Trends in Intense Precipitation in the Climate Record

TLDR

Intense precipitation changes have been studied over half the globe, but reliable assessments are limited to regions with dense observation networks due to the small spatial correlation of such events. The study links these changes to three transient climate model simulations with rising greenhouse gas concentrations, including a doubling in the late twenty‑first century. Both observations and model projections show an increasing probability of intense precipitation in many extratropical regions, including the United States, and the raised event thresholds suggest these events are likely to be disruptive.

Abstract

Abstract Observed changes in intense precipitation (e.g., the frequency of very heavy precipitation or the upper 0.3% of daily precipitation events) have been analyzed for over half of the land area of the globe. These changes have been linked to changes in intense precipitation for three transient climate model simulations, all with greenhouse gas concentrations increasing during the twentieth and twenty-first centuries and doubling in the later part of the twenty-first century. It was found that both the empirical evidence from the period of instrumental observations and model projections of a greenhouse-enriched atmosphere indicate an increasing probability of intense precipitation events for many extratropical regions including the United States. Although there can be ambiguity as to the impact of more frequent heavy precipitation events, the thresholds of the definitions of these events were raised here, such that they are likely to be disruptive. Unfortunately, reliable assertions of very heavy and extreme precipitation changes are possible only for regions with dense networks due to the small radius of correlation for many intense precipitation events.