good afternoon and welcome to the
administrators seminar series we're here
once again to discuss the nation's
future in space this is the fourth in a
series of dialogues that looks at
different aspects of what might comprise
a driving goal for the next era a goal
that's fundamentally character and
that's important to the public that
supports the space program Martin Luther
King said as marvelous as the stars is
the mind of the person who studies them
and so when we began this series in
January we started with life what is
life mean how would we recognize it
elsewhere either in our own solar system
or on another earth orbiting a distant
Sun the mind of the person who studies
the Stars created cosmology by virtue of
this activity we put ourselves squarely
at the center of the universe looking
outwards this theme life and it's self
conscious exploration of itself in the
cosmos form the basis of our first three
seminars today's seminar is called new
frontiers and climate research the
refrain from lynn margulis the speaker
at our first seminar runs through
today's to life is a planetary
phenomenon that she said the images we
have gotten back from our shuttle
missions show clearly the climate and
its change are a planetary phenomenon
life thrived in abundance without self
awareness for perhaps three and a half
billion years yet nor much briefer
history on the planet we have
transformed it what is the impact of the
climate on climate of our own actions
and what is the interplay of our doings
and that of nature's how do all the
different aspects of climate research
fit into one overall planetary picture
understanding this has motivated a u.s.
Global Change Program and NASA's part of
it which is called mission to Planet
Earth today we're going to hear how
science and space contribu
to this mission and our distinguished
speakers dr. Ellen Mosley Thompson and
dr. Michael McElroy will address the
question of what should be our long-term
vision for monitoring the planet and
communicating this information widely
I'd first like to bring up the NASA
Administrator Mr Dan Goldin whose vision
shaped these seminars and whose
leadership propels us to consider a
future beyond the 96 budget mr. golden I
was recently in a set of discussions
with some of the people from Robert
Mondavi wineries and they have a problem
it's called philosophy that comes around
every hundred years or so and it wiped
out the grapes in France and it's now in
the process of beginning to destroy some
of the grape vines in Northern
California it's very interesting about
falaka when you're on the ground you
don't see it you don't know that it's
beginning to destroy the plants down in
its root system but from the height of
space you could look down with a
hyperspectral device and you could
actually see the stress on the grape
vines from the philosopher so what this
tells us is when you're close you can't
necessarily they say you can't see the
forest from the trees space gives us an
ability to holistically look down on our
own planet and get a sense not just
about what's happening in this spot oh
that's pot we get a broad holistic view
of our own planet and it touches
everybody's life and as we have 5.5
billion strong on this planet preparing
for as many as 10 billion perhaps in
30-40 years from now it's very very
important that we understand the forces
of nature
and we understand the forces of the
human species and right now most of the
debate that takes place with regards to
our environment is based on passion and
emotion and who could print the most who
could get the best press bite what we'd
like to do is have rational decisions
about our environment about our own
planet and how we manage those resources
and that could only come with a holistic
view so we are set out on a course and
we only see maybe five or ten years out
on this course but let me take you out
20 or 30 years to what I think we could
have I think we could have virtual
coverage of our own planet that's active
and passive coverage multispectral with
a matta a small spacecraft hooked up
either through photons or through RF
waves so they're coherently coupled so
we could get pixel registration that
will allow us to understand the stresses
on our life forms the stresses on our
planet so we could understand how to
make rational decisions at the same time
when we have this wonderful data we
could close the biological circle people
are very very isolated from nature today
and I've said this before you know in
big cities like Washington and New York
you know it's fall not by when the
leaves fall off the trees but when the
football season starts you know it's
spring when the baseball season's
thoughts as technological as we are we
are ecologically isolated from our own
environment so by having this ability
which technology could give us it should
be able to close the loop but towards
what purpose are we going in the right
direction and this is what I think we'd
like to explore today the why and the
what not the how because this is what we
concern ourselves with NASA too much how
are we going to do it how many
spacecraft what
look at so we'd like to explore the what
and the why and then understanding the
what and why the problem we could get to
the hell so I look forward to the
discussions today thank you okay our
first speaker to talk about the what and
the why is dr. Ellen stone Mosley
Thompson she received her higher degrees
in climate ology from Ohio State
University and is now an associate
professor there she's also a research
scientist for the Byrd Polar Research
Center's one of her specialties is paleo
climactic reconstructions based on
evidence preserved in ice cores from
