[ Music ]
>> Today and maybe you'll all wish you had brought some
of your kids and family members to this talk.
We have with us a colleague from just
around the beltway, Bruce Molnia.
He's going to talk about baked Alaska
and changing climate, changing landscapes.
I first heard about Bruce and his work in an article
in the Smithsonian Magazine back in August,
which was also called Baked Alaska to catch your attention
and it talked about some of the research he's been doing
over the last 30 or so years in Alaska and it was augmented
by a number of the photographs he's taken, this being one
of them, the one that you see up on the screen right now,
which is a comparison I believe of the New York glacier
between 1941 and 2004.
So we invited him to give and a talk and he graciously accepted.
So here he is today.
But occasionally we hit these things.
This wasn't by any sort of planning
and Gary Presser is going
to put another view graph right now for you to look at.
This is Time Magazine this week.
You must have known we made this invitation.
"Be worried", it says.
"Be very worried."
If you can't read the rest of it, it says,
"Change isn't some vague future problem.
It's already damaging the planet at an alarming pace."
And I love that graphic as well.
It's a lonely polar bear wondering
where he's going to go next.
A colleague of mine had been to Alaska recently and she told me
about her experience there when she was on a tour of the glacier
and the tourist person said, "You know when you stand here",
as they were standing some place nearby,
"This is where the glacier was in 1980."
Of course the glacier was off in the distance.
So then they walked a bit and the guy said this is
where the glacier was in 1985.
And so they continued to walk towards the glacier
and the impressive thing about it was
that the glacier was still a long way off and that was
when my colleagues said that she realized for the first time
that these are affects that you really see in real time.
Bruce is a research geologist, or as he likes to call himself,
a glacial geologist at the USGS,
the United States Geological Survey in Reston, Virginia.
He has also been located in Menlo Park during his career,
but basically has spent 30 to 35 years with USGS.
He has a bachelor's degree in Geology from Harper College,
now the State University of New York in Binghamton.
He was a pre-med major interestingly enough in college
until he got a summer job with Columbia University
on a research ice breaker in the Antarctic.
How would you like that for a summer job?
Well most of us would.
In fact, it impressed him so much when he went back
to college he said, "I think I want to be a geologist."
So he got his bachelor's degree in geology.
He then went back to get a master's degree
from Duke University in marine geology and a PhD also
in marine geology at the University of South Carolina.
Bruce has authored more than two hundred articles.
Often times the articles consist of maps and he's authored
or edited several books as well,
one of the more popular ones being The Glaciers of Alaska.
Another book was Glacial Marine Sedimentation.
He's also authored the Alaska chapter
of the satellite image atlas of the glaciers of world
and I think maybe you'll see some photographs
from that atlas in the talk today.
He is also the forum editor of GFA Today, which is a newspaper
of the geological society of America.
And in that capacity he's authored more
than one hundred monthly columns
on various issues affecting geology
and in particular glaciers.
He's done research for 35 years and has been
on field expeditions in all sorts of climates, equatorial,
temperate, subpolar and polar regions, but the focus
of his research has for the most part been Alaska.
And he really has a love of Alaska,
which has motivated most of his research.
He has other positions simultaneous
with his position at USGS.
He's an adjunct professor in Duke University
in the School of the Environment.
He's been a research associate at the University of Ohio,
I'm sorry Idaho, where he's been working
on a Juno ice field research project.
He's been I think significantly also a senior legislative fellow
for Congressman, Kurt Welden of Pennsylvania.
He did this detail from USGS for almost four years
from about 2000 to 2004.
And as part of that assignment he was responsible
for developing and organizing
and coordinating the oceans caucus,
which he tells me still exists and it was a group of people-
congressmen- who were really interested
in legislation affecting oceans.
While at USGS he's also been acting chief
of international programs and he has spent two years also
as the senior program officer of the NRC academy
of science board on polar research.
Would you join me in welcoming Bruce Molnia.
>> Thank you very much.
As you can see my title is Baked Alaska: Changing climate.
And as soon I get the buttons organized here, what we're going
to do for the next hour is take what I hope will not be much
of a world wind tour but a very rapid look at the last 20
or so thousand years of climate and glaciers on earth,
what glaciers are, a little bit about current climate, change,
global climate change, regional climate change
as it affects Alaska.
Then we'll at the question what's happening specifically
in a region by region basis throughout Alaska.
Is Alaska baking?
And then we'll focus into Glacial Bay National Park,
one of the areas that I've spent quite a number of years working
and in the last decade my focus there has been
on reoccupying locations
where photographs have been made anywhere as early as the 1880's
and going back and finding the same location,
which in many cases, in fact
in almost all cases we have no information on the old photos
as to where they're from.
It's a matter of recognizing landscapes going back
and saying this is where that picture was taken
and then taking a new shot and doing both a qualitative
and quantitative assessment of the changes between images.
So I hope we'll make in the hour,
but we'll certainly have a lot of fun trying.
I'm probably the only earth scientist in the room
and so I don't want to insult your intelligence but I want
to talk to you about what we refer
to quite commonly as the earth system.
And we talk about the earth being different
from almost every other body in our solar system
because it consists not only of the lithosphere,
but it has an atmosphere, a biosphere,
hydrosphere and a cryosphere.
The common ingredient, the common entity
in all of these is water.
And water is also the reason we have glaciers
and it's also the reason we have climate change.
The hydrologic cycle and the climate cycles are directly
based on water.
And we're going to do is look at where water on earth is
and see how important glaciers are in terms
of this total water volume.
The parts of the earth system that we're going to deal
with this are this glacier ocean coupling in here and the changes
in land features, vegetation and heat budget due
to both climate change and changes in snow and ice.
And so if I had several more hours we could talk
about a large number of other interactions but that's time
for another interaction between us.
Let's focus in on glaciers and climate change.
97.2 percent of the earth is salt water.
Everybody knows that.
The oceans are the biggest reservoir of water on earth.
Another 2.8 percent of water on earth is fresh water.
Three quarters of that is glacier.
And so glaciers are the second largest reservoir of water
on earth than the largest reservoir or fresh water.
I'll throw in a couple of simple analogies,
but if there a thousand drops of water on earth, 972 would be
in the inland seas, 21 would be in glaciers, 6 in ground water
and soil moisture, less than 1 in the atmosphere,
less than 1 in lakes and rivers and less than 1
in all living plants and animals.
And so as glaciers melt where do you think this water goes?
It goes into the ocean system and it disappears
from the other 7 percent of the earth's water.
So as glaciers change the amount of [Inaudible]
and irrigation water also changes dramatically.
And as population increases there's going
to be a smaller quantity of water available
for handling the needs of growing earth populations.
Now other things about water that are interesting,
water as it freezes forms hexagonal crystals.
And the crystals have all of the properties of the mineral.
Glacier ice is a mineral, definite physical
and chemical properties.
Among these is the fact that glacier ice, which has a density
of .917 is about 8 percent less dense than fresh water
and significantly less than salt water.
So when glacier ice enters the ocean, it floats.
And also as you'll see as glaciers are thinning
and lose contact with their beds because of their buoyancy,
many glaciers are rapidly breaking up and falling apart.
The same is true of the ice shelves in Antarctica.
And this is a function of the density of the ice as well
as the temperature change.
But when you remove that ice from the Antarctic,
it doesn't have a major impact on sea level
because it's already sitting in the ocean.
But there's a major impact of the flow rate
of the ice coming off the continent.
And one of the biggest things that we're concerned
about isn't the increasing rate of melting of glaciers,
which is significant, it's the increasing rate of glacier flow
into the oceans from land into the oceans without melting.
This flow of ice, the capping of icebergs
where there is a direct transfer of larger volumes of water
from the land into the ocean, then anything
that we're looking at through melting.
Now a glacier, simple definition,
peroneal accumulation of ice, snow, rock, sediment
and liquid water, liquid water is important.
There are two kinds of glaciers that we talk about.
We talk about polar glaciers, which are such as the glaciers
in central Greenland and the Antarctic.
At the South Pole you've got 3000 meters of glacier ice,
mean annual temperature of minus 40 degrees.
You can anything to earth temperature
and it will still be 10 or 15 degrees below the melting point
and showing no impact of changing climate.
Temperate glaciers like these two mean annual temperature
of the ice about 0.05 degrees C. So a small amount
of temperature change has a dramatic impact
on both the amount of fresh water in contact
with this temperate frozen ice and on the rate of melting.
A small amount of climate change impact the temperate glacier
And it's this temperate glacier ice
that had been our biggest focus.
If you melt all the temperate glaciers on earth as you'll see,
you can contribute up to about a third
of a meter of sea level rise.
If you melt all the polar ice, you're looking at close
to 80 meters of sea level change.
So, .9, excuse me a second did I miss one, no.
