Global Warming Bringing More Extreme Heat Waves

“Global warming is bringing more frequent and severe heat waves and the result will be serious for vulnerable populations,” said Dr. Amanda Staudt, climate scientist, National Wildlife Federation.

“That means air pollution in urban areas could get worse, bringing increased risk of heart attacks, strokes and asthma attacks. Children, the elderly, poor, and people of color are especially vulnerable to these effects.”

To explain the bigger picture and provide recommendations for how to cope with projected changes and how to avoid the worst impacts of global warming, More Extreme Heat Waves: Global Warming’s Wake-Up Call details how:

• Global warming will bring more extreme heat waves

• Urban air pollution could be exacerbated by more extreme heat

• Heat waves disproportionately impact people who are poor, elderly, children, or have asthma or heart disease, or live in big cities

• Natural habitats and agriculture are also vulnerable to heat waves

• We can reduce the severity of heat waves and their impacts on vulnerable people

“Global warming is one of the gravest health emergencies facing humanity. It’s life-threatening and it’s affecting us now,” said Dr. Peter Wilk, MD, executive director, Physicians for Social Responsibility. “The science confirms that the frequency and duration of heat waves has increased significantly over the last 50 years. In the United States, heat waves already kill more people during a typical year than floods, tornadoes and earthquakes combined. Given these worsening trends, taking decisive action to stop global warming becomes a medical necessity.”

While the data show indisputable warming over the past several decades, cooler-than-average temperatures across the Midwest and Northeast in summer 2009 make it is easy to lose sight of this long-term trend. According to the most recent science on heat waves, this temporary respite is due largely to natural climate oscillations working in our favor. “We are nearing the end of a minimum in the 11-year solar cycle during which the Earth is receiving slightly less heat from the Sun,” Staudt explained. “At the same time, the jet stream took an unusually southern track across the nation this summer, bringing more Arctic air and less tropical air to the Midwest and Northeast. These sorts of natural variations will continue to take place as the climate warms.”

When it comes to heat waves, communities need to prepare for the years when the natural variations line up in the opposite way: a year with maximum solar heating, a northward shift in the jet stream, and global warming could add up to record hot weather, Staudt explained. Furthermore, while it has been pleasantly cool in some parts of the country, the South and the West have been sweltering. At the end of June, numerous daily temperature records were equaled or broken in Texas, Louisiana and Mississippi. In late July, the Pacific Northwest had an extreme heat wave as a high pressure weather system stalled overhead.

From New York to Los Angeles, the report details 30 large U.S. cities where major risk factors associated with heat-related mortality make residents especially vulnerable to heat waves:

• Number of oppressively hot days each year
• Fraction of homes without central air conditioning
• Ground-level ozone pollution
• City population living in poverty
“When the thermometer goes up, when the waters rise, our communities are most at risk,” said Benjamin Todd Jealous, president & CEO of the NAACP. “There is a climate gap in our country. Black Americans, other people of color and the poor are disproportionately impacted on by the consequences of global warming.”

“The effects of extreme heat waves are, unfortunately, a deadly serious reality here in Louisiana,” said Jerome Ringo, past chair, National Wildlife Federation and president of the Apollo Alliance. “This became personal when an associate of mine here recently lost his life due to the effects of extreme heat.”

“We need to take these trends toward more extreme heat waves into account when designing urban areas and public health programs,” said Dr. Staudt. “We can no longer plan based on the climate we used to have.”

“Certainly vulnerable populations will suffer earliest and most from the heat waves global warming is causing, and clearly it’s time for us to consider the public health implications we'll face, but a lot more of us are going to become vulnerable and ill if we don't work to reduce what we're doing to warm the planet,” stated Dr. Cindy L. Parker, Johns Hopkins Bloomberg School of Public Health. “Let's be honest: We cannot simply adapt to ever-rising temperatures. We have to do all we can to keep those temperatures from soaring past our ability to cope. This is not just a wake-up call; it’s a call to action.”

Important steps to reduce the risks include curbing global warming pollution to minimize future extreme heat waves, making cities cooler and greener, implementing public health measures that reduce the impact of extreme heat waves, and safeguarding wildlife, fish and habitats from extreme heat.

National Wildlife Federation is America's conservation organization inspiring Americans to protect wildlife for our children’s future.