Antarctica Greenland China and Peru
she's been involved in global
reconstruction of the Little Ice Age
event the role of volcanism in the last
millennium of climate variability the
reconstruction of abrupt changes in the
environmental system and the impact of
these changes on human activity she has
served as a member of several national
academy and NRC committees and global
change in the environment and is
currently president of the atmospheric
sciences section of the american
geophysical union dr. Mosely Thompson
thank you dr. Cordova and thank you for
coming and it's quite a pleasure to be
here I'll start with my first slide the
title of my talk is I score records as
windows on the past and keys to our
future I like to start my talks with
this picture this is the margin of the
Cal kaya ice cap which sits in the Andes
of Peru at 14 degrees south at over
6,000 or at about fifty seven hundred
meters what you see here are the annual
layers each of those is the snow that
accumulated in a given year I'll come
full circle at the end of the talk I
will show you how this ice cap no longer
looks this way and it's no longer
preserving this unique archive if we
drill through ice caps and ice sheets we
get an ice core much like this drilled
here using a thermal drill I showed this
some people might not know what a nice
core looks like this slide outlines the
type of environmental data that we get
from ice cores the beauty of an ice core
is it produces a multi-faceted record
it's a cylinder if we take a cut through
there we get a cross-section like this
and then we can partition the samples
and make a variety of measurements for
example one of the most common
measurements is that of the oxygen
isotopic ratio which we use as a proxy
for temperature we can also measure
atmospheric chemistry the dustiness of
the atmosphere vegetation changes not in
the polar regions but outside the polar
regions bulk at the Earth's volcanic
history and as dr. McElroy will show you
anthropogenic emissions carbon dioxide
methane and nitrous oxide in ice course
where we can discern the annual layer we
can say something about how much snow
accumulated in a given year in other
words we can go back and reconstruct the
precipitation history in that region
this slide is busy but it shows all of
the places where we have either had a
nice scoring project or we anticipate
having one in the next slide I'm just
going to show you the upper 40 meters of
a core from the dire plateau located
right here on the Antarctic Peninsula
it's a busy slide I'd like to call your
attention to these two profiles the
oxygen isotopic ratio and the sulfate
concentrations this is just the upper 40
meters of a 200-meter core I'm using
this to illustrate to you how we date
course ideally we like to date them year
by year to do that requires that we
discern or measure something that has a
seasonal signal and here in Delta o-18
we see summer winter summer winter
summer winter we see high flux of
sulfate every spring so essentially we
can drill through it's like a layer cake
and when the accumulation rate is high
enough we pick up these seasonal
variations and we can precisely date
these cores these cores provide an
opportunity to reconstruct the Earth's
volcanic history this happens to be the
eruption of mount pinatubo in 91 and we
know that it the sulfur the sulfuric
acid droplets have essentially the
cooling in 92 and 93 was attributed to
the sulfuric acid suspended in the
stratosphere well we can take a record
like that with ice cores and go back in
time this again a busy slide but the
to this is excess sulfate we have to
extract the oceanic sulfate component
and we do that by measuring chlorine or
sodium what we are left with is the
excess and the two prominent sources of
excess sulfate are volcanism and the
burning of fossil fuels both of which we
see in this diagram these are the
individual eruptions the spikes this is
Northern Hemisphere two sites in
Greenland and two sites in Antarctica
and you can see that although there are
many many eruptions in the northern
hemisphere those eruptions that are
preserved both in the North and the
South are much fewer I'd point out the
eruption of tambora right here it's part
of this couplet tambora erupted in 1815
and it was credited with the year
without a summer in 1816 however if you
go back and you look at the climate
history the temperature records it was
found that actually the climate in that
decade from 1810 to 1820 the
temperatures were actually declining
before tambora erupted and this was used
as evidence against the potential of a
volcano temperature linkage however with
these ice cores putting them together we
found another eruption in 1809 virtually
the same magnitude as tambora very
outstanding event of the same magnitude
in terms of the sulfate it produced in
the northern hemisphere but not recorded
historically but well preserved in the
ice core and we speculate that was this
eruption in 1809 that really set the
stage for the cooling of that decade and
then of course adding insult to injury
with tambora we recorded the lowest the
decade 1810 to 1820 the lowest
temperatures on record
when we collect the ice course from many
locations in other words we have a
diversity of ice core records we can
begin to study different components of
the earth system just a brief word about
preliminary results actually this was a
small project preliminary funded by NASA
to look at the ice caps in franz josef
land in the rut in the Russian Arctic
and franz josef land located here at 80
degrees north is the furthest north land
mass in that sector we looked at five
different ice caps and we found that on
the island of Graham Bell the windy dome
