How much would it really cost to cut the United States' carbon emissions and help save the planet from catastrophic climate change?
Not much, according to a new MIT study that finds that the health savings from slashing greenhouse gas pollution will exceed most, if not at all, the cost of building a low-carbon economy in the U.S.
“We estimate that human health benefits associated with air quality improvements offset 26–1,050 percent of costs depending on the flexibility of the carbon policy,” wrote the researchers in the study, which was published in the journal Nature Climate Change.
That’s because the main sources of carbon dioxide emissions that are warming the planet—coal-fired power plants, cars and trucks—also spew particulate matter, mercury and other pollutants that harm human health.
Scientists have known that cutting carbon emissions would have such an effect but the MIT study is the first to undertake a rigorous analysis of proposed climate change polices and the resulting health benefits.
The researchers found that not all policies would result in the same savings. For instance, the health benefits from directly regulating vehicle emissions by imposing strict fuel economy standards would only pay 26 percent of the cost of the $1 trillion policy.
But the health savings of a nationwide cap-and-trade carbon market would be 10 times the $14 billion cost to implement such a program. Establishing clean energy standards for power plants would save $247 billion versus the policy’s $208 billion cost, according to the study.
So why do politicians and policymakers tend to focus the economic costs of fighting climate change and not the economic benefits?
“From a scientific perspective, few analyses have comprehensively evaluated how air pollution connects to economics in a fundamental way,” Noelle Selin, an assistant professor of engineering systems and atmospheric chemistry at MIT and the report’s co-author, said in an email. “This is something we’re hoping to change, with our study being a first step in that direction. I hope that some of our new results in this area can help fully inform debates over cap-and-trade and different climate policies.”
The study comes with some caveats. The researchers based their computer modeling on a target of reducing greenhouse gas emissions 10 percent below 2006 levels by 2030. The health benefits decline with policies that attempt to achieve drastic reductions, such as the 80 percent cut set by many climate scientists.
That’s because most of the health upside to cutting emissions is captured at a certain point, and the costs mount with further reductions.
“This means that although initial policy actions can be motivated based on air pollution co-benefits, this strategy has important limits,” the researchers wrote.
But Selin said the same may not be in the case in other countries, such as China and India.
“We would actually expect that the health co-benefits would be larger to start with in rapidly industrializing countries, because existing air pollution controls are not so stringent as they are in the U.S.,” said Selin. “While co-benefits will eventually decline, this would occur less rapidly than the U.S.”
“That’s actually related to one of the key insights of our study,” she added. “It was previously thought that substantial co-benefits were only available in places with few air pollution controls. We show that there are still co-benefits to be achieved at current U.S. air pollution levels.”