New study has found that the most widespread and extreme weather events in the United States, are now occurring more frequently and are significantly warmer than the long-term average. Specifically, a warmer climate is making the heat waves and droughts that have become synonymous with heat-related disasters more frequent and more intense.
For example, a heat wave in the mid-1990s killed an average of 9,000 Americans per year. As a result, heat waves accounted for about one-fifth of all weather-related deaths in 2005, 2010, 2011 and 2012, according to the National Center for Health Statistics; the average annual death rate due to heat waves averaged almost 20 people per day, according to the CDC.
And while many studies have suggested that the U.S. experienced fewer heat-related-disaster-related deaths over the last decade, this new study finds that they’re actually quite common, occurring at rates greater than in prior decades. Heat waves (a combination of heat and humidity) killed an average of 11 Americans per year between 1960 and 2005. This number increased to 17 deaths per year in 2006, to 24 in 2007 and 32 deaths per year between 2008 and 2012. While this data is limited, it’s likely that heat waves contributed to around 50,000 annual emergency room visits for Americans each year.
The researchers say that heat stress has both long-term and short-term consequences. Although many people think about heat stress in terms of its long-term consequences, many of these effects can be avoided even if the temperature at a specific location remains below an official ‘heat advisory’ level. There are effective cooling measures that can be taken to limit heat-related health risks, such as wearing light-colored sweats and limiting exposure to outdoor temperatures above 80 degrees Fahrenheit.”
Heat stress has significant short-term benefits, such as reducing mortality. But in addition, heat stress can produce serious health consequences as it increases the incidence of death by other causes, such as infections, heart failure, heat-related stroke, burns and respiratory complications.
Droughts and other extreme events are also increasing in frequency during the 21st century, according to the data.
During the past 60 years, the average number of droughts per year over the contiguous United States has increased by approximately one-third, from an average of 1.8 in 1961-70 to an average of 4.1 droughts per year in 2010-14
This means that this season, as in previous years, many of the nation’s most devastating storms, such as the 2013 North American and European heat waves, are already projected to be even more damaging than previously thought.
To put this in perspective, climate scientists estimate that the United States has experienced around seven climate extreme events per year, including heat waves during the summers of 2011 and 2012, the 2010 and 2011 floods in Florida, the floods caused by Harvey in Texas and the 2012 drought caused by Hurricane Sandy:
In addition to more frequent and intense storms, climate impacts will also be worsened by a warmer planet, with increased frequency of extreme heat and drought — leading to longer periods of drought and more intense rainfall events.
Extreme rainstorms are now on the rise around the world, and they will likely become an increasing feature of American winters and summers in the future if these trends continue. A warmer planet will likely lead to more intense and frequent heavy precipitation events, with the potential for increasing floods and flooding in the future. For now, however, these kinds of extreme events are relatively rare. According to the latest global atmospheric analysis from NASA’s Goddard Institute for Space Studies:
In general, most of North America and Europe are now experiencing conditions they have not had in at least the previous 50 to 100 years with this kind of warmth.
There has only been one record warmth over the past 50 years. Even in the past few summers, there have been exceptional warmth conditions,” Thomas Karl, director of NOAA’s National Centers for Environmental Information, told The New York Times. “What’s different this year is the severity of warmth.
Scientists say that the United States has already exceeded the 20th-century average for extreme heat in some areas — with a big exception, a record-shattering drought in the Northwest. The biggest danger comes in a number of U.S. states where severe drought has caused millions of acres of farmland to turn to dust.