Climate Change

 

With the earlier definitions of weather and climate in mind, it is important to understand that most of the extreme climate change in Earth’s history occurred before humans existed. That being said, the rapid release of carbon dioxide into the atmosphere from human activity is causing a global warming event. The seemingly slight increase in the average annual temperatures in the Midwest has been accompanied by more frequent heat waves and shorter winters. In addition to the previously mentioned risks associated with heat waves, increasing temperatures allow for certain bugs, such as ticks and mosquitoes, to live longer, thereby increasing the risk of contracting the diseases they carry. Heat waves can also be associated with droughts that hurt crop production. In contrast, scientists are predicting more severe rainfall events in the Midwest in the coming years. This has recently resulted in an increase in severe flooding, damage to infrastructure, and even death. While the coexistence of these two types of events may seem contradictory, it is indicative of an increase in extreme events overall. Ultimately, the Midwest, unlike the coastal US states, should be able to more easily endure the effects of climate change because of its considerable distance from an ocean that would be subjected to rising sea levels.

Humans have designed and built air conditioning and heating systems for protection from extreme weather. The crops, fish, and livestock, upon which humans depend for food, however, live without these climate control systems, and will therefore experience the impacts of environmental changes more directly. Increasing temperatures and changes in rainfall patterns will alter the type of crops that can be successfully grown and harvested across the Midwest (Figure 10.2). Models have predicted that the climate of Midwestern states, such as Michigan and Illinois, will be more similar to the current climate of Texas by the end of the 21st century (Figure 10.3).

Figure 10.2: Shifts in USDA Hardiness Zones as a result of climate change.

Figure 10.3: Prediction of the relative climates for Illinois and Michigan’s Lower Peninsula due to climate change.

Another concern regarding hazards exacerbated by climate change in the Midwest is whether or not there has been or will be an increase in the number or the severity of storms, such as hurricanes and tornadoes. According to NASA, the present data is inconclusive in terms of whether the Atlantic Ocean hurricanes are already more severe, but there is a greater than 66% chance that global warming will cause more intense hurricanes in the 21st century. Since tornados are hard to predict, involve a complex mix of atmospheric conditions, and occur on a much smaller geographic scale than hurricanes do, it is difficult to determine if global warming is currently influencing the frequency or severity of tornado activity. Since climate is weather averaged over decades, it might take many years to determine that a change has occurred with respect to these two types of storms. Scientists are certain that the conditions necessary to form such storms are becoming more favorable due to global warming.

The Union of Concerned Scientists has created an infographic that demonstrates the relative strength of the evidence that various hazards are increasing as a result of climate change (Figure 10.4).

Figure 10.4: The strength of evidence supporting an increase in different types of extreme weather events caused by climate change.