Climate Change Imprint on Spring 2019 Floods
For much of U.S. crop country, the major weather event of the 2019 crop year is flooding. The magnitude and area of coverage are mind-boggling.
The Mississippi and Missouri rivers reached or exceeded levels set in 1993 and 2011, respectively, that were thought of as once-in-500-year occurrences. The Arkansas River had so much water flowing through the meter at Little Rock that its volume was greater than Niagara Falls.
The recovery time from damage to farmland, equipment, storage, roads, livestock herds and, literally, producer health will likely be measured in years, not months. And, as everyone knows, corn planting was the slowest on record. The greatest touch screen technology, autosteer and super-sized planters are still useless if the ground is wet--and wet it was, indeed.
This is not the first season when such extreme precipitation has occurred, but it’s the worst I can recall in my career. And, as in recent years when the skies unloaded on the fields, I’ve been asked from multiple angles, “What’s causing this?” My answer is “… the continued impact of climate change.” The following details regarding global warming-related climate change and its resulting impact on extreme precipitation are taken from the Fourth National Climate Assessment, Vol. II: Impacts, Risks, and Adaptation in the United States (2018).
First, regarding warming, the National Climate Assessment has this summary: “… global annual average temperatures for the period since 1986 are likely much higher and appear to have risen at a more rapid rate than for any similar climatological (20 to 30 years) time period in at least the last 1,700 years.” But, within that 33-year period is the fact that new records have been frequent. The National Climate Assessment noted that, regarding global temperatures, “Sixteen of the last 17 years have been the warmest ever recorded by human observations.”
And, when it comes to heavy precipitation, the National Climate Assessment had these details: “The frequency and intensity of heavy precipitation events across the United States have increased more than average precipitation ... Observed trends and model projections of increases in heavy precipitation are supported by well-established physical relationships between temperature and humidity. These trends are consistent with what would be expected in a warmer world, as increased evaporation rates lead to higher levels of water vapor in the atmosphere, which in turn lead to more frequent and intense precipitation extremes.”
How the season finally turns out is yet to be determined. But, the impact of extreme precipitation--and the long-term influence of climate change--will not go away at harvest. We’ll feel the ramifications of this experience for a long time.
Read Bryce’s weather blog at about.dtnpf.com/weather.
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