When you combine warm water and flash flooding, you get a risk of water-borne disease. That's because many harmful microorganisms favor higher temperatures. If floods overwhelm water-treatment facilities, those organisms can find their way into the pipes, out of the tap, and into your glass. This isn't something that happens only in underdeveloped countries or other places we can write off as "not like home." The sanitation infrastructure of American metro areas is impressive, but it's not infallible. Many parts of the Midwest have experienced increased precipitation from more numerous large storms. This isn't only a Kansas problem. In 1993, Milwaukee, Wisconsin, suffered an outbreak of gastrointestinal disease caused by the bacteria Cryptosporidium. This bacteria doesn't merely give you a tummy ache. Instead, it leads to a week or more of diarrhea, cramps, vomiting, and fever. Fifty-four people died. Just before the illness struck, the region had received its heaviest rainfall in fifty years.
Since 1993, researchers have found that heavy rainfalls are associated with higher levels of potentially dangerous bacteria. This has been measured in drinking water and in recreational waters. It's also turned up in floodwater. In 2008, when major flooding inundated Iowa City and Cedar Rapids, Iowa, raw sewage came right out of the Cedar Rapids water-treatment plant and into the flood. Those contaminated waters sloshed into people's houses, and when the water finally receded, it left behind buildings full of muck and mold. The people tasked with cleanup duties suffered from what they called "flood crud," weeks of fatigue, cough, and other respiratory symptoms.
Speaking of breathing problems, warmer springs that bloom earlier in the year have also led to longer allergy seasons, and scientists say that the higher CO2 concentrations found in traffic-heavy cities and metros are causing plants to have higher pollen counts. This means that people who weren't affected by allergies thirty or forty years ago might be sniffling and stuffy today, and Merriam residents who have always had allergies now have to deal with them for longer periods of the year.
Air pollution is another big problem. In the heat of a hot and sunny day, tailpipe emissions from cars turn into lung-damaging, heart-straining smog. In any metro area, including Merriam, the more relatively hot days you have, the greater the risks of smog-associated asthma and heart attacks. Kansas City, Kansas, and Overland Park—two cities near Merriam—spent more than $13 million on asthma treatment in 2001. The more risk there is of smog-related lung damage, the higher those costs will rise.
During the next thirty years or so, a warmer, wetter Merriam might be, in some ways, a more comfortable place to live—the last few decades have brought longer growing seasons for plants and winter temperatures that are more reliably pleasant. Yet Merriam is also becoming a more expensive place to live and a place where the individual risk of illness and property damage is going up—and up and up. The more greenhouse gases are added to the atmosphere, the higher the global average temperature will eventually climb. As that happens, Merriam and places like it all around the United States will be exposed to risks that are greater and more numerous.