Research Explores Impact of Climate Change on Future Hurricanes in GOM and Caribbean Sea

9 October 2008

The National Center for Atmospheric Research (NCAR) in Boulder, Colo., working with federal agencies as well as the insurance and energy industries, has launched an intensive study to examine how global warming will influence hurricanes in the next few decades.

The researchers are homing in on the hurricane-prone Gulf of Mexico (GOM) and Caribbean Sea to assess the likely changes, between now and the middle of the century, in the frequency, intensity, and tracks of these powerful storms. Initial results are expected early next year.

The goal of the project is to provide information to coastal communities, offshore drilling operations, and other interests that could be affected by changes in hurricanes. The National Science Foundation (NSF) is funding the project.

This science builds on years of previous investment. The outcome of this research will shed light on the relationship between global warming and hurricanes, and will better inform decisions by government and industry.

—Cliff Jacobs, program director in the NSF Division of Atmospheric Sciences

The new study follows two major reports, by the US Climate Change Science Program (CCSP) and Intergovernmental Panel on Climate Change (IPCC), that found evidence for a link between global warming and increased hurricane activity. But many questions remain about future hurricane activity. For example, the CCSP report concluded that future changes in frequency were uncertain, and that rainfall and intensity were likely to increase, but with unknown consequences.

Improved understanding of climate change and hurricanes is an especially high priority for the energy industry, which has a concentration of drilling platforms, refineries, pipelines and other infrastructure in the region that are vulnerable to severe weather.

The project, which is part of a larger effort examining regional climate change between 1995 and 2055, relies on an innovative combination of global climate and regional weather models, run on NCAR’s bluefire supercomputer with support from NSF, and through a long-term collaboration with the insurance industry through the Willis Research Network.

For the project, the model will examine three decades in detail: 1995-2005, 2020-2030, and 2045-2055. Scientists will use statistical techniques to fill in the gaps between these decades.

A major goal is to examine how several decades of greenhouse-gas buildup could affect regional climate and, in turn, influence hurricanes and other critical weather features. Scientists will also investigate the impact of the powerful storms on global climate.

One of the most difficult technical challenges for such a project is to create a model that can capture both the climate of the entire world and the behavior of a single hurricane.

To address this, NCAR developed an approach called Nested Regional Climate Modeling (NRCM). The center nests a special version of its high-resolution weather model (the Weather Research and Forecasting model, or WRF) inside its lower-resolution, global climate model (the Community Climate System Model, or CCSM). The resulting simulations show fine-scale detail for certain regions, like the Gulf of Mexico, while also incorporating global climate patterns.

For each of its decade-long time slices, the NRCM’s resolution will be about 20 miles across Africa, Europe, and the South Atlantic, 7.5 miles across the tropical Atlantic and northeastern United States, and an even sharper 2.5 miles over the Caribbean and Gulf of Mexico, southeastern United States, and drought-prone western United States.