1. Energy, space, and Earth's effective temperature
Unit 1 of Earth’s Thermostat InTeGrate Module
This slide commences Part 1: the Global Temperature Record
Slide 1: R. St ̈ockli, E. Vermote, N. Saleous, R. Simmon and D. Herring (2005). The Blue Marble Next Generation - A true color earth dataset including seasonal dynamics from MODIS. Published by the NASA Earth Observatory. Corresponding author: Freely available for re-publication or re-use
Image: January 2004 Blue Marble Composite – Reto Stöckli, NASA Earth Observatory

2. NOAA State of the Climate, Jan. 2016
New York Times, Jan. 20, 2016
NOAA State of the Climate, Jan. 2016
Note to instructors: these headlines can easily be updated for your class use. If you google for NOAA’s State of the Climate, you can find the most recent statistics (monthly and yearly).
World Meteorological Organization, July 2016

3. Today’s learning objectives
Analyze temperature data, determine temperature trend, and predict future temperature
Describe how averaging period affects conclusions
Describe how the temperature trend may have affected natural and human systems
Calculate running mean from solar irradiance data
Compare solar irradiance to temperature and describe any observed relationship
Describe how energy moves through space and is received by Earth, calculate Earth’s effective temperature

4. We are going to analyze temperature data by looking at anomalies
We are going to analyze temperature data by looking at anomalies. What is an anomaly?

5. An anomaly tells you how different a number is from the average value.
What would a positive temperature anomaly indicate?
What about a negative?

6. What you and your group should do for Part 1:
The instructor may wish to take a few moments to plot out a couple of example points. Students occasionally have problems plotting the decimal correctly (e.g. they will plot 0.8 degrees instead of 0.08 degrees and therefore show a much larger anomaly).
What you and your group should do for Part 1:
Plot out the temperature anomaly data for your decade
Draw a straight best fit line through your data, extending it outward to predict the anomaly in 2025
A best fit line captures the slope (or trend) in the data

7. What’s happening with temperature during this decade?

8. Slope is -0.029°/yr; temperature decreasing by .029° per year
What would it be in 2025?
-3.5°C anomaly in 2025

9. What happened to global temperatures in this decade?

10. Slope is 0.001°/yr; temperature increasing by .001° per year
0.07°C anomaly in 2025
Slope is 0.001°/yr; temperature increasing by .001° per year
What would it be in 2025?

11. What happened to global temperatures in this decade?

12. Slope is 0.012 °/yr; temperature increasing by .012° per year
0.82°C anomaly in 2025
Slope is °/yr; temperature increasing by .012° per year
What would it be in 2025?

13. What’s going on with global temperatures
What’s going on with global temperatures? Why do we see different patterns at different times?

14. What is the pattern since 1880?
How is it different from what your group observed?

15. Temperature varies on yearly, decadal, and longer timescales

16. Slope 0.007°/yr; temperature increasing .007°C per year since 1880

17. The rate of warming has increased in recent years
Trend since 1950
The rate of warming has increased in recent years

18. The rate of warming has increased in recent years
Trend since 1950
Trend since 1980
The rate of warming has increased in recent years

19. The rate of warming has increased in recent years
Trend since 1950
Trend since 1980
Trend since 2010
The rate of warming has increased in recent years

20. Understanding Earth’s Energy Balance and the Atmosphere
Earth’s Thermostat
This slide commences Part 2: Introduction to the whole module, Solar Irradiance and Earth's temperature
Image is from NASA and considered public property
Understanding Earth’s Energy Balance and the Atmosphere

21. Earth’s average surface temperature has warmed by 0
Earth’s average surface temperature has warmed by 0.8°C since measurements began in 1880, and most of the warming has been in the last 30 years

22. Over the next two weeks, we will explore:
What factors control earth’s energy balance
How changes to this balance affect the rest of the earth system (e.g. temperature, atmosphere)

23. Open ended question to the class
Open ended question to the class. Solicit opinions, make a list on the board. For this class, we’re just going to be looking at solar radiation, but this will start students thinking about other things that could be important (atmosphere, volcanic eruptions, etc.)
What factors do you think are important for determining earth’s surface temperature?
Let’s build a conceptual model – a framework of the factors that are important in controlling surface temperature

24. Conduction and radiation
On Earth, energy is transmitted via:
Conduction (direct transfer of heat between two objects of different temperature)
Convection (movement of a fluid, such as air or water, in response to a temperature & density difference)
Image credits:
Left from: Photo by Fir0002/Flagstaffotos. Covered by Creative Common license BY-NC. Non-Commercial users are free to copy, distribute, transmit and adapt this work provided that correct attribution is provided.
Right from Image created by NOAA and in the public domain.
Convection
Conduction and radiation

25. On Earth, energy is transmitted via:
Conduction (direct transfer of heat between two objects of different temperature)
Convection (movement of a fluid, such as air or water, in response to a temperature & density difference)
Electromagnetic radiation (flow of energy through space in the form of waves)
Outer space contains very few molecules, so only electromagnetic radiation can transmit the Sun’s energy to Earth

