.7 (Mod ) Winter Precipitation (inches)1 4.2 4.6 4.7 5.3 4.7 Spring (Mar-Apr-May) Temperature (oF) 56.0 59.6 61.2 63.1 65.3 Spring Precipitation (inches)1 11.0 13.0 12.5 15.5 12.8 Summer (Jun-Jul-Aug) Temperature (oF) 78.7 83.4 82.5 88.8 85.6 Summer Precipitation (inches)1 13.9 13.4 12.9 13.7 13.1 Fall (Sep-Oct-Nov) Temperature (oF) 57.9 61.0 59.3 65.3 61.7 Fall Precipitation (inches)1 9.5 9.6 10.4 10.4 10.9 Table 3: Projected changes in seasonal temperature and precipitation. in the future. Highlights drawn from the summary of relevant climate indicators related to temperature and precipitation presented in Table 3 include:  Spring precipitation and temperature is projected to increase substantially (relative to the last forty years). Under the moderate emissions scenario, precipitation is projected to increase by 14 percent (1.5”) by mid-century and 17 percent (2”) by the end of the century. These increases in precipitation would be accompanied by a roughly 5°F increase in temperature by mid-century and a roughly 9°F increase by end of the century. Under the high emissions scenario precipitation is projected to increase by 17 percent (2”) by mid-century and 40 percent (4.5”) by the end of the century. These increases in precipitation are projected to be accompanied by a roughly 7°F increase in temperature by mid-century and a roughly 9°F increase by end of the century. Thus, springs overall are expected to be warmer and wetter, suggesting the potential for heat stress–a phenomenon currently associated with summer–will increase in the late spring months.  Summer precipitation and temperature is projected to change (relative to the last forty years) in a more complex manner. Under the moderate emissions scenario, precipitation is projected to decrease by 7 percent (1.0”) by mid-century and 6 percent (roughly 2”) by the end of the century (suggesting latter part of the century will be slightly wetter than the mid- century, but still drier than recent history). This overall decrease in precipitation is projected to be accompanied by a roughly 4°F increase in temperature by mid-century and a roughly 7°F increase by end of the century. Under the high emissions scenario precipitation is projected to decrease by 4 percent by mid-century and by roughly 2 percent by the end of the century (again suggesting latter part of the century will be slightly wetter than the mid-century, but still drier than recent history). This overall decrease in precipitation is projected to be accompanied by a roughly 5°F increase in temperature by mid-century and a roughly 10°F increase by end of the century. Thus, summers overall are expected to be hotter and drier, suggesting the potential for summer drought–a phenomenon already of concern–will increase over the rest of the century.  Fall and winter trends in projected temperate and precipitation appear less significant than those observed for spring and summer. Winters are projected to become warmer, but not significantly wetter in terms of absolute change. The largest

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Understanding Long-Term Climate Changes for Kansas City, Missouri: A Climate Assessment

projected change in precipitation under both scenarios and over both time periods is roughly 1”. Furthermore, current limitations in climate modeling do not support any conclusion about whether this additional precipitation will take the form of rain or snow. Falls are projected to see the least change in both temperature and precipitation of any of the four seasons. Milder projected wintertime temperatures contribute to the projected decline in heating degree days shown in Figure 12.

