The changing of the guard at City Hall continued Monday when Mayor Martin J. Walsh announced the appointment of a California clean energy executive to take over as the city’s environmental chief.
Walsh tapped Austin Blackmon to replace Brian Swett, the chief of environment, energy, and open space since August 2012.
Swett’s removal follows a string of terminations by the Walsh administration last week. On Thursday, the mayor’s office revealed that environment commissioner Nancy L. Girard had been “separat[ed] from employment.” Girard was appointed to her post by former mayor Thomas M. Menino in August 2013. After her dismissal, Girard told the Globe she was “terminated without cause.”
Walsh discharged eight other managers within the past two weeks and has been slammed for firing longtime municipal employees without notice. The mayor has said the terminations affected a small fraction of the city’s workforce of 18,000, and his aides have contended that the immediate dismissals are better than keeping disgruntled employees.
Swett’s departure is different in that he will step down at the end of the year. The mayor’s office would not say whether Swett is being forced out.
“He is stepping down at the end of the year,’’ said the mayor’s press secretary, Kate Norton.
Swett had been tapped by Menino in 2012 to lead the next phase of the city’s sustainability efforts, which city officials hailed as significantly improving the neighborhoods and pushing Boston into the top tier of green cities nationally.
Soon after taking office in January, Walsh kept Swett as part of a series of permanent reappointments, along with Sheila Dillon as chief of housing and neighborhood development, Vivian Leonard as director of human resources, and Michael Galvin as chief of public property.
Swett led a variety of major policy and program initiatives at City Hall, such as developing and passing a rental housing inspection ordinance. He also oversaw the launch of Greenovate Boston, a sustainability education and outreach initiative, and spearheaded the city’s efforts to prepare for climate change. In addition, he completed the 2014 update of Boston’s Climate Action Plan.
“Cities are and must be the biggest drivers for a more sustainable planet,” Swett said at the time of his 2012 appointment. “I feel privileged to be able to help make Boston the leader among sustainability leaders.”
But on Monday, Swett was bidding adieu to the job he has held for less than two years.
“It has been an honor and privilege to serve Boston in the Walsh and Menino administrations,” Swett said in a statement. “Working with talented management and staff, I am proud of our efforts to make the city greener, healthier, safer, and more climate prepared for the decades to come.”
Swett will continue to serve the administration through Dec. 31 and will work with Blackmon to ease the transition, Norton said.
In his new role, Blackmon will be in charge of the parks and recreation, environment, and inspectional services departments, the mayor’s office said. He will also head the Office of Energy Policy and Programs.
Currently, he serves as interim head of project finance for TerraVerde Renewable Partners, a clean energy consulting firm that advises schools, municipalities, and companies on solar power, energy storage, and alternative fuel projects.
He had previously worked for C12 Energy, which produces low-carbon energy. Blackmon has also worked in energy investment banking for Wells Fargo Securities, and with consulting firm Booz Allen Hamilton.
Blackmon is a graduate of Harvard College and Harvard Business School, where he earned his master’s in business administration, according to the Walsh administration. At the business school, Blackmon was a leader of the Harvard Council of Student Sustainability Leaders.
“I am excited to announce the addition of Austin Blackmon to my Cabinet, as we continue to grow our focus on energy, environment, and sustainability across the city,” Walsh said in the statement.
According to the Walsh administration, Boston is the highest-ranked city in the country for energy efficiency policies and programs by the American Council for an Energy-Efficient Economy.Meghan E. Irons can be reached at email@example.com. Follow her on Twitter @meghanirons. John R. Ellement can be reached at firstname.lastname@example.org. Follow him on Twitter @JREbosglobe.