ALAN ALDA (NARRATION) There's no clearer illustration of Alaska warming
up than what you see here -- or rather, what you don't see. Thirty
years ago there would have been sea ice right out here on the Arctic
Ocean. Today, there's none in sight. We're getting a ride along
the coast with Barrow Brower, an Inupiat Eskimo - the native people
of Alaska's Arctic coast. We're looking for the lone inhabitant
of a small island. Last winter Barrow dragged a cabin out here across
the ice for him. BARROW BROWER I think he likes it. He's a lot warmer
I guess. And more protected from the bears.
ALAN ALDA (NARRATION)
It was a surprise to the locals that after 28 summers living in
a tent, George Divoky had not yet been eaten by polar bears. But
George is more interested in a different kind of wildlife. Every
summer he comes here to Cooper Island to study the Guillemots. Guillemots
nest on the island, and catch fish in the Arctic Ocean. This year
they're not doing so well.
GEORGE DIVOKY This guy's over 30 days,
which means he should look much older than this. But he's been one
of the malnourished ones.
ALAN ALDA (NARRATION) Guillemots are quite
common around the world, but this must be their strangest colony.
George first found them here in 1972, nesting in the remains of
ammunition boxes left by the Navy in the 50s. He built up the colony
by carefully arranging the bits of wood to form just the right kind
of nesting cavities. Starting from about 10 adult pairs, the colony
grew to 225 pairs. George's aim was to study the basic biology of
the birds, but it turned out his guillemots would tell a story about
the impact of changing climate. The story is filled with new insights
into nature's reactions to climate change. One critical factor for
the guillemots has to do with the vital flights the adult birds
take out to sea.
GEORGE DIVOKY One of the problems guillemots have
here is that the food source has to be within a flying distance
from the colony. Guillemots are not great oceanic flyers like albatross
and even puffins, and feed in the near shore, typically. So they
go out maybe 15 to 20 kilometers or so and come back with food.
ALAN ALDA (NARRATION) Life at the extremes of the earth has little
room for error. The guillemots arrive at the island as the snow
melts in June, lay and hatch their eggs, feed and raise the chicks,
and leave to go south by September. They need plenty of high-energy
food to be successful, and for this they depend on a small, oily
fish called Arctic cod. Arctic cod, in turn, depend on the shelter
and food they find under the sea ice. So all the guillemots have
to do is fly out to the ice, dive down and grab the cod. It's a
great system - so long as you can find the ice.
GEORGE DIVOKY This
year with the ice being well off shore and this being open water,
large numbers of chicks died in the nest because parents were unable
to find food after the pack ice pulled off shore.
ALAN ALDA (NARRATION)
George has discovered what the adult birds do when they can't find
GEORGE DIVOKY This is a chick that is around 30 days old. He
is one of the lighter chicks on the island for that age. He's almost
290 grams today, which isn't bad. But one of the problems is that
since the Arctic cod are gone, parents are having to feed the chicks
things like this four-horned sculpin. And sculpin actually can maintain
those horns sticking out like that, which makes it very hard for
a chick to feed on.
ALAN ALDA (NARRATION) George knows what happened
in every nest on the island, every day of every summer, for the
last 3 decades. He's tracked 8 successive breeding generations,
and he's beginning to see that some adults are better than others
at finding cod when there's no ice nearby. Maybe guillemots can
adapt to a different climate. He regularly traps adult birds to
see how their health varies, along with their chicks.
This is a great way to catch a bird that you know is the parent
of the chick inside. You're certain that a bird will be walking
over these nooses, within the next half hour of so.
ALAN ALDA (NARRATION)
The parents soon show up to feed their chick. And our camera caught
a rare sight for this year - a lucky chick gobbling down an Arctic
cod. If it had been one of those nasty horned sculpin, the chick
probably would have ignored it. One of the adults got caught as
it left the nest. George's colony has been in steady decline since
the 1990s. Its numbers are now down more than third from their peak.
He can relate the fortunes of the colony directly to the steady
warming that Alaska has experienced in the last three decades. At
first -- in the 1980s -- things went well as the island became snow-free
earlier in the year.
GEORGE DIVOKY When the snow-free period opened
up here and the ice was just offshore, things were very good for
guillemots here, because they had no constraint about the snow melt
or the snow accumulation, and they had prey offshore. As the warming
continued, and now the snow is melting in May, well before they
even want to breed, so even though now they can essentially breed
whenever they want in the spring, they can't raise young as successfully
because the pack ice has receded from the colony.
ALAN ALDA (NARRATION) Nature's thrown in a new, complicating factor.
In the last 2 years puffins - sub-Arctic birds that prefer warm
conditions - have been prospecting for nests in the colony. Puffins
are aggressive, and this year George counted 10 of them attacking
guillemot eggs and chicks. Quite rapid change is underway on Cooper
Island, but it's not just local. Summer sea ice now recedes hundreds
of miles offshore all along the Siberian and Alaskan coasts, whereas
in the 70s it stayed right at the shore line. Of course the impact
can't be confined to guillemots. We just happen to know about them,
thanks to George's unique study. Many other animals - from whales
to polar bears - depend on the Arctic sea ice. And native hunters
depend on many of those animals, in turn. They're all vulnerable,
but right now nobody can be sure to what extent.
