Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From...
Transcript of Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From...
![Page 1: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/1.jpg)
GLOBAL CLIMATE AND ENERGY PROJECT | STANFORD UNIVERSITY
Energy Tutorial:
Geoengineering 101
Ken Caldeira Staff Scientist – Carnegie Institution
Professor (by courtesy) – Environmental Earth System Science
Stanford University
GLOBAL CHALLENGES – GLOBAL SOLUTIONS – GLOBAL OPPORTUNITIES
GCEP RESEARCH SYMPOSIUM 2012 | STANFORD, CA
![Page 2: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/2.jpg)
Caldeira, Cao, and Bala, submitted
![Page 3: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/3.jpg)
Distribution of corals and
ocean acidification
![Page 4: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/4.jpg)
0 1 2 3 4 5
Corrosive Optimal ΩAragonite
Carbon
dioxide
level,
Coral reef
distribution
,
and
chemical
conditions
helping
drive reef
formation
Cao and Caldeira, 2008
![Page 5: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/5.jpg)
0 1 2 3 4 5
Corrosive Optimal ΩAragonite Cao and Caldeira, 2008
Carbon
dioxide
level,
Coral reef
distribution
,
and
chemical
conditions
helping
drive reef
formation
![Page 6: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/6.jpg)
0 1 2 3 4 5
Corrosive Optimal ΩAragonite Cao and Caldeira, 2008
Carbon
dioxide
level,
Coral reef
distribution
,
and
chemical
conditions
helping
drive reef
formation
![Page 7: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/7.jpg)
0 1 2 3 4 5
Corrosive Optimal ΩAragonite Cao and Caldeira, 2008
Carbon
dioxide
level,
Coral reef
distribution
,
and
chemical
conditions
helping
drive reef
formation
![Page 8: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/8.jpg)
0 1 2 3 4 5
Corrosive Optimal ΩAragonite Cao and Caldeira, 2008
Carbon
dioxide
level,
Coral reef
distribution
,
and
chemical
conditions
helping
drive reef
formation
![Page 9: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/9.jpg)
0 1 2 3 4 5
Corrosive Optimal ΩAragonite Cao and Caldeira, 2008
Carbon
dioxide
level,
Coral reef
distribution
,
and
chemical
conditions
helping
drive reef
formation
![Page 10: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/10.jpg)
Photo: sookietex
![Page 11: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/11.jpg)
Global mean temperature for the
past 136 years
![Page 12: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/12.jpg)
Probability of 2040-2060 summer
being hotter than hottest on record
![Page 13: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/13.jpg)
Probability of 2080-2100 summer
being hotter than hottest on record
![Page 14: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/14.jpg)
Temperatures continue to increase throughout this
century in every plausible emissions scenario
IPCC TAR
There is no practical way for
emissions reduction to reduce
temperatures this century
What do we do if there is
a climate emergency?
![Page 15: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/15.jpg)
www.environmentalsociety.ca
![Page 16: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/16.jpg)
Can carbon dioxide be removed from the atmosphere?
Caldeira, Cao, and Bala, submitted
Most carbon dioxide removal (CDR) proposals are
either expensive or cannot be scaled up
![Page 17: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/17.jpg)
If we removed all excess CO2 from the atmosphere
today, that would offset only about half the warming
Cao et al 2011
![Page 18: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/18.jpg)
Volcanoes caused global cooling by putting small
particles in the stratosphere
Mt. Pinatubo, 1991
Soden et al., 2002
![Page 19: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/19.jpg)
Photo: Sharee Basinger
Can sunlight be deflected away from the Earth?
Caldeira, Cao, and Bala, submitted
![Page 20: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/20.jpg)
Sunlight deflection
approaches
Space reflectors
Stratospheric aerosols
Cloud albedo
Surface albedo Desert
Urban
www.tau.ac.il
![Page 21: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/21.jpg)
Sunlight deflection
approaches
Space reflectors
Stratospheric aerosols
Cloud albedo
Surface albedo Desert
Urban
Henning Wagenbreth
![Page 22: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/22.jpg)
Sunlight deflection
approaches
Space reflectors
Stratospheric aerosols
Cloud albedo
Surface albedo Desert
Urban
![Page 23: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/23.jpg)
Sunlight deflection
approaches
Space reflectors
Stratospheric aerosols
Cloud albedo
Surface albedo Desert
Urban
Mark Brodie, KJZZ
![Page 24: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/24.jpg)
Sunlight deflection
approaches
Space reflectors
Stratospheric aerosols
Cloud albedo
Surface albedo Desert
Urban
Montepulciano – ItalianVisits.com
![Page 25: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/25.jpg)
Sunlight deflection
approaches
Space reflectors
Stratospheric aerosols
Cloud albedo
Surface albedo Desert
Urban
Santorini - Telegraph
![Page 26: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/26.jpg)
Rate of radiative forcing increase
• Each doubling of CO2 traps ~2 × 1015 W
• To counteract a doubling of CO2 over 100 years, we
would need to be satellites between the Earth and
Sun at a rate of 2.4 km2 hr-1
![Page 27: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/27.jpg)
Thin/small is the answer
• To compensate for a CO2 doubling,
• Disk area (out in space)
• you need 2 × 106 km2 area
• Spherical area (in atmosphere)
• you need 8 × 106 km2 area
volume @ 0.1 μm = 0.0008 km3
This is equivalent to a cube
of less than 100 m on a side.
