China's dirty air threatens darker days for Northwest
Research suggests pollution over the Pacific will make Oregon
RICHARD L. HILL
Severe air pollution from Asia is expanding the winter cloud cover
over the north Pacific Ocean and could bring cooler, wetter weather
to the Northwest, a new study suggests.
The booming industrial age in China and India has fired up
factories, cook stoves, diesel engines and coal plants, sending
gritty particles blowing over the Pacific Ocean toward North
America. Those particles have expanded clouds in the storm track
that sweeps west to east across the Pacific each winter, researchers
say. Those changes ultimately could alter weather patterns in the
U.S. and even globally.
"The bottom line from our study is that if you change the Pacific
storm system, then you're going to change the weather in some
places," said Renyi Zhang, a professor of atmospheric chemistry at
Texas A&M. "This is definitely going to change the weather system
over the United States."
The pollutants sweep into the Northwest with storms and prevailing
wind, bringing dust, salt, soot and fine particles of mercury,
arsenic, copper, lead and zinc across the Pacific in a few days. The
particles can alter the size of the water droplets that form clouds.
The larger, deeper clouds that result would reflect more sunlight
back into space, cooling the surface, as well as boosting the chance
of precipitation, Zhang said.
The researchers looked only at the cloud changes -- mostly brought
on by soot and sulfate particles from such activities as coal
burning -- not what specific weather changes resulted. "But this is
the first study that demonstrates that pollution can change a part
of the weather system, which in turn can change the climate," Zhang
The Texas A&M researchers used a combination of satellite
measurements and computer models to study the pollutants. They
compared the deep clouds in January between two decades: 1984-94 and
They found that the average amount of deep clouds in the north
Pacific had increased by 20 percent to 50 percent during the most
recent decade compared with the previous 10 years.
The study findings are reported today in the Proceedings of the
National Academy of Sciences.
Though the study measured only cloud cover and not the changes in
temperature and rainfall that might result, some towns along the
Oregon Coast recorded an impressive increase in rainfall during the
last years of the study. For example, January rainfall in Newport
totaled 89 inches in 1984-1994 but hit 128 inches for 1995-2005.
Some scientists with expertise in clouds and climate are skeptical
about the findings. They say that the change in winter clouds may be
connected to varying regional climate cycles and other dynamic
weather processes rather than Asian pollutants.
They say the cloud changes may be linked to the Pacific Decadal
Oscillation, a little-understood phenomenon in which the climate
flip-flops between wet-cool and dry-warm phases about every 10 to 30
years. A shift to a wetter, cooler phase in the Northwest occurred
in the mid-1990s, which coincides with the most recent years
James A. Coakley, an atmospheric science professor and cloud expert
at Oregon State University, said the study authors didn't show a
clear link between pollutants and clouds. He said other factors may
be triggering the change, perhaps global warming or the Pacific
Decadal Oscillation. "What they've found may have little to do with
increases in pollution from Asia."
David Covert, a research professor and atmospheric chemist at the
University of Washington, agrees. Pollution sources "are a minor
player in the clouds, storms and storm track," he said. "This is not
to say that the effects are insignificant but that they are very
hard to detect" above typical variations in weather and climate.
Zhang emphasized that the study looked only at the changing storm
track over the Pacific Ocean. "But I think other regions are going
to be affected. That needs to be further studied."
The Arctic especially may be susceptible to the pollutants and their
effects on the weather, Zhang said, with black soot absorbing more
heat from the sun and increasing the melting of ice.
"There's a lot of unanswered questions about the changes to the
large weather systems that these pollutants may be bringing," Zhang
said. "The scientific community needs to look at this a lot closer."
Richard L. Hill: 503-221-8238; email@example.com
China's dirty exports: Mercury and soot
Dust plumes blow across the Pacific from cities and factories and
dump pollutants on the Northwest
Friday, November 24, 2006RICHARD READ
The enormous dust clouds gather in the Gobi Desert. They sail on
Siberian winds to China. They pick up mercury, aerosols and carbon
monoxide spewed by Chinese coal plants and factories.
Then every five or six days in spring, eastern China flushes like a
gigantic toilet. The dust plumes, now as large as countries, ride
high over the Pacific Ocean, pushing hydrocarbons, nitrogen oxides
They reach Oregon in less than a week, sullying springtime views at
Crater Lake and scattering dust as far as Maine. Researchers climb
an ice-encrusted ladder atop Mount Bachelor's Summit Express ski-
lift tower and collect the evidence.
Beyond the views, China's contaminants affect Oregon in two key
A growing amount of the greenhouse gases that trap heat, shrink
Northwest glaciers and raise ocean levels comes from China.
A substantial share of the mercury that pollutes the Willamette
River, making fish unsafe to eat, has traveled thousands of miles
across the Pacific.
"It's kind of frustrating because it's limiting our choices here,"
says Bruce Hope, the Oregon Department of Environmental Quality
researcher who estimated the share of global mercury reaching the
Willamette. "As long as these foreign sources are there -- and God
forbid that they should get any bigger -- we'll be hard-pressed."
But China's emissions are getting bigger. It plans to add at least
500 coal plants to more than 2,000 operating already. It spews more
soot than any other country.
Yet it's all too easy to blame China for the mess. U.S. consumers,
who buy China's goods and use far more resources than the Chinese,
"Americans in our cleverness are not good Boy Scouts," says Greg
Carmichael, a University of Iowa atmospheric chemist, "because we've
put the latrine upstream of the campsites."