National Climate Assessment predicts harsh future for Southeast; what does that mean for East TN?
Brittany Crocker- Summer highs have already increased in East TN. The National Climate Assessment said it's not over.
- Increased wildfire risks, mosquito-borne illnesses and worsening air quality likely in the future
- Warmer temperatures in the Arctic can send deceptively cold jet streams southward
- NOAA predicts warm, mild winter for much of the U.S. Forecast is less clear for the Southeast
A controversial government report predicts a harsh future for the Southeast if the planet fails to significantly curb harmful emissions that trap heat in the atmosphere.
The National Climate Assessment, an interagency government report that summarizes the effects of climate change on the United States, now and in the future, said the Southeast is already seeing the effects of climate change and will likely see more in the future.
Such effects include extreme fluctuations in temperature and weather, wetter spring seasons, and dryer autumns, and more frequent flooding along the coasts.
Southeastern states are major energy producers of coal, crude oil and natural gas. The Southeast is also the highest energy user of any of the National Climate Assessment regions, including the highly populated Northeast and the coasts.
President Donald Trump's administration came under scrutiny for releasing the Congressionally required National Climate Assessment the day after Thanksgiving, which USA Today reported is typically the "slowest news day of the year."
Trump, a longtime opponent of climate science, later told reporters he did not "believe" the 1,600-page report his administration issued.
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Southern Alliance for Clean Energy weighs in
Environmental groups continue to push for responsible energy use and the reduction of harmful emissions. The Southern Alliance for Clean Energy, of Knoxville, held a seminar on the report soon after it was published.
"This continues to be a key moment of choice on whether or not we will invest significantly in needed reductions of greenhouse gas emissions to avoid the worst impacts of climate change," said Kirstin Dow of the University of South Carolina Department of Geography during the seminar.
"It is still possible to avoid the worst impacts, but it's more urgent and more difficult the longer that effort is delayed."
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What does this mean for East Tennessee?
In 1998, Knoxville saw about 53 days that reached temperatures over 90 degrees, according to Climate Impact Lab scientists. In the last 20 years, that number has increased to an average of 63 days where temperatures reach more than 90 degrees.
Hot days are expected to continue increasing in frequency, as the National Climate Assessment predicts much of the Southeastern United States will experience a climate similar to Florida's by the mid-21st century.
Wildfire, Zika, allergies, other health risks
The report warned paved urban areas like downtown Knoxville may present health risks for residents as they become "heat islands" when temperatures rise. Urban heatwaves can increase risks of heatstroke, cardiovascular and respiratory complications and death, the report said.
Extreme temperatures could also cost between a 2 and 4 percent decrease in hours worked in East Tennessee's outdoor labor sectors like agriculture and forestry, according to charts within the report.
Outside the urban centers, livestock and crop production may suffer, and wildfire risks may become more common.
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Dow said areas of Tennessee are becoming drier than normal, and experiencing changes in precipitation making the fall season wetter and the spring season much drier.
Disease-carrying mosquitoes may also begin to thrive further north as summers begin to warm up and last longer, according to the report. Widening the pests' geographic range could threaten East Tennesseans with dengue, Zika, Chikungunya and yellow fever.
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The warming climate has already created air quality concerns, including longer and more intense allergy seasons, the report pointed out.
The Asthma and Allergy Foundation of America reported warmer temperatures between 1995 and 2011 have caused pollen seasons in the United States to be between 11 and 27 days longer.
The Tennessee Valley's topography could exacerbate those effects for residents. The Knox County Health Department has said the tendency for pollutants in the air to settle between the mountains has been a challenge to improving air quality in the area.
If the atmosphere is warming, why has East Tennessee been unseasonably cold?
Unusually cold November temperatures might give some East Tennesseans reason to doubt the federal government's report on increasing global temperatures.
But it's not that simple, Doug Marcy of the National Oceanic and Atmospheric Administration explained.
"We get these cold snaps from the jet stream dipping down lower than normal," said Marcy.
As temperatures in the Arctic Circle heat up, the jet stream swings further south, bringing arctic blasts like much of the area saw in early November. The swings can last for some time, Marcy said, leading to larger differences in air masses and more acute fluctuations in the weather.
"With climate change, it's really about more extremes," Marcy said, "not necessarily just hotter weather." He also said that consequences include more intense storms and temperature differences.
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Despite the November cold snap, the National Oceanic and Atmospheric Administration's winter outlook forecasts a mild, warmer-than-normal winter for most of the United States, though the Tennessee Valley has equal chances of below-, near- or above-average temperatures.
Much of the Southeast's outlook is up in the air due to the effects of weather patterns that are harder to account for, the NOAA said. For one, warming sea surface temperatures signal a weak "El Nino" may be in store in the early winter, creating wetter-than-normal conditions in the Southern states and drier conditions further North.
The agency said other climate patterns that might affect winter weather in the south this year depend on "Arctic Oscillation," which influences the number of arctic air masses that penetrate into the South, resulting in below-average temperatures in the Southeast.