Okay, .7 percent of the earth's ice is in temperate areas
and by temperate we mean areas
where the mean annual temperature is within a fraction
of the degree of the melting point.
And so glaciers in all seven of these areas, six continents,
North America, Asia, Europe, South America
and Africa are melting.
In fact, we'll lose almost all the ice in Africa probably
within the next 50 years.
New Zealand's glaciers are growing.
In fact, I spent two weeks in New Zealand a month
and a half ago and I was surprised to learn
that there is a significant increase in glacier growth
at higher elevations in New Zealand
because as it's been warming there has been increased
precipitation at higher elevations and the glaciers
on Mt. Cook, the highest mountain
in the country have been thickening and have been studied
for a number of years as are the adjacent glaciers thickening.
In [Inaudible] we're losing all the glacier ice and in fact,
it may be just a matter of a few years before it's
So going back to that thousand drop of crystal analogy
if you look at all the glacier ice
on earth 91.4 percent is in Antarctica.
7.9 percent or 79 drops are in Greenland.
Approximately 4 are in North America and one of those being
in Alaska, about 2 are in Asia and less than 1 in all
of the other glacier covered areas on earth.
Now it's this 7 drops here that are the temperate ice on earth.
It's this 93 percent, this 930 drops of --
I'm sorry 970 drops that are the remaining polar ice
that will have minimal changes because of melting
but dramatic changes perhaps because of draw down.
So, as I've mentioned a small change
in temperature can have a dramatic impact
on temperate glaciers.
And when we talk about temperate glaciers in some
of the photos you'll see, don't be surprised to see liquid water
on the ice, in the ice and under the ice.
Glaciers are quite fractured,
they're quite broken, they're quite porous.
They're conduit systems.
There are streams both in, on and under
and water moves freely through glaciers.
Now one of the things that we're seeing in Greenland,
and that's what this article in Time Magazine
and in fact this week's cover article
in Science Magazine are focusing on an increase in the velocity
of glacier -- or outlet glaciers,
increasing the velocity of glacier ice in Greenland.
And what you're looking at there is probably directly related
to the fact that more melt water is lubricating the bed
of the glacier reducing the frictional forces
that normally restrain glacier flow and contributing
up to a half an order magnitude increase in velocity.
And so those are the kinds of things that we're now talking
about when we talk about the impacts
of changing climates on glaciers.
Not only is melting an issue but we're now concerned
about a number of other types of changes in flow dynamics
that may even have more dramatic impacts on the interactions
between glaciers and sea level.
Now Alaska even though it's less than one drop out of the four
in North America has over 75 thousand square kilometers
of glacier cover.
The largest glaciers, that being the Bering and Maspina,
each are about 5 thousand square kilometers.
Now that may be meaningless numbers to you but if you were
to take a map of the Bering glacier and superimpose it
on the same scale map of the east coast of North America,
the Bering glacier would go from Philadelphia
to the White House lawn.
It's that long.
It's 140 miles long.
There's enough ice in the Bering glacier to cover the state
of Maryland covering to a depth of about 30 feet.
These are insignificant glaciers in terms of comparison
with the Polar Regions, but they are used volumes of ice.
In fact, one of my calculations is that there's
about 45 thousand cubic kilometers of water tied
up in the glacier ice in Alaska.
And what does it amount to?
If you would melt it, it would amount to less
than a centimeter of sea level rise.
So again, it's a substantial number
but it's really insignificant when you start talking
about the Polar Regions.
Now how important are the glaciers of Alaska.
Here are a group of comparisons you can make between Alaska
and all the other glacier covered areas of earth.
You know there is about a thousand times less glacier ice
in Africa, about 100 times less glacier ice
in the U.S. compared to Alaska.
And you can see the numbers.
Canada had far more ice and it's mainly in the Canadian Arctic
and northeastern Canada.
Alaska is about half the glacier ice of Asia.
Here's a photo that I took last summer
and what you'll see is a number of pictures that I tried to put
in the context of trying to explain the changing climate
but this is the surface of the Mendenhall glacier.
This is a picture in August and there are several things
that strike me and one being here's the glacier ice surface.
There is no snow on it.
In previous years of snowfall and probably a number
of years past ice accumulation had already melted away
by this time when we're still in the melt season and the fact
that there is almost a 40 meter high waterfall in the middle
of the glacier is a very unusual site to see
but this is not unusual in the temperate glaciers of the world.
We're seeing more and evidence of melting especially in Alaska.
And why do we see that.
Well here is a temperature record.
This is departure from 0, for mean annual temperature.
You can read the dates 1945.
The record starts in 1947.
By 1947 there are 21 incremented weather stations in Alaska.
So here we're looking at temperature change
and you can see degree C
and notice the temperature actually looked
like it was decreasing through the 1970s.
Then we had a major shift in the pacific decadal oscillation.
We had a major shift with the maritime fronts moving inland.
So we're getting more maritime as opposed
to continental climates throughout southern Alaska
and this has had a major impact
with a 2 degree C temperature increase
over the last 30 plus years.
However, as you'll see when we look at some
of the other evidence, Alaska has been warming
for the last 250 years and in many places glaciers
in Alaska have retreated or began retreating
as early as the mid 1700s.
Now let's talk about the current observations of the glaciers
in the context of the last several thousand years
or in the last 20 thousand years.
20 thousand years ago most of the northern part
of continental America was covered by glacier ice.
New York City had a mile of ice on it.
So did Chicago.
So did Pittsburg.
So did Seattle.
So did Minneapolis.
That ice began to melt.
Well let me back up.
Even before that ice melted 8 percent of the land surface --
8 percent of the earth surface was covered by glaciers,
about a quarter of all of the land surface
and about a third Alaska.
And during this last glacial maximum sea level was
down more than 100 meters.
If you were standing on the Maryland shore today
and we're looking out beyond the horizon you still would not be
able to see where the shoreline was.
The shoreline was about 100 kilometers further east today
than it is today.
And global sea level rose beginning
about 15 thousand years ago and by about 6 thousand years ago
so it took about 9 thousand years for it
to come up over 100 meters.
It stabilized at a level not too much different than today
and since then it's fluctuated significantly.
And so today when you compare those numbers about 3.1 percent
of the earth's surface is covered by glacier ice
as opposed to 8 percent by the last glacial maximum.
Remember it was 25 percent of the earth's land surface
and now it's about 10.7 percent and it was about 5 percent.
So there's been a dramatic disappearance of glaciers
over the last 15 thousand years.
And that's not the first time it happened.
When you look at the geologic record we can find
at least 100 comparable events over the last 2 billion years.
So glaciers come and go.
Glaciers will come and go as long as there's a climate,
as long as there's an atmosphere and as long as there's an ocean.
However, during all of these past events no lived
in the coastal areas and no one was dependent on resources
such as water to provide their existence.
That's the only real difference.
We may be changing climate or accelerating the rate
of climate change, but it's not the first time climate has
And it's not the first time glaciers will melt
and it's certainly not the last time.
Keep that in mind because a lot
of what we're seeing we have no control over.
The part that we may have an impact on we certainly can try
to ameliorate or try to do something about
but we can't stop natural climate variability.
We have to understand it does exist though.
We have to understand what its limits are.
We have to understand how good or bad it's been in the past.
To give you some other numbers,
the last time there was no Antarctica
with ice cover was 20 million years ago.
Last time Greenland might have been ice free
about 125 thousand years ago.
How many times has Greenland been ice free
in the last 200 years, we don't know, at least four or five.
But it's something that does happen and we need
to be cognizant of what the indicators are
that it may be coming to fruition so we need
to pay attention to a number of things,
including the geologic past.
Okay, some numbers.
As I mentioned before all of Alaskan ice would melt,
global sea level would go up about a 20th of a meter.
If all the temperate glaciers on earth were
to melt global sea level would go about a third of a meter.
That would start having some impacts,
especially at the tidal basin where the tidal basin is
under water a certain part of the year anyway.
You melt Greenland global sea level could go up to 6 meters
and if you melt Antarctica you're looking
at 73 meters of sea level change.
No one is predicting that this, the melting of Greenland
and the melting of Antarctica are going
to take place in the short-term.
But as the article in Science and Time Magazine we're finding
out something different now than we knew two years ago
and that is that the rate of the outlet glaciers
that are draining Greenland and the rate of the outlet glaciers
that are draining the peninsula
of Antarctica are accelerating possibly because of two things,
one the melt water I mentioned lubricating the bed
and two the removal of the ice shelf, the floating ice shelves
that you heard about all over the last two decades to break
up the Antarctic ice shelves.
Those acted as breaks.
They kept the ice behind it constrained.
You take away the ice shelves and the unconfined glacier
and velocities increase.
Well what does that mean?