ice cap contains a reasonably well
preserved record and is 500 meters thick
now give you these data are very
preliminary we were only drilling with a
hand auger this means we extracted a
20-metre core so the record does not go
back very long in time but what we found
is that increased chloride concentration
chloride isn't green that when chloride
concentration is high the concentration
of sea ice in that area is low so in
other words low sea ice more open water
a greater concentration of chloride and
the r-square this is only a 10 year
record but they are square or
coefficient of determination is 0 point
3 4 it's pretty good to explain 4334
percent of the variance and this is just
a linear plot of the increase in
chloride against the decrease in sea ice
concentration so we're optimistic that
course particularly from the windy dome
may provide a long record of sea ice
variability I'd like to move to the
southern hemisphere to the cal kaya ice
cap it sits at about 18,000 feet in the
Andes at 14 degrees south this was
actually one of the first
drilling projects outside the polar
regions kal kya sits here it covers
about 60 square kilometers the local
mode of transportation shows you that it
is a very remote area the precipitation
to this ice cap comes from the Andes in
the form of these convective storms
these are people on the surface for
scale just to show you that once you're
up on these ice caps they are very large
this was the first use of solar power
because of the remote nature of the site
it was virtually impossible to drill
this in the usual antarctic tradition
and we used 60 solar panels to extract
two cores to bedrock now this is the
same ice cap in which i initially showed
you that vertical margin and this is
what it looks like if you drill through
it these are core sections and these are
those visible dust bands at a hundred
and thirty nine meters in the core we
still have well-preserved s bands this
is what i mean by annual resolution
where we count back year by year the kel
kya provided a 1500 year record from
this region the first record of that
length of that quality from the tropics
we extracted a history of the dustiness
of the atmosphere the accumulation in
other words the changes in precipitation
and the oxygen isotopic ratio tells us
something about temperature and I want
to focus in the next few slides just on
this record the 0 18 and this feature
here which is the little ice age and the
precipitation history on the the bottom
or the bottom and the middle graph are
the oxygen isotopic records going back
to 1600 from kal kya we always drill to
parallel course at a minimum the reason
is if you find something unusual in your
core history and you cannot replicate it
in a parallel core then you have to
suspect it may be you have an artifact
if you can reproduce it it gives you
confidence that you are reconstructing a
respectable history so you can see the
two cores give essentially the same
isotopic results but we've plotted those
here against the northern hemisphere
10-year average temperatures and I'd
like to point out two things first you
can see that the general shape of the
curves is very similar secondly that
this Little Ice Age period and you'll
hear more about that from dr. McElroy
but it was essentially a cool phase in
the Earth's climate history from around
1450 to about eighteen eighty ad in
which it's estimated that temperatures
were about a half a degree cooler also
notice this decade that I've already
mentioned the coolest decade on record
18 10 to 18 20 faithfully recorded by
this ice cap at 18,000 feet at 14
degrees south south america is very rich
in archaeological history this happens
to be Machu Picchu in this slide we've
plotted the 1500 year record of net
accumulation showing essentially periods
where we had less accumulation and more
accumulation in the southern highlands
of Peru over here we're looking at the
rise in the fall of the cultures in that
area and I want you to focus on the
cultures here in the southern highlands
and we can see that during this this
time we have fairly high accumulation
and we have this particular culture the
whorey culture
as we enter this period of reduced
accumulation that culture essentially
leaves the highlands and the cultures
that does not return to the southern
highlands of Peru until this more
pluvial period and this is actually was
the rise of the Inca Empire and of
course determination is the entry of
Spanish into South America when all of
the Highland when all of the cultures
essentially ceased what we know is that
the Highland that the the cultures in
the highland areas and in the coastal
areas tend to function in anti-phase
that is when one culture is flourishing
another culture is diminishing and when
I talk about El Nino here in a minute I
want you to remember this the general
the climate in Peru is dominated by the
El Nino and that system called El Nino
Southern Oscillation or ENSO essentially
during in so we get drought conditions
in southern Peru and flooding conditions
in northern Peru along the coast it just
happened that the drilling project on
kal kya the big drilling project
occurred in 1983 in the middle of the
mega El Nino of 82 83 the largest in so
on record on this side we see the kel
kya ice cap as it normally appears in
19th it appeared in 1978 these are
people for scale this is the same shot
taken in 1983 and you can see that the
essentially the drought in that area is
taking a toll on that ice cap this is
just a very short record of the annual
layer thicknesses essentially what we
found is that during the end so the
accumulation rate on this ice cap drops
by at least twenty five percent