JOHN WALSH The Alaska Range is out there. You can see it just about
ALAN ALDA (NARRATION) Climate change has become literally a hot
topic at the University of Alaska, Fairbanks - now a world center
for this research. My first stop was with John Walsh, a meteorologist
who's a sea ice expert. He showed me what computer simulations -
or models - are saying about the future.
JOHN WALSH On this computer we have some computer model output.
ALAN ALDA (NARRATION) Five research groups around the world have
developed computer models of the global climate. This display shows
what all five combined are predicting for Arctic sea ice. The views
look directly down at the North Pole.
JOHN WALSH The winter coverage is over on the left. Summer coverage
is over on the right. And there's a calendar ticking away through
the next century. It's at 2055 right now. You'll notice the summer
sea ice essentially vanishes by the end of the century.
ALAN ALDA (NARRATION) Disappearing ice is one reason the top of
the planet is warming more than lower latitudes. The white Arctic
ice is a global cooling system -- it reflects the sun's heat into
space. But dark, open water absorbs heat. This is self-reinforcing
- ice melts, it gets warmer, so more ice melts, and so on.
JOHN WALSH You're creating a much darker surface where the ice
retreats. That darker surface is able to absorb a lot more sunlight.
It's much less reflective. So there's an extra gain in the polar
regions. It's a gain that the tropics do not have...
ALAN ALDA Oh, because they're already absorbing the heat.
JOHN WALSH Exactly. Yes.
ALAN ALDA And here
you were reflecting the heat back. So the change is going to be
much more pronounced.
ALAN ALDA (NARRATION) Alaska has warmed up
about 4 degrees Fahrenheit on average over the last 150 years --
glaciers really are melting. We're going to spend most of the program
with scientists looking at many remarkable effects of warming -
from guillemots to glaciers. But why Alaska -- and the earth as
a whole - are warming is addressed not by field science, but by
the same computer climate models that produced the sea ice predictions.
The models say it's caused by greenhouse gases, like CO2, that humans
have added to the atmosphere for the last 200 years. This is politically
controversial, of course -- but no longer, scientifically.
GUNTER WELLER Many people have questioned, you know, so how reliable are
these models? Climate is driven by many different factors, including
natural variability -- for example, the energy that comes from the
sun, the so-called solar constant -- but also by carbon dioxide.
So the models have attempted here to model the climate only using
natural parameters. And you can see that in recent years, they've
done fairly poorly. This is the observed record in black here. That's
the observed temperature. You see that it's gone up. For the natural,
in recent years, the computer ensembles, the computer runs don't
do very well. If you only use the greenhouse effect, anthropogenic
factors, manmade influences, then in this region here, the models
do very poorly. You know you can see the color graphs don't coincide
with the observed. But if you combine both, and that's the critical
issue, then they do very well, and then this gives you some confidence
that projections in the future are also probably not all that bad.
ALAN ALDA We're always ready to say, Well, maybe this is a 20,000
year cycle that hasn't really been observed before, and we got through
this, maybe we got through this before, and we'll get through it
again, and it's really not going to be affected by what people do.
How would you answer that?
GUNTER WELLER You bring up a very good
point. Because there are all kinds of cycles, including Ice Ages.
Remember every 100,000 years or so we've had an Ice Age, and then
that was followed by a warm period. At the present we are in a warm
period, and by rights -- the warm periods are only short, 10,000
years or so, compared with 100,000 for an Ice Age -- and we should
move into another Ice Age. But I think, and I think the scientific
community is behind this idea, that mankind, humanity has begun
to interfere with these natural cycles, and instead of moving into
the Ice Age, we'll continue this warm interglacial.
ALAN ALDA (NARRATION) It was over the 10,000 years of the current
warm interglacial that the distinctive natural landscapes of the
north emerged - including the huge boreal forest, or taiga, that's
about a third of the earth's entire forested area. We're going to
see that great change is now coming to these regions, with consequences
for grizzlies and salmon and all the other inhabitants of the north,
people included, that we cannot yet predict. We're in the St. Elias
Mountains which run between southern Alaska and Canada. This region
has a vast, 600-mile stretch of mountain ranges that's sometimes
thought of as North America's Himalayas. In front of us is part
of Jeffries Glacier, an immense river of snow and ice that's sliding
gradually down into the valley.
PAUL CLAUS Ready to roll? Looks like a beautiful day.
ANTHONY ARENDT Yeah. Looks great.
ALAN ALDA (NARRATION) Today, Anthony Arendt and Paul Claus are
going glacier flying. PAUL CLAUS Are you good to go? ANTHONY ARENDT
Yup. PAUL CLAUS Power's on. Everybody's clear?
ANTHONY ARENDT OK, the gyro is zeroed and we're ready for takeoff.
ALAN ALDA (NARRATION) They're flying out of the strip at Paul's
remote hunting lodge. He's an expert bush pilot, who's just started
working with the glacier group from the University of Alaska, Fairbanks.
