Steam rises from storage tanks at an oil refinery facility under a clear blue sky. Photo by Brett Sayles, Pexels.

By Bethany Blankley
The Center Square

WASHINGTON, D.C. — Carbon dioxide emissions have decreased in every state over an 18-year period analyzed by the U.S. Energy Information Agency, with Indiana seeing the eighth-largest change at -41%.

“Per capita CO2 emissions from primary energy consumption decreased in every state from 2005 to 2023,” according to data from the EIA’s State Energy Data System. “Total energy-related CO2 emissions in the United States fell 20% over that time,” as the U.S. population increased by 14%, “leading to a 30% decrease in per capita CO2 emissions,” a new EIA report states.

The report credits the decline primarily to less coal being burned in the electric power sector and increased electricity generation from natural gas.

Natural gas releases roughly half the amount of CO2 emissions as coal combustion; greenhouse gas emissions have dramatically reduced in the last few years as improved technological advancements have been made in the oil and natural gas industry, The Center Square reported.

The EIA report uses data from emissions from primary energy consumption of fossil fuels like petroleum, natural gas, and coal for all energy consumption sectors — residential, commercial, industrial, transportation and electric power. EIA counts CO2 emissions “released at power plants in the state where they are located, even if the electricity generated is sent across the grid for use in other states or countries,” EIA states. It says it also “accounts for transportation CO2 emissions in the state where fuels are sold to end users, even if the vehicles, boats, or planes later travel across state or international lines.”

Maryland saw the largest drop in CO2 emissions -49%, followed by Georgia, Delaware, North Carolina, Tennessee, Utah, Indiana, New Hampshire, Nevada and Massachusetts. The U.S. averaged 30% less over the 18-year-period evaluated.

Graphic from The Center Square, U.S. Energy Information Administration.

Maryland’s drop is due to the state’s CO2 emissions falling 43% and its population increasing by 11%, the report explains. This is due to natural gas replacing coal for in-state electricity generation. In 2005, coal and natural gas accounted for 56% and 4%, respectively; by 2023, that reversed to 5% coal and 41% natural gas, EIA says.

“Similar coal retirement and replacement trends,” including wind and solar, “occurred in each of the states with the largest reductions in per capita CO2 emissions from 2005 to 2023,” the report notes.

The 10 states with the least emissions reductions reported include Mississippi -1%, followed by Idaho, South Dakota, Rhode Island, Nebraska, Arkansas, Louisiana, North Dakota, Alaska and Iowa.

Nationwide, the electric power sector accounted for the largest share of CO2 emissions until 2016 when it was surpassed by the transportation sector, the report notes. In 2023, the transportation sector accounted for the largest share of CO2 emissions from energy consumption in 28 states.

In 2023, the electric power sector created the greatest amount of CO2 emissions in 18 states, with most of them being net electricity suppliers to other states. Many of them generate a large share of their electricity from coal. In five states, West Virginia, Wyoming, Kentucky, Missouri and North Dakota, more than half of their in-state electricity was generated from coal in 2023.

The industrial sector, which includes manufacturing and agriculture, accounted for the largest share of CO2 emissions in 2023. Five states with the highest industrial CO2 emissions, Texas, Louisiana, California, Pennsylvania and Indiana, accounted for more than half of the total emissions reported in 2023, according to the EIA.

Indiana remains the lowest-ranked state for environmental friendliness in a set of US News study rankings. The Hoosier state contains 2,846 pounds per square mile of industrial toxins, over three times the national average of 901. It also sees 169 days out of the year with unhealthy air quality, compared to the national average of 143, and nearly four drinking water violation points per thousand customers compared to the national average of 3.26.