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2021 Emissions Update

June 20, 2022
2021 Emission Update

We’re committed to achieving carbon-neutral business operations by 2030. We established this goal in 2012, and since then have been reaching our targets by reducing energy use wherever possible and offsetting emissions for business-critical activities.

Although our largest impacts on climate change are from our services, we’re aware that the carbon footprint of our operations is significant as well. A global firm with 46 offices, Thornton Tomasetti’s most recent carbon footprint analysis (2021) shows an operations footprint of 3,547 metric tons (MT) of CO2e before offsets – equivalent to the annual footprint of 74 average U.S. households (Source: Center for Sustainable Systems). So we’ve set reduction targets to help us reach climate neutrality:

  • 10% reduction in per capita emissions each year
  • 50% reduction in our per capita emissions from 2018 levels by 2030
  • We are currently setting a target reduction for absolute emissions. Our reduction targets have previously been set for per capita emissions

We make progress toward these targets by:

  • Designing high-performance offices. Eleven of our office fit-outs have been LEED Gold or Platinum (or equivalent program) certified, and we apply our sustainable fit-out policy to all major office moves and renovations, so our energy-performance goals exceed minimum standards. In our existing offices, our green champions work to reduce energy use according to our sustainable-office guidelines.
  • Using renewable energy. We’ve met our green-energy purchasing percentage targets each year since 2015 as a member of the U.S. Environmental Protection Agency’s Green Power Partnership, and we continue to purchase renewable energy certificates (RECs) for 25 percent or more of our U.S. electricity use.
  • Flying less, offsetting the rest. The pandemic required us to be more agile about building relationships without traveling; we have the tools that enable remote meetings, and we’re asking the questions that minimize unnecessary travel. Every year since 2014, we’ve offset all our air travel through, which supports renewable energy and efficiency projects.
  • Enabling flexible work. In 2017, we established a global flexibility policy, offering work options that reduce commuting emissions while maintaining our collaborative culture. At the height of the COVID-19 pandemic, remote work became the norm.
2021 Emissions Update


In 2021, the pandemic continued to affect our work in ways that lowered our carbon footprint. Our business travel emissions remained low throughout the first two years.

At 531 metric tons of CO2e, our 2021 emissions from air and train travel were about one third less than those of 2019.

We calculate our carbon footprint by examining electricity use and heating (Scope 2) and business travel, employee commuting, and office waste (Scope 3). Our last complete carbon-footprint analysis, conducted biennially, indicated that in 2020 we met our reduction target of 10 percent per capita from the previous year (before offsets), achieving a 2020 per capita carbon footprint of 2.73 metric tons of CO2e. Carbon offsets brought that down to 2.33 metric tons, with a total reduction of 478 metric tons of CO2e achieved through carbon offsets and renewable energy certificates (RECs) for electricity use. Since 2014, we’ve used carbon offsets and RECs to neutralize 5,198 metric tons of CO2e. Our biennial carbon footprint calculations analyze even years; our 2021 numbers show updates only for business travel and electricity use.

2021 Emissions Update

Since 2018, we’ve achieved a 29 percent reduction in our average per capita emissions and are making good progress toward our reduction targets for carbon neutrality in 2030.

Our challenge now is to maintain the low emissions levels we’ve seen throughout the pandemic as people return to their offices and engage in more business-related travel. 


Our carbon-footprint analysis uses 2018 as the base year for calculations. Although we began calculating our operations carbon footprint in 2012, we readjusted our baseline year following a 2016 merger that increased our employee numbers by 25 percent. We conduct a biennial analysis for even-numbered years, and 2018 was our first year of analysis after the merger. That year, our firm-wide carbon footprint was 4,757 metric tons of CO2e without offsets. With offsets, it was 3,401 metric tons. Our organization-specific metric for the intensity ratio is number of employees. In 2018, our intensity ratio showed 4.07 metric tons of CO2e per person without offsets. With offsets, it showed 2.91 metric tons of CO2e per person.

Our location-based method uses calculations that draw from the U.S. Environmental Protection Agency’s emission factors for U.S. regions. Emission factors for our offices outside the United States are obtained through each country’s environmental agencies.

We annually purchase carbon offsets for all air and train business travel emissions (CO2e) and renewable energy certificates (RECs) for a minimum of 25 percent of the CO2e emissions from electricity used by our leased offices. Our base year for RECs is 2015, which was when we joined the U.S. Green Power Partnership and began disclosing our green power percentage to the program. Our baseline year for carbon offsets is 2014, when our carbon footprint analysis showed that business travel was one of our largest areas of emissions. At that time, we decided to offset emissions resulting from business-critical activities, starting with travel.

Since 2014, we have offset 8,281 metric tons of CO2e of Scope 3 emissions through third-party certified and validated renewable energy and energy-efficiency projects. In the reporting period, we’ve offset 531 metric tons of CO2e and purchased Green-e® Climate certified RECs for 318.59 metric tons of Scope 2 CO2e emissions. We account for business travel emissions through ticket invoices and a regression model formula that estimates emissions based on the relationship between ticket purchases and emissions. We account for electricity emissions through direct electricity bills and, when precise electricity use data for our offices is not available, records from the buildings in which we lease space.