Carnegie Mellon University
April 20, 2012

Press Release: Carnegie Mellon University Researchers Report That US Cities Need To Respect History To Improve Sustainability Planning

Contact: Chriss Swaney / 412-268-5776 /

PITTSBURGH—Works by famed industrial landscape artist Aaron Gorson are visual reminders of the 1940s, when Pittsburgh was the nation’s steelmaking center. Surprisingly, new research from Carnegie Mellon University shows that today’s carbon dioxide (CO2) emissions are as low as those of that gritty decade.

CMU researchers recently published the first-ever study estimating long-term energy use and carbon dioxide emissions from 1900 to 2000 for a metropolitan area in the U.S. The sobering results suggest a need for beefed up regional strategies to avoid missing the goal of reduced CO2.

The research team, led by CMU’s Rachel Hoesly and H. Scott Matthews, and Michael Blackhurst of the University of Texas at Austin, found that Allegheny County’s emissions (home to Pittsburgh) dropped by about 1 percent per year from 1970 to 2000. However, per capita emissions in 2000 were nearly the same as they were in 1940, according to the report published in Environmental Science and Technology.

And although the countywide reductions experienced only approximate those called for by recent climate plans, the researchers point out that the Pittsburgh region experienced some extreme changes far greater than anticipated by the current plans.

“Pittsburgh lost most of the energy-intensive metals industry and the jobs that went with that era by the 1980s, which led to a very large reduction in energy and carbon emissions. That’s a massive shock to the social and economic structure of the region, far beyond the kinds of incremental changes that other cities are envisioning. And it only reduced the total footprint by 25 percent. Cities will need to develop more rigorous engineering and economic analysis to meet emission goals,” said Matthews, a professor of civil and environmental engineering and engineering and public policy at CMU.

More than 100 cities and counties in the U.S. have developed climate action plans to reduce greenhouse gas emissions, many of which have set a goal of cutting about 1 percent of greenhouse gas emissions per year. But many environmental experts question whether these action plans are sufficient to curb CO2 linked to climate changes.

“The Pittsburgh region is unique. Since 1970, it experienced decreasing carbon emissions coupled with economic changes and population loss, but reducing emissions in most cases involves reversing a long history of growing emission trends. Ultimately, big reductions will require big changes, especially in areas with growing populations,” said Hoesly, a Ph.D. student in CMU’s Civil and Environmental Engineering Department from Manhattan Beach, Calif.

“The fact that the energy footprint per person hasn’t changed in 30 years is sobering news for metro areas that want to achieve similar reductions, given the devastating impacts that losing industry and population had on this area,” Blackhurst said.