written 5 Sep 2021
published 12 Sep 2021
Uniformitarianism expects tomorrow will be much like yesterday, assuming a linear, slowly changing world, where small movements produce small outcomes. Because it is easy to understand and makes future planning simple, it is seductive. However, such planning has little bearing on complex non-linear systems, where small movements can create abrupt outcomes. Climate is a massive, non-linear, complex system, currently experiencing rapid global changes, demanding more nuanced planning.
One example of this is how floods are classified. Historical and geologic records are used to determine how often an area has been inundated, then flood zones are designated by the probability of repeat flooding. A 100-year flood zone has a 1 percent chance of flooding in any given year, assuming climactic forces are stable over time.
In 1992, a friend bought a vineyard in Minnesota which had just experienced a 500-year flood. Over the next 14 years, they had two 100-year floods, and just after she sold it, they had a 1000-year flood. In 2017, Hurricane Harvey brought a 500-year flood to the Houston area, which had been preceded by 500-year floods on Memorial Day in both 2015 and 2016. Climate is clearly no longer stable.
In the 20,000 years between the last ice age and the beginning of fossil fuel usage, atmospheric carbon increased 55 percent. In the 200 years since then, humanity has added another 50 percent, 13 percent in the last 20 years. This increase is so rapid that the Earth's temperature has yet to reflect the full extent of the impact. Since warmer air holds more moisture, the current 1°C warming supports a 7 percent increase in atmospheric water vapor. Consequently, the frequency and intensity of extreme flooding events is increasing.
NOAA reported in 2018, that from 2010 to 2017 the US experienced 25 separate 500-year flooding events, nationwide. Last month the national Weather Service reported 17 inches of rain fell in Humphreys County, Tennessee, in less than 24 hours, shattering the state record for one-day rainfall by more than 3 inches.
Two days before hurricane Ida made US landfall, it was a category 2, but then it traveled over unusually warm water in the Gulf of Mexico. By the time it destroyed the Gulf Coast it had grown to category 4, with wind speeds of 150 mph, and a diameter of 400 miles. A few days later, the remains of Ida dumped 6"-10" in the New Jersey and New York area. Central Park in Manhattan recorded 3" of rain in one hour, drenching streets and flooding subways.
While the Midwest and the East are getting flooded, the West is experiencing drought and fires. In the last five years, California has experienced 6 of the 20 deadliest fires (by people killed), 10 of the 20 largest fires (by area burned), and 13 of the 20 most destructive fires (by structures destroyed), since the State began keeping records. Here in Ukiah, we have been fortunate this summer, so far. The fires are far enough from us that we aren't under direct threat, and the air quality is only moderate, as opposed to the hazardous air of last year. Yet we aren't escaping the impact.
Water shortage on the coast has stunted essential local tourism, already affected by the ongoing pandemic. Overall tourism in the State is affected by air quality and roads closures due to fires, and all the National Parks are closed. At least two more California towns have been burned to the ground (Greenville and Grizzly Flats), and South Lake Tahoe is being threatened as I write this, further depressing summer travel.
Real estate transactions are finding more fire insurance problems, even for coastal sales. The wine industry is dealing with smoke taint contamination, described as "tasting like a used ash tray", which degrades the value of the wine. The heavy smoke last year cut the value of the crop by 2/3.
We are in a new, rapidly changing climate reality, and we ignore that at the risk to our life and our economy. However, some people are still planning as if tomorrow will be like it used to be. The Ukiah Planning Commission recently voted 4-1 to approve residential development in the Western Hills based on "historic patterns of development". The longer we deny reality, the shorter the odds of avoiding catastrophe.
