Kansas
Kansas lies in the central Great Plains, straddling the transition from relatively abundant precipitation (more than 45 inches annually; 1991–2020 normals) in the southeast, supporting forests and rain-fed agriculture, to semiarid conditions (less than 20 inches annually) in the west. The state is located far from the moderating effects of the oceans, and temperatures vary widely across seasons. The statewide average temperature is 33.0°F in the winter and 76.8°F in the summer.
Figure 1
Temperatures in Kansas have risen about 1.5°F since the beginning of the 20th century (Figure 1). Recent multiyear periods have been among some of the warmest on record for Kansas, comparable to the extreme heat of the Dust Bowl era of the 1930s, when intense drought and poor land management likely exacerbated the hot summer conditions. Many record-high temperatures were set during the summer of 2012, which was the hottest year on record with an average temperature of 58.2°F. Recent spring temperatures have been above average (Figure 2a), which may have implications for crop planting. Summer temperatures have been near or above average since 2000 (Figure 2b). There is no long-term trend in very warm nights or extremely hot days, although both were slightly above average during the 2010–2014 period (Figures 3a and 3b). The number of very cold nights has been mostly below average since 1990 (Figure 4). The freeze-free season has also lengthened, especially in eastern Kansas, averaging about 9 days longer in this century than the 20th century average.
a)
b)
Precipitation is highly variable from year to year, with the majority of precipitation falling during the warm-season months (Figures 3d and 3e). Throughout the period of record (1895–2020), total annual precipitation has ranged from a low of 15.3 inches in 1956 to a high of 40.6 inches in 1951 and has generally been above average since 1985 (Figure 3c). The driest multiyear periods occurred during the 1910s, 1930s, and 1950s and the wettest during the 1940s, 1990s, and since 2015. The driest consecutive 5-year interval was 1952–1956, and the wettest was 2015–2019. The frequency of extreme precipitation events has been highly variable but shows a general increase; the number of 2-inch precipitation events was well above average during the 2015–2020 period (Figure 5). The increase in extreme precipitation events has been more pronounced in the eastern part of the state. Several major floods have occurred since the beginning of the 20th century. The Great Flood of 1951 extended over about half the state, with both rural and urban areas suffering severe losses, including more than $2 billion in total damages and 19 fatalities.
Figure 3
a)
b)
c)
d)
e)
Due to the state’s geography, which allows cold, dry air from the north to combine with warm, moist air from the Gulf of Mexico, severe thunderstorms are common in Kansas. Some of these thunderstorms can produce large hail, high winds, and tornadoes. During 1991–2010, the state experienced an average of just under 100 tornadoes each year, which occasionally caused major damage and loss of life. The Topeka tornado of June 8, 1966, one of the most destructive in Kansas’s history, killed 17 people, injured more than 500, and caused more than $200 million in damages (at the time, it was the costliest tornado in U.S. history, and as of 2015, it was the fourth costliest). Since 1950, Kansas has had six F5/EF5 tornadoes, the third most of any state. The most recent EF5 tornado occurred on May 4, 2007, when nearly 95% of Greensburg was completely destroyed and 11 people were killed.
Droughts pose a particular risk to Kansas’s agricultural economy (Figure 6). A multiyear drought impacted the state from late 2010 through late 2015. The peak of the drought occurred in 2012, which was one of the state’s driest years on record. The critical growth months of May–July were the driest on record, with a statewide average of only 4.9 inches of rain. By August, nearly 90% of the state was in extreme or exceptional drought status. The drought, combined with the extreme summer heat, had significant negative impacts on crop yields, livestock production, and pasture conditions. Despite the occurrence of this very intense drought, the late 20th and early 21st centuries generally have been characterized by few droughts, either short-term or long-term.
Under a higher emissions pathway, historically unprecedented warming is projected during this century (Figure 1). Even under a lower emissions pathway, temperatures are projected to most likely exceed record levels by the middle of this century. However, a large range of temperature increases is projected under both pathways, and under the lower pathway, a few projections are only slightly warmer than historical records. Heat wave intensity is projected to increase, posing a risk to both livestock and human health, while cold wave intensity is projected to decrease. The freeze-free season is projected to lengthen.
Although projections of overall annual precipitation are uncertain, summer precipitation is projected to decrease across the state (Figure 7), while winter precipitation is projected to increase. Winter precipitation increases could benefit winter wheat production, but summer drying would have negative impacts on rain-fed summer crops and rangeland.
The intensity of future droughts is projected to increase. Droughts are a natural part of the climate system. Although projections of overall precipitation are uncertain, higher temperatures will increase the rate of soil moisture loss during dry spells, leading to more serious conditions during future naturally occurring droughts, including an increase in the occurrence and severity of wildfires.