The Jacobson Effect: Local Health Problems from Carbon Dioxide Emissions


The Jacobson Effect asserts that emissions of carbon dioxide (CO2) impact health and life expectancy more negatively where it is emitted (locally) than in other areas.1  This is contrary to current thinking that the health effects of CO2 emissions are distributed globally through their effect on the global environment and atmosphere. Most air pollutions laws assume that CO2 will not harm health locally. Research on the Jacobson Effect was conducted by Mark Jacobson, PhD, a professor of engineering at Stanford University.


The implication of this research is that communities and regulators need to include CO2 emissions (in addition to criteria pollutants) when assessing the potential health impacts of air pollution from a power plant or other project. The question is whether advocates can use the Jacobson Effect to change the current emissions regulation paradigm. Can advocates get regulators and the general public to understand that CO2 emissions have direct health impacts locally, and then get them to consider communities’ health and welfare when ruling on emission source siting and operation decisions?


What is the Jacobson Effect?

A study was done by Dr. Mark Jacobson, an engineering professor at Stanford. He created models of CO2 and its effects on local atmospheric chemistry and meteorology and compared this to actual empirical data. He then modeled the effects of local CO2 on local pollution and health.

Premise of the Jacobson Effect

The premise of the Jacobson effect is that higher CO2 leads to increased H20 vapor and higher ambient temperatures. These effects lead to certain effects on ozone (O3) concentrations in the local atmosphere:

• Increased H20 vapor 
--> increases O3 more with higher O3
--> increases particulate matter (PMs)

• Increased temperatures 
--> increases O3 more with higher O3 
--> increases particulate matter (PMs)

The phrase “increases O3 more with higher O3” above means that as the ambient concentration of O3 increases, the higher the rate of O3 produced per unit of H2O vapor.

Health Effects of increased O3 and PMs

The Jacobson Effect predicts the following additional health impacts: 


  • May increase US annual air pollution deaths by ~ 1000 (350 – 1800) per 1 degree Celsius (1.8 degree Fahrenheit) rise in CO2-induced Temperature  
  • May increase US annual air pollution cancer deaths by  ~ 20 - 30 per 1 degree Celsius (1.8 degree Fahrenheit) in CO2-induced Temperature


In another paper by Dr. Mark Jacobson, he writes that a dome of CO2 tends to form above a source of large CO2 emissions.2

Using the Jacobson Effect to Advocate for Environmental Justice

This section briefly presents some of the ways in which the Jacobson Effect might be used:

  • Setting a Precedent
  • Community Organizing
  • Media Campaigning


Set a Precedent

Currently, the Jacobson Effect is being used by Citizens Against Pollution (CAP) in Hayward, California, to try to fight the Russell City Energy Center (RCEC) being proposed in Hayward. The Bay Area Air Quality Management District (BAAQMD), which is considering issuing a permit for the facility, in the end may or may not include the Jacobson Effect in its deliberations on whether to issue the permit for the RCEC. 

However, the more that communities and advocates can raise awareness of the Jacobson Effect among agencies and among the general public, the greater the likelihood that it could be given weight by a permitting agency in a permitting deliberation. This could set an extremely useful precedent for other communities that need to stop projects that emit CO2 but seem otherwise “clean”

There are benefits to setting a Precedent.If a project appears to have low levels of the six main criteria air pollutants (established under the federal National Ambient Air Quality Standards (NAAQS)), permitting agencies may dismiss or not investigate further the idea that proposed energy facility has significant impacts on local health. If they were made to consider and understand the Jacobson Effect, they would be more likely to consider the impacts of CO2 on local health, and the environmental injustice that this entails.

The Jacobson Effect also questions the assumption underlying proposals for cap and trade policies that all CO2 emitted regardless of location has the same impact on health & the environment.

Some Policy Arenas where the Jacobson Effect could set a Precedent:

• Prevention of Significant Deterioration (PSD)
• Authority to Construct (ATC)
• BAAQMD 2009 Clean Air Plan
• BAAQMD CEQA GHG guideline amendments

Community Organizing and Coalition Building

The idea that CO2 affects health is more likely to motivate people in the community to act, rather than are concerns about climate change or endangered species. In addition, it increases the likelihood that organizations concerned with health will join coalitions that are working on these issues, since the campaign would not exclusively be about the environment.

Media Campaigning and the General Public

Even if consideration of Jacobson Effect does not become a part of public policy immediately, it could be used when campaigning in the media, in messaging, press releases, press conferences, and public education.

Precedent-setting, community organizing, and media campaigns are not the only ways the Jacobson Effect could be used to improve public health and environmental justice, but they would be highly effective ways to do so.


1. Jacobson, Mark. "On the Causal Link Between Carbon Dioxide and Air Pollution Mortality." Mark Z. Jacobson. Stanford University, 12 Feb. 2008. Web. <>.

2. Jacobson, Mark. "The Enhancement of Local Air Pollution by Urban CO2 Domes." Mark Z. Jacobson. Stanford University, 3 Oct. 2009. Web. <>.