Well if you increase the glacial velocity you're sucking ice
out of the interior in order to keep that flow moving.
So you're losing ice from higher elevations and drawing it
into the lower elevations where it either goes directly
into the sea and melts
in the ocean causing global sea level rise or it melts
at the accelerated rate at the lower elevations
because temperatures are warmer then.
So it's this combination of melting
because of increased temperature plus
in the coastal environments the increasing rates
of flow are the major factors that influence the role
of glacier ice transfer into the World Ocean and sea level rise.
Now as I mentioned we have a name for this.
We talk about static sea level change,
the change in global sea level and when we're talking
about the total melting of all ice under --
which doesn't happen perhaps for more
than 25 million years you're looking a maximum
of about 80 meters of change.
What we are anticipating over the next couple of hundred years
up until this new information
about Greenland was perhaps sea level change of a third
of a meter from melting the temperate glacier ice.
When you start coupling loss of polar ice
as well you have another interesting
and presently still minimally understood issue
that leads a lot more attention.
And I'm sure we'll start seeing a much greater focus
over the next year.
In fact it's happening now and that's what resulted
in the science article on what the implications are
of the Greenland and Antarctic Peninsula loss of ice.
So, having said that we've got a context now of looking at Alaska
and how Alaska changes.
What we're going to do is take a quick survey and look
at the 14 geographic regions in Alaska that support glaciers.
Most people who look at a map
of Alaska think the glaciers should be up here
in the north where it's coldest.
The reality is where are they?
Well they're along the Pacific Ocean
where you've got the moisture.
Moisture drives the system and in this area
up here even though you've got the Arctic Ocean most
of the year the Arctic Ocean has been completely ice-covered
and the temperatures have been low enough year round
that the amount of water transferred
from the Arctic Ocean
to the atmosphere although significant isn't enough
to produce substantial participation
and build glacier ice in the northern hemisphere.
In fact, as you'll see here when we talk about the Brooks Range,
every single glacier in the Brooks range is melting.
And many of them when you look at what we call the ELA,
the equilibrium line altitude, that's the altitude
where snow remains at the end of the melt season,
that elevation is above the tops of the glaciers.
So we lose the 100 percent
of the previous year's snow plus a significant percentage
of all their ice.
And that's not uncommon in many places in Alaska.
So we're going to start in the coastal mountains
and work our way around Alaska quickly because I want
to spend some time enjoying the photo pairs in Glacier Bay.
I just throw this in to show that there's all sorts of data
that we're using everything from historic descriptions going back
to the 18th century aerial photography in Alaska
that is spanning 80 years now,
satellite imagery including declassified corona data
that goes back to the 1960s and meteorological data as I pointed
out that covers the last 50 or so years.
Let's start with the Coast Mountains.
Most people go to Alaska as tourists end up in Juneau
and they end up looking at the Mendenhall glacier.
It's the most visited glacier in Alaska.
It's the one here in the Coast Mountains.
But in Alaska in the Coast Mountains about 99 percent
of all the glaciers that descend below about a mile in elevation,
about 15 meters, are melting, they're thinning
or they're retreating.
A handful of glaciers in this area are advancing
and we'll talk about some of them in a minute;
a total of area of about 7 thousand square kilometers
of ice in the Coast Mountains.
This is the South Sawyer glacier,
it's a typical what we would call tidewater glacier.
It's where this transition from land to ocean takes place.
In Alaska there used to be hundreds
of tidewater glaciers now it's less than 50.
Most of them were treated out of the fjords onto land
so calving loss is less of a factor in Alaska but melting
in this lower region is significant.
But it's this area this transition between ice and ocean
that is the most critical area we need to be focused
on for future studies on how glaciers are changing in Alaska.
This is the Taku glacier which has been advancing
for the last 110 years.
It actually was a tidewater glacier through about the 1940s
but it have enough sediment that it was producing
that it built a protective barrier in front of it
so now calving, and this happens to many glaciers,
calving has become reduced and their rates
of advance have increased.
This is the Norris glacier, which used to be much larger
about 100 years ago and is in retreat
for the last 80 or so years.
The two of them side by side, one advancing
and one retreating are not unusual.
You get differences in regional behavior of glaciers.
And for the most part it's not a function of what you see here,
but you see way up here in the areas of accumulation.
Advancing glaciers typically have higher accumulation
and larger accumulation areas and what happens
down here the rate of melting increase is being augmented
by increased ice volume flowing through whereas a glacier
like the Norris has a lower accumulation area
and there is nothing coming back
to reestablish the volumes in lost melting.
This is a glacier called The Hole in the Wall,
which only has been in existence for the last 60 years.
As the Taku thickened it overrode this ridge,
prior to that it was in this basin.
It overrode this ridge and a new arm
of glacier ice made it down to sea level.
This one has also built a protective barrier
in front of it.
But this is the profile of a healthy glacier,
a bulbous terminus, a profile a convex profile
and there aren't many of these left in Alaska,
less than two dozen advancing glaciers in all of Alaska.
This is more typical.
This is the Mendenhall glacier.
The Mendenhall glacier was off the picture in the early 1800s.
Actually let me go back.
It was off the picture in early 18th century.
About 1750 it was out here.
You can barely make out a series of ridges in here.
Each of these is a recessional moraine that represents a point
in the retreat of the Mendenhall glacier.
Mendenhall Lake didn't exist prior to about 1940
and if you were standing here the example that you heard
from Bill, if you were standing here in the visitor's center
in 1940, you would have been under the ice.
Since then the glaciers were treated 4 kilometers,
opened up this huge basin and here now we're not looking
at melt as the biggest factor, it's something very much
like what I described to you the draw down.
In fact, it's a new process I've described
that I call disarticulation.
And everybody has heard of calving.
In fact, typically people went to Alaska
to watch glaciers calve and calving meant the ice falling
from height into the ocean, big splash,
lots of noise, small pieces of ice.
In disarticulation what happens is glaciers that are in basins
like this one, and basins are the result
because the glacier is thinning and there is a ridge at the end
that traps the melt water.
This glacier has been to the point
where it's not thick enough to maintain content of its bottom
with the bed that it was on.
So it's floating.
As it floats it starts coming apart along old fracture zones
and in this picture, this is a part of the Bering glacier
that we'll talk about a little later.
The width across this island is 1.5 kilometers.
So some of these pieces of ice,
and you can see several hundred pieces
of ice separating simultaneously some
of them are half a kilometer in maximum dimension.
And that's because the glacier has thinned to the point
where it's floating and comes apart upon old planes
A little bit of tidal flux, a lot of structural weakness
in the ice, melt water gets in and lubricates the fractures.
That was one of the causes that was identified for the glacier,
for the failure of the ice shelves in Antarctica.
We're seeing the same things in temperate glaciers in Alaska.
And just last summer I identified 20 of them
from a two-day aerial survey that are rapidly repeating.
One I'll show you a little bit earlier called The Bear has
retreated 3 kilometers in the last three years.
So moving on to the St. Elias Mountains, St. Elias is one
of the largest in terms of both elevation and size
of glaciers in Alaska.
There are a handful of glaciers that are currently advancing
and we'll take a look at a couple of them.
The biggest story there is Glacier Bay.
This is a MODIS image.
This a 250 miter pixel size image taken by one
of the Noah satellites and what you see here is Glacier Bay.
What you see here is the Brady ice field.
This is part of the ice field.
This is part of the Glacier Bay National Park.
When you look at Glacier Bay the two things
that strike me are blue and green.
If you were back here 250 years ago everything would have
The glacier that filled Glacier Bay was here in 1750.
So we've seen more than 100 kilometers of glacier retreat
and this is what we'll look at and document
at the latter part of this presentation.
But I'll sort of a bit of a tease now and we'll take a look
at changes in Glacier Bay.
1750 to 1850 about 4 kilometers of glacier retreat.
We probably lost a thousand cubic kilometers of ice during
that 100 year time period, 1750 to 1850.
We're not talking about 1950 to 2000.
We're talking about the time 250 to 150 years ago.
Glaciers in Alaska were melting long before the concern
about industrial revolution, long before the big concern
about greenhouse gas buildup.
Glaciers in Alaska have been responding
to post ice age climate, in some cases for 300 years.
The same is true in many other parts of the earth's surface.
Make sure you understand
that there's no question we have major concerns about the impact
of humans on climate, but climate was already warming
for at least in terms
of impacting temperate glaciers long before increase
in human population and increase in human activities.
So let's go back, 1750, 1850, 1890 we've lost 80 kilometers
of ice, linear kilometers.
And Glacier Bay is now becoming a series of separate fjords.
1937, 1964, 1985, by 1985 all of the major glaciers
in the eastern part have retreated off this map
so I don't bother going any further,
but that's what we're going to look at.
There's rapid change in Glacier Bay over the last 250 years
at the end of this presentation.