this is the 82 83 El Nino and the 76 77
El Nino so we were encouraged that the
ability to reconstruct these annual
layers and their thicknesses might allow
us to reconstruct a much longer record
of El Nino Southern Oscillation for this
region and in fact we have here the last
500 years it's very very busy slide and
we have plotted here the El Ninos as
reconstructed by bill Quinn back to 1500
ad to make a long story short we
essentially found that many of the that
most of the in cells were recorded in
kal kya as thin layers but we had more
thin layers than we had in so and if you
think about it it makes sense in that
there are many other reasons why you
would have a year with reduced
accumulation later I'll show you I'm not
going to follow up on the in so part but
we've just completed a project in
northern Peru in the previous slide
remember northern Peru gets more
accumulation so we now hope to put these
two records together matching in the
South thin years within the North thick
years and see if we can better calibrate
our current ability to reconstruct El
Nino Southern Oscillation ice cores also
have the ability to provide us a
long-term perspective and this
perspective is critical if we're going
to understand the natural variability of
the climate system and we must
understand the natural variability if
we're going to separate it from recent
anthropogenic effects we all run up
against this all the time well how do
you know the 20th century is unusual how
do you know that the 1980s were unusual
the only way you know is to look back
through time and use that history as a
measure
stick I want to move now from kal kya
cross the Pacific Basin to the Tibetan
Plateau I would just point out this is a
NASA image taken I think this is
November of 82 and you see here the
Pacific warm pool in Asia the dominant
climate system is the monsoonal
circulation system and the monsoonal
circulation system is driven primarily
by the intense heating of the Tibetan
Plateau the Tibetan Plateau is the most
outstanding feature on the earth it has
an elevation of over 4,500 meters and it
contains over 60,000 square kilometers
of snow and ice this is the dune to ice
cap located in the north on the north
central part of the Tibetan Plateau for
scale this is a party with horses going
to the summit the dune to ice cap if
epitomizes what we call an ideal ice cap
shown here in a schematic and what we
look for in these drilling projects are
dome shaped ice masses with relatively
flat basil bedrock so that the flow
regime is fairly simple but for any ice
sheet ice cap there are three things
that determine the length of the record
that you will get the first is the
amount of accumulation that falls the
second is how thick is the ice and the
third is whether that ice is frozen to
the bedrock because of course if it's
not frozen to the bedrock you're losing
your record from below in theory weren't
your ice cap frozen to the bedrock and
had it been so throughout time the first
snow that fell in that region
theoretically should still be there
we know however that it would be thinned
infant essa melis mall and could not be
discernible but the idea is you want to
look for ice caps frozen to the bed the
oxygen isotopic record that I've been
talking about we use Delta o-18 as a
proxy for temperature and I just want to
show you because we have had this long
term collaborative project in China we
have the ability to have snowfall
collected and the temperature measured
at the same time contemporaneously this
is something that is very difficult to
do over the polar ice sheets essentially
we have the Delta o-18 here and the
temperature we have more negative Delta
when we have colder temperatures less
negative Delta and warmer temperatures
the dune to ice cap contained a record
well over 40,000 years long this was a
surprise to us actually we had
anticipated a record maybe a five to ten
thousand this is the this they do the
course represent the very first ice
recovered outside the polar regions that
contain ice deposited during the last
glaciation over 12,000 years ago but
more importantly it provides that
backdrop or that measuring stick let me
use this to illustrate this is a 12,000
year record of Delta o-18 more negative
is cold and what we see here is the end
of the last major glaciation and the
overlying Holocene the shaded area
represents the Delta o-18 average for
the last 50 years 1937 to 1987 the year
we drilled the core as you can see the
last 50 years have been the warmest
in the last 12,000 now climate models
which we know are in precise and
imperfect and dr. McElroy will mention
that I'm sure given all their warts
still suggest that the interior hi
portions of large continents should be
one of the first places where we would
see evidence of an anthropogenic ly
induced warming and that's what we see
here at over 5,000 meters on the Tibetan
Plateau I just want to point out that
the types of projects that we conduct
require international collaboration we
could not do projects in China and South
America without our international
partners I'd like to move now from the
dune to ice cap here to the Galia ice
cap in the Western Kunlun galia sits at
sixty seven hundred metres that's over
21,000 feet and you see it here
virtually in the clouds but it has
annual layering and this vertical margin
that you see tells us that it is frozen
to the bed this is the profile that one
expects to see I on polar glaciers that
are frozen to the bed and this is just a
drill site of the drill camp and again
in this ice cap these are the annual
layers that have allowed us to count
back what to point out that at a hundred
and thirty five meters we are still
