Daily extreme precipitation and the outlook for 2100
In a future scenario marked by high carbon dioxide emissions, daily extreme precipitation over land could increase by nearly 41% by 2100.
Daily extreme precipitation events depend on complex multiscale atmospheric dynamics fueled by available moisture. These events are expected to intensify with climate change, posing serious risks for human communities and ecosystems. The study’s findings highlight the crucial role of high resolution climate modeling in providing accurate climate risk assessments that support more effective adaptation strategies.
A new high resolution model for more accurate projections
A new study published in Nature Geoscience examines several overlooked characteristics in current low resolution climate models. These models struggle to represent the main processes that drive extreme precipitation, limiting the scientific community’s ability to deliver strong and reliable future projections.
The research team developed a high resolution model that divides the atmosphere into 10 to 25 kilometer grid cells instead of 100 kilometer cells. The model is based on the Community Earth System Model v1.3 (CESM HR), covering the period from 1920 to 2100. Its results are then compared with the low resolution version (CESM LR).
High resolution climate simulations and a better representation of mesoscale convective systems allow scientists to evaluate future changes in daily extreme precipitation and identify their driving factors. This is possible because high resolution simulations capture a more realistic spatial distribution and intensity of daily extreme precipitation.
A sharper view of rising daily extreme precipitation
The refined resolution of these simulations shows that in the coming decades, daily extreme precipitation over land is likely to increase more significantly than previously projected. According to the study, these events could rise by almost 41 percent by 2100 under high emission conditions, compared to the 24.8 percent projected by the CESM LR model. The CESM HR model estimates an annual increase of 16.6 millimeters per day in maximum daily precipitation, nearly 2.5 times more than the 6.4 millimeters per day projected by the CESM LR model.
Extreme precipitation and the factors that drive it
High resolution models appear more capable of predicting extreme precipitation events because they can identify and simulate mesoscale convective systems and other atmospheric phenomena linked to rising temperatures. These dynamic factors are essential for understanding the incidence of extreme precipitation and are not adequately described by lower resolution models.