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Climate Change: General Introduction(Basic Introduction for Students with
Some Science Knowledge)
Richard B. RoodCell: 301-526-8572
2525 Space Research Building (North Campus)[email protected]
http://aoss.engin.umich.edu/people/rbrood
September 30, 2015
Getting Started
• Rood Blog “Just Temperature”
• Rood The Conversation “30 Years”
November 2013: Global Temperature
August 2015: Global Temperature
Overview
• Climate Change in a Nutshell• Climate-Energy-Policy Interface
Some Basic References
• Intergovernmental Panel on Climate Change– IPCC (2007) Working Group 1: Summary for Policy Makers– IPCC (2013) Working Group 1: Summary for Policy Makers
• Spencer Weart: The Discovery of Global Warming• Carbon dioxide greenhouse effect:
http://www.aip.org/history/climate/co2.htm• Simple climate models
http://www.aip.org/history/climate/simple.htm• Paul Edwards: A Vast Machine• Rood
– Rood Climate Change Class
Naomi Oreskes, Why Global Warming Scientists are Not Wrong
Climate Change in a Nutshell
• How and what do we know?• Increase of carbon dioxide• Some predictions• Some observations (and attribution)• How do we organize our responses?• Reading about 4 degrees of warming
– New et al. 2010, Phil. Trans. Roy. Soc.
Starting point: Scientific foundation
• The scientific foundation of our understanding of the Earth’s climate is based on budgets of energy, mass, and momentum. (Conservation principles)
• The scientific foundation of our understanding of the Earth’s climate is based on an enormous and diverse number of observations.
Starting point: A fundamental conclusion
• Based on the scientific foundation of our understanding of the Earth’s climate, we observe that with virtual certainty– The average global temperature of the Earth’s
surface has increased due to the addition of gases into the atmosphere that hold heat close to the surface. The increase in greenhouse gases is due to human activities, especially, burning fossil fuels.
Starting point: A fundamental conclusion
• Based on the scientific foundation of our understanding of the Earth’s climate, we predict with virtual certainty– The average global temperature of the Earth’s surface
will continue to rise because due to the continuing addition of gases into the atmosphere that hold heat close to the surface. The increase in greenhouse gases is due to human activities, especially, burning fossil fuels.
– Historically stable masses of ice on land will melt.– Sea level will rise.– The weather will change.
Scientific Approach
• Climate science is observationally based• Climate change is computational science
– Relies on models
Models are an Important Part of Climate ScienceWhat is a Model?
• Model– A work or construction used in testing or perfecting a
final product.– A schematic description of a system, theory, or
phenomenon that accounts for its known or inferred properties and may be used for further studies of its characteristics.
• Numerical Experimentation– Given what we know, can we predict what will
happen, and verify that what we predicted would happen, happened?
Scientific Investigation
OBSERVATIONS THEORY
PREDICTION
Past FuturePresent
Understanding ProcessesEvaluation, Verification
Predictions Projections
Time
Summary Points: Science
Theory / Empirical EvidenceCO2 and Water Vapor Hold Heat Near
Surface
Correlated ObservationsCO2 and Temperature Observed to be strongly related on long time scales (>
100 years) CO2 and Temperature not Observed to be strongly related on short time scales (<
10 years)
ObservationsCO2 is Increasing due to Burning Fossil
Fuels
Theory / Conservation PrincipleMass and Energy Budgets
Concept of “Forcing”
Prediction Earth Will
Warm
ValidationEvaluation
Consequences
Land Use / Land ChangeOther Greenhouse GasesAerosolsInternal Variability
Feedbacks
Air Quality“Abrupt” Climate Change
Conservation principle: Energy
Energy from the Sun
Energy emitted by Earth(proportional to T)
Earth at a certain temperature, T
Stable Temperature of Earth could change from how much energy (production) comes from the sun, or by changing how we emit energy.