They head over to Jeffries Glacier, about 40 miles away and 6,000
feet up. These mountains have some of the largest glaciers in the
world. That's because the snow and ice are built up by constant
storms coming in from the Pacific Ocean just to the south. For the
last 10 years the Fairbanks group has been keeping track of a hundred
representative glaciers in Alaska and Canada. They do it with precision
flying. Year after year, they've flown the same tracks down the
glaciers, bouncing a laser altimeter off the surface as they go.
They end up with the exact heights of the glaciers, accurate to
within about 12 inches.
ANTHONY ARENDT I'll start logging right when you cross the pass.
ALAN ALDA (NARRATION) Paul banks the plane round to the center
line of the glacier, while Anthony prepares to log the plane's position
in relation to GPS satellites, along with its exact height above
ANTHONY ARENDT OK, laser's in range right now, 200 meters. Looking
good. And we're logging. 50 meters. 25 meters. It looks good. We'll
just fly right down the center line.
PAUL CLAUS Alright.
ANTHONY ARENDT 50 meters.
ALAN ALDA (NARRATION) They also plot the terminus point in the
valley where the glacier transforms into a river.
ANTHONY ARENDT Pretty distinct terminus on this one.
PAUL CLAUS Oh, I guess. Ice ends right now.
ANTHONY ARENDT Okay.
ALAN ALDA (NARRATION) Back at the
lab there's a lot of number crunching to come up with the latest
height contours of each of their hundred glaciers.
This is our glaciology lab …
ALAN ALDA (NARRATION) Keith Echelmeyer
started the glacier project, and used to do all the precision flying
himself. They found that, compared to the maps of 50 years ago,
the glaciers have shrunk dramatically. And that's not all.
ALAN ALDA Is it really accelerating? What do you mean, accelerating?
BY VALENTINE We find that, on average, every year, that the glaciers
are thinning by a half a meter. Every year.
ALAN ALDA Every year.
BY VALENTINE So. You know. So...
ALAN ALDA You mean, from the '50s
up through the '90s every year they lost an average of a half a
BY VALENTINE Half a meter.
ALAN ALDA Wow.
BY VALENTINE Then,
if you look at the period from the early 1990s to 2000, 2002, that
rate goes up to 1.8 meters per year. So nearly two meters every
year of ice is lost on average, over the entire surface of the glacier.
ALAN ALDA So that really is zipping ahead, isn't it?
Oh, it's zipping ahead, really a lot. And if that continues in the
future, that's what I was saying, a lot of these glaciers won't
ALAN ALDA (NARRATION) The findings translate into staggering
volumes of water added to the oceans - 900 trillion gallons just
from Alaska and western Canada in the last 50 years, enough to raise
sea levels by about a quarter of an inch worldwide. Like Alaska's
other climate changes, all we can say right now is that whatever's
happening is speeding up.
ALAN ALDA Can you tie this acceleration
into some human activity that happened at the same time? Or are
KEITH ECHELMEYER Yeah, we can't do it for sure.
And it's not like the industrial revolution started in the '50s
or something like that. It's not that clear. But, this could be...
it's really interesting. If it's long term, then it means the climate's
really doing something.
ALAN ALDA (NARRATION) We're a few miles
from Fairbanks, right in the center of the state. We'd be on firm
ground here, you'd think.
ALAN ALDA Why does this drop away so steeply
on both sides here?
VLADIMIR ROMANOVSKY Because there was a big
ice wedge here.
ALAN ALDA There was a lot of ice in there?
VLADIMIR ROMANOVSKY Yeah, yeah.
ALAN ALDA And that melted, and then it eroded?
VLADIMIR ROMANOVSKY Yeah, yeah.
ALAN ALDA (NARRATION) Beneath the
boreal forest's lush carpet of mosses and lichens, there's ice -
permafrost. Vladimir Romanovsky is keeping a close and fascinated
watch on the permafrost, because he may soon see something that
hasn't happened here for 8,000 years.
ALAN ALDA So that's it?
VLADIMIR ROMANOVSKY Yes, this is our borehole which goes down 25 meters.
ALAN ALDA (NARRATION) Vladimir maintains a string of permanent boreholes
running north to south through the state. Powered by solar cells,
they're constantly measuring temperatures underground and in the
air, and logging the results.
VLADIMIR ROMANOVSKY So it's a little
bit messy wiring here, but it works well.
ALAN ALDA (NARRATION)
Once a year Vladimir comes by to download the records.
VLADIMIR ROMANOVSKY So the upper number is 16.9, that's the temperature of
the ground surface. And then it's every approximately ten centimeters
is depth, and the deeper one, is minus zero point four, is at one
meter. And down to...
ALAN ALDA Minus zero point four. That's really
close to melting.
VLADIMIR ROMANOVSKY It's warm, yeah. About, approximately
the same temperature is going down to fifteen meters. So at fifteen
meters, it's about minus zero point seven. And this temperature
stay there like this over the year. So upper part, of course, warmer
now because it's summer. But at that depth,15 meters, there is practically
no seasonal changes. It stays like this and it's slowly warming.
ALAN ALDA (NARRATION) We'll come back to Vladimir in a moment, but
first let's take a look right below him. This is the way into a
tunnel driven into the hillside underneath the borehole. The entrance
has to be refrigerated so as not to damage the permafrost inside.