Other glaciers, this is glacier called the Agutak glacier,
it's about oh may be 100 kilometers from Glacier Bay.
This past summer I was flying over it
and I noticed it's already coming apart distances
of as much of 4 kilometers from the terminus.
It has almost no relief.
The entire thing is mimicking
to some extent an Antarctic ice shelf
and it's already showing the same kind of failures
and cracking that we saw the last two decades
in the Ross ice shelf and some of the other ice shelves
in Antarctica, the Ronne ice shelf and so on.
It's also spewing pieces from its margin some of which are
up to a kilometer in size.
Less than 50 miles, less than 80 miles to the west
on the other hand is the Hubbard glacier.
The Hubbard glacier has been advancing for the last 130 years
and twice in the last 20 years had blocked this fjord called
Russell fjord, caused water to build up in here to a point
where it rose 25 meters in terms of water level.
The catastrophic outburst flood that took place in 1986
and I can't give it to you metrically.
The number that I have is 4 million cubic feet per second,
about two and half times the largest Mississippi River flood
And the flood that took place here 2002,
the last time it blocked Russell fjord was 1.8 million cubic feet
This glacier advances about 3 to 4 meters a day,
but there's such a tremendous tidal flux through here
that about 105 percent
of the ice that's moving forward simply gets removed in summer
and spring and it holds its own by its rapid flow.
But as it builds sediment in front of it which I mentioned
to you before is the protective factor that causes many
of these tidewater glaciers to cease losing ice by calving
as it continues to build its next sediment protective moraine
it will again close this off.
The two times it closed in 1986 and 2002 it was a push of --
it was what we call a push moraine, sediment being pushed
up from the floor of the fjord that was effective
in protecting and damming this.
Eventually when the ice gets here and it will there some time
in the next 50 years it's going to make a major dam.
And when that happens this will flood
through an alternative route
into the Pacific Ocean destroying one
of the best salmon fisheries in all of Alaska.
This is the largest piedmont glacier
in Alaska, the Malaspina.
It's immediately to the east of the Hubbard and this mass
which is larger than the state
of Rhode Island has been thinning on the order
of 2 meters a year at least for the last 100 years.
So it lost over 200 meters of glacier ice thickness
over an area of about 3500 square kilometers, a huge volume
of water entering the oceans.
However, there's still places here
where there's 500 meters of ice.
So at the rate of melting we've got expectations this will be
here a significant period of time,
but definitely seeing dramatic changes.
This is the next area to the west, Icy Bay.
Icy Bay didn't exist; like Glacier Bay it didn't exist.
Glacier Bay started to form in the 1750s.
Icy Bay started to form in 1905.
And since 1905 this is only the upper end of the bay.
There's been about 50 kilometers of retreat
and this particular glacier,
which is called the Tindal sitting up here,
was here in the 1930's.
A colleague of mine climbed Mt. Saint Elias just off this map
in 1944 and at that point the ice thickness here was
And so there's been almost 20 kilometers of retreat and more
than 2 kilometers
of ice thinning just in the last 55 years.
This is more typical of what you see
when you get away from the coastline.
Here's an old set of moraines.
This is glacier ice here.
I don't know if the color stands out.
This is blue ice, white snow.
This is a picture took in August of 2002 of unknown glacier
in the Alaska in the St. Elias range
but this bear surface here is where the terminus
of the ice was in 1951.
Here's where it was in the 1740s.
So continuous thinning and retreat and every glacier
in the interior of the St. Elias range is melting
and down wasting in this fashion.
Chugach Mountain, some really interesting unusual situations
here and we'll look at a couple of them.
The Bering glacier, this is the one I've spent most
of my career focusing on,
the largest glacier in North America.
At the beginning of the 20th century this black area here is
At the beginning of the 20th century it was solid ice,
it went from here all the way around like this.
During the 20th century more than 150 square kilometers
of lake have formed by the melting and thinning retreat
of the glacier but this is an unusual glacier
because of something called surging,
which means periodically it has a rapid advance in velocity
and parts of the terminus will advance up to 10 kilometers.
And at various times during the 20th century,
at least four separate times, most of this lake has filled
by ice that moved from a reservoir off the top
of the image through the glacier at velocities of more
than 100 meters a day and filled the lake.
And the last time this happened was in 1996.
Since then, here's a photo.
This first photo, I'm sorry this was before 1990,
before the surge.
Here's the 2001 landsat image.
When you compare the two you'll notice
that the lake is only about, it's a third smaller than it was
because of the ice having filled it.
Now in 2006, it's almost the same size it was again in 1990.
So compare, look at the length of this peninsula
of land versus, it's hard to see here
because it's only half exposed, in 2001.
But you're looking at areas here
where we get a kilometer per year on average of push
or retreat following each of these surges.
And this is what the terminus of it looks like now.
See all these dotted lines.
It's literally falling apart
through disarticulation along pre-existing fracture lines.
This is a 2002 photograph of part of the terminus.
Here we are in the anterior of the Chugach Mountains
and there are a number of tell-tale signs
that tell glacial geologists what the ice has been
Notice this change from vegetation to bare sediment.
That's what we call a trimline
and we can date this vegetation from photography.
In fact, 1948 the ice was in contact with it.
So here in the anterior about 100 kilometers inland
from the coastline, the ice is thinned by more
than 100 meters in the last 50 years.
And also what you see, this is typical throughout Alaska.
You see what had been small tributary glaciers
that had been contributing to much larger valley glaciers
and now they are just small masses of snow left in the heads
of their circs and they no longer make contact
with the main valley glaciers.
But not only that, when you look at the sides
of the valley glaciers you see these vertical planes,
the tops of which are the trimline
that represent the recent down wasting in the last 50 years
in this case of the Bering.
Another thing, this happened last September.
Huge landslide came off of Mt. Stellar,
the highest peak behind the Bering glacier.
This is what the toe of it looked like.
I was fortunate to get a photograph
that was taken the day after and the picture looked like this.
Here we are at 33 hundred meters.
Here's the summit.
What caught my eye was this dark circle.
That's a screen channel in the side of this --
this is a 30 meter thickness of ice from here to here.
This had been a hanging glacier that had come down like this.
The whole thing fell 25 hundred meters vertically
onto the back end of the barren glacier, total volume,
50 meters of ice and rock fell.
It created a magnitude 3.9 earthquake
that was picked up around the world.
That's how people knew there had been a landslide.
Someone went out and took pictures but this shows
that there had been melt water.
There had been a stream flowing just below the summit
of this mountain.
It's hard to comprehend where that volume
of water could have come from, but there's no question
and we have other photos that show the channel continuing.
On this side there was a stream that went like this
through the head of this mountain.
And it apparently lubricated this 60 degree slope hanging
glacier and it failed in September.
And we have photos in November, excuse me late October
and early November showing there's still water dripping
down the face of that mountain.
Hard to comprehend because I would have thought this would
have been well below the freezing point
by the beginning of September.
But climate change is not only impacting the lower elevations,
it's beginning to impact higher elevations
in the coastal environment as well.
This part of Alaska has probably seen a 2 to 3 C degree increase
in temperature over the last five decades with most
of the warming being focused on the winter.
Here's another interesting glacier.
This is the Tunak glacier.
In 1950 the ice, here's your trimline again,
the ice came down like this.
This is now the terminus of the glacier.
Here's vegetation growing on the terminus.
You can see some ice here that's falling off the wall
but this is a glacier that is melting away in place.
It's stagnating and as it melts the sediment becomes a source
for trees and shrubs to become established
and they occur rapidly.
And when we start looking at Glacier Bay I'm hoping you're
as amazed as I am at how quickly mature forests become
established on what had become their bedrock less
than 100 years before.
And we'll see that all over southern Alaska.
But here's a good example of an unusual [Inaudible]
in rapid glacier melting and stagnation.
College fjord, a little story here, the Harriman expedition
in 1899 came up here and most of the scientists were
from Ivy League schools.
So this was named the L glacier, this is Harvard,
The Seven Sisters are the main tributaries on the west wall
and Harvard has been advancing
for the better part of the last 80 years.
Yale has been in retreat for half a century, side by side.
So Yale and Harvard and Smith has been advancing and stable.
Now Bryn Mawr has been rapidly retreating, but Radcliffe is one
of the reasons Harvard is rapidly advancing
because Radcliffe actually makes up the entire eastern,
I'm sorry the entire western half
of the terminus of Harvard glacier.
Okay so, interesting social dynamics in here.
[Laughter] So here's Yale and the picture is taken
from the location where the glacier was in 1909.
So you're looking at 6 kilometers of retreat
but not only is it retreating because of calving,
but it's thinking on its margins
because of both draw down and melting.
Here's what Harvard looked like in 1909.
