-- by Dave
So now scientists are saying that forest fires are putting mercury into the air at an alarming rate:
- In the past decade, scientists have become increasingly aware of a previously overlooked source of atmospheric mercury—fires. When fires sweep through forests or any other kind of vegetation, they release mercury that was taken out of the air by plants and deposited in leaf litter and soil. Now, a new study published in ES&T (DOI: 10.1021/es071289o)suggests that agricultural and forest fires together are responsible for nearly one-third of the atmospheric mercury in the U.S.
With average emissions of 44 metric tons (t) of mercury per year (yr), fires in the lower 48 states and Alaska contribute almost as much mercury to the air as coal-fired power plants, the study finds.
This must come as particularly good news to people in places like Oregon, where wildfires spewed more mercury into the air between 2002 and 2006 than any other state its size (it was outdone only by Alaska and California).
Or in Montana and Idaho, where much of the past summer was spent with an amber haze clouding the bright daylit Big Sky.
Of course, this isn't just an issue for people living in the West, in the vicinity of the fires. There's also a downwind effect:
- In contrast, states in the Midwest and Great Lakes emitted comparatively little mercury from fires. However, they could potentially be affected by emissions from western wildfires.
... One of the next steps for the researchers will be to examine how much mercury from fires is deposited on nearby downwind areas, compared to how much travels around the hemisphere. Most of the mercury in fire emissions is in gaseous form, traveling thousands of miles before coming down in small amounts in rain or snow. But about 15 percent of the mercury is associated with airborne particles, such as soot, some of which may fall to Earth near the fire.
"We would like to determine the risk of mercury exposure for residents who live downwind of large-scale fires," Friedli says.
It's important to take note of the increasing scale of forest fires on our public lands as a reflection of global warming. As the ES&T report notes:
- The results also indirectly emphasize the need to cut greenhouse gases and fight climate change, says Michigan State University's Merritt Turetsky. Increasing global temperatures, thawing permafrost, and drier conditions associated with climate change are changing fire regimes around the world. Burn area across Canada and Alaska has doubled over the last 50 years, and the southwestern U.S is also witnessing changes in fire regimes. Last year, Turetsky's group showed that these changes led to increased mercury emissions from forests and wetlands in Alaska and Canada. The Wiedinmyer and Friedli study also corroborates these findings for the blazing boreal forests in Alaska.
Global warming is depriving us of an important ecosystem service—"trapping and storing industrial mercury," says Turetsky. "We know that mercury can be very concentrated within soils," she says. The carbon-rich soils of the boreal forests, especially peat, have been accumulating mercury for thousands of years. "In the past, those ecosystems have been probably too wet to burn very often, but that's not the case anymore," she says.
Ah, but this is just one of those "adjustments" the White House says we have to make to deal with global warming, isn't it?
Recall that when the EPA first acknowledged the reality of global warming back in 2002, it nonetheless refused to recommend any action to change course:
- But while the report says the United States will be substantially changed in the next few decades — "very likely" seeing the disruption of snow-fed water supplies, more stifling heat waves and the permanent disappearance of Rocky Mountain meadows and coastal marshes, for example — it does not propose any major shift in the administration's policy on greenhouse gases.
It recommends adapting to inevitable changes. It does not recommend making rapid reductions in greenhouse gases to limit warming, the approach favored by many environmental groups and countries that have accepted the Kyoto Protocol, a climate treaty written in the Clinton administration that was rejected by Mr. Bush.
A few days after the report was issued, Bush dismissed it outright -- for even acknowledging the reality of the phenomenon. But White House policy afterward has been geared toward doing as little as possible to lower carbon emissions because, after all, we can just "adjust."
Now we're starting to see a little bit of the big price we'll be paying for those "adjustments."
But then, it's just the little people who will be paying, isn't it?