CHARLES COLLINS OK. Here we go into the tunnel.
ALAN ALDA (NARRATION)
The tunnel was built by the Army in the 1960s to develop permafrost
excavation methods. It's a great place to see what permafrost is.
The forest floor's now about 50 frozen feet above us.
Does the permafrost keep going down?
CHARLES COLLINS The permafrost
keeps going down. Another... maximum about two hundred, two hundred
and fifty feet in this area, depending on the local terrain.
ALAN ALDA So we're right in the middle of it.
CHARLES COLLINS We're right
in the middle of the permafrost in this tunnel.
ALAN ALDA (NARRATION)
The walls are made of wind-blown silt, bound with ice, that filled
up the valley during the hundred thousand years of the last Ice
Age. There are ice wedges, formed when surface water drained down
and froze. This ice has been here at least since the end of the
Ice Age, 10,000 years ago. Then the area became as warm as it's
ever been since. But Vladimir has his eye on the future.
The concern of scientists is that it'll get worse, it'll get warmer
than it was 10,000 years ago.
VLADIMIR ROMANOVSKY Warmer than it
was 10,000 years ago.
ALAN ALDA And the reason for that concern
is what? Is it that you just see the trend going and you don't see
any abatement in it, it's not slowing? How do you know...
VLADIMIR ROMANOVSKY It's actually accelerating, yeah. It's accelerating.
ALAN ALDA It's accelerating. Ah, so, as long as it's accelerating...
VLADIMIR ROMANOVSKY And the scale of changes, of course, is very
different. Because the scale of changes in that time, of course
we have some kind of...
ALAN ALDA What do you mean, scale of changes?
VLADIMIR ROMANOVSKY Well, ah, the changes in temperature for the
last, say, century, and especially for the last twenty, thirty years
was very... All changes were very rapid, and if this trend or changes
in temperature will continue at the same rate, we actually will
cross this threshold in another fifteen years.
ALAN ALDA (NARRATION)
If we do cross that threshold, at some point the ancient permafrost
will begin to break down. That will introduce a whole new factor
into global climate calculations.
CHARLES COLLINS These roots are
from grasses that were growing at the surface here, oh about 30,000
years ago, and they're just preserved in the permafrost. So even
though they're 30,000 years old they're just very fine organic material
just trapped in the permafrost.
ALAN ALDA (NARRATION) The Ice Age
roots and sticks never had a chance to decompose - they were just
frozen in place. It's a warehouse of organic material that, once
thawed, will release the CO2 it's made of.
VLADIMIR ROMANOVSKY If
this material will be exposed to warm temperatures, and together
with erosion, it could happen very, very rapidly. So all this --
not all, but a pretty significant part of this organic material
will turn into CO2.
ALAN ALDA Is that measurable? Can we make a
prediction now about what that's liable to do?
We can estimate. There is estimations of the amount of carbon in
the soil in the frozen state. And this estimation show a very significant
number, actually it's the largest number -- it's much more than
growing vegetation on top. It's much more organic matter here. And
compared to CO2 concentration in the atmosphere, it's also comparable
numbers. So if all this organic matter will go as CO2, so we can
double actually CO2 in the atmosphere.
ALAN ALDA (NARRATION) So
thawing permafrost could greatly reinforce the warming of the global
climate. We're heading out to the Tanana River flats, again in central
Alaska, where we can see what disappearing permafrost looks like.
This is 800 square miles of meandering channels, wetlands, and low-lying
forest. It's prime moose habitat, too. Since the last Ice Age, there's
been permafrost under everything here except the large river channels.
At least, there was until about two hundred years ago. Before then,
most of the flats would have been forest, growing on a permafrost
plateau just above water level. Now about half the area consists
of these waterlogged fens, covered in thick floating mats of vegetation.
You can see this transformation continuing today in the remaining
forest areas. They call them "drunken forests" - collapsing as the
ground disappears beneath them.
ALAN ALDA I see a lot of trees tipped
TORRE JORGENSON Yeah, well welcome to the twenty first
century in central Alaska, where the ice rich become the poor. And
then I've got to present you with a stick. And you need this for,
if you punch through the floating mat out here. It's a way to get
ALAN ALDA So, you're serious about that.
Oh yeah. These trees through here are about 65 years old. So we
can see that, from this age structure, that most of this collapse
has happened just during the last thirty years. This is where you
start using the stick as a life-saving device. And you can feel
a little bounce to that mat so you know that we're really floating
on water out here.
ALAN ALDA (NARRATION) I'd really prefer some
nice, solid permafrost to walk on.
TORRE JORGENSON See this is what
happened to the last guy that came out here. He ended up here...
ALAN ALDA (NARRATION) When I made it through the floating buckbean
and horsetail, Torre Jorgenson explained that where we were now
standing had actually been a wetland fen only a few hundred years
ago. It shows that there are natural cycles in the climate, and
it's been warm enough here in the past to thaw the permafrost.
TORRE JORGENSON This is old fen peat developed from buckbean and horsetails,
so this tells us that this area used to be a fen at one time. So
we've gone through a cycle of it being a fen, becoming uplifted
into this permafrost plateau, and then becoming forested by birch
trees. And now it's starting to degrade again back into fen.
