Fires and Floods
The dynamics of heat on a warmer planet
NOAA recently declared July of 2021 as the hottest July on record since record-keeping began 142 years ago. Record heat was a harbinger of other climate extremes, with wildfires and floods dominating the global environmental news during the month. A hotter planet is not all about heat and drought. Remember, heavy rain and flooding are also products of the added heat from global warming. The atmospheric dynamics of a warmer planet tie together the extreme fires and floods of this past July.
California wildfires are raging again this summer, and devastating fires plagued some of Europe’s Mediterranean countries during July. Farther north, a ten-million-acre fire burned large areas of Siberian wilderness. However, let’s not forget the rain. The Atlantic Ocean’s earliest fifth-named tropical storm, Elsa, formed on July 1. Severe rainfall in western Germany and Belgium smashed existing records, causing catastrophic flooding. New Zealand also received heavy rains with unexpected flooding, and Central China was inundated with heavy rains and massive flooding. Atmospheric heat connects all of these events.
The Fire
The American West is into year twenty-one of a megadrought, and average temperatures are rising. The word drought denotes a prolonged period with less water than average. The term megadrought simply changes the understanding of “prolonged” to encompass decades as opposed to years. There are two paths to a drought. A region receives less precipitation than normal, or hotter temperatures cause more water loss through evapotranspiration. Both of these paths converged to create the current megadrought in the American West.
European settlers occupied the American West during a relatively wet period. Farms and cities sprang up, utilizing the available water resources, and communities assumed the long-term water supply was stable. No one understood how the previous 200 to 300 years of weather represented a wet cycle. Nor did the concepts of climate change and global warming factor into people’s visions of the future. Now the region is impacted by long-term climatic changes, limiting the availability of a precious resource, water.