That same day that Yale was taken from that other spot,
this is what Harvard looked like and here's Radcliffe coming in
and you can see this is the width of Radcliffe,
this moraine here marks the Radcliffe side of Harvard
and the non-Radcliffe side of Harvard.
And here's the same location, same photograph.
Notice this mountain peak and notice these mountain peaks
in the background, same mountain peaks in the background.
Harvard is -- the entire glacier is advanced to the point
where the Radcliffe part is well off the plane of the photograph.
But Harvard has thickened by almost a hundred meters
and advanced a kilometer and a half
since 1909, before and after.
And you'll see a lot of these before and after pairs.
I find it's a great way
of conveying not only glacier change
but no vegetation/vegetation and we'll see that as well later.
Same thing here, this is the next fjord over.
Harvard and Yale are over here, this is called Harriman fjord.
This is Barry Arm.
I put this in here because I want to show you a pair
of photos that I took.
The old one is 1909, the 2000 photo
of Toboggan glacier gives you another good idea
of not only how climate is changing now
but it gives you some idea of insight since 1909.
This is a 1909 photograph of Toboggan.
Notice the trimline here.
I showed you modern trimlines.
Well it seems that by 1909 Toboggan had thinned and lost
about half of its maximum thickness.
And from some of the dendra-chronology
that we've done, we and others have done,
it turns out that it was probably about 1840 when it was
at its thickest, same location now.
Notice this tributary no longer makes contact
and in fact all you can see
of the glacier is a small amount of ice here.
Notice the abundant vegetation that's come in.
I mean it's almost instantaneous.
You don't go through centuries of succession.
The seeds blow in from adjacent areas the glacial till
if there is any, serves as the footing for them
to get established more than a decade ago.
We've got multiple species established very, very rapidly.
It was most surprising to me.
There are places where is no till.
There I just bare bedrock with some cracks
in the bedding planes.
The seeds blow in and before long they're established
into some really interesting examples of that in a minute.
Okay so that's Toboggan glacier.
Now let's move to the Kenai Mountains.
Same thing there, almost all of this fjords were filled
with ice in the late 1800s.
The glaciers have retreated anywhere from a few kilometers
to 20 kilometers during the 20th century.
And some of them like Excelsior are starting to thin
and shed huge pieces of ice by this articulation.
This one is about 600 meters in maximum dimension.
This is Bear glacier.
This is a picture that was taken in 1909, just watch it evolve.
[ Silence ]
>> That's August 5th of last year.
The glacier as you'll see in an ASTER image I'll put
up in a minute has retreated about 7 kilometers
but the entire landscape has changed dramatically
from just there a sediment plane
to mature Sitka spruce and hemlock.
This is where the photo was taken.
The star marks that photo.
And the glacier terminus at 1909 was along this line
of white stars.
Here's the large lake basin that's warmed
over the last century but this is a 2001 ASTER image.
Notice the terminus of the glacier.
There is this long finger of ice extended
to within a kilometer of the 1909 position.
And also notice these two little pluses in here
because those are going to become very important.
The distance from here to here is more than 3 kilometers.
Okay so here we are on June 9, 2001.
Here we are September 2002, notice the two pluses.
Remember the finger of ice that was down here?
Look at this now.
Here we are August of last year.
There's the two pluses.
We've lost about 4 square kilometers of glacier ice
with a length of 3 kilometers through this disarticulation.
Look at the size of this piece of ice.
But that's what's happening.
We're seeing more and more glaciers now transitioning
from melting to falling apart to disarticulate.
And even though this is an insignificant amount
of water compared to what comes out of the Polar Regions,
it is a dramatic change in the volume of water caught
up in the lasting glaciers.
Okay I don't even put the 2001.
Here's the 2002, 2005.
Another interesting glacier, this is McCarty,
which was already in retreat in 1909, same location in 2004.
The glacier is actually about 20 kilometers off to the right
up its fjord before and after.
Now one of my colleagues
at the National Park Service took two photos one from 1909
and one that he and I took last summer and did this.
[ Silence ]
>> And here's the change over a 90 --
we're looking at a 96 year, I'm sorry 86 year time period
with loss of glacier ice and separation
into this rapidly retreating, thinning forming tributaries.
Another example, same thing, this is 1909.
This is the terminus of the Northwestern glacier.
That's the current landscape.
Whoops, come on, move forward.
So that was the Kenai Mountains.
That was this area.
The last range photo Steven Capps took in 1919,
one of my Park Service colleagues Ron Karpilo was back
there two summers ago, same location.
Notice the height of the ice in 1919, notice the trimline.
Here in the center of Alaska,
in the Alaska range there was already melting taking place.
The glacier was already
in retreat even though it had a significant recover that reduced
that rate of melting, it
since retreated much more significantly.
There's about an 80 meter thinning that's taken place
over that 1919 to 2004 time period.
And also notice the abundant vegetation that's moved
in here, before and after.
The Talkeetna Mountains, just one photo
to give you an example of the change.
A glacier sat here in 1950.
It's retreated about 3 kilometers since 1950
and that's a picture I took in 2000.
In 2000 it was a flat gradient glacier.
You could walk up it as if you were walking on a highway.
It had separated from its tributaries
and continued to retreat.
About a third of the glaciers in the Talkeetna Mountains,
and the Talkeetna's are the next mountain range
of the Chugach Mountains.
About a third of the smaller glaciers
in the Talkeetna's disappeared between the middle of the 1950s
and the beginning of the 21st century.
Wood River Mountains, an interesting glacier --
there was a major project during the international geophysical
year to visit eight glaciers in Alaska
and to do detailed topography of them.
This is one of them, the [Inaudible] glacier.
So this is a 1957 Navy photo.
At that time the glacier was down here.
Of all of the eight it was the most rapidly retreating.
It retreats about 15 meters a year.
And so it's been thinning, and down wasting down here.
One of my colleagues at the University
of Alaska did laser altimetry studies not only
across the lower regions but went up both
of the major tributaries.
And what we discovered is its thickening up here
and the total volume of ice in this glacier,
in 2001 I believe he did it,
is greater than he calculated for 1957.
It was a complete redistribution of mass, more accumulation
in the upper reaches
and a continuous loss in the lower reaches.
And so one of the things I'll generalize about is
that higher elevations in Alaska were not seeing significant
glacier ice loss.
We actually may have seen thickening in places.
But most lower elevations unless you have a glacier that's fed
by a substantial accumulation of upper elevation ice,
what we see is rapid glacier loss.
[Inaudible] Mountains an area around Seward, Alaska there were
about 10 glaciers that were identified and mapped
in the first decade of the 20th century.
By the 1950s only three of them were left.
One of my colleagues
from Northern Arizona University was back there probably a decade
and a half ago.
At that point the three were there
but they were all rapidly disappearing.
And the one that he focused on, the grand union glacier
which had been here the beginning
of the 20th century was just stuck under the head
of its circ valley with a little bit of ice up here
but the main part of the glacier here.
But you can see all this abandoned sediment
that represented the moraines that the ice was in contact
with in the last 100 years.
Brooks Range I gave you the statement before
that every glacier in the Brooks Range is retreating
and many have disappeared.
I'll give you some photographic evidence of that.
Leffingwell was one of the first geologists to go
up to the Arctic and mapped more than 90 years ago,
in fact about 95 years ago.
He photographed the Okpilik glacier in 1910.
Matt Nolan, University of Alaska took this picture
in the summer of 2004.
Again thinning of about 100 meters.
You can see that even in 1910 the glacier extended
out of this basin and then down off the picture.
But as this glacier retreated probably somewhere
around the 70s or 80s it retreated back, exposed its lip
and then was fronted by a lake.
The rate of retreat probably accelerated
because it began calving and disarticulating into this lake
through the latter part of the 20th century.
In the Aleutian Range we have some interesting anomalies.
All of the large glaciers in the Aleutian Range,
and this Glacier Fork glacier,
all of them have been retreating,
in fact probably during the little ice age,
the Glacier Fork glacier was way down here.
But a number of these smaller glaciers,
based on a landsat analysis by some colleagues at USDS
in Anchorage, about a third of these are currently advancing.
Why we don't know, but it was an interesting observation
that just came out.
They didn't have any explanations.
They just observed that a third of them are now advancing
but in the 1950s more than half of them were.
So the number that is advancing is decreasing although they are
still advancing smaller glaciers.
But the larger ones are all retreating.
Wrangell Mountains, interesting.
There's one glacier on the flank of Mount Wrangell
that has been advancing for at least -- since 1964.
The '64 earthquake changed the entire thermodynamics
of the Mount Wrangell area.
And in fact, there's about 200 meters
of melting ice in the crater.
The crater has a temperature of minus 20 year round
and the thickness of the ice in the crater has decreased
by 200 meters because of increase, almost an order
of magnitude increase in geothermal heat flow.