ALAN ALDA (NARRATION) It's now even warmer here than when the area was
last a fen. You can see the process of degradation. As the ice in
the ground melts, the soil shrinks, so the surface sinks. The trees
become waterlogged and die, and eventually the patchwork of sink
holes coalesces into one big wetland. Well, I hadn't fallen through
the floating mat, so Torre thought he may as well try me out on
drilling a permafrost borehole. We're going down below the level
where any annual seasonal variations would be seen.
OK let's take a look right there and extract what we've got inside.
OK, so we've got a little core coming out. It's kind of got slop
along the outside of it from drilling, but we're gonna clean that
off. So look at that. That's all peat running right through there.
And then we're getting into the silts. They're all part of this
loess deposit. And just look how wet and sticky that is. That's
a real good indication that this is already degrading.
(NARRATION) Since the area was last a wetland, a couple of hundred
years ago, the climate briefly cooled, and this ice was formed.
Then a steady warming - about 4 degrees Fahrenheit so far - began
to switch it back to wetland. That's all it takes for the transformation
ALAN ALDA If the present trend continues, how much higher
would the average temperature be?
TORRE JORGENSON We would anticipate
that within 50 to 100 years, that temperatures will increase on
order of 3 to 5 degrees centigrade -- so about 5 to 8 degrees Fahrenheit.
ALAN ALDA Well, wait a minute. So from what you're telling me that
means that all the permafrost will melt.
ALAN ALDA (NARRATION) The
Tanana flats are especially sensitive to change because the land
is already relatively warm, thanks to the waters of the nearby Tanana
River. If the predictions of warming coming from the computer models
are correct, then the future of this area is pretty clear.
ALAN ALDA What's worrying you is the models that suggest that this is
going to keep going, this warming. Is that right?
That's a good interpretation of it, so my initial concern is that
this landscape is very sensitive to small changes. So if we add
just a one-degree change, we're losing our permafrost in this area.
And we're already, have been losing substantial amounts in the last
fifty years with just a half a degree or a one-degree change. So
imagine what would happen if you add three degrees or five degrees.
It's way beyond the capacity for permafrost to exist in this area,
so it'll be fairly quickly eliminated.
ALAN ALDA (NARRATION) Alaska has permafrost under 85 percent of
its land area. Sensitive parts like the Tanana flats will be first
to go, but there could be very large-scale disruption. This is a
Canadian projection showing that the permafrost line could move
north by several hundred miles during this century, again if those
computer predictions of warming are right. Everything that depends
on solid foundations - from forests to roads and buildings - will
be affected. Now we're going to look at another kind of change.
Alaska is a largely pristine land, with rivers, streams and lakes
as far as the eye can see. What's happening to them is not a prediction
- it's here and now.
DAVE VERBYLA The question is, Where in Alaska is it getting drier?
And what Brian's found is -- most places in Alaska, it's getting
ALAN ALDA (NARRATION) Brian Riordon, who's Dave Verbyla's student,
has been looking at ten representative areas around the state. He
started with government maps produced in the 1950s.
BRIAN RIORDAN What we're attempting to do is look at water bodies
across these maps and see how they've changed from the 1950s to
the present day.
ALAN ALDA (NARRATION) In the 1950s, lake 405 was 180 acres. Here
it is again in a 1980 picture - it's down to 28 acres. It's the
same with the surrounding lakes - the outer rings are the 1950s,
the inner rings 1980. It seemed like a clear result, but look at
the lake at the bottom right. The original photograph the map was
based on, shows a patchy wetland at best. The maps were filled with
BRIAN RIORDAN What that led me to have to do is go through, order
all these black and white photographs which we have right here,
for each one of these areas, and go through and recreate each one
of these water bodies.
ALAN ALDA That sounds like it would take
you fifty years to do that. That's a lot of work.
ALAN ALDA (NARRATION)
So far Brian has re-traced about 17,000 water bodies, and he's extended
the comparison later in time, using recent satellite pictures. Here's
lake 405 again. By the year 2000 - outlined in blue - it had shrunk
to 10 acres. The startling overall conclusion is that, just in the
last 50 years Alaska has lost on average 15 percent of its open
water area. At this point we don't really know why, but it's probably
a combination of increased evaporation from warming, and drainage
away through cracks in degrading permafrost. I'm with Glenn Juday,
a leading expert on the boreal forest - which around here is not
GLENN JUDAY OK now we're entering a sick forest.
ALAN ALDA (NARRATION) The boreal -- or northern -- forest rings the globe
in a huge band running through Canada, the US, Russia and Scandinavia.
It's about one third of the planet's total forest area, and easily
the largest in North America.
ALAN ALDA Is this alive or dead?
GLENN JUDAY This one is alive but it's been attacked by spruce bark beetles.
You can see in the lower section here there's pockets of hardened
sap. When the wood boring beetles went into the tree, the tree tried
to defend itself by flooding those holes with pitch. When the trees
are weak, the beetle attacks are more successful.
ALAN ALDA (NARRATION)
In recent years, these trees - they're white spruce - have been
weakened. Especially heavy winter snow falls have simply overloaded
the tops and broken them off. And in summer there are more insects
around, just because it's warmer.