The first place that we apply the conservation principle is energy
• We reach a new equilibrium
HT
THt
T
LossProduction
-0
The first place that we apply the conservation principle is energy
• We reach a new equilibrium
HT
THt
T
LossProduction
-0
Changes in orbit or solar energy changes this
Conservation principle: Energy
Energy from the Sun
Earth at a certain temperature, T
Add some detail:
SurfaceInsulating Blanket
The first place that we apply the conservation principle is energy
• We reach a new equilibrium
HT
THt
T
LossProduction
-0
Changing a greenhouse gas changes this
Observed Increase of Atmospheric Carbon Dioxide (CO2)
Data and more information
Primary increase comes from burning fossil fuels – coal, oil, natural gas
Presentation of some results
• These are drawn from the Reports of the Intergovernmental Panel on Climate Change. I deliberately mix graphs from reports in 2001, 2007, and 2013. The messages from these reports are quite similar, which is a measure of – Consistent measure– Stable scientific understanding
Projected Global Temperature Trends: 2100
2071-2100 temperatures relative to 1961-1990.Special Report on Emissions Scenarios Storyline B2 (middle of the road warming).
IPCC 2001
Observed Temperature Anomaly in 2005http://data.giss.nasa.gov/gistemp/2005/
See Also: Osborn et al., The Spatial Extent of 20th-Century Warmth in the Context of the Past 1200 Years, Science, 311, 841-844, 2006
IPCC 2013: Observed Temperature
Rood: What would happen if we stopped emitting now?
What does this mean for design and engineering?
IPCC 2007: The last
~100 years
Fig. 2.5. (State of Climate 2009) Time series from a range of indicators that
would be expected to correlate strongly with the surface record.
Note that stratospheric cooling is an expected consequence of greenhouse gas increases. A version of this figure
with full references is available at www.ncdc.noaa.gov/bams-state-of-climate/ .
Correlated behavior of different parameters
Length of Growing Season
From Ranga B. Myneni, Boston University
Summary In Progress: Observations
• Observations of climate change (global warming)– Average surface temperature of planet is increasing– Ice is melting
• Glaciers• Ice sheets
– Sea level is rising• Ocean is warming up• From the melting ice
– Weather is changing• Coherent and convergent evidence
Summary In Progress: Projections
• Observations are consistent model projections– Past century– Evolving
• Model projections– Planet will warm– Ice will melt– Sea level will rise– Weather will change
Summary In Progress: Uncertainty
• Identified major categories of uncertainty– Scenario – future emissions– Model – deficiencies in simulation capability– Observational – quality of observations,
inability to completely observe– Dynamic variability – internal variability due to
transfer of energy between components of a complex system
Summary in Progress: Attribution
• Have suggested several aspects of extent and attribution of warming to greenhouse gases– Spatial distribution of warming– Decrease of temperature in the stratosphere– Changes in growing season– Changes in seasonal cycle of carbon dioxide– Warming in the ocean– ….
What parameters/events do we care about?
• Temperature• Water
– Precipitation– Evaporation– Humidity
• Air Composition– Air quality– Aerosols– Carbon dioxide
• Winds• Clouds / Sunlight
• Droughts• Floods
• Extreme Weather
The impact of climate change is Water for EcosystemsWater for PeopleWater for EnergyWater for Physical Climate
Science, Mitigation, Adaptation Framework
Mitigation is controlling the amount of CO2 we put in the atmosphere.
Adaptation is responding to changes that might occur from added CO2
It’s
not
an
eith
er /
or
argu
men
t.
Some Points
• Science-based conclusions– The surface of the Earth has warmed and this
warming is consistent with increasing greenhouse gases. CO2 is most important.
– The Earth will continue to warm.– The concept of “stabilization” of CO2 is
challenged by the consideration of ocean-land-atmosphere time scales• Accumulated carbon dioxide is important. • 1 trillion tons 440 ppm
Climate-Energy-Policy Interface
• Problem solving: Reduction of complexity• Policy (global): Goals• Climate-Energy-Population-Consumption• Notional Solution Strategy
Responses to the Climate Change Problem
Autonomous/Individual
Policy/Societal
Reactive Anticipatory
Adaptation Mitigation
Stabilization / Total burden of Greenhouse Gases
• Have this notion of controlling emissions to stabilize the concentration of CO2 in the atmosphere at some value.– That is, there was some value of emissions that would match the
loss of CO2 into the plants, soil and oceans.
– However, CO2 is exchanged between plants, soil and ocean, and it takes a very long time for CO2 amounts to decline.
• We know that the CO2 that we emit will be with us essentially forever. Therefore, it is the total amount that we emit, rather than controlling emissions.– Arguably, we get to emit 1 trillion tons before climate change is
“dangerous”– “Dangerous” = 2 degrees C average surface warming
What is short-term and long-term?
25 years 50 years 75 years 100 years0 years
ENERGY SECURITY
ECONOMYCLIMATE CHANGE
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, ...
LONGSHORT
There are short-term issues important to climate change.
