Meeting at the crossroad—the application of global/regional climate modeling for policy and decision-making

Projections of climate change in the late 21st century provide important guidance for policymakers in adopting mitigation and adaptation strategies. However, over the last few decades, advances in global climate models (GCMs) have provided new information about weather/climate processes and their links to ocean variability, aerosols and chemical processes. GCM results are being downscaled or used as boundary conditions thereby providing regional details on atmospheric processes for intra-seasonal, seasonal, annual and decadal timescales. Furthermore, GCM ensemble and sensitivity studies provide additional insight on the ranges of variability for important atmospheric variables such as precipitation. In Sub-Saharan Africa, where rain-fed irrigation is still the primary source of water for agriculture, future projections of mean changes or decadal variability remain unclear. However, the use of climate models to identify the causes of 20th century precipitation variability in locations such as the Sahel have greatly facilitated our understanding responsible for wet and dry conditions. The use of Global Chemical Transport Models (GCTMs) have also played an important role in understanding tropospheric ozone variability driven by natural and anthropogenic sources. The use of boundary conditions to mesoscale models in weather, climate and chemical studies is still a viable option because many relevant processes are driven at sub-grid GCM scales. New scientific knowledge gained from GCM/regional climate model studies are expected to facilitate policymakers and improve decision-making in areas such as land-use management, air quality, water resource management, agriculture and pubic health in locations such as West Africa during the “Climate Century.”