In 2021, Vermonters emitted fewer greenhouse gases than any year since 1990 except 2020, when the COVID-19 pandemic dramatically changed how much people traveled and heated their homes, according to a new inventory the Agency of Natural Resources released last week.

The findings show that in 2021, Vermont produced 8.28 million metric tons of carbon dioxide equivalent (CO2e), the metric used to measure the impact of various greenhouse gases.

(The inventory contains Vermont’s most recent available emissions data, which is 2½ years behind because of challenges obtaining figures, particularly from the agriculture and working lands sector.)

In 2020, Vermont produced 7.97 million metric tons of CO2e. In both 2018 and 2019, the state produced 8.76 million metric tons.

“Overall, emissions went up from 2020 to 2021, but in our modeling that accompanies the inventory, we are hopeful that some of the rebound won’t be as significant or lasting,” said Jane Lazorchak, program manager at the Agency of Natural Resources’ Climate Action Office.

She credited the slight general decline in emissions to policies that incentivize people to install electric heat pumps in their homes and an increase in electric vehicle sales.

“I also think there are policies that stayed in place after the pandemic, such as telework and other things similar to that, that are helping Vermonters drive less,” Lazorchak said. “So those are the kinds of policies that we hope will have lasting impacts.”

Those patterns could be complemented in the future by policies such as the clean heat standard and a boost in federal funding, which has already helped provide incentives for people to purchase more electric vehicles and weatherize their homes, Lazorchak said.

Vermont’s 2020 Global Warming Solutions Act requires the state to reduce its emissions to 7.3 million metric tons of CO2e by 2025, 5.14 million metric tons of CO2e by 2030 and to 1.71 million metric tons in 2050.

The 2020 law was designed to reduce Vermont’s contribution to global climate change in accordance with the Paris Agreement, in which leaders from around the world agreed to try to prevent the planet from warming by more than 1.5 degrees Celsius.

When people use fossil fuels for energy, pollutants including carbon dioxide and methane enter the atmosphere, trapping heat from the sun.

The more pollutants enter the atmosphere, the warmer it becomes, creating a chain of consequences that includes more frequent flooding, drought and heat waves in Vermont.

Experts disagree about whether Vermont is on track to hit its first deadline in 2025.

State officials argue that the state is, indeed, “generally on-track” to meet that benchmark, according to a press release about the inventory from the Agency of Natural Resources.

Critics, however, have questioned the data the state is using to make that claim. Jared Duval, a member of the Vermont Climate Council and the executive director of the Energy Action Network, raised concerns at a meeting in January, and The Conservation Law Foundation filed a lawsuit earlier in the week calling for the state to use a different method to calculate the state’s emissions trajectory.

The Agency of Natural Resources is using data from the Energy Futures Group, a consulting firm based in Hinesburg, which it hired to map out how various policies and rules could potentially reduce emissions in Vermont in the future.

But Duval and the Conservation Law Foundation both assert that the model wasn’t created to assess whether Vermont is on track to meet the Global Warming Solutions Act’s deadlines, and therefore it shouldn’t be used that way.

Dvual points to the Global Warming Solutions Act, which says the state should use inventory data to create forecasts, rather than using a model that projects what could happen in the future.

Until this year, the state has used inventory data to predict what emissions will be looking forward, but this year, it switched to using data from the Energy Futures Group model.