What People Think Will Happen

Consequence: Warmer temperatures
Average temperatures will rise, as will the frequency of heat waves.

Warning signs today

• Most of the United States has already warmed, in some areas by as much as 4 degrees Fahrenheit. In fact, all states experienced either "above normal" or "much above normal" average temperatures in 2006.
• The National Oceanic and Atmospheric Administration (NOAA) declared 2006 to be the second warmest year on record for the United States, with an annual average temperature of 55 degrees Fahrenheit -- within 0.1 degrees of the record set in 1998.
• Every year from 1998 through 2006 ranks among the top 25 warmest years on record for the United States, an unprecedented occurrence, according to NOAA.

Consequence: Deadly heat waves and the spread of disease
More frequent and more intensive heat waves could result in more heat-related deaths. These conditions could also aggravate local air quality problems, already afflicting more than 80 million Americans. Global warming is expected to increase the potential geographic range and virulence of tropical diseases as well.

Warning signs today

• In 2003, extreme heat waves claimed an estimated 35,000 lives in Europe. In France alone, nearly 15,000 people died due to soaring temperatures, which reached as high as 104 degrees Fahrenheit and remained extreme for two weeks.
• Much of North America experienced a severe heat wave in July 2006, which contributed to the deaths of at least 225 people.
• Studies have found that a higher level of carbon dioxide spurs an increase in the growth of weeds whose pollen triggers allergies and exacerbates asthma.
• Disease-carrying mosquitoes are spreading as climate shifts allow them to survive in formerly inhospitable areas. Mosquitoes that can carry dengue fever viruses were previously limited to elevations of 3,300 feet but recently appeared at 7,200 feet in the Andes Mountains of Colombia. Malaria has been detected in new higher-elevation areas in Indonesia.