The video above shows aerosol emission and transport from September 1, 2006, to April 10, 2007. Also included are locations, indicated by red and yellow dots, of wildfires and human-initiated burning. (NASA Goddard Space Flight Center)
Humans across the globe are connected now more than ever before; actions taken on one continent can affect people on another. Now, scientists from NASA’s Jet Propulsion Lab (JPL) and the California Institute of Technology (CIT) are showing this is true even for weather.
New research out of JPL and CIT reveals that during our cold-weather season, pollution in China is altering weather patterns in the United States and other parts of the Northern Hemisphere. Jonathan H. Jiang, a JPL research scientist, explained to weather.com what this means.
“During the wintertime, human-induced pollution such as coal burning in many Asian cities can create smog that lasts for weeks,” he wrote in an e-mail. “Under favorable wind conditions, pollution particles can be transported downwind across the North Pacific, where winter storms are prevalent.”
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In other words, those particles hitch a ride on the jet stream, notes Chris Dolce, a digital meteorologist with weather.com. “Once these pollutants enter the atmosphere in Asia, they can follow the jet stream, which waves its way from west to east through the Northern Hemisphere.”
Then those particles can act as a “cloud nucleus,” according to Jiang, helping clouds to form and as such, changing storm prevalence and strength.
For the past three decades, have gained some strength and clouds have grown deeper, NASA reports. (According to Dolce, that means clouds growing taller and bigger to allow to them to produce precipitation.) Also during that time, China and other Asian countries experienced an economic surge — a fact that prompted Jiang and colleague Yuan Wang to explore whether one affected the other.
As it turns out, they were connected. “Before, we thought about the North-South contrast: The Northern Hemisphere has more land, the Southern Hemisphere has more ocean,” Jiang told NASA’s Earth Science News. “That difference is important to global atmospheric circulation. Now, in addition to that, there’s a West-East contrast. Europe and North America are reducing emissions; Asia is increasing them. That change also affects the global circulation and perturbs the climate.”
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Such a link had previously been made already, back in 2007, according to Jiang. But he and Wang took a new and different approach to crunching the numbers, playing out two simulations — pre-Industrial Revolution concentrations of aerosols, those pollution particles mentioned above, compared to current levels — to determine any changes. Into these scenarios, they incorporated weather factors like temperature, precipitation and barometric pressure, as well as how aerosols move around the globe.
Jiang said it’s still possible to reverse course if the right changes happen, if emissions levels decrease enough, a notion some studies indicate could happen by 2030, he said. And he doesn’t just mean in China.
“Not only Asian pollution matters,” he said. Reducing pollution levels in Europe and the United States can counterbalance the pollution in Asia to “modulate regional climates as well as global circulations,” he noted, adding that specific connections to U.S. weather patterns still need to be explored in greater detail.
MORE FROM WEATHER.COM: Smog in China (PHOTOS)
A bus is seen at a toll booth on a highway as vehicles are forced to wait due to heavy smog in Jilin, northeast China's Jilin province on October 22, 2013. (STR/AFP/Getty Images)