Street Roots • February 27-March 5, 2015
Commentary
Page 9
charred stands of trees that are basically
just snags covered with this black material
after a wildfire. My simple hypothesis is that
those trees are acting as a source of black
carbon to the snowmelt post wildfire. And
then within that, the questions I’m wanting
to ask are: How large of a scale is that
effect? And how does that effect vary with
burn severity or the age of the burn? We’ve
done sampling over the last couple winters,
after that 2012 Table Mountain fire burn.
The past two springs I’ve gone up and made
some measurements Within that bum area, ; L
but this past fall we also had thé Snag
Canyon fire, which was also near my
university. This spring weTl be doing
fieldwork comparing the amount of black
carbon deposited on the snowpack in that
2012 fire, the 2014 fire and some other fires
that are a little hit older.
E.G.: Do you think black carbon is having
a worse effect today than it m ight have had
during the mid-century, as we are now seeing
the effects o f climate change?
S.K.: It depends on which effect you’re
talking about You’ve got the effect of
atmospheric warming, you have the effect
happening with black carbon when it gets
deposited on snow and glaciers, and then
you also have the health effect of people
breathing those aerosols in, which cause a
lot of respiratory problems and can be
carcinogenic.
Even though concentrations have
dropped, everything is compounded by the
atmospheric warming that’s happening as a
result of all the other activities that we’re
doing.
E.G.: Do you know, globally an d regionally,
where the highest concentrations o f black
carbon are, a nd w hat is the result?
P RO TO BY CHRISTI TURNER
S.K.: The largest emissions right now are
in Asia — in India and eastern China where
you have rapidly growing economies and
large populations, so that’s the largest
source. From natural sources, places where
you can get a lot of biomass burning like the
Siberian forest or the wildfires that we’re
having in the western part of United States
today, those can be big sources also.
If yon take the studies done in Asia, the
black carbon in the atmosphere ends up
absorbing the solar radiation. Some of that
energy that would have otherwise made it to
the surface doesn’t make it there, so there
is some indication,, that black, carbon and.
other pollutants are causing atmospheric
warming higher up in the atmosphere, but
the surface can actually end up cooling
because that energy is getting absorbed
higher up.
In the Pacific Northwest, when I first
started this work, I had no idea what it was
going to look like. What we found so far is
that during the wintertime it snows so much
in this region that the black carbon ends up
being really diluted in the snowpack. As we
move into the springtime, we start to get
less precipitation and the snowpack starts to
m elt Then black carbon ends up either just
falling out of the atmosphere and onto the
snowpack, or as the snow starts to melt, the
black carbon can get trapped on the surface
and get consolidated into higher and higher
concentrations.
But the highest concentrations are
related to when we have wildfire activity.
There are only so many areas that still have
snow when the wildfire season is happening,
and so more high-elevation snowpacks on
the glaciers is where those fire emissions
are going to end up.
E.G.: A s you know, 2012 a n d 2013 were the
worst fire seasons on record fo r the Pacific
Northwest. W hat k in d o f impact did that have,
a nd do you know what the impact m ight be i f
we continue to see more than a m illion acres
go up in flam es every fire season in this
region?
S.K.: From the work I did on the Olympic
Peninsula, we saw that there was a fire out
there that ended up resulting in a deposition
on Mount Olympus, and the work that we’ve
done indicates that fire would have
accelerated melt on those glaciers
somewhere on the order of two to four
times higher than if you didn’t have
Susan Kaspari, professor a t Central Washington University, collects samples in a snow p it on
Table M ountain, located on the north side o f the Columbia R iver in Washington. The area
was burned durin g a fire in 2012.
wildfires. So from the perspective of how
quickly our snowpack and our glaciers melt,
it’s something that we should definitely be
paying attention to.
E.G.: Tell me a little bit more about the
research yo u ’ve been conducting in the
Cascades. W hat kinds o f things have you
discovered th a tm a y have been ja surprise to
you or that people should take into account
because it could be a warning sign o f trouble
ahead?
there is way more dust than there is black
carbon, so you have to take into account
both thè properties and how much is
actually getting deposited, but defining
properties of dust is not that easy to do.
E.G.: W hat are some o f the things we don’t
know about yet that you would like to figure
out or see someone else figure out?
