Karen E. Kelley, PE, Research and Development Manager, CDM Smith
On April 8, 2025, the BSCES Freeman Committee hosted more than 150 in-person and online participants for the annual Freeman Lecture, held at Wentworth Institute of Technology. The Freeman Lecture carries out the bequest of John Ripley Freeman, one of New England’s most influential civil engineers, which is intended to support the engagement of young people in BSCES. Freeman’s pioneering work in hydraulics, public water systems, dam design, and fire protection helped to lay the foundation for modern civil engineering infrastructure. This year is the 100th anniversary of Mr. Freeman’s bequest to BSCES.
In New England, the annual Freeman Lecture has come to be regarded by many as the premier annual lecture in water resources engineering, broadly defined. The lecture is provided free of charge, thanks to the sponsorship of the John R. Freeman Special Fund, and was preceded by a catered buffet dinner that allowed students and other prospective members of BSCES to attend, network, and recruit or look for employment. The Freeman Committee performed outreach to the local ASCE student chapters at several regional universities and the Younger Members Group (YMG).
This year’s Freeman Lecture tackled the topic of climate change in New England. Our speakers were Professor Mathew Barlow of UMass Lowell’s Department of Environmental Earth and Atmospheric Sciences, Climate Change Initiative and Professor Bruce T. Anderson of Boston University’s Department of Earth & Environment. Professors Barlow and Anderson provided perspectives on the current state of the science regarding climate change impacts on the hydrology and coastline of Massachusetts informed by their research. Professor Gautham Das of Wentworth, a member of the Freeman Committee, introduced the speakers.
Barlow, who researches the dynamics of extreme precipitation and has contributed to major climate assessment studies at the local, state, regional and international level, began the lecture with a discussion of the causes of different kinds of extreme precipitation events in New England, and how well our current climate models are able to capture those events. Barlow emphasized the importance of understanding the areas of climate change science that we have great confidence in separately from areas where there is more uncertainty.
According to Barlow, the history of climate change science began nearly 200 years ago with Joseph Fourier in 1824, and the idea that the hydrologic cycle is closely linked to atmospheric carbon dioxide levels and the greenhouse effect was added later, specifically the physics-based concepts that warmer air holds more moisture and a warmer surface results in more evaporation. Because these concepts rely on basic physics, we have confidence in our understanding of the role of water vapor as a fundamental contributor to climate change impacts. Direct observations of atmospheric carbon dioxide over the last 67 years show that atmospheric carbon dioxide levels have steadily increased approximately 50 percent over the post-Industrial period, from less than 320 parts per million (ppm) before 1960 to nearly 430 ppm today. By comparison, a study of carbon dioxide levels over the last 800,000 years attributed to Scripps Institute of Oceanography shows fluctuations between just 200 – 300 ppm prior to the industrial era.
While uncertainty about future climate conditions greatly depends on actions that we take, or don’t take, Barlow demonstrated that hindcasts using the global models have been able to accurately predict global temperature changes directly observed over the 1970-2000 period, lending confidence to our understanding of climate change. As expected, changes have been observed, including increases in the intensity and frequency of storms and flooding and coastal hazards in New England. Periods of dry extremes can paradoxically be expected as well in what Barlow calls the “water whiplash.” Sea level rise is also well understood. These are fundamental predictions of climate science for which we have high confidence. However, as climate change predictions become more localized in scale, more uncertainty is introduced.
Anderson then related what is projected in terms of the impacts of storm intensity and duration and sea level rise on flooding and economic impacts in the New England coastal regions, and specifically on the Boston area. Anderson’s research has focused on the frequency and severity of coastal flooding events in Boston that can be expected in the next 30 years and the need for actions to adapt to this challenge. Anderson dived into the causes of future sea level rise in Boston, included changes to the Gulf Stream and, interestingly, gravitational redistribution of ocean waters as a result of melting Antarctic ice. By the year 2100, sea level rise in Boston could exceed 2.4 feet, greatly changing the landscape of the city.
Altogether it was a fascinating discussion on one of the most important topics of our day, and it was very well received by the audience. A library of videos of past BSCES Freeman lectures, including this one, is maintained on YouTube. The Freeman Committee was pleased to mark a century of outreach with this lecture and looks forward to extending our legacy of highlighting the technical achievements in the fields of hydrology, hydraulics, and water resource and environmental engineering in the New England region well into the future.