And this one glacier called the Athnea glacier which comes off
of one side of Mount Wrangell behaves
as if it were a surging glacier.
Its bed is continuously being lubricated by melt water
from the higher geographic thermal values that underlie it.
And it is advancing even though it's not being nourished
so it's getting thinner as it's being drawn
out as all the other glaciers that come off
of Mount Wrangell are retreating.
In the Alexander Archipelago these are the small islands
in southeastern Alaska, every glacier is retreating.
And on Kodiak Island where there are about 50 glaciers,
every single glacier is retreating.
Lucian's we don't know that much about.
We know that where we have good maps,
the glaciers are disappearing.
However, and I should have mentioned this before.
There are two interesting sort of anomalies but they make sense
when you put them in the context.
In 1912 Katmai erupted.
Katmai was one of the most famous eruptions
in the 20th century.
It completely destroyed all the glaciers in its summit.
In fact there are number of glaciers on the periphery
of Katmai and now Katmai National Park that are covered
by enough volcanic ash that they haven't melted
in the last 94 years.
In the crater though, it was ice free after the eruption.
And since then, these four glaciers have formed
in the crater, descending into the crater.
So there's enough moisture and its cold enough there
that under the right conditions moisture and temperature,
you can still form glacier ice even close
to the ocean in Alaska.
The other example is Mount Redoubt.
Redoubt erupted in 1989 and again melted the entire snow
and ice content of its crater.
It's completely filled with snow and ice again.
Redoubt is in an elevation of about 28,
almost 3 three thousand meters.
Higher elevations about 15 hundred meters
in the right moisture environments,
we are still accumulating ice and snow in parts of Alaska.
So, quick conclusions and then we'll move on to Glacier Bay.
Every Alaskan mountain range, island group characterized
by significant glacier retreat and thinning,
all but a few glaciers, and there are probably about 20,
in Alaska they are currently advancing.
In many locations glaciers have completely disappeared during
the 20th century and early 21st century.
Some areas retreats started 250 years ago and more.
Some areas, and I didn't mention this.
In some areas we actually have more glaciers then we did a
decade ago or a century ago because as some
of these larger glaciers retreat, they separate
into individual glaciers, so we have a larger number
but a smaller area in volume.
Not significant change at higher elevations.
I didn't mention the number, but there are
about 650 named glaciers in Alaska of about 50 thousand.
Of the 650 named glaciers, there are only about a dozen
that are currently advancing.
Now let's move on to Glacier Bay and let's have some
for about 10 minutes and then I'll have used up my hour.
This is map of Glacier Bay National Park.
I showed you what the Bay looked like in the 1750s at the end
of the little ice age.
You can see where the ice is now --
it's retreated more than 100 kilometers in places.
And this is similar to that animated diagram
but I put glacier names on it.
Grand Pacific glacier was the glacier that filled all
of Glacier Bay in the 1750s.
By 1850 it began to separate.
So Grand Pacific became the principal filling the western
part of the bay and Muir glacier,
which actually didn't get its name
until 1881 became the principal glacier
that filled the eastern part of the bay.
By 1890 Grand Pacific retreated from here all the way
up to the head of its fjord and during that period
of time Reed glacier, Lampu glacier, Johns Hopkins glacier,
Carroll glacier, and Rendu glacier all separated from it.
Each of them now have their own fjords in the west arm
of Glacier Bay and they each act independently now.
Glacier Bay is very interesting because in the west arm
about 20 percent of the larger glaciers are
The other 80 percent are rapidly retreating.
In the east arm which is a much more continental type
of an environment every single glacier is rapidly retreating.
So A is Adams, the main Muir, Casement glacier,
Burroughs plateau, these all separated
out during the 20th century and some of them have retreated
and continue to retreat almost to the point of non-existence.
So, by 1937 Muir inlet had opened almost to the point
where the glacier retreats off the map.
And by 1985 it's long gone and we'll have to look at it
in photographs to see what's happened to it.
So that takes us up to here.
This is the area that was off the map.
The map went across like this.
And so we're going to look at about a dozen locations
and you'll see a yellow star on the image beforehand
to give you some idea of where we are in Glacier Bay.
So we're going to start way down here.
This is an area that was ice free, probably about by 1830.
And so when it was first visited in 1906, no glacier to be seen.
There are some icebergs on the beach.
The ice is somewhere off here in the haze and the fog.
What's interesting is that there's no vegetation
to be seen, lots of pure bedrock.
This is a big piece of limestone.
This is a boulder of granite and it's been covered by weathering
so it's already black in color here.
So what's interesting here the only vegetation that's there are
6 thousand year old stumps.
Once of things about Glacier Bay, it's got very,
very dramatic history that's tree, forests in place buried
by sediment, sheared by advancing glaciers,
during the post Pleistocene time period.
So over the last 10 thousand years there have been
at least three advances in retreats in Glacier Bay,
all documented by spectacular institute stump
So we know that the trees in Glacier Bay,
the stumps in Glacier Bay, this has been called ghost forest
by some people, actually span a period of time
from about 8 plus radiocarbon years before present
to 15 hundred radiocarbon years before present.
And we have chronologies in advance and retreats
in different parts of the bay based
on sequences of these trees.
Having said that okay, keep this rock in mind
because the next picture is going to be
from the identical location that this one was taken
and what you see is very little.
You can just make that -- make out the cubic boulder.
But we're going to move about 15 yards to the right
so you can have a better comparison.
And so here's the boulder.
Remember, here's one of these fossil stumps --
maybe not one of the ones that were there in 1906.
But you can see how dense the vegetation is coming.
Here's the storm high tide line.
So vegetation expands right down to the high tide line.
I didn't mention anything about isostatic.
I mentioned eustatic sea level rise.
I didn't say anything about isostatic change.
Isostatic change has to do
with when you load the crust it deforms, you unload it rebounds.
All the ice that was on the crust here at Glacier Bay,
probably depressed the crust as much as 50 meters.
Once the ice disappeared, this land surface has been rising,
independent of the regional tectonics.
It's been rising because of isostatic readjustment
and here it's come up about 10 centimeters, excuse me,
it's about 3 cm a year.
So in the almost 100 years
since that photo was taken it's come up 3 meters.
And so even though the sea level --
even though the land surface is coming up the vegetation keeps
on encroaching right down to the limits of salt water,
because it moves in so rapidly.
So these are the before and after, 1906 and 2004.
We're going to move over here and take a look at Reed glacier.
This is an 1899 photograph
by Grover Karl Gilbert during the Harriman expedition.
The ice space here was probably about 30 meters high.
It's June and there is snow cover so you can't tell much
about what the vegetation looks like.
But when you see the next picture you'll know
that there certainly were no trees there compared
with what it looked like two years ago.
Same location, you can see cottonwoods in yellow.
You can see this is a willow tree, Alaska cotton in here
and some alders, but this arch
of sediment is the moraine the glacier sat on in 1899.
And so the ice is now off the edge of the photo
and the vegetation is becoming quite abundantly.
Here is the before and the after.
And to put that in perspective here is an aerial.
This is where the glacier was in 1899, here is where it is now,
almost two and half kilometers up its fjord.
I won't take the time to go into the map but we have a number
of intermediate positions and as you'll see when we move
to Johns Hopkins glacier, we've used that to build a little bit
of a story about the how the glacier has changed during the
So we're going to move over here to Johns Hopkins glacier
and here is a map of Johns Hopkins glacier.
Here's where it was in 1929.
Here's where it is in 2003.
This is a glacier that's been advancing
for most of the 20th century.
And so where you're sitting that may look like a mass of colors
and it may be difficult to understand.
But each of these is a timeline with a date on it.
1945, 1961, 1988, 1998, let's take a different approach
and let's look at it differently.
This is where Johns Hopkins was in 1929, 36, 41, 45, 48, 50,
retreated a little bit in the 50s.
Some of these glaciers fluctuate.
When we talk about an advancing
or a retreating glacier we're talking
about what it's doing now
but it may have done something different a year or two ago.
In 61 it was continuing to retreat into the early 60s.
By '64 it was re-advancing, 70 , 98, retreated between 98
and 99 advanced again to 2003.
And this year it's back here a little bit.
This is Gilman glacier.
Johns Hopkins and Gilman have separated.
So that's one way that we're trying
to explain not only long-term glacier change
but short-term variability.
These are dynamic landscape features that respond
to climate response precipitation,
respond to even small changes in annual differences.
We're going to move up here into Tar Inlet and this is
where the Grand Pacific glacier is now located.
Interesting story about it -- here's the Canadian border.
Grand Pacific retreated into Canada
after the 1920s time period and remained in Canada
until about 1970 at which time it crossed the border back
into the U.S., recombined with Marjorie glacier.
