Why Seattle Had The Worst Air Quality In The World At Some Points This Summer

NPR interview, August 31: “Why Seattle Had The Worst Air Quality In The World At Some Points This Summer.” A professor of atmospheric sciences talks about wildfire smoke and air quality, but also forests (which, of course, he’s less qualified to comment on). Still, it is interesting that he says “only a small proportion of this is climate change.” Excerpts:

At some points this summer, the big city with the worst air quality anywhere in the world was not Beijing or New Delhi. It was Seattle, Wash. To talk about why and what this means for the future, professor Cliff Mass joins us now. He’s a professor of atmospheric sciences at the University of Washington in Seattle. Welcome.

MASS: Well, the big problem is our forests. We’ve suppressed fire now for almost a century. A lot of the forests surrounding Seattle are in very bad condition. They’re overgrown. They have a lot of slash, a lot of low bushes and trees. And they’re completely unlike the forests that were here 150 years ago. And the problem is when they burn, they burn catastrophically.

SHAPIRO: And I’m sure climate change doesn’t help.

MASS: That’s right. The question is how much of this is climate change. I suspect that only a small proportion of this is climate change. I think that the main problem is the forests, which are ready to burn. We have invasive grasses that have moved in that burn very easily. And human beings are increasingly starting fires with this huge number of people going in for recreation, other uses of the forested areas.

Now, on the long term, as the planet warms up, we certainly would expect more fires. So climate change, global warming probably contributed a small amount to it, but probably the key thing is what we’ve done to the surface of the planet.

SHAPIRO: Are there things that the government or citizens could do to try to prevent this from happening more?
MASS: Well, the key thing is to fix our forests. People know what to do. I mean, if you talk to the people in the Forest Service, it’s clear. We have to thin the forests and then let fire come back regularly but at a much lower intensity.

6 thoughts on “Why Seattle Had The Worst Air Quality In The World At Some Points This Summer”

  1. Cliff Mass also has a well-informed blog entry that discusses this subject:


    It’s great to see this discussion occurring outside of just the forestry realm. After a few summers of breathing heavy smoke in the PNW, I believe the greater population is coming around to seeing the problems, and more importantly, the solutions to this issue that’s been a hundred years in the making.

  2. I know you did mention it Steve, but jeez…good thing us “environmental terrorist groups” didn’t use a professor of atmospheric sciences to make huge over-generalizations about forest ecology.

  3. For whatever it’s worth…This article, featuring actual forest ecologist and fire ecologists talking about the forest ecology and fire ecology of west-side forests in Washington might be more useful than a professor of atmospheric sciences opining about forest and fire ecology.



    On a remote ridge, the hemlock, silver and noble firs stood for several centuries, nurtured by deep winter snow and drenching rains. Then last year, amid the searing August temperatures, the Norse Peak fire on the east side of the Cascades pushed over the range’s crest and engulfed this stand, killing most of these trees.

    Now the charred trunks rise like ghostly sentinels in a forest littered with charcoal, which still gives off whiffs of the smoke that billowed from the 55,909-acre blaze. This austere burn zone is a typical aftermath to intense fires that, over the course of centuries, periodically feast upon the huge amounts of wood that grow in the west-side forests of our region.

    The fire ecology of such forests, and how it may evolve amid climate change, is of increasing importance as wild-land smoke emerges as a regional concern. The polluted air that hung this summer over a vast stretch of the West Coast — from San Francisco to Vancouver, B.C. — has generated a fresh wave of support for more logging and cool-season burns to thin the forests and reduce the potential fuel.

    These tactics are standard practice east of the Cascades. But in a peer-reviewed paper published this year, a research team of University of Washington, state Department of Natural Resources and U.S. Forest Service scientists caution that such tactics won’t do much to tame or head off west-side fires, which are forecast to happen more often — and burn more acreage — as climate change spurred by the combustion of fossil fuels reduces winter snowpack and increases summer temperatures.

    But wetter forests, such as the stand torched in the Norse Peak blaze, have a very different relationship with fire. They burn infrequently but the toll on the trees often is severe. Trying to head off these fires would require thinning these public lands every decade or so, and that would change the natural character of these lands in what Franklin calls a “fool’s exercise.”

    There also are benefits to these west-side fires, which Franklin says can act as powerful sources of forest renewal.

    • Matthew, with all due respect to Jerry and the other forest scientists..

      “By late in the 21st century, some climate models indicate that the amount of west-side forests that will burn in an average year will be more than double that of the last half of the 20th century. And, in any one particular patch of forest, fire is expected to make more rapid returns than in past centuries.”

      How could you predict acres burned without considering ignition sources and fire suppression?

      IMHO It’s kind of like talking about flooding on rivers without considering dams and levees.


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