Climate Change: The Move to Action (AOSS 480 // NRE 480)
Richard B. Rood Cell: 301-526-8572
2525 Space Research Building (North Campus) [email protected]
http://aoss.engin.umich.edu/people/rbrood
Winter 2014 January 28, 2014
Class News
• Ctools site: AOSS_SNRE_480_001_W14 • News / New Book
– MacKenzie Funk, who took this class on 2012, published the book Windfall: The Booming Business of Global Warming . Good interview on Fresh Air 20140128. In Windfall: The Booming Business of Global Warming, journalist McKenzie Funk looks into how some entrepreneurs and even some nations stand to benefit from a changing climate.
Politics of Dismissal Entry Model Uncertainty
Description
This lecture:
• Projects • Back to the past
– Why is the past important? – How do we investigate the past? – Observation and model-based science – Radiative balance of the Earth
• Things that absorb energy • Things that reflect energy
Course Project
• Reflective of workplace … – “Complex Problems with no Known Solutions.”
• Groups of individuals with varied expertise • Responsive to “news”
– Relationship of news to science • Project will provide recommendations, a strategy for addressing the
complex problem. – What are first steps? – What do we need to look out for as these steps are taken?
• Monitor progress // briefing during the course • Presentation at end of course • Ideally:
– Imagine that I am the proverbial decision maker and I have a problem – You provide me with a set or a portfolio of knowledge-based scenarios
weighing different decisions – Usually, some sort of analysis and position paper
Use of climate information
• Research on the use of climate knowledge states that for successful projects, for example: – Co-development / Co-generation – Trust – Narratives – Scale
• Spatial • Temporal
Lemos and Morehouse, 2005
Projects
• Broad subjects and teams defined • Meeting 1 with Rood
– Now to early March: Project vision and goals
• Meeting 2 with Rood – Mid to late March: Progress report, refinement of goals if needed
• Class review – Short, informal presentation, external review and possible
coordination
• Oral Presentation: April 10 and 12 • Final written report: April 25
Scientific Method and Earth’s Climate
• We will first break the scientific investigation down into pieces. – Theory … Draw a Picture – Observations – Prediction – Attribution – Impacts
• We will look at the links of climate change to the other parts of the problem. – There is not a simple “solution;” we will not solve this problem and walk
away from it. – We will be required to manage the climate
• We will define ways forward.
Potential Projects
• Emissions from agriculture • Communications
– Alaska and climate change • Heat and cold and human health • Fracking: What does it really mean for
climate change? • Evaluation of adaptation tools
This lecture:
• Back to the past – Why is the past important? – How do we investigate the past? – Observation and model-based science – Radiative balance of the Earth
• Things that absorb energy • Things that reflect energy
Temperature and Carbon Dioxide (CO2): The last 350,000 years
350,000 years of Surface Temperature and Carbon
Dioxide (CO2) at Vostok, Antarctica, from bubbles of air trapped in
ice cores
Ø During this period, temperature and CO2 are closely related to each other
Ø Times of low temperature have glaciers, ice ages (CO2 <~ 200 ppm)
Ø Times of high temperature associated with CO2 of < 300 ppm
This has been extended back to > 700,000 years
From the Ice Core Data: Questions?
• We see a relationship between carbon dioxide (CO2) and Temperature (T) – What is the cause and effect? – Why do we bounce between these two regimes? – Dynamic equilibrium?
• Are these oscillations forced in some way by an external force? – Are there other parameters or attributes which are
correlated with this behavior? • What is different from the stock market, where
“past behavior does not indicate future performance?”
Thinking about these figures and ice ages
• Correlations • Cause and effect • Scientific method
Let’s Look at the past 1000 years
• We have more sources of observations. • We have better observations. • We have public records and literature and
natural history.
Let’s look at just 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.
q Medieval warm period
q “Little ice age”
q 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.
Let’s look at just 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.
Note that on this scale, with more time resolution, that the fluctuations in temperature and the fluctuations in CO2 do not match as obviously as in the long, 350,000 year, record. What is the cause of the temperature variability? Can we identify mechanisms, cause and effect? How?
{
What do we see from the past 1000 years
• On shorter time scales the CO2 and T are not as cleanly related.