CONCLUSION Analysis in this report indicates Kansas City can expect to see changes consistent with those expected regionally. While the recent change in temperatures observed in Kansas City is relatively modest, temperature is projected to increase substantially over the remainder of this century. Temperature will increase in all seasons, summers will accumulate more cooling degree-days and winters will accumulate fewer heating degree-days. Heat waves will become more frequent and summer nights will become hotter. Recent and projected increases in precipitation for Kansas City are substantial, with seasonal rainfall increases clear for both spring and fall. In addition, rainfall increase is clear for extreme events including annual maximum of daily, 5-day, and 15- day amount. Clearly, mitigation efforts at all scales from local to global would reduce the effects of many of the extreme events discussed in this report. Recent trends and projected changes indicate that near-term climate adaptation might be best focused on water systems than heat adaptation, because changes in rainfall are already present and expected to continue; whereas, temperature will be an emergent change. The projected concomitant changes in spring and summer temperature and precipitation extremes discussed above can be expected to increase demand for summertime cooling, degrade local air quality, adversely impact human health, and place additional stress on storm-water management systems and other components of the local infrastructure. REFERENCES Google Maps, https://www.google.com/intl/en-US_US/help/terms_maps.html Meehl, G. A., and Coathors. 2007, The WCRP CMIP3 multimodel dataset: A New Era in Climate Change Research." Bull. of the Amer. Meteor., 88, 1383-1394. Melillo, J. M., T. C. Richmond, and Yohe, G.H., 2014, Climate change impacts in the United States: the Third National Climate Assessment. U.S. Global Change Research Program, 841 p. Moss, R. H., and Coauthors, 2010: The Next Generation of Scenarios for Climate Change Research and Assessment. Nature, 463, 747-756. Nakicenovic, N., and Swart, R., 2000: Special Report on Emissions Scenarios, Edited by N. Nakicenovic and R. Swart, Cambridge University Press, pp.612. NOAA, 2016a, U.S. Climate Divisions, http://www.ncdc.noaa.gov/monitoring-references/maps/us-climate-divisions.php. NOAA, 2016b, NOAA Atlas 14: Precipitation Frequency Atlas of the United States, http://www.nws.noaa.gov/oh/hdsc/index.html). Olson, R., and Coathors, 2015: Adapting Infrastructure and Civil Engineering Practice to a Changing Climate, Am. Soc. Civil Eng. doi: 10.1061/9780784479193 Stoner, A. M. K., Hayhoe, K., Yang, X. and Wuebbles, D. J. 2013: An asynchronous regional regression model for statistical downscaling of daily climate variables. Int. J. Climatol., 33: 2473-2494. doi: 10.1002/joc.3603.

APPENDIX A: SOURCES OF UNCERTAINTY AND THEIR TREATMENT As discussed in the "Method" section above, several climate scenarios are used for each emissions scenario to identify the clearest signals across a range of future circumstances that are inherently uncertain at present. While widely useful for decision making and risk analysis, it's important to understand that projections of future climate contain uncertainty for four main reasons: 1. Natural variability, which causes temperature, precipitation, and other aspects of climate to vary from year to year and even decade to decade; 2. Scientific uncertainty, as it is still uncertain exactly how much the Earth will warm in response to human emissions and global climate models cannot perfectly represent every aspect of Earth's climate; 3. Scenario or human uncertainty, as future climate change will occur largely in response to emissions from human activities that have not yet occurred; and 4. Local uncertainty, which results from the many factors that interact to determine how the climate of one specific location will respond to global-scale change over the coming century. To address the first source of uncertainty, natural variability, the climate projections summarized here are averaged over 40-year periods: historical (1960 - 1999), near-term planning (2021 - 2060) and long-term planning (2061 - 2100).

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Understanding Long-Term Climate Changes for Kansas City, Missouri: A Climate Assessment

To address the second source of uncertainty, scientific uncertainty, future projections are based on simulations from nine global climate models from the Coupled Model Intercomparison Project phase 3 (CCSM3, CGCM3, CNRM, ECHO, ECHAM5, GFDL-2.1, HadCM3, HadGEM, and PCM; Taylor et al. 2012). Differences between the models represent the limitations of scientific ability to simulate the climate system. Scientific uncertainty is an important source of uncertainty in determining the magnitude and sometimes even the direction of projected changes in average precipitation, as well as dry days and extreme precipitation. To address the third source of uncertainty, that of human activities and heat-trapping gas emissions, future projections use two very different scenarios, the report references the Intergovernmental Panel on Climate Change moderate emissions reduction scenario A1B and minor emissions reduction scenario A1FI (Moss et al. 2010). Scenario uncertainty is an important source of uncertainty in temperature---related projections, particularly over the second half of the century as the scenarios diverge. Finally, to address the fourth source of uncertainty, that of local change, global climate model simulations were downscaled to long- term weather station using the Asynchronous Regional Regression Model as described in Stoner et al. (2012). As these projections are based on one location only, they are not intended to be used for anything except illustrative purposes. To generate robust projections for future planning purposes, it is recommended that a similar analysis be conducted for all long- term weather stations in the area, and the results of this comprehensive analysis be used to calculate a broad range of secondary climate indicators identified by city departments as directly relevant to historical impacts and future planning.

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