counting annual layers we encountered
late glacial stage ice at a hundred and
fifty three meters on this ice cap that
should be the next slide the ice the ice
caps three hundred and seven meters
thick we essentially layer counted to
right here
we had estimated that we should
encounter late glacial stage that's
12,000 years or older ice at a hundred
and fifty five meters we encountered it
at 153 these analyses are still under
we're still making the analyses we're
halfway through but what I want to point
out is we have late glacial stage ice
this is the second time we've found late
glacial stage ice on the Tibetan Plateau
but we still have half the thickness of
that ice cap get to analyze so we
anticipate that we're going to have a
record of multiple glaciations when we
begin to put together a global array of
records we begin to see large-scale
teleconnections this is the accumulation
from the Galia core the last 1000 years
compared to the cal kaya core the
similarity is is striking hi
accumulation low accumulation when you
consider that the Galia sits on the far
western edge of the Tibetan Plateau at
35 degrees north kal kya sits 20,000
kilometers away across the Pacific Basin
at 14 degrees south in the Andes we know
from current day observations that the
El Nino Southern Oscillation dominates
the Pacific Basin and we also know that
its variability is tied intimately to
the monsoonal circulation system and the
failure of the monsoons we've proposed
that the earth actually has what we call
excuse me mega El Ninos periods of time
for hundreds of years in which the earth
operates in an El Nino like state we
know El Ninos today last 1 or 2 years
although in the last decade
you haven't it hasn't operated quite the
way we thought it should the point is
what you begin to collect these records
you can begin to put these connections
together this is again a busy slide this
shows the 10-year averages for the last
1000 years from nine different ice core
sites all the way from South Pole
Station to central Greenland and camp
century maybe those people who would
like to believe that the little ice age
is a global phenomenon might be
disappointed because what we see is that
in Peru the little ice age was a very
dominant feature it's recorded in the
Greenland course it's also recorded at
South Pole Station but we do not have
evidence of the Little Ice Age in China
if you were to take 11 meteorological
stations chosen at random but to give a
global coverage I suggest that you would
not find coherences any stronger than
these it is very difficult to
reconstruct climate from point sites but
that's what we have to do the one
feature that comes through very clearly
in this record is the warming of the
last century and a half when we go
places in drill new ice cores we find
that they often challenged our existing
paradigms the way we think about things
want to return now to Peru but go to
northern Peru to a site crossed Quran we
drilled here in this call at a little
over 6,000 meters the access was
difficult this is the drill cap in the
call and this was the second use of
solar power for ice core drilling to
date the core we again count annual
layers I'm showing you just
four sections from the core each section
with the same three parameters used for
dating Dust oxygen isotopic ratios and
nitrate concentrations in green this
diagram shows the layer thinning with
depth and we we thin essentially from a
layer thickness of about a metre and a
half of water equivalent very quickly we
thin to centimeters scale when we have
this degree of thinning we can generally
and if we're frozen to the bed we can
generally count on having a very long
record and in fact we extracted from Los
Quran just in 1993 the first glacial
stage ice from the tropics I'm showing
you now just the lower portion of the
Huascar encore and we see the Delta o-18
very negative this shift from maximum or
most depleted to most enriched is eight
parts per mil also a substantial
reduction in my trait concentration
of two or three and in an increase of
two hundred fold indust the increase in
dust the decrease in nitrate is very
consistent with the climate that has
been reconstructed the late glacial
stage climate shown on your right based
upon a variety of glacial geologic
evidence and palin illogic evidence
essentially at the height of the last
glacial maximum deserts were twenty-five
twenty-five percent more extensive the
area was much drier the tropical
rainforest which we see here in dark
green was much less extensive much more
Savannah and the Amazon but the Amazon
River ran in a canyon a deep in size
Canyon that drained the moisture out of
this basin very effectively so the
decrease in nitrate we think is
associated with the reduction in
vegetation the increase in dust is
associated with the increased frequency
of eolian features now let's compare the
hot the cross quran record to similar
records from both polar regions on the
extreme right we have the die three
record this is dust late glacial stage
hi dust depleted or more negative Delta
o-18 this is don't see this is in
Central East Antarctica again hi dust
for the Glacial stage and much more
negative Delta o-18 and then on your on
your left hi Dustin huascaran and more
negative Delta o-18 in fact the Delta
shift from late glacial to holocene
conditions is eight parts per million
huascaran compared to
six parts per million doses per mil @
die three just point out briefly also
evidence for the Younger Dryas during
the deglaciation sequence seen best here
in Greenland there was as there the
warming was interrupted by a return to
near full glacial conditions for a
matter of a thousand years or so and dr.