About 25 liters per second
![Page 28: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/28.jpg)
Low direct costs of placing aerosols in stratosphere
Economist 2010
![Page 29: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/29.jpg)
Temperature effects of doubled CO2
ΔTemperature Statistical significance
Caldeira and Wood, 2008
![Page 30: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/30.jpg)
Temperature effects of doubled CO2
ΔTemperature Statistical significance
Caldeira and Wood, 2008
with a uniform deflection of 1.84% of sunlight
![Page 31: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/31.jpg)
Precipitation effects of doubled CO2
Caldeira and Wood, 2008
![Page 32: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/32.jpg)
Precipitation effects of doubled CO2
Caldeira and Wood, 2008
with a uniform deflection of 1.84% of sunlight
![Page 33: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/33.jpg)
Caldeira and Wood, 2008
Deflecting 1.8% of
sunlight reduces
but does not
eliminate simulated
temperature and
precipitation
change caused by
a doubling of
atmospheric CO2
content
![Page 34: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/34.jpg)
Climate models indicate –
Deflection of sunlight can offset
most climate change in most places
most of the time
![Page 35: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/35.jpg)
Climate intervention could cool
Earth within years
with deflection of sunlight
Matthews and Caldeira (2007)
![Page 36: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/36.jpg)
“Turning off” climate engineering
could cause rapid warming
Matthews and Caldeira, 2007
![Page 37: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/37.jpg)
Can the pattern of aerosols be
optimized to diminish the amount of
climate change?
![Page 38: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/38.jpg)
Aerosols
Temperature
Runoff
Ban-Weiss and Caldeira, in prep.
Climate response to a linear
combination of climate forcings is
similar to a linear combination of
climate response to each forcing
taken separately.
Climate model responses
to idealized stratospheric
aerosol distributions
![Page 39: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/39.jpg)
Aerosols
Temperature
Runoff
Ban-Weiss and Caldeira, in prep.
A combination of
temperature and runoff
changes can be minimized
simultaneously
![Page 40: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/40.jpg)
Ban-Weiss and Caldeira, in prep.
∆T
em
pe
ratu
re (
K)
∆R
un
off
(m
m/d
ay
)
Minimize
∆Temperature
Minimize
∆Runoff
2xCO2
with uniform
aerosol distribution
with parabolic
aerosol distribution
rms differences based on
zonal mean analysis
Approximate linearity of
climate system makes it
easier to find near-
optimal aerosol loadings
![Page 41: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/41.jpg)
Climate models indicate –
Stratospheric aerosols can offset
most climate change in most places
most of the time
(for both temperature and precipitation/runoff)
![Page 42: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/42.jpg)
But won’t the reduction in solar
radiation hurt the biosphere?
![Page 43: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/43.jpg)
Geoengineering
and plant growth
In the model, plants grow
much better in the
geoengineered world than
in the natural world.
Geoengineering results in
CO2 fertilization without
the increased heating that
leads to increased plant
respiration
Govindasamy et al., 2002
![Page 44: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/44.jpg)
44 From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change, 2012.
% increase in crop yields in a high-CO2 world
without and with deflection of sunlight
2xCO2
minus
pre-
industrial
2xCO2 +
geo minus
pre-
industrial
2xCO2 +
geo minus
2xCO2
Maize -3 11 14
Wheat 6 26 21
Rice 19 28 8
![Page 45: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/45.jpg)
From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change, 2012.
Crop yields in a high-CO2 world
without and with deflection of sunlight
Benefit of CO2-fertilization without the
costs of higher temperatures
![Page 46: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/46.jpg)
46 From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change, 2012.
Crop yields in a high-CO2 world
without and with deflection of sunlight
Benefit of CO2-fertilization without
the costs of higher temperatures
![Page 47: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/47.jpg)
Probability of 2080-2100 summer
being hotter than hottest on record
![Page 48: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/48.jpg)
Unanticipated outcomes
Reuters: David Gray
![Page 49: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/49.jpg)
There are many sources of risk
associated with climate intervention –
international political risk
risk of complacency
chemical risk
ecological risk
management risk
etc, etc, etc
![Page 50: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/50.jpg)
Little
knowledge
Potential
for risk
reduction
Increased
risks
![Page 51: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/51.jpg)
Intentional intervention in the climate
system has the potential to reduce
climate risk.
It is unknown whether it can reduce
overall risk.
![Page 52: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/52.jpg)
Hoffert et al, Nature, 1998
Massive amounts of carbon-emission-free power
are required to stabilize atmospheric CO2 content
![Page 53: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/53.jpg)
Caldeira, Cao, and Bala, submitted
![Page 54: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/54.jpg)
![Page 55: Energy Tutorial: Geoengineering 101gcep.stanford.edu/pdfs/symposium2012/KenCaldeira... · From Pongratz, Lobell, Cao &-Caldeira, Nature Climate Change46 , 2012. Crop yields in a high-CO2](https://reader033.fdocuments.in/reader033/viewer/2022042921/5f68da3003d71a7a8d19ec8c/html5/thumbnails/55.jpg)