Rising CO2 levels tied to increasing human mortality
January 3, 2008

Rising carbon dioxide levels have been tied to increases in human mortality, reports a study to be published in Geophysical Research Letters.

Using a complex computer model of the atmosphere, Stanford University professor Mark Jacobson estimates that air pollution resulting from each increase of 1 degree Celsius caused by carbon dioxide, would lead annually to roughly a thousand additional deaths and many more cases of respiratory illness and asthma in the United States. Worldwide, Jacobson projects upward of 20,000 air-pollution-related deaths per year per degree Celsius may be due to carbon dioxide.

"This is a cause and effect relationship, not just a correlation," Jacobson told Louis Bergeron of Stanford News Service. "The study is the first specifically to isolate carbon dioxide`s effect from that of other global-warming agents and to find quantitatively that chemical and meteorological changes due to carbon dioxide itself increase mortality due to increased ozone, particles and carcinogens in the air."

Jacobson says his findings are particularly relevant in light of the Environmental Protection Agency's recent decision to prohibit individual states — led by California — from setting specific emission standards for carbon dioxide. The agency based its ruling in part on the lack of data showing a link between carbon dioxide emissions and their effects on health.

Jacobson says California is likely to suffer the brunt of health damages from higher emissions, due to its high population (12 percent of that of the entire Untied States) and existing air pollution problems, especially with ozone. Jacobson estimates that more than 30 percent of the 1,000 excess deaths due to each degree Celsius increase caused by carbon dioxide occurred in California.

"Ozone causes and worsens respiratory and cardiovascular illnesses, emphysema and asthma, and many published studies have associated increased ozone with higher mortality," writes Bergeron.

"[Ozone] is a very corrosive gas; it erodes rubber and statues," added Jacobson. "It cracks tires. So you can imagine what it does to your lungs in high enough concentrations."

Jacobson found that higher temperatures due to carbon dioxide increased the chemical rate of ozone production in urban areas and boosted water vapor, which made existing airborne pollutants even more toxic.

"That added moisture allows other gases to dissolve in the particles-certain acid gases, like nitric acid, sulfuric acid and hydrochloric acid," he said.

"Ultimately, you inhale a greater abundance of deleterious chemicals due to carbon dioxide and the climate change associated with it, and the link appears quite solid. The logical next step is to reduce carbon dioxide: That would reduce its warming effect and improve the health of people in the U.S. and around the world who are currently suffering from air pollution health problems associated with it," he concluded.


mongabay.com (January 03, 2008).

Rising CO2 levels tied to increasing human mortality.