Science: If Your State Government Is Pro-Environment, You’ll Have Cleaner Air


A state legislature’s strong environmental voting record can translate into real results for states, according to a new study.

The study, published this week in Proceedings of the National Academy of Sciences, looked at greenhouse gas emissions data for all 50 states going back to 1990. Researchers then compared that emissions data to a range of other factors, including the environmental record of state legislators — determined by the League of Conservation Voters scorecard system — employment rate, and population. The researchers, both from Michigan State University, found that there was a correlation between the voting records of legislators and a state’s greenhouse gas emissions.

“For each 1 percent higher a state scored in environmentalism, it’s about half a percent lower in greenhouse gas emissions,” study author Thomas Dietz told the AP. “Overall, environmentalism matters.”

The researchers referred to the voting record data as “environmentalism” — the impact that the environmental movement has had in each state, as shown by that state’s legislative voting record.


“The effect of environmentalism is a potentially powerful mediating factor,” the authors wrote. “By counteracting the time trend toward increased emissions and by moderating the overall effect of population and affluence, environmentalism seems to have been effective at reducing greenhouse gas emissions below levels that would have otherwise occurred.”

The study also looked at potential factors that could influence greenhouse gas emissions. It found that population and state gross domestic product (GDP) are strong drivers of a state’s carbon footprint: wealthier states with higher levels of employment tend to have higher emissions. But if a state legislature votes with environmental concerns in mind, the emissions associated with population and GDP growth can be curbed, the study found.

“A strong environmental movement can open space in policy systems for advocacy coalitions to influence decision making,” the authors wrote. “It appears that solutions to environmental problems do not emerge more or less automatically as growth occurs, quite the opposite, it takes a strong movement presence to counteract the effects of growth.”

Some outside researchers questioned the study’s use of the LCV’s environmental scorecard as a measure of “environmentalism.” But the study’s authors said their research is “just the start of a conversation” about how environmentalism impacts actual environmental issues, and that more research on the subject is needed.

It’s true that a state’s leadership can make major environmental changes by implementing greenhouse gas reductions targets or goals for renewable energy. And states will be the ones responsible for coming up with their own plans on how to implement the Environmental Protection Agency’s proposed Clean Power Plan, which aims to cut U.S. emissions by 25 percent below 2005 levels by 2025 and 30 percent below 2005 levels by 2030. Some states’ leadership is already planning on blocking the final rule: Wisconsin’s Gov. Scott Walker has said his state won’t comply with the rule “without significant and meaningful changes.” But for states that do want to comply with the rule, an initiative launched earlier this year aims to help them figure out ways to do so.