Study Links Carbon Dioxide Emissions to Increased Air Pollution Deaths

Contributed by Dr Karabi Dutta
30 July 2008

A model created by Stanford University Professor Mark Jacobson estimates that for every 1 degree Celsius increase in global temperature caused by carbon dioxide, the world will experience upwards of 20,000 additional air pollution-related deaths per year.

For the first time, a climate change model has drawn direct links between CO2 emissions and increased human mortality. The model has been created by Stanford University Professor Mark Jacobson. It estimates that for every one degree Celsius increase in global temperature caused by carbon dioxide, the world will experience upwards of 20,000 additional air pollution-related deaths per year.

Developed over the past 18 years, Jacobson's model incorporates many complex and interrelated factors, including gas chemistry, ocean processes, soil processes, and the atmospheric effects of weather patterns. The study, has been published in Geophysical Research Letters , is the first to isolate carbon dioxide's effects from other greenhouse gases.

Specifically, it determines the amounts of ozone and airborne particles (common causes of respiratory and cardiovascular disease) that result from temperature increases caused by rising carbon dioxide emissions.

Some of the most interesting results include:

  • Higher temperatures due to CO2 increased the chemical rate of ozone production in urban areas.
  • CO2 also increased water vapor in urban areas, boosting temperatures even more.
  • Air temperatures rose more rapidly than did ground temperatures, which changed the vertical temperature profile and decreased pollution dispersion, concentrating pollution near where it formed.
Urban areas already suffering from pollution will be affected most.

Yet because it does not affect respiration directly, CO2 is not considered a classic air pollutant. Noting that increasing levels of CO2 cause temperature and water vapor content to rise, Jacobson uses photochemistry to determine that these factors independently feed back to increase ground-level ozone concentrations.

This can harm lung function and irritate the respiratory system. Using a high-resolution model that correlates pollution levels to human health, the author finds that each one degree Celsius rise in temperature may increase U.S. annual air pollution deaths by about 1000.

About 40 percent of these deaths may result from elevated ground-level ozone concentrations. The rest are likely from particles, which would increase due to CO2-enhanced stability, humidity, and biogenic feedbacks.

The author notes that many of these deaths would occur in urban populations subject to smog, as are residents of some areas of California. Extrapolating U.S. deaths to global population yields about 22,000 excess deaths expected worldwide each year.

Read Jacobson's full article: " On the Causal Link between Carbon Dioxide and Air Pollution Mortality.