In the absence of an ambitious federal climate strategy in the United States, a new study shows state-led action can make a significant difference in reducing carbon emissions and addressing climate change. The study also found that while state-led action is only slightly more expensive than a coordinated national effort, it would likely result in the adoption of different decarbonization technologies.

“Given that there is little expectation the Trump administration will promote a national effort to reduce greenhouse gas emissions to address climate change, we think there is significant value in assessing what kind of difference state-led efforts could make,” says Jeremiah Johnson, corresponding author of the study and an associate professor of civil, construction and environmental engineering at North Carolina State University. “For this study, we looked at a combination of 23 states that, based on political and policy indicators, seem most likely to consider joint action to reduce carbon emissions.

“Specifically, we looked at what the cost of such an effort would likely be, which decarbonization technologies would likely be adopted, and the extent to which these efforts could reduce our carbon footprint – and we compared all of these things to the cost, technology, and impact of a coordinated federal effort.”

The researchers drew on publicly available data across the full energy system for all 48 contiguous states, including everything from power generation and transportation to building operation and consumer needs, such as heating and cooling. This data was then fed into existing decarbonization models that were adapted to allow users to look at the impact of changes in individual states.

“We first looked at what the costs and technologies would be if the 23 states that already seemed inclined to strive for net zero carbon emissions actually achieved it,” says Gavin Mouat, first author of the paper and a former graduate student at NC State. “That would reduce U.S. carbon emissions by about 46% by 2050. We then looked at what the costs and technologies would be if all 48 contiguous states worked together to achieve that same 46% reduction.”

The researchers found costs were closer than anticipated between state-led and federal efforts; there was only a 0.7% difference in overall cost. However, the technologies adopted to reach the carbon emissions target were very different.

“That’s because different states have different resources,” Johnson says. “For example, some Great Plains states are excellent locations for establishing wind farms but are less likely to participate in a state-led initiative to address climate change.”

For example, in a state-led scenario, researchers found that industrial decarbonization – such as cleaner manufacturing technologies – played a far more prominent role than would be seen in a federally coordinated effort. On the other hand, a federally coordinated effort would rely more on clean energy production, such as wind and solar power generation.

The researchers also found there was potential for a state-led effort to affect climate-related pollution in neighboring states.

“Essentially, our model suggests it is possible that non-participating states could increase greenhouse gas emissions, because they might produce a product or service more cheaply for export to those states working to reduce their emissions,” Johnson says. “However, the model also suggests that non-participating states might also reduce their greenhouse gas emissions. This could be due to the fact that clean energy technologies save them money, or because those states may be drawing power from power generation facilities in other states where emissions are falling.

“Ultimately the most important takeaway here is that state-led action can achieve substantial emission reductions, even without federal support, but that the world looks very different than one where there is federal coordination,” Johnson says. “This has some important implications, not just for those states that choose to participate, but also for those who don’t.”

The paper, “State-led Climate Action Can Cut Emissions at Near-federal Costs but Favors Different Technologies,” is published in the open access journal Nature Communications. First author of the paper is Gavin Mouat, a former graduate student at NC State. The paper was co-authored by Christopher Galik, a professor of public administration at NC State; Aditya Sinha, a former research scholar at NC State; and Aranya Venkatesh, Katherine Jordan and Paulina Jaramillo of Carnegie Mellon University.

This work was done with support from the Alfred P. Sloan Foundation.