climate change and antarctic glaciology dr. andrés rivera laboratorio de glaciología y cambio...
TRANSCRIPT
![Page 1: Climate change and Antarctic glaciology Dr. Andrés Rivera Laboratorio de Glaciología y Cambio Climático Centro de Estudios Científicos (CECS), Valdivia](https://reader035.vdocuments.us/reader035/viewer/2022070401/56649f1e5503460f94c35be1/html5/thumbnails/1.jpg)
Climate change and Antarctic glaciology
Dr. Andrés Rivera
Laboratorio de Glaciología y Cambio ClimáticoCentro de Estudios Científicos (CECS), Valdivia
(Universidad de Chile, Santiago)
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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?
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Global Atmospheric temperatures compared to 1951-1980 mean
Source: Hansen et al, PNAS. September 26, 2006
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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
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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
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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
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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..?
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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
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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
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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