26. Radiation is classified by its wavelength
Only a small portion of the spectrum is visible
Often divided into shortwave (UV, visible, and near-infrared) and longwave (mid- and far-infrared)
Image is public property via NASA:

27. Blackbody radiation describes how a perfectly absorbing object (like a star) absorbs & emits radiation
All objects emit radiation according to the Stefan-Boltzmann law: Energy Flux = σ T4
Objects emit at all wavelengths; the peak wavelength depends on Wien’s Law: λpeak =
After bullet 2: What does that say about the amount of energy released as a function of temperature?
Image is public property via NASA:

28. Using the graphs below, determine the approximate intensity and peak wavelength for the Sun, a light bulb, and the Earth
Sun
5700°K
Light bulb
3045°K
Earth
300°K
What patterns did you see with increasing temperature?
Hotter objects release more energy
Hotter objects have a shorter peak wavelength
The Sun emits primarily in visible; the earth in infrared
Images generated from calculator at (referenced in previous slide)

29. Solar irradiance: amount of solar radiation received by the Earth
The small text from the figure gives the data source, which is: “Myhre, G., D. Shindell, F.-M. Bréon, W. Collins, J. Fuglestvedt, J. Huang, D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza, T. Nakajima, A. Robock, G. Stephens, T. Takemura and H. Zhang, 2013: Anthropogenic and Natural Radiative Forcing Supplementary Material. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Available from and
Solar irradiance: amount of solar radiation received by the Earth
Measured in watts of energy per square meter ( )

30. The small text from the figure gives the data source, which is: “Myhre, G., D. Shindell, F.-M. Bréon, W. Collins, J. Fuglestvedt, J. Huang, D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza, T. Nakajima, A. Robock, G. Stephens, T. Takemura and H. Zhang, 2013: Anthropogenic and Natural Radiative Forcing Supplementary Material. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Available from and
Examine the solar irradiance data, determine an average for the 11 years centered around 2005 (we call this a running mean), and share your findings with your adjacent classmates

31. What patterns are visible in the data?
The small text from the figure gives the data source, which is: “Myhre, G., D. Shindell, F.-M. Bréon, W. Collins, J. Fuglestvedt, J. Huang, D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza, T. Nakajima, A. Robock, G. Stephens, T. Takemura and H. Zhang, 2013: Anthropogenic and Natural Radiative Forcing Supplementary Material. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Available from and
What patterns are visible in the data?
What is an approximate running mean for 2005?

32. Do you see a connection between solar irradiance and the long-term temperature pattern?
Top figure: The small text from the figure gives the data source, which is: Myhre, G., D. Shindell, F.-M. Bréon, W. Collins, J. Fuglestvedt, J. Huang, D. Koch, J.-F. Lamarque, D. Lee, B. Mendoza, T. Nakajima, A. Robock, G. Stephens, T. Takemura and H. Zhang, 2013: Anthropogenic and Natural Radiative Forcing Supplementary Material. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Available from and
Bottom figure: small text gives the data source, which is: National Aeronautics and Space Administration Goddard Institute for Space Studies, Global Land-Ocean Temperature Index, Available from

33. Energy In (from sun) = Energy Out (from earth)
To understand Earth’s temperature patterns, we need to understand its energy balance
Energy In (from sun) = Energy Out (from earth)
Plot by Hannes Grobe
Albedo of earth system materials
Energy in depends on:
S (solar irradiance)
A (albedo: how much sunlight is reflected)
Earth’s albedo is 0.3; approximately 30% of incoming radiation is reflected by surface or atmosphere
Instructor could pose some questions for the class, like “What types of surfaces do you think are reflective?”
Image from NASA’s educational resources: accessed 9/28/2015
“Albedo-e hg.svg” (at right) by Hannes Grobe, Alfred Wegener Institute for Polar and Marine Research, Bremerhaven, Germany, Own work, share alike, attribution required (Creative Commons CC-BY-SA-2.5),

34. Energy In (from sun) = Energy Out (from earth)
Energy in depends on:
S (solar irradiance)
A (albedo: how much sunlight is reflected, unitless)
Energy out depends on:
T (earth’s temperature, K)
So what is Earth’s surface temperature?
Tearth (in K) = 45.8 x
At the end, you could introduce some causal loop diagrams. I.e., what will happen to Tearth if A goes up? If S goes up?
What do you think would happen to Tearth if…
Earth’s albedo increased?
Solar irradiance decreased?

35. Homework for next class: find Earth’s effective temperature
Tearth = 45.8 x
We already know albedo: A = 0.3, so the equation can be simplified to:
Tearth = 41.9 x
For next class, use your estimate of average solar irradiance to calculate Earth’s effective temperature in K, then convert your answer to °C, and °F
°C = K
°F = (°C x 1.8) + 32