Transcript Slide 1 - climateknowledge.org

Climate Change: An Inter-disciplinary
Approach to Problem Solving
(CLIMATE 480 // NRE 480)
Richard B. Rood
Cell: 301-526-8572
2525 Space Research Building (North Campus)
[email protected]
http://climate.engin.umich.edu/people/rbrood
Winter 2016
March 17, 2016
Class Information and News
• Ctools site: CLIMATE_480_001_W16
– Record of course
• Rood’s Class MediaWiki Site
–
http://climateknowledge.org/classes/index.php/Climate_Change:_The_Move_to_Action
• A tumbler site to help me remember
– http://openclimate.tumblr.com/
– http://openclimate.tumblr.com/tagged/COP-Paris
Resources and Recommended Reading
• Socolow and Pacala, “Stabilization
Wedges,” Scientific American, 2006 (link)
• Other versions, additional reading
– Pacala and Socolow, “Stabilization Wedges,”
Science, 2004 (link)
– Socolow, “Wedges Reaffirmed,” Climate
Central, 2011 (link)
– Blog at climateprogress (link)
Wedges on the Web
• Carbon Mitigation Initiative @ Princeton
University
Outline: Class 15, Winter 2016
•
•
•
•
Some Synthesis
Mitigation Wedges
Energy Futures
Enormous number of background slides
Basic Constraints (e.g. Pielke, Jr)
• The need for technology to make solutions
possible.
• Inequity of wealth, access to basic resources,
desire for economic growth makes energy use
an imperative
• Must go
– From, we use too much energy, fossil fuels are cheap
– To, we need more energy, fossil fuels are expensive
What is short-term and long-term?
Pose that time scales for addressing climate
change as a society are best defined by human
dimensions. Length of infrastructure investment,
accumulation of wealth over a lifetime, ...
LONG
SHORT
Election
time scales
ENERGY SECURITY
CLIMATE CHANGE
ECONOMY
0 years
25 years
There are short-term issues
important to climate change.
50 years
75 years
100 years
Emissions Trajectories
https://www.climateinteractive.org/tools/scoreboard/scoreboard-science-and-data/
What tools do we have to reduce emissions?
Factor
Lever
Approach to Policy
P
Population
Less people
Population management
GDP/P
GDP per person
Smaller economy
Limit generation of wealth
TE/GDP
Energy intensity
Increase efficiency
Do same or more with less energy
Carbon intensity
Switch energy sources
Generate energy with less emissions
C/TE
Carbon emissions = C =
P * GDP
-----P
*
TE
---GDP
* C
---TE
GDP Technology
From R. Pielke Jr. The Climate Fix
link
Mitigation Wedges
• “Practical” or “Possible” Response Space
From Lecture on International Policy
• “Avoid dangerous climate change”
– Avoid 2°C (1.5°C) global average warming
– Keep carbon dioxide ( + other greenhouse
gases) to less than 450 ppm equivalent
World at 450 ppm CO2 ?
• We get to emit a trillion tons of carbon to
stay below 450 ppm CO2
Trillion Tons: Carbon Visuals
Increase of Atmospheric Carbon Dioxide (CO2)
Data and more information
Past Emissions
Princeton Carbon Mitigation Initiative
The Stabilization Triangle
Princeton Carbon Mitigation Initiative
The Wedge Concept
Princeton Carbon Mitigation Initiative
Stabilization (2006)
Princeton Carbon Mitigation Initiative
CO2 stabilization trajectory (2006)
• Stabilize at < 550 ppm.
Pre-industrial: 275 ppm,
current: ~400 ppm.
• Need 7 ‘wedges’ of
prevented CO2 emissions.
(2011)
Princeton Carbon Mitigation Initiative
Where Do We Sit?
• Concept that we can take these actions to
limit emissions.
• Growing population.
• Economic and development imperatives.
• Need for more energy.
• Technological development.
• Societal inertia.