• Periods on noted warmth and coolness are separated by changes in average temperature of only 0.5 F.
• Changes of average temperature on this scale seem to matter to people. – Regional changes, extremes?
• Recent changes in both T and CO2 are unprecedented in the past several hundred thousands of years. – And the last 10,000 years, which is when humans have thrived in
the way that we have thrived.
Why do we need to understand these bumps and wiggles?
How do we investigate these bumps and wiggles?
Conservation (continuity) principle
Mtoday = Myesterday + I - E
Let’s get some money and buy stuff.
Income
Expense
Energy from the Sun
Energy emitted by Earth (proportional to T)
Earth at a certain temperature, T
Balancing the Budget
• Today’s Money = Yesterday’s Money + Money I Get – Money I Spend
• Today’s CO2 = Yesterday’s CO2 + CO2 I Get – CO2 I Spend
• Today’s Energy = Yesterday’s Energy + Energy I Get – Energy I Spend
Some jargon, language
• Income is “production” is “source” • Expense is “loss” is “sink” • Exchange, transfer, transport all suggest
that our “stuff” is moving around.
Point of View
Focus attention on the surface of the Earth
Simple earth 1
What do we do?
• We develop models based on the conservation of energy and mass and momentum, the fundamental ideas of classical physics. (Budget equations)
• We break things into pieces, deconstruct, reduce • We determine the characteristics of production
and loss energy (heat) from theory and observations of, for instance, the eruption of a major volcano and the temperature response as measured by the global observing system.
What changes energy at surface of the Earth?
Natural • Sun
– Solar cycle • Volcanoes
– CO2 – Sulfuric acid droplets
(aerosols) • Greenhouse gases
– Water, CO2 (biogeochemistry) • Aerosols
– Smoke – Dust – Water clouds
Human or Anthropogenic • Greenhouse gases • Deforestation
– Changes CO2 • Emits • Eliminates sink
– Changes albedo (changes the color earth)
• Pollution (LA)
Let’s look at just 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.
Schematic of a model experiment.
T
T Start model prediction
Model prediction without forcing
Model prediction with forcing
Model prediction with forcing and source of internal variability
Observations or “truth”
Eat+Δt = Ea
t + Δt((Pa – LaEa) + (Traßàoil + Ma ))
Studies like this are important
• Abrupt onset of the Little Ice Age triggered by volcanism and sustained by sea-ice/ocean feedbacks – Miller et al. 2012, Geophysical Research
Letters • Link from Journal • PDF from NCAR • Some commentary
Let’s focus on the balance of the energy at the Earth’s surface
Let’s build up this picture
• Follow the energy through the Earth’s climate.
• As we go into the climate we will see that energy is transferred around. – From out in space we could reduce it to just
some effective temperature, but on Earth we have to worry about transfer of energy between thermal energy and motion of wind and water.
But the Earth’s surface temperature is observed to be, on average, about 15 C (~59 F).
The sun-earth system (What is the balance at the surface of Earth?)
SUN
Earth
Based on conservation of energy: If the Earth did NOT have an atmosphere, then, the temperature at the surface of the Earth would be about -18 C ( ~ 0 F).
Welcome Back Radiative Balance. This is conservation of energy, which is present in electromagnetic radiation.
Building the Radiative Balance
What happens to the energy coming from the Sun?
Energy is coming from the sun. Two things can happen at the surface. In can be:
Reflected
Top of Atmosphere / Edge of Space
Or Absorbed
Building the Radiative Balance What happens to the energy coming from the Sun?
We also have the atmosphere. Like the surface, the atmosphere can:
Top of Atmosphere / Edge of Space
Reflect
or Absorb
Building the Radiative Balance What happens to the energy coming from the Sun?
In the atmosphere, there are clouds which :
Top of Atmosphere / Edge of Space
Reflect a lot
Absorb some
Building the Radiative Balance What happens to the energy coming from the Sun?
For convenience “hide” the sunbeam and reflected solar over in “RS”
Top of Atmosphere / Edge of Space RS
Building the Radiative Balance What happens to the energy coming from the Sun?
Consider only the energy that has been absorbed.
What happens to it?
Top of Atmosphere / Edge of Space RS
Building the Radiative Balance Conversion to terrestrial thermal energy.