ALAN ALDA So that snowfall, that's
a natural event that occurs all the time, right?
GLENN JUDAY Yes
it can be, but it happens to be associated with warmer winters.
But it's the frequency and the magnitude and the intensity of these
conditions that is very unusual right now and reflects the strong
influence of the climate warming, that it's having on the health
of these forests.
ALAN ALDA (NARRATION) Trees contain a history
of their lives, in their annual growth rings. During 20 years of
study, Glen Juday has drilled thousands of tree cores at Bonanza
GLENN JUDAY We use this high tech device here to keep everything
all solidly in place. You're looking at about, at least a hundred
and fifty years worth of growth. We can see that the rate of growth
was very rapid in the early years -- big rings. And it slowed down.
Well that's pretty typical of most trees, just from the geometry
of the growth. And then there's some really narrow rings here in
the late twentieth century. Suggesting that it's rate of growth
in the last couple of decades was not very good. And in general
that's the signal that we find in these trees.
ALAN ALDA Why don't
trees grow well in a warm summer? You would think that warmth would
make things grow.
GLENN JUDAY What we've discovered is that it's
a temperature-induced drought stress.
ALAN ALDA Drought? It's drought,
GLENN JUDAY They run out of water.
ALAN ALDA (NARRATION) So
far we've had winter snowfall, insects, summer drought … and now
GLENN JUDAY Here we go. This is a tree that's being
attacked by the spruce budworm, and you can see the tips of the
growing points here, where buds used to be. Now repeated episodes
of this, enough years in a row, will just kill the tree. The interesting
thing here is, the budworm, as far as we know, was never here before.
And number two, it's one of these temperature-controlled insects.
ALAN ALDA Where did it come from?
GLENN JUDAY South of here, in
Canada, south and east of here. And it was just too cold for it
to live here until the last few years.
ALAN ALDA (NARRATION) We've
jumped a couple of hundred miles south, to the Copper River valley.
Alaskans can still enjoy the abundance of nature that surrounds
them, but here it's against a shocking background. On the slopes
above, the boreal forest largely consists of dead spruce trees,
killed by bark beetles. With a string of warm summers in the 1990s,
there was a beetle population explosion. The die-off stretched hundreds
of miles through Canada and Alaska - the largest forest insect attack
ever recorded on the continent. Glenn Juday has been growing increasingly
alarmed at what he's seeing in the boreal forest.
GLENN JUDAY What
we're looking at is aspen leaf miner damage. It's called the leaf
miner because it makes these tracks by feeding on the green tissue
between the outer and lower layers of skeleton tissue. This is another
one of those insects that's triggered by warm temperatures and stress
on the trees.
ALAN ALDA (NARRATION) This insect also is widespread.
The attractive light gray color of the Aspen leaves signifies leaf
miner damage, and it's everywhere.
ALAN ALDA Why do we care about
GLENN JUDAY The boreal forest in Alaska has only got
about four major species. This one has a major insect problem. The
white spruce has major insect problems. And paper birch has major
insect problems. So that only leaves the black spruce which is not
a very productive tree. So if you take four major species and hit
the three most productive of them with major insect problems, you've
really made a hit to the amount of growth that's taking place in
the forest as a whole.
ALAN ALDA (NARRATION) Glenn likes to take
visitors to a popular local overlook on this bluff - but not to
admire the view. Here's the bluff from below. It's actually a dry
grassland -- not usually part of the boreal forest.
We may be looking at the future here, because this environment is
so warm, and so dry because of its steepness of slope here.
ALAN ALDA (NARRATION) A little warmer, a little dryer, says Glenn, and
the forest will give way to grassland.
GLENN JUDAY You can see,
we're just this close to being too warm and too dry for forests
ALAN ALDA (NARRATION) Will Alaska's - and the world's
--- boreal forest turn to grassland? Of course we don't know, but
we do know enough to say what would happen if recent trends continue,
and those computer climate models are right.
ALAN ALDA What do you
think is going to happen to this forest if these temperatures continue
GLENN JUDAY They're going to slow way down in growth. They're
going to be hit by insect attacks that'll be more and more severe.
And with a sufficient amount of warming, they won't be able to grow.
ALAN ALDA (NARRATION) We've jumped 250 miles north to the tundra
of Alaska's North Slope. Like the boreal forest, there's a ring
of tundra around the top of the globe. Tundra simply means "treeless"
in Finnish. Thirty years ago, an isolated field station was set
up here at Toolik Lake. The aim was to do basic long term research
on how the tundra works - the plants and animals, land and water.
But like George Divoky and his guillemots, many scientists who come
to Toolik have found themselves studying the changing climate, through
the lens of their various specialties. Arctic ground squirrels are
a good example. They fatten up in the brief summer, then hibernate
underground for 8 months of winter. As spring approaches they feed
on underground food stores, to be ready for mating just as the snow
begins to melt. That's when they emerge above ground once again.
Brian Barnes has been studying the ground squirrels around Toolik
for 15 years, working out how they achieve this amazing feat of
survival. He's an expert on the biology of hibernation, but his
studies are also beginning to show what happens when climate changes.
