factory with smoke stacks and pollution


Quantifying the Environmental Justice Consequences of California’s Cap-and-Trade Program


In 2013, California implemented one of the world’s most comprehensive and ambitious cap-and-trade climate change policies. The economic benefit of cap-and-trade is well understood: by leveraging market forces, this system allows the state to meet its statewide greenhouse gas target at the lowest possible cost. But because cap-and-trade does not require specific emission reductions from any particular location, the same market forces that make the program so cost-effective may also result in undesirable equity consequences. While this program has the potential to generate clear benefits for certain subsets of the population, it also has the potential to impose diverse costs on others.  

In this project, we seek to understand whether the introduction of California’s cap-and-trade policy in 2013 has increased local levels of pollution exposure and adverse health outcomes for disadvantaged communities across the state. 


Equity consequences are a central concern in the debate about the future of California’s climate policy, but unfortunately, there is little empirical evidence on this subject that can be used to inform state lawmakers. The Climate Solutions Group at emLab is working on the most rigorous and comprehensive outcome-based analysis to date to determine if the cap-and-trade program has caused the state’s disadvantaged communities to be exposed to higher levels of pollution relative to other communities. Our findings will provide policymakers with valuable information upon which they can base future decisions.


Through our careful design of this research study, we are able to establish causality between the changes in local pollution exposure following the introduction of cap-and-trade and human health outcomes across all community types. We are using big data techniques to analyze local pollution and health data at the finest possible spatial scale to evaluate the effects of this new program. We have also enlisted support and input from several major environmental justice NGOs operating in the Central Valley to ensure that we focus our analysis on outcomes that matter most to disadvantaged households. Together with our NGO partners, we will disseminate our research findings and conduct workshops aimed at designing climate policy reforms that sufficiently address the concerns that emerge from our research.   


Quantifying the Environmental Justice Consequences of California’s Cap-and-Trade Program is a collaborative effort between emLab, the Bren School, the Central Valley Air Quality Coalition (CVAQ), and the Central California Asthma Collaborative (CCAC).