Since then it's been separating
and retreating back into Canada again.
What's interesting, we have an agreement with the Canadian Navy
and they come in here and do maneuvers in front
of what was formerly their passage into their homeland.
And they were out there last summer.
They had three cutters but this a glacier
that I predict will retreat back into Canada
within the next several decades.
So here's the Canadian border.
Here's the terminus of what is called the Grand
But in reality this dark mass of ice that comes
out of this valley here is the Ferris glacier,
which used to a tributary to the Grand Pacific.
The Grand Pacific is back here.
Its 100 meters lower than the Ferris
and the Grand Pacific doesn't even reach its terminus anymore.
Show you another example of that.
Here is a photo, this is the Ferris in 1936.
This is the Grand Pacific, you can see it's about 80 percent
of the width of its terminus.
This is Marjorie.
Here's Ferris completely covering its debris covered
dirty glacier completely covering the width
of the fjord and the Marjorie.
Let's move over here to Queen Inlet and this is --
I've got three or four photo pairs
that are among my favorites in Glacier Bay.
This area is by far the most interesting
and the most dramatic with the exception
of one picture I'll show you in Muir inlet.
This is a photo from what's called Triangle Island in 1906.
No bedrock, no vegetation a tidewater cabin glacier
of the Carroll that's about 3 kilometers across
and water depths here of 125 meters based
on no asoundings in 1920.
Same area in 2003, notice willow, shrubs,
abundant vegetation, the Glacier terminus now in massive debris.
This area, this is a stream now that's coming out of here
but more than 130 meters of sediment fill
in the last 80 years, before and after, okay.
Now if you don't believe me,
we'll go up the side of the valley here.
A picture taken the next day in 1906
by C.W. Wright the same photographer.
Here we are looking, this is the deep fjord.
Here is the terminus of the glacier, a little bit of shrubs
in here, but mostly bare bedrock,
but certainly no large trees.
This is August 1906.
June of 2004, notice this total mass
of sediment covering the entire what had been open inlet.
You can see a good Sitka spruce here.
These are all alders, but the vegetation is coming
in very, very rapidly.
Now let's put it into perspective.
There is the before and the after, but let's look
at in a year and see how this has changed.
Here's Triangle Island, this little dark mass over here.
So that first photo was looking
at what was a vertical tidewater calving terminus
of the glacier here.
That second photo was taken up the side
of the valley looking this way.
So you can see this huge mass of sediment,
probably 2 cubic kilometers
of mud have filled this during the latter part
of the 20th century.
And the entire lower part of the glacier is covered
by large amounts of debris-covered ice.
This is the only bare ice that you can see in the photo.
Let's move over here to east arm and let's go back into the 1890s
and this is what it looked like at the entrance east arm,
when Gilbert took this photo in 1899.
And let's do a slow dissolve and look at this thing disappear.
What's left the Muir glacier this is actually a tributary
called the Riggs.
We'll go back if you want to see that one more time.
This is a distance of about 30 kilometers.
So we're over here now.
We had just looked at the mouth of Muir Inlet.
We'll take a look at Wachusett and we'll finish
up with three photos in the upper part of Muir Inlet.
1961 Bill Field who spent 60 years
of his career documenting Glacier change
in southeastern Alaska took this photo
and this is Plateau glacier
which filled what's now called Wachusett Inlet sitting here.
Again no vegetation, individual cobbles, probably a thin layer
of glacial silt and sand, same location 2003.
Let me go back, because notice the two people standing here?
There are two people standing there okay.
>> [Inaudible background question]
>> We couldn't get them up there the vegetation was so dense.
So if you look really hard there's two orange float suits
over here on the side of the cliff here.
But if you remember the ice was right across here and down here.
And there was certainly no vegetation but look
at the dramatic change here.
Muir glacier I showed you disappeared through the 1930s.
Here's where it was in 1940.
We're going to look at a photograph taken in 1941
from this location between 1940 and 1960 retreated
about 6 kilometers, 60 in 80, about 8 kilometers,
in 1980 to 2000 it retreated out of the water and on to land
and is continuing to waste away up here well
above the fjord head in Muir Inlet.
We're going to go over here by Thunder Ridge.
And this is a picture -- this is the picture
that was on the flyer.
It's a photograph taken in the field in 1941.
The thickness of ice here, from here down to the bottom
of the fjord is about 800 meters.
The ice was up here in 1941.
Let's go back.
I don't even see any soil.
I see some rocks.
I see lots of foliations and bedding planes.
I have no idea how all that vegetation is rooted.
Somehow it's stuck into something, but it's there
and it's not just scraggly little trees.
I mean you got big cottonwoods, you got willows.
You got alder and there are even some spruce coming in.
But I mean dramatic change, in a 60 year time period you've gone
from totally virgin soil to mature forest.
The interesting thing, and I'll take 10 seconds,
20 seconds to tell you this.
The description of Bill Fields 41 photos says go
up Wolfcreek drainage, come to a defile, go up the defile
and you're on the top of the Bear bedrock.
So it's a 15 minute walk.
It took us 6 hours of beating through the bottoms
of the alders going by GPS to find this location [Laughter]
because there was no visibility.
You had no idea what was up, which way was east or west.
And we didn't have the GPS we would have never gotten there.
We'd still be looking our way through the woods.
So that's 1941, 2004.
Okay now we get to the realm
where the older pictures are pictures I took.
So I'm going back to places I went
when I was a mere child, 1980.
And this is McBride glacier.
Notice its height.
Notice its extending down to Muir Inlet.
This is the shoreline of Muir inlet.
2003 it's thinned by 150 meters, there actually is a fjord
in here now that you can't see that's a kilometer
and a half long, before and after.
Now this one is -- let's put things in perspective.
This is the ridge where the 1941 photograph was taken from.
This is the Wolfcreek drainage that Bill Fields said you go up.
You up this defile and you're there.
We got lost somewhere around here.
[Laughter] This is where Muir glacier was,
right across here in 1941.
It is now over here.
This is where McBride was in the 1980 photo I took.
It's now back here.
So now what we're going to do is we're going
to work our way around the corner.
And that picture was here, and we're going
to start looking over here now.
This is a picture I took in 1976
when Muir glacier had a vertical face that was probably 40
to 50 meters high and where people came
from around the world to visit the great Muir glacier.
It was still the dominant glacier
in Glacier Bay National Park.
And you can still see one
of its tributaries coming off the mountainside
and connecting to it.
Also, there enough water because of the calving,
the big splash waves that this lighter colored dike stays wet,
and algae can grow on it.
It probably also is covered by the extreme high tides.
So this is 1976.
Here we are in 2003.
No icebergs, before and after, dramatic change.
And we're talking about less than a lifetime now.
One last pair, which is a little further around the corner.
Okay 1978, again we're kayaking that year on vacation.
Did our field work and then went to spend time looking
at the great Muir glacier.
I took this and a number of other photos
but I'll be very honest with you.
I didn't know there was a 4 thousand foot high mountain,
12 hundred meter high mountain sitting right there.
Glaciers are really good at concealing things.
But you just saw my idea.
Notice the height of the ice.
I mean you know we've lost about 85 percent
of the total thickness of glacier.
This is 2003.
It continues to retreat.
It's on the verge of separating from its major tributary
over here on the left-hand side.
So to put everything in perspective for upper Muir,
the 1941 photo I showed you was taken in way
around the corner over here.
That 1976 photo with the algae on it was taken from this area
over here, and this the valley that the ice was coming
over to connect to the terminus sitting here.
The 1978 photo looking at the mountain was taken
from about here looking this way.
And here's the shoreline and here's the Muir glacier,
which used to be the main reason people went to Alaska
as tourists in the 1880s and 1890s,
now a rapidly disappearing,
rapidly thinning, stagnate mass of ice.
And is Alaska baking?
If you look at Muir glacier, the answer is unequivocally yes.
Is all of Alaska baking?
Pretty much so, but we still have higher elevations getting a
lot of precipitation.
And that pretty much puts in perspective the story
of climate change, glacier change and the dynamics
of Alaska over the last few hundred years.
Thank you very much.
>> Those are -- awesome photographing.
Really an awesome story as well and you tell it extremely well.
Larry Lucas, a question?
>> Sure I'll be happy to take questions.
>> Is there any indication during previous cycles like this
of the rate of the [Inaudible]
All we can tell you is if you look
at the maximum sea level lowering
at the last glacial maximum and point of stability,
you know it took 8 thousand or so years for sea levels
to rise, 110 meters maximum.
What we're thinking is the worst case scenario now is
significantly faster than that.
Beyond that we don't really have a good indicator.