Energy Futures
Energy Decarbonization Tools:1. Efficiency Gains
• The low-hanging fruit
• Essentially three kinds:
– End-use electricity efficiency (fluorescent bulbs instead of
incandescent bulbs, buildings / insulation)
– Energy generation efficiency (coal plant operating at 60 %
efficiency instead of current 40 %)
– Transportation efficiency (60 mpg instead of 30 mpg)
• Efficiency gains are generally cheap mitigation options
• But will only get so far before cutting into primary energy
used for economic activity
McKinsey 2007: Large
McKinsey 2007
Energy Decarbonization Tools: 2. Renewable energy
• Hydro-power
– Already widely
used - not much
potential for
expansion
• Wind
– Abundant and
competitive
• Solar
– Photovoltaic (PV)
– Concentrating solar
Energy Decarbonization Tools: 2a. Wind
• A promising renewable
energy source
Wind energy cost in $/kWh
$0.40
$0.30
$0.20
• Supplies ~1 % of world
electricity, ~0.3 % in US
• Is cost-effective against coal
and natural gas
• Is undergoing very rapid
growth
$0.10
$0.00
1980
1984
1988
1991
1995
2000
2005
Energy Decarbonization Tools: 2a. Wind
• Advantages:
– Wind energy is relatively
mature technology and is cost
effective
– Can be utilized at all scales
• Large wind farms
• On small agricultural farms
– Total theoretical potential of
wind energy on land/near
shore is 5x current energy
consumption
Large potential for
expansion
Energy Decarbonization Tools: 2a. Wind
• Disadvantages:
– Dependent on Production Tax Credits
provided by congress (~2 cents/kWh) to
be competitive
– Horizon pollution and NIMBY siting
problems
– Birds…(though this is often over-stated
– about 1-2 birds per turbine per year)
– Wind is intermittent. It can therefore not
make up a large fraction of base load
(unless effective energy storage)
Energy Decarbonization Tools: 2b. Solar
• Essentially three kinds:
1. Solar heat
–
–
Water is heated directly by
sunlight
Used cost-effectively on
small scale in houses
2. Solar photovoltaic (PV)
–
–
Uses photo-electric effect
(Einstein!) to produce
electricity
Supplies ~0.04 % of world
energy use
3. Solar concentrated
–
–
Use large mirrors to focus
sunlight on steam turbine or
very efficient PV panels
More cost-effective than just
PV
Energy Decarbonization Tools: 2b. Solar
• Advantages:
–
–
–
–
Enormous theoretical potential
Applicable at various scales
(individual houses to solar plants)
Solar heating can be cost effective
Economy of scale and/or
breakthroughs might reduce costs of
PV and solar concentrated
• Disadvantages
–
–
–
Expense: But likely more than cost
competitive by 2020.
Intermittent – can not make up large
portion of base load (except with
storage capability)
Covers land with solar panels
Energy Decarbonization Tools:
3. Carbon Capture and Sequestration (CCS)
• Main idea:
– Burn fossil fuels for
electricity/hydrogen production
– Capture CO2
– ‘Sequester’ it in geological
formation, oil/gas field, or ocean
floor
• This principle is immensely
important for future CO2 mitigation
– Fossil fuels are abundant and cheap
– Renewable energy generally not
mature enough to replace fossil fuels
– Coal-fired power plants with CCS
could provide low-carbon energy at
competitive costs
CCS: Carbon Capture
• Both conventional and modern types of
coal-fired power plants can be adapted for
CCS
• Conventional coal-fired power plant:
– Burn coal in air (much like the old days)
– Exhaust gas is ~15 % CO2 (rest is mostly
nitrogen and water vapor)
– Exhaust gas flows over chemicals that
selectively absorb CO2 (‘amines’)
– The amines are heated to ~150 ºC to give up
the CO2 and produce a (nearly) pure CO2
gas that can be sequestered.
• Modern coal-fired power plant:
– Coal is burned with pure oxygen in a
gasification chamber to produce hydrogen
and CO2
– The CO2 is filtered out and the hydrogen is
burned for electricity
CCS: Sequestration
 CO2 can be sequestered at ~1 km underground, here pressure
is high enough to liquify CO2, which helps prevent it from leaking
 Several options for sequestering CO2:
1.
2.
3.
4.
Depleted oil/gas reservoirs
(can even be used to
enhance oil/gas recovery –
reduces costs)
Deep saline (brine)
formations – these are
porous media in which
CO2 can be stored and
dissolve in the salty water
Use for coal-bed methane
recovery (one of those
‘unconventional’ fossil
fuels)
Ocean floor (very
controversial!)
CCS: economics
• CCS could become cost-effective with
future carbon legislation
Energy Decarbonization Tools: 4. Biofuels
• Initially hailed as a sustainable
substitute for oil
• Can help reduce oil imports and
improve national security
– In US, this is probably main motivation
for recent push (“addicted to oil”,
Bush’s 2006 State of the Union)
• Two main kinds of biofuels:
1. First generation:
Produced by converting sugar in corn,
sugar beets, etc., into ethanol (alcohol)
2. Second generation:
Produced through “cellulosic
conversion” of biomass into sugar,
then sugar into ethanol
• Climate change impact of different
biofuels is very different
Biofuels – First Generation
• In US, mainly corn-based ethanol
– Heavily subsidized by federal government to reduce oil dependence
(~$1.90/gallon)
• Effect on climate change is negative:
– Energy used in production is comparable to energy content
– Significant amounts of N2O (a potent GHG) can be produced through fertilizer
use
– Often, more carbon would be sequestered by letting crop land lie fallow
– Raises food prices  Tropical deforestation, which releases more carbon
than saved from fuel production over > 30-year period
Source: Fargione et
al., Science, 2008
Biofuels – Second Generation
• Produced from plants containing cellulose
– Cellulosic conversion to sugar is very difficult and expensive (cows
have 4 stomach compartments for a reason…)
• Second generation biofuels are better for climate change:
– Similar amount of carbon sequestered as fallow cropland
– But, competition with food could still lead to tropical deforestation and
net release of carbon
US 1st
generation
biofuel
US 2nd
generation
biofuel
Biofuels – do they help or hurt?
