California Warned to Prepare for Hotter, More Deadly Heat Waves

SACRAMENTO, California, August 28, 2011 (ENS) – California will be subject to more frequent and more dangerous heat waves that will kill thousands of elderly people each year, finds a new climate-modeling study commissioned by the California Air Resources Board.

As a result of global climate change and the state’s aging population, researchers using a new, more comprehensive weather-modeling method found that hot spells lasting 10 or more days could rise 10-fold by the 2090s.

Sunset in Tustin, California, August 22, 2011 (Photo by Altus)

“Along with reducing our climate-warming emissions, we need to prepare for longer and hotter heat waves,” said Board Chairman Mary Nichols. “Raising public awareness of the risks and having safety nets such as community cooling centers can greatly reduce those risks.”

Currently, an average of 500 elderly people die from excessive heat each year in the nine major urban areas studied: Fresno, Los Angeles, Oakland, Santa Ana, Riverside, Sacramento, San Diego, San Francisco and San Jose.

By the 2090s, the death toll within this population group could rise to a range of roughly 4,700 to 8,800, depending on the climate scenario, according to the study.

A warmer climate plays a role, but as much as 75 percent of the projected increase in potential heat-related mortality is attributed to demographics.

The elderly are particularly vulnerable to extreme heat, and the proportion of Californians 65 and older is expected to continue growing at unprecedented rates well into the 21st century.

Scott Sheridan, a Kent State University geographer who led the study, and co-principal investigator Laurence Kalkstein of University of Miami, say the analysis is the first to include demographic factors in predicting changes in California’s heat-related deaths.

Senior couple on a San Diego beach (Photo credit unknown)

Also, the projections are based on stronger climate modeling techniques than those Sheridan used in a 2006 preliminary analysis for the Air Resources Board.

The latest model accounts for a fuller suite of weather conditions that affect how the human body responds to heat – cloud cover, dew point and wind speed, among other variables – making it a better predictor of potential heat-related deaths.

“The public is generally under-educated about the dangers of extreme heat and heat waves,” say the researchers. “Because of this, many of the most vulnerable people are unaware of the risks associated with excessive heat events or of the proper steps to take to reduce their risk to heat exposure, and are uninformed about the locally funded assistance that is available to them, such as cooling shelters or water trucks.”

The impacts of heat on human health actually transcend the climate change issue, as heat is already the major weather-related killer in the United States,” the researchers say, pointing out that many communities around the country already have sophisticated heat mitigation plans in place.

These include public education and increased interaction between stakeholders, politicians, and the local National Weather Service office.

“We strongly recommend that systems like these are developed for every weather forecast office in California, irrespective of the impacts of climate change,” say Sheridan and Kalkstein.

The researchers recommend that California set up extreme heat warning system at weather forecast stations statewide and organize a heat-health task force in every major city to coordinate and update safety plans. Click here to read the full study, “A Spatial Synoptic Classification Approach to Projected Heat Vulnerability in California Under Future Climate Change Scenarios.”

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