Temperatures over the next century expected to rise, with increased likelihood of more frequent heat waves and severe storms.
On a hot day, when the sun is right and delirium high, waves of heat can be seen rippling through the air. While people from Texas to Maine felt the sweltering heat augmented by the humidity last week, people living along the “Ring of Fire” in Minnesota, Wisconsin and Michigan were threatened not just with a succession of severe storms, rather derechos, a Spanish word pronounced, dor-ā-chōs, ushering in 70 to 90 mph winds.
According to the National Weather Service, “A line of severe thunderstorms moved across much of central and east-central Wisconsin during the late morning and early afternoon hours on July 20,” where “widespread tree and power line damage was reported” from “straight-line winds and six, weak, fast-moving tornadoes.”
Last summer, straight-line winds and tornadoes caused significant damage to homes and barns on the Cheyenne River Sioux Reservation and throughout South Dakota, and unrelenting heat reduced yields for ranchers and farmers alike. On the other hand, heavy rains have drowned out fields and resulted in similar setbacks this year.
The oval of heat that moved across the middle to northeastern portions of the United States last week is just a taste of what scientists promise will be more frequent and more intense waves of heat in the future – not only in the States, but world-wide.
Temperatures in 2019 are already breaking heat records from the Eastern Block to the West.
“Heat waves will strongly increase with climate change, and that’s a big problem for society,” said Dim Coumou in an article by Quiron Schiereier, published in both Nature and Scientific American. Coumou is a climate scientist with Free University of Amsterdam.
The heat wave that hit France recently provided a chance for climate scientists to use real-time data to study the likelihood that human activity is influencing the strength and intensity of extreme weather conditions, in particular the rash of heat waves sweeping across the planet in the past several months.
The World Weather Attribution Project used temperatures in France while attending the International Conference on Statistical Climatology in Toulouse, France.
The results of the attribution study support predictions made by scientists in the Fourth National Climate Assessment (NCA) published by the Trump administration in November 2018.
In attribution studies, scientists take existing weather records and compare them to models, including simulations about how weather would behave in a world that is not warming, according to Schiereier’s article.
The team in France found that the hot days in June in France increased 100 times since 1900, and that increase results from climate change and human factors such as pollution.
Since models of the weather do not take into consideration certain variables, such as cloud cover, land use, irrigation or hot air pollution, the predictions are based on probability factors, but often estimate milder rather than worst-case scenarios.
However, in the United States, temperatures are expected to increase by 2.2 degrees Fahrenheit (1.2 degrees Celsius) relative to the increase from 1986-2015 regardless of future scenarios, according to the NCA.
Larger increases are projected for later in the century: 2.3 -6.7 degrees F (1.3 – 3.7 degrees C) is the lower projection and the higher projection is 5.4 -11.0 degrees F (3.0-6.1 degrees C).
The NCA also reports that average temperatures in Alaska, the Northwest, Southwest, and Northern Great Plains have increased by 1.5 degrees F (.8 degrees C) between 1986-2016, and these rates of increase in temperatures have accelerated since the 1960s.
While some may consider Earth to be going through a natural cycle, evidence over longer timescales provide more accurate predictions in relation to overall increases and decreases in temperature. Shorter timescales contain many aspects subject to natural variability, such as El Niño and La Niña.
The NCA points out that in an El Niño year, Southwest winters will be wetter than average in the U.S., and global temps in will be higher; in a La Niña year, Southwest conditions will be dryer and overall global temps will he higher.
However, predicting specific patterns depends on the variables, such as the salinity of the air and ocean temperatures, and the chaotic nature of interconnected weather systems. Still, climate specialists make seasonal predictions, and sometimes even decadal predictions, and regularly make 10-day weather predictions that the general public checks and accepts as a means of dictating aspects of daily life.
The probability of hurricanes and other severe weather storms are traced for people regularly, providing the range of areas and degrees of strength likely when the storms travel over various geographical areas.
Using the same idea of probability, the attribution scientific studies look at patterns of weather and the likely temperatures over longer timescales and are able to make more reliable predictions over a 20-30-year time period, also known as climatological time, according to the NCA.
“The probability calculated by the models is likely to be an underestimate, say the researchers. That’s because unlike the real-world data, the simulations consider only climate-related factors, and don’t represent aspects such as changes in cloud cover, land use, irrigation and air pollution, which all seem to have an influence on temperature, says Robert Vautard, a climate researcher at the Laboratory for Climate Sciences and the Environment in Gif-sur-Yvette, France, who is part of the attribution team,” Schiereier writes in Scientific American.
Given the current data, the NCA predicts that as time progresses, the human influence over global temperatures will increase such that they exceed the influence of natural variability.
Ultimately, the climate scientists in France determined in their real-time study that more than two-thirds of the extreme weather events analyzed were more likely to occur and were more severe because of the increase in global temperatures caused by the build-up of green-house gases in the atmosphere, Schiereier explained in his article.
“In a typical year, heat is the top weather-related killer in the United States, beating out tornadoes, hurricanes, floods and other weather hazards. . . .Heat-related illnesses increase when the human body is not given time to cool off overnight. Heat stress and poor air quality can exacerbate other illnesses and even lead to heat stroke, which can be deadly,” writes Andrew Freedman for the Washington Post in his article, “‘Potentially deadly heat wave grips two-thirds of the US with dozens of records likely to fall.”
“The groups most vulnerable to heat-related illnesses include the elderly, chronically ill, children and outdoor workers. Pets are also vulnerable, particularly if they are left in areas without air conditioning and proper hydration,” reported Freedman.
Human health conditions, planting, growing food, infrastructure, energy use and accessibility are just a few factors that will continue to be challenged by the extreme heat and storm conditions plaguing not only regions of the US, but regions across the globe, requiring practical, economic and social changes as we enter into the third decade of the twenty-first century.