Report predicts that Boston in the summertime could feel more like Maryland or even South Carolina by 2100.
Jennifer Weeks
Over the coming century, global climate change could raise average summer temperatures throughout the Northeast states by as much as 14 degrees Fahrenheit, according to a report released yesterday by the Cambridge, MA-based scientific advocacy group Union of Concerned Scientists (UCS). But if states and communities can reduce greenhouse gas (GHG) emissions by about 3 percent annually, the authors say that warming and related impacts—such as flooding, heat waves, droughts, and stress on ecosystems—would be much less severe.
The report, Climate Change in the U.S. Northeast, is part of a recent trend to make climate change predictions at a more local, rather than global, level. Regional assessments are important because many policy options for reducing GHG emissions and adapting to climate change are managed by state and local authorities, such as permitting requirements for new power plants and creating new energy-efficiency provisions in building codes. The authors say their report is intended to provide state and local officials with information specific enough to inform planning and policymaking.
The report is the first product of the Northeast Climate Impacts Assessment, a collaboration between UCS and more than 60 scientists from universities, state and federal agencies, and research institutions such as the Marine Biological Laboratory in Woods Hole, MA. Nearly all of the participants are based within the area covered by the study—the six New England states plus New York, New Jersey, and Pennsylvania.
The researchers base their analysis on three of the same climate models used by the Intergovernmental Panel on Climate Change (IPCC) to make its predictions of global climate change: ones developed by the National Oceanographic and Atmospheric Administration (NOAA), the United Kingdom Meteorological Office’s Hadley Centre, and the National Center for Atmospheric Research in Boulder, CO.
To fine-tune these models for use on a regional level, the team developed grid-based maps of the region, incorporating weather data from NOAA’s U.S. Historical Climatology Network database. The researchers then determined the relationship between the global models’ calculations and the actual Northeast climate variables to see how well the models replicated past regional trends, and used this relationship to translate the models’ projections into regional temperature changes.
“The models do quite well at estimating many of the type of trends we’re seeing across the region,” says Katherine Hayhoe, professor of atmospheric sciences at Texas Tech University in Lubbock, TX and co-leader of the subgroup that analyzed Northeast climate trends. “If anything, they’re a little conservative.”
Hayhoe and colleagues forecast climate change impacts in the Northeast under two scenarios developed by the IPCC: a fossil fuel–intensive path and a low-carbon path that assumes a shift to clean, resource-efficient technologies. Year-round average temperatures would increase by 6.5 to 12.5 ^o^F by 2100 in the high-emission scenario or by 3.5 to 6.5 ^o^F in the low-emissions scenario. For comparison, in its most recent assessment, the IPCC projected that global average surface temperatures will rise by 2.5 to 10.4 ^o^F during the 21st century, with greater warming in many regions.
The team details its analysis in two peer-reviewed articles, one in press at Climate Dynamics and the other under review with the Bulletin of the American Meteorological Society. Hayhoe and Peter Frumhoff, director of the UCS global environment program, were coauthors of a study published in the Proceedings of the National Academy of Sciences in 2004 that used the same methods to project climate change impacts in California.
In the future, global climate models may become precise enough to predict local impacts without making the type of statistical adjustments that researchers used in this study, says meteorologist Alan Robock of Rutgers University in New Brunswick, NJ. “But this approach is the best we can do now, and it’s worth using those techniques to make our best estimates,” says Robock.
Reports from the Northeast Climate Impacts Assessment scheduled for release next year will detail how climate change may affect regional agriculture, forests, oceans, and coastal areas, as well as local residents and industries, while laying out options for reducing GHG emissions. But the authors say that immediate action can limit the impacts significantly. Researchers are already seeing changes in the Northeast—shorter snow seasons, higher summer heat indexes, and earlier appearance of leaves and flowers in the spring—and saying that they are consistent with climate change.
The study was funded by private foundations, including the Davis Conservation Foundation, Energy Foundation, Henry P. Kendall Foundation, Oak Foundation, Orchard Foundation, Scherman Foundation, and Wallace Global Fund.