A new report says that global warming is bringing more frequent and severe heat waves and the result will be serious for vulnerable populations.
The new report was given from the National Wildlife Federation and Physicians for Social Responsibility, US.
"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," said Dr. Amanda Staudt, climate scientist, National Wildlife Federation.
"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," he added.
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," he added.
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 US, the South and the West have been sweltering.
"We need to take these trends toward more extreme heat waves into account when designing urban areas and public health programs. We can no longer plan based on the climate we used to have," said Dr. Staudt.