McElroy will talk more about these type
of rapid changes but I want to point out
that the Younger Dryas is also recorded
on this ice cap at nine degrees cell
this is what I mean about challenging
the existing paradigm the existing
paradigm with regard to tropical climate
is that the tropics don't change much
and based on the climb a pre
constructions the thinking was that the
tropics during the last glacial stage
were not substantially colder this ice
core record along with records that are
now emerging from corals and from some
other pollen cores in the basin
challenge that and suggest that
temperatures during the last glacial
maximum were as much as possibly five
degrees colder we have to remember that
the current climate models that are used
to make future projections have been
tested in terms of their validity
against their ability to reproduce known
conditions the problem is the known
condition to which their feet were held
to the fire were not really known that
so these new course tell us that we have
a lot more work to do with the climate
modelling finally during the last two
decades it's important to recognize that
ice caps and glaciers outside of the
polar region primarily have been
diminishing or disappearing at an
astonishing rate in the last few weeks
if you've been listening watching
watching on your inner
it you'll notice there has been there
been the reports of the increased
frequency of icebergs from the wadell
sea area but in reality there have been
other observations such as the warty ice
shelf which since about nineteen in the
since the 1950s is now down to something
on the order of thirty to twenty five
percent of its size just three decades
ago and for the first time in history
this year ships could circumnavigate
Ross Island because the land bridge
connecting it to the mainland has
disappeared the ice core record from the
dire plateau shows us this is Delta o-18
shows us essentially that since the 40s
there has been a marked warming in this
region if you might look back and say oh
yeah but there was a warm time back then
the difference is not the degree of the
warmth the differences in is that warmth
sustained and this is a 50-year warming
period returning for the last time to
kill kya we've had the opportunity to
observe in this area since nineteen
seventy-four and I have to use what used
to be called the dirty word the M word
that's monitoring we were always told
fuel in the I scoring business that we
don't monitor we just go out and get
records what we have found is that
monitoring is critical just like the ice
course that provide this long-term
history we need to be monitoring now we
need to start these records whether
they're people will say yeah but if we
start a satellite record we're only
going to have in 20 years we're just
going to have 20 years but that's 20
more years then you would have if you
don't start the program and I'll just
show you the value of monitoring on kal
kya in 1976 we drilled the core here at
the summit and you can see the beautiful
preservation of oxygen isotopic ratios
at the same site in 1991 we drilled a
core and you can see that record is
obliterated it's obliterated by the
percolation of meltwater if we were
looking at the Cal kya ice cap today and
trying to determine whether it had the
potential for a long-term climate record
we would pass it up this is the quarry
Kahless glacier it's the largest outlet
glacier on kal kya and we have been able
to get terrestrial photography that
shows the retreat of that outlet glacier
since 1963 6880 391 more importantly
this graph is the rate of retreat from
nineteen sixty three to nineteen seventy
eight it retreated at a rate of four
meters a year then seven meters a year
and since 1978 I'm sorry since 1983 it's
retreated 14 meters a year finally we
just have basic observations this
Boulder is about the size of this stage
and this ice cliff which is vertical
this is kal kya again I'm coming back
now to that vertical margin is about 20
meters high and this picture was taken
in 1977 this is one year later in
nineteen seventy eight nineteen seventy
1983 1989 this is the boulder now this
is the margin and in 1993 this is the
boulder this is the margin and it's 20
centimeters high this is happening
around the world in the tropics and
subtropics the Lewis glacier has lost
forty percent of its of its mass in the
last 25 years in the ruined zorry the
speak glacier
they're all disappearing the sad part is
not only is there an omen here that
something is different that these ice
masses that have lasted for centuries
are going away that should concern us
but with them they're taking these very
valuable archives so I hope that I have
convinced you that I scores offer a
multi-phase