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Climate change and Antarctic glaciology
Dr. Andrés Rivera
Laboratorio de Glaciología y Cambio ClimáticoCentro de Estudios Científicos (CECS), Valdivia
(Universidad de Chile, Santiago)
Key questions:
Climate change; natural variability or human induced?
Are the Antarctic glacier responses indicating ongoing
climatic changes?
What are the consequences of the Antarctic glacier
behavior?
It is possible to forecast/mitigate/manage the
consequences of glacier dynamics?
Global Atmospheric temperatures compared to 1951-1980 mean
Source: Hansen et al, PNAS. September 26, 2006
Greenhouse gases: Carbon dioxide (CO2)
CO2 in the recent past from air and ice core measurements
Year (AD)
1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000
CO
2 (p
pm
v)
200
220
240
260
280
300
320
340
360
380
South Pole Air SamplesLaw Dome Ice Core Data
CO
2 a
mo
un
t
Greenhouse gases: Carbon dioxide (CO2)
CO2 in the past from air and ice core measurements
Year (AD)
-400,000 -350,000 -300,000 -250,000 -200,000 -150,000 -100,000 -50,000 0
CO
2 (p
pm
v)
180
200
220
240
260
280
300
320
340
360
380
South Pole Air SamplesLaw Dome Ice Core DataVostok Ice Core Data
CO
2 a
mou
nt
Years before present400,000
300,000
200,000
100,000400,00 400,00 400,00 400,00 0
Greenhouse gases: Methane (CH4)2D Graph 1
Year
-4e+5 -3e+5 -2e+5 -1e+5 0
meth
an
e (
pp
bv)
200
400
600
800
1000
1200
1400
1600
1800
meth
an
e a
mou
nt
Years before present400,000
300,000 200,000
100,000 0
Temperature…
We know CO2 has increased through time
Wide discussion over potential for enhanced CO2 to alter global climate
What can we learn of this association by looking at past climate..?
Climate and greenhouse gases have been very closely connected
200
250
300
350
400
01x1052x1053x1054x1050
200
400
600
800CH
4
(right axis)
CO2
(left axis)
Years BP (before present)
CO
2 / pp
mv
CH
4 / pp
bv
-10
-5
0
5
Est
imat
ed T
diff
eren
cefr
om to
day
/ C
400,000 300,000 200,000 100,000 0Years before present
Esti
mate
d T
diff
ere
nce
from
tod
ay /
oC
CO
2 a
mou
nt
A
Meth
an
e
am
ou
nt
Take Home Message:
Ice core data shows us that:
CO2 concentrations are currently ~30% greater than in the previous 400,000 years
Methane is more than 2 times greater than in the previous 400,000 years
Clear association between changes in Greenhouse gases and changes in global temperature
ANTARCTICAThe seven continent; the coldest, windiest, highest, driest
13,5 millions of km2 (10 % of Earth surface)
98 % is ice covered
70 % of fresh water on Earth
91 % of ice on Earth
Equivalent to 65 m of sea level
Mean ice thickness: 2000 m
>4500 m of ice thickness in places
Ice velocities from 10 to 2500 m/year
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