• In general, biofuels that compete with food will not contribute to
mitigating climate change
– Direct link between food demand/prices and tropical deforestation
• Production of first generation biofuels (directly from food such as corn)
is not a solution to climate change and should be avoided!
• Production of second generation biofuels (from biomass) is only helpful
if it doesn’t compete with food production (so not grown on cropland)
– Second generation biofuels from marginal farmland or agricultural waste
could play important role, but is currently not cost-effective
– Could play an important role in mitigating transportation emissions if
breakthroughs in cellulosic conversion are made
Water Energy Intersection
• Both energy and water are
critical resources
• Many areas already suffer
water stress
– note Africa, India, China, where
greatest population growth is
projected to occur
• Projected to become worse with
increasing population, pollution,
and climate change
– Dry areas are generally projected
to become drier.
• Must address energy challenge
without exacerbating water
scarcity
Some Biofuel References
• Searchinger, Ethanol and Greenhouse
gases, 2008
• Tilman, Biofuels and Food and Energy and
Environment, 2009
• Fargione, Biofuels and Land Use, 2008
• Royal Society, Biofuels, 2008
• DOE, Energy and Water Use, 2006
Energy Summary (1)
• Energy is far more important to policy
makers than climate change
– Energy Security
– Existing versus Potential Futures
• Interface of Climate, Economics and
Policy
– Standard of living
– Employment
Energy Summary (2)
• Energy is highly controversial amongst climate
scientists worried about mitigation
– Role of nuclear energy
• Jim Hansen and nuclear energy
• Rocky Mountain Institute
• Union of Concerned Scientists
• Nathan Lewis Summary
– Coal with sequestration
– Nuclear with breeder reactors
– Solar with technology development
Summary: Class 15, Winter 2016
• Mitigation: Limiting the warming is possible.
– Behavior and practice
– Technology and economics
– Personal-scale action matter
• Energy systems
– Transition to cleaner energy in developed world
– Growth of energy production and consumption in
developing world is dominated by fossil fuels
– Efficiency remains the easiest and most cost
effective way to make a difference
Outline: Class 15, Winter 2016
•
•
•
•
Some Synthesis
Mitigation Wedges
Energy Futures
Enormous number of background slides
Slides to Support Analysis
Energy Figures from Mark Barteau
Land requirements for different energy sources
http://news.cnet.com/8301-11128_3-20006361-54.html
International Energy Agency, World Energy Outlook 2012
Water Scarcity etc. from Nancy Love
The world will
experience increased
water stress and
scarcity.
Projections are particularly
dire in low or emerging
economies and the
Western US.
By 2025, 2/3 of the world
population will be under
conditions of water stress.
http://www.un.org/waterforlifedecade/scarcity.shtml
Water stress refers to the availability of water
http://www.zaragoza.es/ciudad/medioambiente/onu/en/detallePer_Onu?id=71
Water scarcity refers to water availability AND water access
http://www.zaragoza.es/ciudad/medioambiente/onu/en/detallePer_Onu?id=71
http://www.unep.org/dewa/vitalwater/article155.html
http://www.unep.org/dewa/vitalwater/article28.html
Climate Analysis: Rood
Scientific investigation of Earth’s climate
SUN: ENERGY, HEAT
EARTH: ABSORBS ENERGY
EARTH: EMITS ENERGY TO SPACE  BALANCE
Sun-Earth System in Balance
SUN
EARTH
PLACE AN
INSULATING
BLANKET
AROUND
EARTH
The addition to the
blanket is CO2
FOCUS ON
WHAT IS
HAPPENING
AT THE
SURFACE
EARTH: EMITS ENERGY TO SPACE  BALANCE
Increase of Atmospheric Carbon Dioxide (CO2)
Primary
increase comes
from burning
fossil fuels –
coal, oil,
natural gas
Data and more information
Temperature and CO2: The last 1000 years
Surface temperature and CO2 data from the
past 1000 years. Temperature is a northern
hemisphere average. Temperature from
several types of measurements are consistent
in temporal behavior.
 Medieval warm period
 “Little ice age”
 Temperature starts to follow CO2 as CO2
increases beyond approximately 300 ppm,
the value seen in the previous graph as the
upper range of variability in the past
350,000 years.
The Earth System
SUN
CLOUD-WORLD
ATMOSPHERE
ICE
(cryosphere)
OCEAN
LAND
Radiation Balance Figure
Radiative Balance (Trenberth et al. 2009)
1998
Climate Forcing
(-2.7, -0.6)
2001
Hansen et al: (1998) & (2001)
(-3.7, 0.0)