Achieving Net-Zero Greenhouse Gas Emissions in California Saves Lives

Transforming the energy system to achieve net-zero carbon emissions by 2100 is vital to fight climate change. This target can be achieved in California, USA, by 2050—alongside air quality benefits especially in disadvantaged communities—by using bioenergy with carbon capture and sequestration.

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When our paper was published on May 4, Californians had been home for 46 days as a result of the global COVID-19 pandemic. Although we had been working on the study for a couple of years, the pandemic gives our findings new urgency.  Emerging evidence suggests that even a small increase in long-term exposure to fine particulate matter (PM2.5), one of the criteria air pollutants related to fossil fuel combustion, could lead to a large increase in the COVID-19 death rate. This further establishes the substantial value in protecting the population from the respiratory vulnerability caused by widespread air pollution.

In public health, we know prevention is better than cure. It’s cheaper and safer to prevent people from catching and spreading the coronavirus than to treat huge numbers of severe cases.  Similarly, in climate change, it is much better to cut down greenhouse gas (GHG) emissions to prevent global temperature rises than to figure out how to deal with the potential catastrophic consequences.

To limit the rise in global temperature to 2 °C above preindustrial levels — the threshold for avoiding the most severe effects of global warming — we need to achieve net-zero GHG emissions by 2100. Achieving this globally is no easy feat, but our study shows how it can be done in California — creating the first-ever roadmap for the state to achieve net-zero GHG emissions sustainably in 2050 by using detailed modeling of energy system transformation, cross-sectoral connectivity, and technology penetration.  

We aim to demonstrate that developing and implementing the right climate policies can bring substantial public health benefits to our society. Specifically, we ask the question:  How many lives will we save by reducing GHG emissions?  Since the sources contributing to GHG emissions also contribute to air pollution, and air pollution is linked to a host of adverse health effects, cutting down GHG emissions means cleaner air and healthier lives.

In our study, we find that approximately 14,000 premature deaths can be avoided in California in 2050, and that these health cobenefits are disproportionately higher in disadvantaged communities (i.e., 35% of avoided deaths will come from 25% of the state’s population, see Figure 1). The annualized monetary benefits ($215 billion) exceed the GHG abatement cost ($106 billion) by $109 billion. This roadmap requires the use of bioenergy with carbon capture and sequestration (BECCS) technology to offset some GHG emissions. However, this BECCS technology comes at a price, as it would emit a considerable amount of air pollutants and reduce health cobenefits by $4 billion. Nevertheless, our analysis shows that ambitious GHG reduction efforts can provide significant health cobenefits.

We encourage policymakers and stakeholders to use our study as a tool to develop stronger regulations and protections that reduce GHG emissions, improve air quality, and protect public health, particularly for communities disproportionately burdened by pollution from fossil fuels.

This study was partially funded by the UCLA Sustainable LA Grand Challenge initiative, which supports interdisciplinary collaboration across UCLA campus. More details about the program can be found here.

Go to the profile of Yifang Zhu

Yifang Zhu

Professor, University of California Los Angeles

Dr. Yifang Zhu, Ph.D., is Professor of the Environmental Health Sciences (EHS) Department in the UCLA Fielding School of Public Health, where she also serves as the Associate Dean for Academic Programs. She works in the field of air pollution, exposure assessment, aerosol science, climate change, and burden of disease estimation. Her current research focuses on measuring and modeling air pollutant emissions, transport, and transformation as well as assessing and mitigating associated adverse health effects. Her scholarship and creativity have been recognized by several national awards, including the Walter A. Rosenblith New Investigator Award from the Health Effects Institute in 2007, the Faculty Early Career Development (CAREER) Award from the NSF in 2009, and the Haagen-Smit Prize from Atmosphere Environment in 2011.

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