Off the charts

Posted 8/7/19

It’s shaping up to be the hottest summer ever, according to the World Meteorological Organization, which released data last week showing that June and July 2019 set new heat records. The …

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Off the charts


It’s shaping up to be the hottest summer ever, according to the World Meteorological Organization, which released data last week showing that June and July 2019 set new heat records. The International Red Cross has noted that 17 of the 18 warmest years in the global temperature record have occurred since 2001. During this period, tens of thousands of people have died from heat-related illnesses around the world, including 70,000 in Europe during a series of heatwaves in 2003. The National Weather Service has warned that heat kills more people in the U.S. than any other type of weather disaster, including floods, tornadoes, hurricanes and cold.

The definition of a heat wave varies from region to region, but here in the Northeast it is usually defined as three days during which the temperature reaches or exceeds 90-degrees Fahrenheit. Relative humidity is also a critical factor in the effect of heat on health. When humidity is high, the body’s natural cooling system can’t work well because perspiration doesn’t evaporate quickly enough. The heat index used by the National Weather Service calculates air temperature and humidity levels to represent the “feels like” temperature. A 94-degree day with 45% humidity feels like 100 degrees; so does an 88-degree day with 70% humidity.

While anyone can suffer ill effects from the heat anytime the temperature rises above 80 degrees, there are several populations considered especially vulnerable. These include infants, children and the elderly; pregnant women and people with pre-existing health problems such as diabetes, cardio-vascular disease, respiratory illnesses, or physical disabilities; people who do strenuous work outside; and student athletes and military personnel who train in high temperatures. Poverty is also a factor; those who lack air conditioning or can’t afford to use it because of high electricity bills are also less likely to have the transportation options to go hang out at a shopping mall or other venue to get cool.

What’s new about the heat we are experiencing now is the trend toward more prolonged periods of extreme heat and lack of overnight cool-downs. A new study published by the Union of Concerned Scientists (UCS) analyzed 18 different climate models and decades of National Weather Service data to project how often the heat index—the “feels like” temperature—will be higher than 90 degrees, 100 degrees and 105 degrees during warm seasons (April through October) in future years. The study correlated this data with three scenarios representing different levels of action to reduce greenhouse gas (GHG) emissions to slow global warming. They found that, even with moderate action to reduce GHG emissions, it is likely that the lower 48 states will experience more than twice as many 100-degree heat-index days by 2050, increasing from an average of two weeks to 30 days. The number of days that feel like 105 degrees will rise to three weeks.

The received wisdom about summer heat has been that people living in hot climates become acclimated to deal with spells of extra-hot weather. The UCS study warns that temperatures may increase to the extent that many locations in the U.S. will experience periods when the heat index is “off the charts”—unprecedented in the experience of the National Weather Service, and demanding new protocols for heat advisories and new understandings of the effect of extreme heat on human health and safety.

The New York State Department of Health has noted that annual average temperatures across the state have increased steadily over the past decade and projects that average summer temperatures could increase by as much as 10.8 degrees Fahrenheit over the next century. What can we do? Perhaps first we should all learn the signs of heat-related illness, especially heat stroke, which requires emergency medical attention, and get some training in the appropriate first-aid measures so we can help each other. Good information is available from the New York State Department of Health and the Centers for Disease Control and Prevention. We should make sure our towns have a plan for activating local venues that can serve as cooling centers and getting vulnerable residents to those locations—including those who lack transportation resources. Residents who qualify for the Home Energy Assistance Program (HEAP) for winter home heating also qualify for home-cooling assistance through HEAP.

Longer term, we should plan for the increased need for air conditioning and the associated electricity demand, while continuing to work to improve the overall energy efficiency of our buildings. We need to speed the adoption worldwide of alternative refrigerant technologies, including those used in air conditioning, that don’t use hydrofluorocarbons (HFCs), which have 1,000 to 9,000 times global warming capacity as CO2. And we have to keep up the pressure for a comprehensive climate policy that reduces GHG emissions across all sectors so we can avoid the worst-case heat scenario.


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