Brian and his student, Ryan Long, closely follow the fortunes of
about two hundred squirrels. In summer it's easy to keep track of
the squirrels - they're partial to carrots. Ryan walks the trap
line twice a day, bringing squirrels in for checkups.
RYAN LONG You look familiar.
ALAN ALDA (NARRATION) To see what's going on for most of the year,
when the squirrels are underground, they've devised a high-tech
solution. This is ground squirrel surgery at the Toolik Field Station.
The squirrel's going to get an implant.
BRIAN BARNES Number 939.
ALAN ALDA (NARRATION) It's a data logger
that will automatically record the squirrel's body temperature for
the next year. Next day the squirrel, fully recovered, goes back
to his burrow system out on the tundra. They'll re-trap him next
summer, and read out the temperature records. The records show that
the squirrels wake up underground in March, then eat their stored
food. The big day comes on May 1, when mating starts above ground.
But lately spring conditions on the North Slope have not been what
the squirrels expect. Weather patterns in an overall warmer Alaska
happen to make spring here colder. BRIAN BARNES The warming of the
annual average temperature is really, is accompanied by quite cool
and wet and even freezing springs.
ALAN ALDA (NARRATION) Timing
is everything in the short Arctic breeding season, and the squirrels'
internal clock doesn't work so well now. BRIAN BARNES The ground
squirrels are emerging and initiating reproduction. But it continues
to snow and plant life is slow to become available, so a lot of
the litters have been lost.
ALAN ALDA (NARRATION) Squirrels are
a key prey species on the North Slope - food for grizzly bears,
eagles, foxes and wolves. Right now we have no idea whether, or
how, any of these animals - squirrels or their predators - will
adapt to changing conditions. We're in a basement at Fort Wainwright,
Fairbanks. On the shelves - 3,000 priceless, high-quality aerial
photographs from the 1940s.
KEN TAPE The original photographs were
taken as part of the exploration of what is now the National Petroleum
ALAN ALDA (NARRATION) It's a detailed portrait
of the North Slope 60 years ago.
KEN TAPE Alright Ed, if we could just head over to the Itkillik,
we'll fly a line running north on the Itkillik.
ALAN ALDA (NARRATION) Ken Tape's group is
now retracing the steps of the Army reconnaissance crews who took
the photographs. Fortunately the crews' meticulous records of their
original flight tracks still exist, simplifying the task of getting
back to the same places.
KEN TAPE So go ahead and cross all the
way over the river. Maybe go a quarter mile past the river, and
then head south, altitude about a hundred feet.
ALAN ALDA (NARRATION)
The idea is simple - take new pictures of the land, and see what's
KEN TAPE Great if you could, just come to the right a little
ALAN ALDA (NARRATION) Over the last 3 years, Ken's flown thousands
of miles, crisscrossing the North Slope and re-photographing the
landscape. So far he's got 270 good matchups.
ALAN ALDA This is
now, and this is then.
KEN TAPE Yeah, this is 2002. And this is,
I think, 1948.
ALAN ALDA Well et me see if I can see what's different
ALAN ALDA (NARRATION) At first glance, you might say the vegetation
has maybe increased a bit. The researchers wanted to be rigorous
about it, so they divided every picture into grid squares about
50 yards long on the ground. Then using convenient landmarks like
large rocks, they matched each old and new pair of grid squares,
and estimated the vegetation cover. Using this method, it's become
clear that the land's now a lot shrubbier.
ALAN ALDA Do you have
a percentage of change -- this much percentage more shrubs than
we had before?
KEN TAPE There's probably a thirty or forty percent
increase in shrubs, which is huge.
ALAN ALDA (NARRATION) Matthew
Sturm started the repeat aerial photography project. He's an expert
in snow and how it interacts with land. Shrubs and snow may sound
like specialized subjects, but to Arctic scientists they are of
vital interest. That's because, just like sea ice in summer, snow
and shrubs govern how well the Arctic radiates the earth's heat
into space in winter. Matthew lives in the forest outside Fairbanks,
but his heart's on the treeless tundra.
MATTHEW STURM These are
related very closely to the alder that we're seeing increasing on
the North Slope. I like these because they kind of remind me of
where things might be going up there. They're very large, and while
we don't see any quite this large up there, maybe some day we will.
ALAN ALDA (NARRATION) No single result has galvanized Arctic scientists
like that of the shrub photography study. It's shown that Alaska
really is changing. What we thought was a timeless landscape isn't
MATTHEW STURM To date we've repeated about 270 photos.
They span all of northern Alaska. The photos show, almost every
one, some amount of positive change. In other words, in each of
the photos we're seeing increased shrubs -- in some, very dramatic,
some other places more modest. But the big finding is, everywhere
we look there are more shrubs today then there were 50 years ago.
KEN TAPE In less than one human lifespan, we are witnessing geologic
time. I mean, we're witnessing changes in our lifespan that are,
I think, dramatic given the fact that we're looking at 50 years.
50 years in geologic time is the blink of an eye, and we don't know
how this is going to fit into the big picture, but this is a fairly
ALAN ALDA (NARRATION) Here's why that change is
important. Shrubs in winter trap the snow, which insulates the land,
so it gets warmer. And if they stick up above the snow, the shrubs
also make the land darker, so it reflects less heat. This is a big
deal, says Matthew Sturm.
