June, 29 2007 (Insidermedicine) Death rates will continue to rise due to high temperatures caused by global warming, say researchers in an article published in Occupational and Environmental Medicine. 

Over the past 100 years, the earth’s surface temperature has risen due to an increase in greenhouse gases. During the past 20 years, about three-quarters of human-made carbon dioxide emissions originated from burning fossil fuels.  

Over the past 25 years, excessive heat exposure caused more than 8,000 deaths in the US. During this period, more Americans died from extreme heat than from hurricanes, lightning, tornadoes, floods, and earthquakes combined. 

Death rates from all causes are known to increase when temperatures rise, while cold weather tends to cause more heart attacks and cardiac arrests. It was therefore anticipated that global warming would increase deaths during hot temperatures, but that this would be offset by fewer deaths in the winter. 

To investigate the association between rising temperatures and death rates, scientists analyzed city-specific weather data related to deaths of more than 6.5 million people in 50 US cities between 1989 and 2000. They found that during heat waves death rates rose by nearly 6%, and a 1.5% increase in deaths was caused by extremely cold weather. 

The findings suggest that a decrease in cold weather as a result of global warming is unlikely to result in a lower rate of cold-related deaths in the US. In contrast, heat-related deaths may increase, particularly if global warming is associated with increased summer temperatures. 

It is thought that central heating, which is more widespread than air conditioning, may protect people against the cold in the winter. Increased use of air conditioning may help to reduce heat-related deaths, although it will contribute to global warming through carbon dioxide emissions from electricity consumption.  

Reporting for Insidermedicine, I’m Dr. Susan Sharma.