Pollution's polar toll

LANL geochemist among scientists studying soot’s impact on Arctic melting

Sue Vorenberg | The New Mexican

5/18/2008 - 5/19/08

Santa Claus might want to buy a good cover and air filter for his sleigh this year, and he also might want to think about investing in a boat in the near future.

The pristine, frigid Arctic just isn't what it used to be.

A multiagency team of 250 scientists from the National Oceanic and Atmospheric Administration, the National Aeronautics and Space Administration and Los Alamos National Laboratory spent several days in late April looking
at what should be Santa's clear, snow-covered winterland.

What's really there, though, is soot, industrial pollution and other junk pumped into the air from countries across the northern hemisphere, said Manvendra Dubey, a geochemist at Los Alamos.

"You expect it to be beautiful and pristine, but actually it's pretty polluted," Dubey said. "We went up there to measure how bad it is, and actually, it's pretty bad."

The area, especially in the spring and summer, functions as a big filter, collecting smoke and particles from forest fires, dust storms, cars and factories. And that filter is getting clogged.

The air pollution isn't just something you wouldn't want to breathe, it's also falling onto the snow, which appears to be making it slightly darker, Dubey said.

And darker snow absorbs more sunlight, which could be speeding the processes of ice sheet breakup and melting of the polar cap, he said.

"Even if it's a little darker, even if you can't see it, it makes a difference, and that makes it get warmer," Dubey said. "We're not sure yet how much darker it is than it was in the past. That's something we took measurements of and we're analyzing right now."

Pollution is also changing the consistency of clouds above the region, making them hold in more heat than they would in a clean environment, said Chuck Brock, a physicist with NOAA.

"If you have a very clean environment, there are usually not many cloud droplets present," Brock said. "But as you have more pollution, there are more droplets. And that makes the clouds optically thicker and brighter. It's like a nighttime blanket trapping the heat in near the surface."

And smog layers in the sky, which are also dark, could add even more heat to the area, Brock said.

"When we flew over we saw thick layers of smoke coming from forest fires in Siberia," Brock said. "It was just visually distinct dirty brown smoke over the ice, thousands of miles from its source."

Those fires weren't natural, either. They were planned burns from an industrializing Siberia, he said, adding that pollution sources from Eurasia and North America are also playing into that mix.

And other evidence is growing that bad things are happening in the Arctic.

Last summer was the first time in modern human history that the Northwest Passage — a shipping route that loops above Canada and Siberia — was clear of ice so that normal ships could go through, not just ice breakers, Dubey said.

This summer, it will likely open again. But there's an added danger of sending ships through that area, he said.

"If you send more ships, and ships are very polluting, it's just asking for disaster," Dubey said. "We don't know what adding a lot of pollution from ships would do to that area. A lot could happen, including causing the ice to melt even faster, but in general we need to slow down until we know better what's going on up there."

Another problem, and part of the reason scientists descended on the place last month, is that the ice is melting much faster than computer models have predicted. That could be because of darkening ice, the thick clouds or both, combined with even more unseen factors, Brock said.

"Most of the models project that most of the ice will be gone, in the summertime, by 2040 to 2050," Brock said. "But there are some suggestions that it could be ice-free during the summers before 2030."

The arctic will still freeze during the winters, but the ice sheet won't be as thick as it has been in the past, he said.

Scientists speculate that an ice-free Arctic could raise sea levels and speed global warming, because the white ice has historically reflected sunlight back into space, rather than absorbing it. But ocean water is much darker and would absorb sunlight.

And ships could make the ice vanish even faster, Brock said.

"So the less ice there is, the more ships could go through, and ship plumes are often very black," Brock said. "That may be more important when ice is forming in the fall and melting in the spring, but we also don't know what that would do to the chemistry of the water up there. You're basically introducing an industrial activity that wasn't there before."

The area is unregulated and not owned by any country, and ships will likely use the passage because it is cheaper than sailing around continents, Dubey said.

"In the absence of law and regulation, the free market will do what it wants," he said. "We would need some sort of policy or international treaties to stop that. But at the very least what we need is more time to learn what's happening and to adapt to that."

There is, however, at least a small bit of good news about the situation. Unlike other global warming problems from carbon dioxide, the pollution from soot and industry is something that policy could impact very quickly, Brock said.

"Carbon dioxide lasts for 50 to 100 years in the atmosphere, but soot has a short lifetime, usually a week or two," Brock said. "This is one of the few climate-forcing agents that we could have a rapid impact on."

And if not, well, nobody's really sure of the exact consequences that an ice-free Arctic will have, Dubey said. "If the ice disappeared, we don't know what would happen," Dubey said. "All we know is that it would be dramatic and extreme."

Contact Sue Vorenberg at 986-3072 or svorenberg@sfnewmexican.com.