PMU199H1F: Computing the Climate

(Fall 2015)


About the Course

This course will examine the role of computers and software in understanding climate change. We will explore the use of computer models to build simulations of the global climate, including a historical view of the use of computer models to understand weather and climate, and a detailed look at the current state of computer modelling, especially how global climate models are tested, what kinds of experiments are performed with them, how scientists know they can trust the models, and how they deal with uncertainty. The course will also explore the role of computer models in helping to shape society's responses to climate change, in particular, what they can (and can't) tell us about how to make effective decisions about government policy, international treaties, community action and the choices we make as individuals.

The course will take a cross-disciplinary approach to these questions, looking at the role of computer models in the physical sciences, environmental science, politics, philosophy, sociology and economics of climate change. However, students are not expected to have any specialist knowledge in any of these fields prior to the course.

General Course Resources

Seminar Notes & Weekly Readings

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As a seminar course, we can be very flexible in what we cover. I've planned a set of core topics that focus on climate models and how they are used, but we can explore much more widely than this if we like.

Key Texts

There's no required text. However, the two books I would most recommend as extra background for the course are:

For more background on the science of climate change, take a look at these online resources:

Course Outline (fall 2015)

  Seminar Topic Notes and Readings

Week 1:
Sept 16



  1. The slides I used this week
  2. My presentation on the history of climate modeling. I only used part of this (on the 19th Century history), but feel free to explore the rest.
  3. We did a memory game exercise, to demonstrate how easily our minds spot patterns, and how we can then fall into the trap of extending the pattern to see things that aren't actually there. We'll watch out for this trap when we look at climate data.
  4. We briefly explored the results of the Six Americas study, which explored attitudes to climate change among the US general public. I don't know of any similar survey of Canadians - let me know if you find one!

Homework (read these for next week):

  1. Steve's draft chapter on the first climate model (see email for link)

Week 2:
Sept 23

The first climate model


  1. newThe slides I used this week
  2. We began with an exercise called "Frames", to explore different ways of looking at the world, and why examining the frame we choose to look through is important.
  3. We explored the first ever climate model, developed by Svante Arrhenius in 1895, and what it tells us about how the greenhouse effect works.
  4. We did an exercise called "living loops" to help us understand how feedback loops work.
  5. We explored some of the major feedback loops in the climate system. (Here are the diagrams I showed)

Homework (read this for next seminar in two weeks time):

  1. Ed Lorenz, Our Chaotic Weather (Chapter 3 from his book "The Essence of Chaos")

Week 3
Sept 30

No Class!


  1. No class this week, as Steve is away.

Week 4
Oct 7

Weather forecasting and chaos theory


  1. The slides I used this week.
  2. We talked about Vilhelm Bjerknes, one of the first scientists to figure out the "primitive equations" for calculating the weather. Here's a longer article about his work.
  3. We talked about Lewis Fry Richardson and his attempt to compute a weather forecast during the First World War. Here's a longer article describing his work.
  4. We talked about the very first computer weather forecast on ENIAC. If you want to read more about this, take a look at this neat paper by Peter Lynch.
  5. During the break, I showed this simulation of a year's worth of climate.
  6. We then talked about chaos theory. Here's a brief guide to the terminology.
  7. We played the chaos game, and discovered the pattern it created. Here's the program that draws it automatically. You can also play with the two spreadsheets I used: Lorenz's example for x'=x2-c and The logistic equation x'=rx(1-x)
  8. If you're still not sure what chaos theory is all about, try this introduction.

Homework (read these for next week):

  1. Pick any two posts from the Climate Central Blog and read them. They should give you ideas for both content and style for your first assignment.
  2. Don't forget to submit your draft assignment 1 by midday next Wednesday.

Week 5
Oct 14

Chaos Theory and Climate


  1. newHere are the slides I used this week.
  2. We began with a brief discussion of the upcoming election. Here's an overview of how each of the parties stand on climate change.
  3. We explored techniques for editing your work. Here's the handout on editing tips, and the worksheet we used for the peer review exercise.
  4. To explore predictability of weather and climate, we began with a video of a flooded river in Melbourne, from 2011, and talked about what aspects might be predictable (e.g. maximum height of the river, timing of the peak flow) and what would might not be (e.g. order and timing of each car floating away)
  5. We explored the Lorenz Attractor, as an example of a (fairly!) simple set of equations that shows sensitivity to initial conditions, and watched this video of three very close starting states eventually diverging.

