Regarding greenhouse gas contribution to the flooding scenario, the article cites previous research which has identified how atmospheric forcing from increased greenhouse gases adds to the atmospheric back-and-forth between air masses to bring about increased precipitation. “The close agreement between observations and climate models lends us confidence to further analyze this weather type in Global Climate Models (GCMs). The ensemble-average frequency of the Midwest Water Hose (MWH) in Coupled Model Intercomparison Project Phase 6 (CMIP6) models exhibits an upward trend significant at the 5% level based on the historical experiments prescribed with all forcing, which include both greenhouse gas (GHG) concentration and natural forcing, consistent with the observed significant upward trend.”
The result is rising levels of GHG in the atmosphere make such heavy rainfall and flooding occurrences more likely. The article summarizes that risk level this way: “Furthermore, the risk ratio by comparing the trend probability for the observed trend of this weather type … is 12.1, suggesting that GHG forcing has increased the probability of the observed trend of this weather type by approximately 12 times … Based on these results, we can conclude that the upward trend of this weather type that causes heavy precipitation over the central USA can be attributed to GHG concentrations, rather than natural forcing such as volcanic eruptions and solar orbiting changes.”
The full article is at this link: https://royalsocietypublishing.org/…
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