Reed Galin

The Natural Resources Defense Council (NRDC) released an interactive tool today that maps climate-related health risks across the country, including extreme heat, poor air quality, drought, flooding, and infectious diseases. The maps present a snapshot of current health vulnerabilities using recent data at the state and county levels.

“If we stay on our present course, we can expect these health vulnerabilities from climate change to accelerate” said NRDC Senior Scientist Kim Knowlton on a conference call with reporters. “We need to prepare for the worst in extreme events and the health vulnerabilities that will result.”

According to the NRDC, one of the main health impacts Californians are facing with climate change is air pollution.  A recent report from the Public Policy Institute of California finds that two-thirds of Californians already see air pollution as a big problem.  The NRDC tool asserts that 90% of Californians live in areas that violate air quality standards, and that climate change will worsen this by bringing smoggier and hotter days.

Highlighted in red are California counties experiencing several unhealthy ozone days. Map: NRDC

The tool illustrates that the Central Valley and Southern California regions already experience several more extreme heat days each year “than expected,” and asserts that more are on the way, according to climate projections. It also plots out the state’s water crunch, which some California cities are already grappling with.

In addition to laying out the challenge, the tool also links to recommendations for adapting to increased health risks from climate change, including a section on California’s Climate Adaptation Strategy.

“We hope that our national maps will be used as a provocation for people to look and say, ‘Gee, we really need to dig in deeper,’” said Knowlton.

The tool’s data comes from a variety of sources, including the Union of Concerned Scientists, the Environmental Protection Agency, and the American Lung Association.

Los Angeles cloaked in smog shortly after sunrise. (Photo: David McNew/Getty Images)

Air pollution, already a problem for much of central and southern California, will get worse as temperatures warm, according to a new report from scientists at UC Davis and UC Berkeley.

By mid-century, trouble spots like the Central Valley and Los Angeles could experience between six and 30 more days per year when ozone concentrations exceed federal clean-air standards, depending on how much temperatures rise, and assuming that pollutant emissions in the state remain at current levels, the scientists project.

Warmer conditions cause ozone levels to increase because hotter temperatures increase emissions from automobiles and the release of gases from plants. They also increase the rate of the chemical reactions that transform the raw emissions into ozone, said the study’s lead author Mike Kleeman of UC Davis.

The authors say the study provides evidence for the ozone “climate penalty,” which refers to the extra ozone that forms as a result of climate change.

“With climate change, we get increased ozone, which can have negative health effects,” said Kleeman. “The ozone climate penalty is the extra ozone that we have to offset with additional emission controls to offset the risk to public health.”

Previous studies have made the link between climate change and increased ozone, said Kleeman, but what’s new about this report is its attention to how climate change will affect airborne particulates, another component of air pollution, and the finding that, unlike ozone, there doesn’t appear to be a clear link.

“It’s not really clear what’s going to happen with climate change and airborne particulate matter,” said Kleeman.  “We looked at temperature changes, humidity changes, wind speed changes, and precipitation changes, and it’s still not clear, but it looks like the effects on particulate matter will be small.”

This is in part due to the fact that climate change is predicted to increase average wind speeds across the state, and stronger winds  decrease particulate matter concentrations, especially along the coast.  However, Kleeman said, the study did find evidence that in the Central Valley, the worst particulate pollution days may get even more severe in the future because even though average wind speeds are expected to increase, the study results suggest that future peak concentration days may have lighter winds than they do under present conditions. Kleeman says that would worsen conditions on the extreme pollution days.

One factor contributing to airborne particulate matter that the study did not consider is fire. Wildfires are projected to intensify as the state grows warmer and drier. “It’s possible that wildfires could be the major impact of climate change on particulate air pollution in California,” said Kleeman.

The study was supported by the California Air Resources Board.

“We already know that climate change will bring us increased forest fires, shorter winters, hotter summers, and impact our water supply,” said Board chair Mary Nichols in a press release announcing the study. “Now we have scientific evidence that higher temperatures are hurting our lungs, too.”

The study, which focused on California’s wildfires September and October of last year, found that the fires repeatedly boosted ozone to unhealthy levels – levels that exceed U.S. health standards — across much of California and Nevada.

While ozone in the upper atmosphere where it blocks ultraviolet radiation from the sun is a good thing for life on Earth, it’s a bad thing down here at the surface where ozone can cause breathing difficulty and aggravate respiratory problems like asthma and emphysema in humans and it can harm agricultural crops.  The EPA’s brochure on “good” and “bad” ozone identifies ozone as the main component of urban smog.

Many climate scientists are predicting hotter and drier weather for the American West, likely increasing the frequency and duration of wildfires.  “Bad” ozone might be something we’ll be getting used to.

Here’s a July article from the San Francisco Chronicle with an overview of California’s fires for the first half of 2008.