Homework (read these for next week):

  1. Read this essay on Climate Models and Modelling

Week 6
Oct 21

Developing and Using Models


  1. We explored the kinds of questions that can be answered by science (either by collecting data or building models) versus the kinds that need to be answered by society, because they involve value judgments.
  2. We then explored the kinds of experiments and data that climate scientists work with
  3. We watched and critiqued some videos of demonstrations/experiments:

Homework (read this for next week):

  1. Chris Martenson, The Crash Course, chapter 5, Dangerous Exponentials.

Week 7
Oct 28



  1. Here are my slides from this week.
  2. We began by re-visiting the ENIAC forecasts from week 2.
  3. We then explored Moore's Law, and the impact it has on scientific computing, and looked at where the fastest computers in the world are.
  4. We took a look at the grid resolution in climate models, and the impact of faster computers on improving resolution
  5. We did a paper folding exercise, to get us thinking about how well we understand exponential growth.
  6. We looked at exponential growth in many different aspects of human impact on the planet.
  7. Finally, we explored the idea of planetary boundaries.

Homework (read these for next week):

  1. Take a look at the Skeptical Science website's list of climate change myths. Pick a few and read the rebuttals. Are they effective? Who are they written for?
  2. Don't forget to submit your draft assignment 2 by midday next Wednesday.

Week 8
Nov 4

Modeling the Climate


  1. Here are my slides from this week
  2. We spent some time exploring past trends three related measurements:
    1. greenhouse gas emissions
    2. Concentrations of CO2 in the atmosphere
    3. Surface temperatures
  3. Then we looked at some simple models of the planet's energy balance. Chapter 4 of Dessler's book has more details.

Homework (read this for next week):

  1. Chapter 8 of Dessler's book, on predicting future climate change

Week 9
Nov 11

Decision-Making and Uncertainty


  1. Here are my slides from this week
  2. We began by examining the idea of radiative forcing.
  3. We looked at how you add time into a model, so that it can simulate the rate at which the warming occurs when a radiative forcing is applied. We explored a very simple model in an excel spreadsheet that includes the thermal capacity of the oceans.
  4. We then did an exercise to explore why it's so hard to understand accumulation. The exercise is taken from this paper by Cronin et al.
  5. We looked out how you develop emissions scenarios as inputs to a climate model for future climate change projections. Here's an explanation of how the current IPCC scenarios (the so-called RCPs) were chosen.

Homework (read this for next week):

  1. Chapter 6 of Weaver's book, on Investing in the Future

Week 10
Nov 18

Climate Solutions


  1. We played some games outside in the abnormally warm fall weather, including one called "Triangles", which explore high and low leverage points.
  2. Incidentally, if you want to know why it's so warm this fall, here's an explanation: it's El Nino added to global warming.
  3. Here are my slides from this week
  4. We began with a review of what scientists do with models, and how the models can be used to answer various scientific questions
  5. We also explored the idea setting a limit for a "safe" amount of warming, including the idea of +2°C of warming, and the more ambitious target of +1.5°C advocated by low-lying island nations.
  6. We explored where emissions come from.
  7. We used the idea of Stabilization Wedges to explore climate solutions

Homework (read this for next week):

  1. Chapter 3 of Garvey's book, The Ethics of Climate Change

Week 11
Nov 25



  1. We'll explore the range of options we have for mitigating and adapting to climate change, as well as the idea of geo-engineering to avoid the worst effects

Homework (read these for next week):

  1. TBD

Week 12
Dec 2

Figuring out what will work


  1. We'll explore how we assess the likely effectiveness of different climate solutions.


There are 3 assignments for the course: two shorter articles and an end of term essay:

  1. Article A - Research a topic related to the course and write a short article (up to 1000 words + references and images) to explain it to a general audience. Write in the style of a blog post or magazine article.
    Due Date: Oct 14th
  2. Article B - Another 1000 word article.
    Due Date: Nov 4th
  3. Final Essay - Detailed explanation with list of essay topics.
    Due Date: Nov 25 Dec 2

Note: 10% of the course mark is for participation in class discussions, and another 10% for submitting weekly reading reflections