A severe weather pattern has been working its way across the United States over the past few weeks with a diversity of effects: heatwaves in the southwest, thunderstorms and tornadoes in the midwest, and thunderstorms and extreme flooding in the northeast. According to meteorologist Alex DaSilva, a dome of high pressure over Texas and an active jet stream pattern across the northern United States have been the driving forces of the extreme weather. Heatwaves are expected to continue to spread up to the Pacific northwest and down across Mexico, while closer to home, Boston and surrounding northeastern areas will likely see more humid wet weather.
The heatwaves, which are also affecting Europe and parts of Asia, are perhaps of most concern given their impacts on human health. They are also the most covered in the national media. From CNN to the Washington Post to the Guardian, headlines everywhere in the first two weeks of July claimed that the earth had experienced its “hottest days on record” – a claim supported by data from the University of Maine’s “Climate Reanalyzer” tool. While it is certainly attention-grabbing, it may not be accurate. As the Associated Press reports, the National Oceanic and Atmospheric Administration (NOAA) “issued a note of caution about the Maine tool’s findings…it could not confirm data that results in part from computer modeling, saying it wasn’t a good substitute for observations.”
The University of Maine’s Climate Reanalyzer relies on a mixture of satellite data and computer model estimates. Other monitors, such as the “temperature.global” website, use actual surface temperatures taken from NOAA stations across the world to calculate average global temperatures. Temperature.global recorded an average temperature nearly 5 degrees Fahrenheit lower than what the Climate Reanalyzer measured in the beginning of July, and according to the Wall Street Journal, the numbers from temperature.global have been steady and have not shown any significant spikes this month. Nonetheless, there are areas in the southwestern United States that are experiencing dangerously high temperatures not seen in years. Is this an anomaly caused by climate change? Once again, things are a little more complicated.
In the United States, heatwaves now and in recent decades have in fact not reached the levels seen in the late 1920s and 1930s, either in frequency or intensity. They have increased since the 1960s, however – but this means that depending on the analysis, heatwaves can be said to have increased or decreased over time. As political scientist Roger Pielke Jr. notes, heatwave data “is a fertile field for cherry pickers.” Reviewing global data, the Intergovernmental Panel on Climate Change (IPCC) concludes that “it is very likely that human influence has contributed to the observed changes in frequency and intensity of temperature extremes on the global scale since the mid-20th century” (emphasis mine), but that “results for the contiguous United States are not as compelling as for global land areas, in part because detection of changes in U.S. regional temperature extremes is affected by extreme temperature in the 1930s.”
None of this diminishes the dangers of current heatwaves in the United States, but it underscores the need for more cautious science journalism. Doomsday headlines can make people lose hope, when there is in fact some good news and positive steps we can take. On the good news front, vulnerability to heatwaves and mortality risk for extreme heat events have declined since the 1970s. Fewer people die because of heatwaves. The World Health Organization (WHO) has also concluded that the societal impacts of extreme heat are manageable, and that mortality need not increase with increased heatwaves if we respond appropriately. Technological adaptations such as increased air conditioning could even result in a mortality attributable to heatwaves of “zero” in the WHO’s estimation. Of course, this is a highly optimistic conclusion, but it shows that the worst consequences are not inevitable.
On an individual level, people living through heatwaves should recognize signs of heat illness or heat stroke and follow certain behaviors to stay safe. According to the National Weather Service, during heatwaves, the body’s “ability to cool itself is challenged. When the body heats too rapidly to cool itself properly, or when too much fluid or salt is lost through dehydration or sweating, body temperature rises” and this could lead to heat exhaustion or heat stroke. Heat exhaustion symptoms include heavy sweating, dizziness, thirst, and even nausea. If you are experiencing these symptoms, you should move to a cool area, loosen clothing, and sip cold water. If these symptoms do not improve, they could lead to heat stroke. Heat stroke symptoms include confusion, sweating cessation, and potentially loss of consciousness. If you suspect someone has heat stroke, you should call 911.
In heatwaves, it’s important to keep your home and your body cool. Drink cold water, take cold showers or baths, wear loose-fitting clothing, and stay indoors if you can. Keep your house cool by using an air conditioner or a fan – if you don’t have access to these, you can cool down your house by closing windows and shutters, turning off artificial lighting, and hanging wet towels (though this may also increase the humidity). If you must go outside, stay in the shade and avoid the hottest times of the day (during the summer, that’s usually between 3 and 5 hours after noon). Young children, people over 65, people with obesity, and people who are ill or who have preexisting conditions must exercise the most caution.
The IPCC has stated that “it is virtually certain that further increases in the intensity and frequency of hot extremes, and decreases in the intensity and frequency of cold extremes, will occur throughout the 21st century and around the world.” Heatwaves will be with us in the future, but they do not need to be incredibly deadly. We can adapt to them, and we can keep ourselves and each other safe by recognizing the effects of heat and adhering to safety protocols when the temperature starts to go up.