And in fact, the last period of geologic time when we had --
the temperatures we were anticipating getting was
in the Pliocene and that's 2 to 3 and half million years back
and we really don't have any way doing decadal, even century
or possibly even millennial scale
We can do marine records and talk about variability
in the marine environment,
but we can't make a direct correlation to land.
>> You showed the temperature record going back in 1947.
How good is the precipitation record?
One the winter snow brings with it precipitation
and the building up of the glacier
but also the summer rain has severe meltdown.
>> Yeah, after World War II.
>> Can you repeat the question?
>> Oh the question if you didn't hear it is how good is the
precipitation record during the same period of time
that I showed you the temperature record?
Give you an answer, first of all in Juneau, to give you an answer
of what the extremes are.
There's a temperature record that goes back to the 1870s.
And it becomes pretty much continuous by 1885.
And there are precipitation records that go with it.
Somewhere around 1940 they move the weather station 15 miles.
So it's hard to correlate.
All of the records that the temperature data are based
on that I talked about are weather stations
that have been set up by the National Weather Service
following World War II using what is now still treated
as first order instrumentation.
So from what I read the precipitation records are
continuous and very good.
Here are the drawbacks though.
I didn't mention for -- I didn't want to take the time.
All of those -- there are 21 stations that were used
to compile that record.
All of those are at elevations above sea level but most
of them I think are at 18 or about 100 meters, and only three
of them below a thousand meters.
So where most of the glaciers that are coming out of mountains
up to 6 thousand meters high,
there are no permanent weather stations
above a thousand meters.
There are only two USGS operated stations,
on at the Gulcana glacier and one at the Wolverine glacier
at elevations between 1 thousand and 2 thousand meters
and those have a 30 year record.
So we have really reliable precipitation data
for the last 60 or so years, at lower elevations.
We can't tell you much what's happening
where the glaciers actually accumulate.
And you can easily compare summer and winter.
I've seen some studies taking individual station data
and doing detail assessment of changes in precipitation.
So yes, the data is good for that
but it doesn't really answer what we need to talk
in big picture stories about glacier change.
>> Have these receding glaciers revealed archeological sites
that folks are interested in?
>> The question is, are there archeological sites coming
up from below these glaciers?
More so in British Columbia than Alaska.
In Alaska, one of my colleagues at University
of Colorado is actually funded by NSF to look
at reindeer herding activities on the margin of one
of the glaciers on the eastern side of the Wrangell Mountains.
But most of these glaciers, because they are so dramatic,
I mean if you look at a typical 10
to 15 kilometer long Alaskan glacier, the total throughput
from snow falling at the head making it
to the terminus is less than 200 years
because of the typical rates of velocity.
Even in the biggest glaciers we calculate
that for Bering glacier from head to toe,
which is 140 kilometers, I'm sorry 200 kilometers, 140 miles,
takes less than 400 years for material to move through.
So it would only be if there were marginal archeological
sites that are covered and then uncovered.
One of the other issues is there are just not enough people
who have taken the time to look.
I'm sure there will be more because we know that there is
at least 8 thousand years of ice marginal hunting
that has taken place in Alaska.
So I'm sure we'll find more.
But the answer is very few up to date.
>> I know one question a lot of congressman will ask is,
but sir is there anything we can do about this
and what is your reply when people ask that question?
>> I mean it almost seems like --
>> Well my answer is you know, I don't say, "Yes you can."
I say, "This is part of a much bigger issue."
What we're looking at is just one of five or six issues
that I would call their attention to:
everything from pollution of almost all fresh water on earth.
Loss of renewal resources, loss of renewable resources at rates
that are not replenishable.
And you can't just say, "Well we're going
to stop greenhouse gas emissions"
because that's not going to fix the big picture.
I would tell you if I had
to prioritize these things my concern is water,
far more than it is temperature change.
We already have water wars and as population may double
over the next 50 years, there are going to be more than two,
maybe even three continents where water is going
to be the major -- the factor for major wars.
And yeah we should be really concerned
about greenhouse gas emission, but our economies
and our lifestyles have involved in a way
that we can't fix it unless we go
to alternative energy sources we haven't even conceived of.
So you know if everybody had a horse, put this in perspective.
Instead of having two cars in your garage, you had a stallion
or a mare, we'd have other problems to deal with.
You know I'm not trying
to completely negate the situation with humor.
But really we need to be concerned but there are a lot
of little things that we can do
that we're not doing that we need to fix.
We need to be much more concerned
about the bigger picture.
We certainly need to be concerned
about things that are fixable.
We need to be concerned in ways
of increasing automobile efficiency.
We need to cut down on consumption of electricity.
We need to do simple things,
things that you don't require a graduate degree to figure out.
Then we need to start looking for the new ways of coming
up with radically new energy and it's hard.
We still have to rely to a much greater extent on the atom
than we are, certainly if we're going
to have population doubling.
But am I concerned?
Should the congressman be concerned?
The one thing that we need to keep in mind you know
if these glaciers were sitting north of all the major cities
in the northeastern United States and the flooding
and the other natural hazards that could come from the impact
of changing climate, you'd have instant response.
The fact that these glaciers are not anywhere
where they have major impacts other than possibly Seattle
or Portland, makes this really low on people's screens.
And if it's outside the limits of the U.S. nobody seems
to pay much attention at all.
>> Tom Gentile?
>> Yeah, I've two questions.
One is just a rephrasing of Bill's question
or the topic of Bill's question.
Are you willing to say or speculate anything
as to whether these affect --
are or are not related to manmade sources
or just a grander picture of climate change
which might be happening?
The second question when you're talking about water sources,
maybe I'm just a little confused
because for the most part we don't rely upon glaciers
We rely upon rainfall and snowfall so it seems to me
that the amount of available water we have,
unless we make a concerted effort to now tap into glaciers
for a source of water has more to do with changes in rainfall
and snowfall then loss of glaciers.
>> Okay let me take your second question first.
It's a big we.
One of the other projects I work on is the water availability
in Pakistan and Afghanistan.
They are at least 40 percent of the melt water --
40 percent of the water that flows into the water is going
from east to west in eastern Afghanistan and Pakistan.
It's coming from glacier and snow melt with a lot
of it coming from glaciers that are rapidly becoming smaller.
Right now they have an over-abundance of water
for hydroelectricity in places where they have dams
because of the increase in glacier melt water.
30 years from now that may be totally different.
There are several cities in the U.S., Bolder being one of them
that get their primary water supply from melting glaciers.
Yes the U.S is not really dependent on its glaciers.
Most of agricultural irrigation water
in central Canada coming off the east side of the Rockies is
from glacier melt, and its decreasing
as the glaciers there have gotten significantly smaller.
So it's not something that has a personal impact on us.
But the hazard from glacier melting
in Europe has been quite significant.
There have been at least 4 or 5 major outbursts floods
from glaciers that have taken extensive numbers of lives.
The last big one was at Kulka in Russia.
I'm not sure if it was in Russia or one of the stands
but that killed about 300 people three years ago.
Major both flood, but the flood was triggered
by a large glacier avalanche.
A similar thing happened in Peru in the 1940s or 50s.
It killed 40 thousand people.
So one thing we'll see is a definite increase
in glacier related flooding and catastrophic flooding
because it's not linear.
A lot of this water is trapped in glaciers
and is discharged catastrophically
But yeah we as a country are note really dependent
on glaciers for a source
of either portable water or irrigation water.
Your other question, yes I mean there's no question
that humans are impacting the system.
The one thing that I can't answer
for you is whether it's a 50 percent, a 60 percent
or a 5 percent impact.
If you look at solar radiation and you look at sun spot cycles
and you look at the long-term radiation trends,
we should have been looking at more of a cooling trend
that we were seeing pre 1975 and continuing into the 80s and 90s
in the beginning of the 21st century.
But we didn't see it.
We actually saw an increase in warming.
And that may be directly as a result of the human activities.
But it's one of these things
that we just don't have a way of quantifying.
We can look at, we can model it, but you know we can't point it
and say you know that three degrees that we're seeing
between 1970 and 2000, 88 percent is coming
from increased greenhouse gas emissions.
But in my mind there is no question it is a definite factor
and it's a significant one.
>> Given the rate of change I can just imagine
that would be an argument that it's something that is happening
on a human type scale than a geologic type scale.
But I understood from a previous lecture
that that's also not so obvious.
>> Well remember I told you between 1715
and 1815 Glacier Bay, the amount of ice lost there,
and it's not clear whether it was solely due
to catastrophic calving
or whether it was a significant melting component,
we have no temperature data,
was greater than the rate of loss currently.
And so I don't want to say without questioning
that the last three decades
of the 20th century were the warmest ever and it's
because of human activity, because there are other events
that we can definitely document that may well have taken place
because of significant warming, local warmings,
regional warmings, that we can't quantify.
Ignoring that, if you only look at the last century,
yeah without question the last three decades much greater<