S.K.: Ultimately the question comes
down to: If this is affecting climate or if it’s
affecting water resources, what can we do
to mitigate it? But
there are enough
imcertainties right
Mow people recognice la the
now in terms of being
able to ask, “Is black
clim ate c o m a w n itj that black
carbon Is second only I® carb®» carbon really
contributing that
d lo ild e la terms o i what It's
much to the melt, or
delag for warm ingr bat
is there so much dust
compared t® cleaning ap
naturally in the
environment that the
greenhoase gases i f s a lot
black carbon isn’t
easier t® be able to redace
really adding that
black carbon emissions.
much more to it?”
S.K.: I though that
we were going to see
the highest
concentrations
associated with
human activity, and
we have more work to
do to geochemically
trace where all the
black carbon is
coming from, but in
the case of what we
did on Mount
Olympus, we know
that it’s from fire.
When we compare
what we saw with one
active forest fire, concentrations were way
higher than what we were naturally seeing
just build up on the glacier during the
summertime. So the wildfire story is really
important around here.
Black carbon is not the only thing that’s
getting deposited on the glaciers. You get
dust, and some of that dust is coming from
natural sources and some dust is being
emitted in increased concentrations because
of land use change, agriculture and that sort
of thing, and then there is also a lot of
organic matter that gets deposited on the
glaciers.
E.G.: Is black carbon the worst o f the three
or is that something yo u ’re still looking into?
S.K.: In terms of how much energy it
absòrbs, definitely, black carbon is way
more absorptive than either organic matter
or dust. Where it gets complicated is that
E.G.: So in the
Northwest, it sounds like most o f the black
carbon is coming from fire. Where is all the
dust coming from ? .
S.K.: If you go on any mountain you have
some rocky outcrops but some of it is
agricultural. In Washington most of the
agricultural land is on the east side, where
it’s drier, but sometimes when the wind
changes direction you can end up with dust
that can move back toward the west where
the mountains are. Roads that exist in the
mountains can be a bigsource. Some of it is
definitely natural, and then some of it’s the
amount of dust that being put into the
atmosphere that is increasing as we
continue to modify the landscape.
E.G.: W hat hypothesis are you working on
with your next project examining the linkage
between wildfires a nd accelerated snowmelt?
S.K.: We know that we’re left with these
E.G.: You’re the expert on black carbon.
W hat’s important? W hat should people know
about?
S.K.: I think more people are hearing
about black carbon, but they haven’t really
known what it is. And now people recognize
in the climate community that black carbon
is second only to carbon dioxide in terms of '
what it’s doing for warming, but compared
to cleaning up greenhouse gases it’s a lot
easier to be able to reduce black carbon
emissions. I don’t want you to leave thinking
forest fires are the only concern around
here, because that’s not the case at all. I
mean especially in glaces hke Seattle and
Portland, and the ports. There’s a lot of
black carbon that’s getting emitted in those
areas, everything from transitioning to more
efficient wood stoves, more efficient diesèl
engines, they’ve cleaned up the type of fuel
being used in some of the ships, that type of
thing.
E.G.: What are the effects o f the increased
snowmelt? Why should we be concerned?
S.K.: The seasonal snowpack is getting
hit hard by temperature as it is. There’s a
couple different things that drive the energy
balance of the snowpack, that drive whether
or not it melts, and temperature is part of it,
but for mid-latitude, albedo (reflection of
solar energy from the Earth and back into
space, in this case, the whiteness of the
snow) can be the dominant factor in terms
of what’s driving m elt In Colorado there’s
an area that gets a lot of dust, and they’ve
been able to show that the snowmelt there
is getting way more impacted by dust
deposition than it is by temperature
increases. That’s really important.
We’re already getting less snow in the
wintertime, snowpack is disappearing
sooner, so you can think of it as well, if
we’re having more black carbon and dust
deposited on our snow, it’s just going to
affect the snowmelt that much sooner. We
have a couple drainages in Washington
where melt water from glaciers can provide
up to 50 percent of the summertime stream
flows, and those glaciers are retreating
rapidly. Right now we continue to rely on
them as a source of water, but once they’re
gone, we no longer have that buffer during
the summer time.