Demonstration to Explain Climate Change

Hello Reader,

I was recently asked by a friend about how to explain to people that one particular weather event (e.g. excessive snow fall in the US) can be reconciled with long-term climate change. As a result, I came up with a "demonstration" of sorts to explain the difference between climate and weather. Please feel free to try it out, and let me know how effective (or ineffective) it may be for explaining climate change. Of course, it is only a metaphoric demonstration, so it will by no means be able to thoroughly explain climate change. (If you can come up with that, I'm sure there will be a Noble prize waiting for you.)

At any rate, to do this demonstration, you will need a pencil and paper, an ordinary deck of 52 cards, someone (0r a group of people) who is confused about how climate change is real when it is not always hot outside, a little bit of time, and a lot of patience. Good luck!

Setting the stage:

Prior to the demonstration, you need to explain the difference between climate and weather. Now, there are a lot of different ways to do this depending on how technically inclined your audience is. However, for the purposes of this demonstration, it will suffice to explain that weather is what is happening in the atmosphere at any particular point in time (or day) and climate is what you will expect to happen during a particular time of year based on the average weather for that time of year. While climate and weather include all conditions that describe the atmosphere, this demonstration will stick to temperature at first.

While you are discussing the difference between climate and weather, you will need to separate the cards into different piles: Ace-5, 6-10, Jack-King. During the first phase of the demonstration, you will need all of the ace-5 cards, a pair of each of the 6-10 cards (one black and one red each), and four Queens. Set the rest of the cards aside out of the way, and shuffle together the cards you plan to use.

Explain that:
-all Queens are going to represent a value of "zero"
-all Aces are going to represent a value of "one"
-all red cards (other than the Queens) represent a positive number of degrees Fahrenheit
-all black cards (other than the Queens) represent a negative number of degrees Fahrenheit

Round 1: the Climate

After the deck is well shuffled, instruct one of the participants to draw 5 cards. Explain to them that each of these cards represent the temperature in a 5-day weather forecast (or actually the difference between the average temperature for that month of the year and the high temperature recorded for that particular day). (e.g. if you are using February as the month and New York City as the place it would be reasonable to use 35 degrees Fahrenheit as your average temperature.) Of course, this will be different for every place and every month, so if you don't what the average temperature should be just use a best guess for the purpose of the demonstration.

As an example, let's assume that 35 deg F is our average temperature, and the first 5 cards drawn are:
5 clubs, 2 hearts, 3 diamonds, 4 hearts, Q spades
In this case, the temperatures for the 5-day weather forecast would be:
30 deg F, 37 deg F, 38 deg F, 39 deg F, 35 deg F

Write down the each of the numbers, and then shuffle the cards back into the deck. At this point, it would also be good to calculate an average for the 5-day week, and write that down as well. (For our example it would be 35.8 deg F.)

Depending on how much patience your group has or how much time you have for your demonstration, I would recommend repeating this 5-day forecast process for at least 10 times or so (a.k.a. a decade's worth of "data" for five days in February). Or if you have a larger group and several decks of cards, split up the group and ask each group to repeat the process at least 10 times.

When you have all of your data compare the averages of each week. Are there any outliers (very hot or very cold weeks)? It may be that there are not, but the more chances you have to repeat the process the more likely that there will be at least one outlier. If you have multiple groups, see if there are any major differences between the groups. Finally, find out what the overall averages of all of the weeks that have been recorded. Unless you have only performed a few repetitions or luck is just not on your side, the average you calculate should be close to what you assumed the average was to begin with (in our example: 35 deg F). At this point, it is probably fair to also discuss how weather can of course have a much wider variability than what is represented by this demonstration.

Round 2: Anthropogenic Climate Change so far...

While you are having your discussion, it is time to alter the deck(s) and add the influence of anthropogenic climate change. Remove all black 9's and 10's. Remove one black 4 and one black 5 from each deck. Add in all of the red 6's and red 7's

Repeat the entire process as described in Round 1. Make sure to use the same baseline average temperature! (If you started by using 35 degrees, continue to use 35 degrees.) Once you have collected all of your data, compare the averages from each of the two rounds. If you have done a sufficient number of 5-day forecasts, there is a good chance that your overall average has shifted upwards.

Even if it hasn't, you should also ask the audience to count up the number of times that the temperature surpassed or stayed below a certain threshold. In our example a good threshold to use would be 32 deg F (a.k.a. the freezing point of water). How many days were there in each round where the high temperature for the day was below freezing? What implications would this have for the way we experience the weather in a particular year, or our impression of climate? If your example was in the summer time instead, it might be good to see how many days rose above 80, 90, or 100 deg F depending on where you live. If you have access to the thermostat, it might be good to also see how many days have surpassed the temperature that the air conditioning is set at (these are the days that people will have to pay for extra electricity to stay cool).

Round 3: What May Happen...

If you have not gotten your point across yet and/or you would like to make your point just a little bit sharper, you can simulate what scientists expect may happen to the climate in the future. At this point it is fair to warn the audience, what scientists expect may or may not come exactly true. It is only the best guess that can be made using decades of real data from across the globe. And in the real world case, scientists can't know with certainty what the impact of various emissions will be.

However, to make this point, it is time to:
-remove all black cards above 4
-remove one black 4 and one black 3
-remove one Queen
-add in all remaining red number cards

Go through the experiment again and compare the differences between this round and the first two rounds.

Conclusion:

It is important to explain that the extent to which the temperature will rise in any particular place will be different. It is also important to note that the timescale at which these sorts of changes occur is difficult to determine. It may be several years to a couple of decades to an entire century. However, it is likely that the global average will rise quite a bit if nothing is changed about the way that greenhouse gases are emitted. Also, it is difficult to predict at what point "feedbacks" might kick in causing the ever-dreaded run-away climate change.

Possible addition:

If you would really like, you are also able to add in a precipitation factor by using the flip of a coin or the roll of a die to simulate whether or not it is going to rain, sleet, snow, etc. I would not recommend doing this unless you really know more about weather than the average person. Also, it may take a little bit of detective work to figure out a reasonable precipitation rate in your region. However, if you do go through this trouble, you may be able to show why there is a chance that "global warming" could cause increased winter snowfall where you live. The science is there, but it is a bit more technical and more difficult to demonstrate.

Well, in any event, I hope that this has given you another tool in your tool box when it comes to explaining climate change to non-scientist types. Please do let me know if you discover anything drastically wrong with this demonstration or have any tips or personal experiences to enhance it. Feel free to augment this however you need to in order to make sense to your audience. Just be careful not to misrepresent the limits of the analogy presented in this demonstration!

Good luck,
Sean Diamond