1) It is converted from solar radiative energy to terrestrial
thermal energy. (Like a transfer between accounts)
Top of Atmosphere / Edge of Space RS
Building the Radiative Balance Redistribution by atmosphere, ocean, etc.
2) It is redistributed by the atmosphere, ocean, land, ice, life. (Another transfer between accounts)
Top of Atmosphere / Edge of Space RS
Building the Radiative Balance Terrestrial energy is converted/partitioned into three sorts
SURFACE
3) Terrestrial energy ends up in three reservoirs
(Yet another transfer )
Top of Atmosphere / Edge of Space
ATMOSPHERE CLOUD
RS
WARM AIR (THERMALS)
PHASE TRANSITION OF WATER
(LATENT HEAT)
RADIATIVE ENERGY
(infrared)
It takes heat to • Turn ice to water • And water to “steam;”
that is, vapor
Building the Radiative Balance Which is transmitted from surface to atmosphere
SURFACE
3) Terrestrial energy ends up in three reservoirs
Top of Atmosphere / Edge of Space
ATMOSPHERE CLOUD
RS
(THERMALS) (LATENT HEAT) (infrared)
CLOUD
Building the Radiative Balance And then the infrared radiation gets complicated
SURFACE
Top of Atmosphere / Edge of Space
ATMOSPHERE CLOUD
RS
(THERMALS) (LATENT HEAT) (infrared)
CLOUD
1) Some goes straight to space
2) Some is absorbed by atmosphere and re-emitted downwards 3) Some is absorbed by clouds and re-emitted downwards
4) Some is absorbed by clouds and atmosphere and re-emitted upwards
Want to consider one more detail
• What happens if I make the blanket thicker?
Thinking about the greenhouse A thought experiment of a simple system.
SURFACE
Top of Atmosphere / Edge of Space
ATMOSPHERE
(infrared)
1) Let’s think JUST about the infrared radiation • Forget about clouds for a while
2) More energy is held down here because of the atmosphere
• It is “warmer”
3) Less energy is up here because it is being held near the surface.
• It is “cooler”
Thinking about the greenhouse A thought experiment of a simple system.
SURFACE
Top of Atmosphere / Edge of Space
ATMOSPHERE
(infrared)
T effective
1) Remember we had this old idea of a temperature the Earth would have with no atmosphere.
• This was ~0 F. Call it the effective temperature. • Let’s imagine this at some atmospheric height.
2) Down here it is warmer than T effective T > T effective
3) Up here it is cooler than T effective T < T effective
Thinking about the greenhouse Why does it get cooler up high?
SURFACE
Top of Atmosphere / Edge of Space
ATMOSPHERE
(infrared)
1) If we add more atmosphere, make it thicker, then
2) The part coming down gets a little larger. • It gets warmer still.
3) The part going to space gets a little smaller • It gets cooler still.
The real problem is complicated by clouds, ozone, ….
So what matters?
Things that change
reflection Things that
change absorption
Changes in the sun
If something can transport energy DOWN from the surface.
THIS IS WHAT WE ARE DOING
Radiation Balance Figure
Radiative Balance (Trenberth et al. 2009)
This lecture:
• Projects • Back to the past
– Why is the past important? – How do we investigate the past? – Observation and model-based science – Radiative balance of the Earth
• Things that absorb energy • Things that reflect energy
Iconic and Fundamental Figures
Scientific investigation of Earth’s climate
SUN: ENERGY, HEAT EARTH: ABSORBS ENERGY
EARTH: EMITS ENERGY TO SPACE à BALANCE
Sun-Earth System in Balance
The addition to the blanket is CO2
SUN EARTH
EARTH: EMITS ENERGY TO SPACE à BALANCE
PLACE AN INSULATING
BLANKET AROUND EARTH
FOCUS ON WHAT IS
HAPPENING AT THE
SURFACE
Increase of Atmospheric Carbon Dioxide (CO2)
Data and more information
Primary increase comes from burning fossil fuels – coal, oil, natural gas
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.
q Medieval warm period
q “Little ice age”
q 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.
CLOUD-WORLD
The Earth System
ATMOSPHERE
LAND
OCEAN ICE (cryosphere)
SUN
Radiation Balance Figure
Radiative Balance (Trenberth et al. 2009)