MATTHEW STURM The whole Arctic system
will begin to change. The land, the tundra, won't function the same.
It will potentially absorb more heat, reflect less sunlight, and
that'll feed back into this whole system of warming. So it's the
bigger picture really that we're kind of thinking about, because
I think humans will be able to adapt to a change from tundra to
shrub, and so will many animals. But, as that very large system
starts to change, it has both local and global implications.
ALAN ALDA (NARRATION) We're back at Toolik Field Station on the
North Slope. For many years, researchers here have been tending
some unusual greenhouses. The tundra is by no means barren, as we
sometimes think. It's filled with mosses, grasses, flowers, lichens
- about 1700 species altogether. The shrubs -- like alder, willow
and birch -- are mixed in, but in these harsh conditions they stay
low and don't dominate. Toolik scientists tend to do a lot of walking.
This is Donie Bret-Harte coming up to the greenhouses. The greenhouse
experiment is to see how the tundra reacts to long-term warming.
Inside the enclosures it gets a few degrees warmer in the growing
season. They also add a little fertilizer, because if the whole
landscape does warm up, the soil would release more nutrients. After
15 years, the result is dramatic.
SYNDONIA BRET-HARTE This is tussock tundra that's been warmed and
fertilized for fifteen years. And you can see that what's in here
is mainly just one species. It's the dwarf birch. But now it's over
a meter tall, it's very bushy and it's pretty much out-competed
all the other plants.
ALAN ALDA (NARRATION) Warmer conditions happen to favor the shrubs,
which then take over. Although it was started long before Matthew
Sturm's aerial photography project, this has become the key experiment
which explains why the tundra is getting shrubbier. It's because
it's getting warmer.
SYNDONIA BRET-HARTE We do know that over the past fifty years,
from the repeat air photo studies, that the shrubs have been expanding
across the North Slope -- not only birch but also alder and some
other shrubs. And so, I can't really tell you the speed with which
it might look like this but we think that if the climate was to
warm dramatically enough, you would end up with something like this
ALAN ALDA (NARRATION) We're going to look at one more change that's underway
on the tundra. The studies began at Barrow about 30 years ago. Like
increasing shrubs or disappearing sea ice, this change also has
global implications. In the 1970s, Walt Oechel was measuring CO2
gas on the tundra. Growing plants take in CO2, while decomposing
soil gives it off. Cold tundra soils don't decompose much, so historically
the Arctic has been a net absorber, or sink, of CO2 from the atmosphere.
It's been that way for 10,000 years, and in the 1970s, Walt found
that's exactly what was happening. Then 10 years later he did some
WALT OECHEL We found to our great surprise that
the tundra was already losing carbon dioxide to the atmosphere.
So that by the start of these experiments, which was in 1982, the
tundra had already warmed and dried enough, that its historic role
as a carbon sink had reversed and changed. It was now losing carbon
dioxide to the atmosphere. That was totally unexpected.
(NARRATION) People had thought that faster plant growth in a warmer
Arctic would absorb the extra CO2 from increased soil decomposition,
but apparently not. The tundra and boreal forest soils store as
much carbon as the entire global atmosphere holds.
WALT OECHEL Together
these two systems contain about 450 billion tons of carbon, in the
soil systems. So if a significant portion of this were lost to the
atmosphere, that would be a huge amplification of the CO2 in the
ALAN ALDA (NARRATION) That in turn could greatly amplify
global warming. Walt Oechel is setting up a series of instrument
towers to continuously monitor CO2 gas above the tundra. He runs
an instrumented plane to check CO2 over large areas. The Russian
and Scandinavian Arctic are also now giving off CO2, so he's working
with their scientists, too. We have to fully understand this big
potential threat to the climate, he says.
WALT OECHEL We know that
the tundra now overall is losing carbon to the atmosphere. What's
much harder and less certain is how the tundra's going to change
over the next 50 or 100 years. And that's really the crucial question.
ALAN ALDA (NARRATION) Alaska and the Arctic are in the grip of change.
No scientist can say right now how it will end up, but it's clearly
going somewhere new.
MATTHEW STURM This is an Arctic where instead
of sea ice existing in the summer we have an open ocean in the Arctic
basin; an Arctic with a much, much smaller icecap in Greenland;
an Arctic with considerably less permafrost, or permafrost that
is not completely frozen in the winter so it has a ground water
system; an Arctic with shrubs, rather than tundra. So it's kind
of a vision of a different Arctic, one that's warmer, shrubbier,
less ice-covered, and consequently not nearly as good at getting
rid of earth's heat as the Arctic we know today. We don't really
know if that's where the state is at, but that's what people are
starting to think about, and trying to understand if that's where
things are headed.
ALAN ALDA (NARRATION) We made our program in
Alaska, but you can be sure that guillemots, ground squirrels, forests,
glaciers and tundra are changing all over the north. Many scientists
said to us that the north is the canary in the coal mine - the harbinger
of things to come in the rest of the globe. Whether we can do anything
about that -- or care to -- is another story entirely.