Election time
scales
Managing Climate Complexity
TEMPORAL
NEAR-TERM LONG-TERM
SPATIAL
LOCAL
GLOBAL
WEALTH
Managing Climate Complexity
TEMPORAL
NEAR-TERM LONG-TERM
SPATIAL
LOCAL
GLOBAL
WEALTH
Being Global, Long Term, Wealth connected, degree of difficulty is high
The Rationalist and Policy
• Determine what is a tolerable ceiling for carbon dioxide.- Gives cap for a cap and trade system.- Tolerable ceilings have been posed as between 450
and 550 ppm.- Ice sheet melting and sea level?- Oceanic circulation / The Gulf Stream?- Ocean acidification?
- Determine a tolerable measure of increased temperature- Copenhagen Accord (2009) 2o C
A trillion tons of carbon
• We get to emit a trillion tons of carbon to avoid “dangerous” climate change
• Where does mitigation, reduction of emissions fit on the spatial and temporal scales?
Trillion Tons: Carbon Visuals
Mainstream approach – targets and timetables
From R. Pielke Jr. The Climate Fix
Climate Change Relationships
• We have a clear relationship between energy use and climate change.
CLIMATE CHANGE ENERGY
The build up of carbon dioxide is directly related to combustion of fossil fuels: coal, oil, natural gas
Context: Energy and Climate Change
• Consumption // Population // Energy
CLIMATE CHANGE
ENERGY
POPULATION
CONSUMPTION
SO
CIE
TAL
SU
CC
ES
S
Have to manage, eliminate the waste of energy production
People
Engage in economic activity that
Uses energy from
Carbon emitting generation
Population
GDP per person
Energy intensity of the economy
Carbon intensity of energy
P
GDP/P
TE/GDP
C/TE
Carbon emissions = C = P * GDP * TE * C ------ ---- ---- P GDP TE
Where do emissions come from?
The “Kaya Identity” see IPCC WG 3
From R. Pielke Jr. The Climate Fix
Less people
Smaller economy
Increase efficiency
Switch energy sources
Population management
Limit generation of wealth
Do same or more with less energy
Generate energy with less emissions
Carbon emissions = C = P * GDP * TE * C ------ ---- ---- P GDP TE
Factor LeverPopulation
GDP per person
Energy intensity
Carbon intensity
Approach to Policy
GDPTechnology
P
GDP/P
TE/GDP
C/TE
What tools do we have to reduce emissions?
From R. Pielke Jr. The Climate Fix
So why has energy consumption increased so much?
• GDP/person is considered the “societal success”
• Energy use increases have been driven by growth in population and GDP/person.
Energy use = (population)*(GDP/person) *(energy/unit GDP)
Pielke Jr. argues
• 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
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.
Princeton Carbon Mitigation Initiative
Some Points
• Analysis and Opinion – Probability of stabilizing at less than 440, 560 … ppm
is very small.• If we decide to stabilize at 350, 440, then we need
to figure out how to remove CO2 from the atmosphere.
Some Points
• Analysis and Opinion – We need to start to plan for a world that is on
average, warmer than the 2 degrees C that we have deemed as the threshold of “dangerous”.
– We have an enormous opportunity provided by predictions of climate change. We have the choice of whether or not to take advantage of this opportunity on personal, professional, local, national, and international levels.• The world 4 degrees warmer: January 13, 2011 issue of
The Philosophical Transactions of the Royal Society
Some Other References for the Interested
• Rood– Rood Blog “Just Temperature”– Rood Blog: Arctic Oscillation and Cold Times in Easte
rn North America– Rood Blog: Trillion Tons of Carbon Dioxide– Rood Blog: Warming Hiatus
• Lemos and Rood (2010)• Koshland Science Museum: Global Warming
Resources and Recommended Reading
• Stern Report: Primary Web Page• Stern Report: Executive Summary
• Nordhaus: Criticism of Stern Report• Tol and Yohe: Deconstruction of Stern Rep
ort
Some carry away messages
• Determine what is a tolerable ceiling for carbon dioxide.- Gives cap for a cap and trade system.- Tolerable ceilings have been posed as between 450
and 550 ppm.- Ice sheet melting and sea level?- Oceanic circulation / The Gulf Stream?- Ocean acidification?
- Determine a tolerable measure of increased temperature- Copenhagen Accord (2009) 2o C
World 4 Degrees Warmer
Stern, 2006
